Case Studies & Application Stories

Study of Physico-Chemical Characteristics of Wastewater in an Urban Agglomeration in Romania –

Posted by 11 Feb, 2013

TweetStudy of Physico-Chemical Characteristics of Wastewater in an Urban Agglomeration in Romania Abstract This study investigates the level of wastewater pollution by analyzing its chemical characteristics at five wastewater collectors. Samples are collected before they discharge into the Danube during a monitoring campaign of two weeks. Organic and inorganic compounds, heavy metals, and biogenic compounds […]

Study of Physico-Chemical Characteristics of Wastewater in an Urban Agglomeration in Romania


This study investigates the level of wastewater pollution by analyzing its chemical characteristics at five wastewater collectors. Samples are collected before they discharge into the Danube during a monitoring campaign of two weeks. Organic and inorganic compounds, heavy metals, and biogenic compounds have been analyzed using potentiometric and spectrophotometric methods. Experimental results show that the quality of wastewater varies from site to site and it greatly depends on the origin of the wastewater. Correlation analysis was used in order to identify possible relationships between concentrations of various analyzed parameters, which could be used in selecting the appropriate method for wastewater treatment to be implemented at wastewater plants.

1. Introduction

Sources of wastewater in the selected area are microindustries (like laundries, hotels, hospitals, etc.), macroindustries (industrial wastewater) and household activities (domestic wastewater). Wastewater is collected through sewage systems (underground sewage pipes) to one or more centralized Sewage Treatment Plants (STPs), where, ideally, the sewage water is treated. However, in cities and towns with old sewage systems treatment stations sometimes simply do not exist or, if they exist, they might not be properly equipped for an efficient treatment. Even when all establishments are connected to the sewage system, the designed capacities are often exceeded, resulting in a less efficient sewage system and occasional leaks.

Studies of water quality in various effluents revealed that anthropogenic activities have an important negative impact on water quality in the downstream sections of the major rivers. This is a result of cumulative effects from upstream development but also from inadequate wastewater treatment facilities. Water quality decay, characterized by important modifications of chemical oxygen demand (COD), total suspended solids (TSSs), total nitrogen (TN), total phosphorous (TP), iron (Fe), nickel (Ni), copper (Cu), zinc (Zn), lead (Pb), and so forth [11] are the result of wastewater discharge in rivers. Water-related environmental quality has been shown to be far from adequate due to unknown characteristics of wastewater . Thus an important element in preventing and controlling river pollution by an effective management of STP is the existence of reliable and accurate information about the concentrations of pollutants in wastewater. Studies of wastewater in Danube basins can be found, for instance, in central and eastern European countries, but we are not aware of extensive studies of wastewater quality at regional/national level in Romania.

This paper analyses the chemical composition of wastewater at several collectors/stations in an important Romanian city, Galati, before being discharged into natural receptors, which in this case are the Danube and Siret Rivers. No sewage treatment existed when the monitoring campaign took place, except the mechanical separation. The study presented here is part of a larger project aiming at establishing the best treatment technology of wastewater at each station. Presently this project is in the implementation stage at all stations. Possible relationships between concentrations of various chemical residues in wastewater and with pollution sources are also investigated. The study is based on daily measurements of chemical parameters at five city collectors in Galati, Romania, during a two-week campaign in February 2010.

2. Experimental Analysis

2.1. Location of Sampling Sites

Galati-Braila area is the second urban agglomeration in Romania after Bucharest, which is located in Romania at the confluence of three major rivers: Danube, Siret, and Prut. The wastewater average flow is about 100000 m3/day . The drainage system covers an area of 2300 ha, serving approximately 99% of the population (approximately 300000 habitants). The basic drainage system is very old, dating back to the end of the 19th century, and was extended along with the expansion of the city due to demographic and industrial evolution. There are several collectors that collect wastewater and rainwater from various areas with very different characteristics, according to the existing water-pipe drainage system. There is no treatment at any station, except for simple mechanical separation. However, industrial wastewater is pretreated before being discharged in the city system. The five wastewater collectors are denoted in the following as S 1 , S 2 , … , S 5. Four of them discharge in the Danube River and the fifth discharges in the Siret River (which is an affluent of Danube River). Figure 1 shows the distribution of the monitoring sites and highlights the type of collecting area (domestic, industrial, or mixed). For the sake of brevity, these stations will be named in the present paper as “domestic,” “mixed,” and “industrial” stations, according to the type of collected wastewater. The mixture between domestic and industrial water at the two mixed collectors is the result of changes in city planning and various transformations of small/medium enterprises.

Figure 1


















Figure 1: Monitoring sampling sites of wastewater from Galati city.

Technical details about each collector/station can be found in Table 1. The first station, S1, collects 10% of the total quantity of wastewater. A high percentage of the water collected at this station comes from domestic sources from the south part of the city (more than 96%). Station S2 collects 64% of the total daily flow of wastewater, out of which 30% comes from domestic sources and the rest (70%) is industrial. Most of the industrial sources in this area are food-production units (milk, braid, wine) while the domestic sources include 20 schools, 4 hospitals, and important social objectives. Station S3 is located in the old part of the city and collects 5% of the total wastewater and has domestic sources. At the fourth station, S4, 11% of the quantity of wastewater is collected from domestic (70%) and industrial (30%) sources. The last collector, S5, collects wastewater from the industrial area of the city, where the most important objectives are a shipyard, metallurgical, and mechanical plants and transport stations.

Table 1

Table 1: Characteristics of collectors S 1 , … , S 5.

2.2. Physico-Chemical Parameters and Methods of Analysis

The physico-chemical parameters which were measured are the following:(i)pH;(ii)chemical oxygen demand (COD) and dissolved oxygen (DO);(iii)nutrients such as nitrate (N-NO3) and phosphate (P-PO4) (these were included due to their impact on the eutrophication phenomenon);(iv)metals such as aluminum (Al+3), soluble iron (Fe+2), and cadmium (Cd+2).

The pH and DO were determined in situ using a portable multiparameter analyzer. Other chemical parameters such as COD, metals and nutrients were determined according to the standard analytical methods for the examination of water and wastewater .

The COD values reflect the organic and inorganic compounds oxidized by dichromate with the following exceptions: some heterocyclic compounds (e.g., pyridine), quaternary nitrogen compounds, and readily volatile hydrocarbons. The concentration of metals (Al+3, Cd+2, Fe+2) was determined as a result of their toxicity.

The value of pH was analyzed according to the Romanian Standard using a portable multiparameter analyzer, Consort C932.

COD parameter was measured using COD Vials (COD 25–1500 mg/L, Merck, Germany). The digestion process of 3 mL aliquots was carried out in the COD Vials for 2 h at 148°C. The absorbance level of the digested samples was then measured with a spectrophotometer at λ = 605 nm (Spectroquant NOVA 60, Merck, Germany), the method being analogous to EPA methods [20], US Standard Methods, and Romanian Standard Methods.

The DO parameter was analyzed according to Romanian Standard using a portable multiparameter analyzer, Consort C932.

Aluminum ions (Al+3) were determined using Al Vials (Aluminum Test 0.020–1.20 mg/L, Merck, Germany) in a way analogous to US Standard Methods. The absorbance levels of the samples were then measured with a spectrophotometer (Spectroquant NOVA 60; Merck, Germany) at λ = 550 nm. The method was based on reaction between aluminum ions and Chromazurol S, in weakly acidic-acetate buffered solution, to form a blue-violet compound that is determined spectrophotometrically. The pH of the sample must be within range 3–10. Where necessary, the pH will be adjusted with sodium hydroxide solution or sulphuric acid.

Iron concentration (Fe+2) was determined using Iron Vials (Iron Test 0.005–5.00 mg/L, Merck, Germany) and their absorbance levels were then measured using a spectrophotometer (Spectroquant NOVA 60; Merck, Germany) at λ = 565 nm. The method was based on reducing all iron ions (Fe+3) to iron ions (Fe+2). In a thioglycolate-buffered medium, these react with a triazine derivative to form a red-violet complex which is spectrophotometrically determined. The pH must be within range 3–11. Where necessary the pH was adjusted with sodium hydroxide solution or sulphuric acid.

Cadmium ions (Cd+2) were determined using Cadmium Vials (Cadmium Test 0.005–5.00 mg/L, Merck, Germany), their absorbance levels being measured with a spectrophotometer (Spectroquant NOVA 60; Merck, Germany) at λ = 525 nm. The method was based on the reaction of cadmium ions with a cadion derivative (cadion-trivial name for 1-(4-nitrophenyl)-3-(4-phenylazophenyl)triazene), in alkaline solution, to form a red complex that is determined spectrophotometrically. The pH must be within the range 3–11, and, if not, the pH will be adjusted with sodium hydroxide solution or sulphuric acid.

Nitrogen content was determined using Nitrate Vials (Nitrate Cell test in seawater 0.10–3.00 mg/L NO3-N or 0.4–13.3 mg/L N O3 −, Merck, Germany). The method being based on the reaction of nitrate ions with resorcinol, in the presence of chloride, in a strongly sulphuric acid solution, to form a red-violet indophenols dye that is determined spectrophotometrically. The absorbance levels of the samples were then measured with a spectrophotometer (Spectroquant NOVA 60; Merck, Germany) at λ = 500 nm.

Phosphorous content was determined using Phosphate Vials (Phosphate Cell Test 0.5–25.0 mg/L PO4-P or 1.5–76.7 mg/L P O4 − 3, Merck, Germany) with a method that was analogous to the US Standard Methods [17]. The method was based on the reaction of orthophosphate anions, in a sulphuric solution, with ammonium vanadate and ammonium heptamolybdate to form orange-yellow molybdo-vanado-phosphoric acid that is determined spectrophotometrically (“VM” method). The absorbance levels of the samples were then measured with a spectrophotometer (Spectroquant NOVA 60; Merck, Germany) at λ = 410 nm.

All results were compared with standardized levels for wastewater quality found in accordance with European Commission Directive [23] and Romanian law [24].

3. Results and Discussion

3.1. The Acidity (pH)

The results for pH for all the investigated five collectors are shown in Figure 2.

Figure 2




















Figure 2: Daily variation of pH at all sites.

Generally, the wastewater collected at the monitored sites is slightly alkaline. The pH varies between 6.8 and 8.3—average value 7.82—thus the pH values are within the accepted range for Danube River according to the Romanian law, which is between 6.5 and 9.0. The pH variation is relatively similar at collectors S1–S4 (domestic and/or mixed domestic-industrial contribution). Lower pH values are observed at S5, which is dominated by industrial wastewater, originating from major enterprises and heavy industry. However, these values are not too low, since usually pH values for industrial wastewater are smaller than 6.5.

A significant decrease in the pH value was observed during the 8th day of the analyzed period at each station. Interestingly, a heavy snowfall took place at that particular time, thus the decrease could be attributed to the mixing between wastewater and a high quantity of low pH water, resulted from the melting of snow . One could speculate that the snowfall, which has an acidic character, might have affected the pH of the wastewater through “run off” phenomena.

No other snowfall took place during the monitoring campaign, thus no definite conclusion can be drawn for a possible relationship between pH and snowfalls.

3.2. Results for Chemical Oxygen Demand (COD)

Detection of COD values in each sampling site of wastewater is presented in Figure 3.

Figure 3




















Figure 3: Daily variation of COD at all sites.

All COD values are higher than the maximum accepted values (125 mg O2/L) of the Romanian Law . Both organic and inorganic compounds have an effect on urban wastewater’s oxidability since COD represents not only oxidation of organic compounds, but also the oxidation of reductive inorganic compounds. That means some inorganic compounds interfere with COD determination through the consumption of C r2O7 − 2. Two different behaviors can be observed, which are associated with the type of the collected wastewater as follows.(i)The first group consists of stations S2, S4 and S5 where the wastewater has an important industrial component. At these stations, COD values are approximately between 150 and 300 mg O2/L, smaller, for instance, than COD values found by in the raw wastewater produced by an industrial coffee plant where COD values were between 4000 and 4600 mg O2/L. Also, the temporal variation of COD values at all three stations is similar with no significant deviations from the average value, which is about 250 mg O2/L. Interestingly, the lowest COD level can be seen, on the average, at S5, which has the highest percentage of industrial wastewater. The second group comprises the “domestic” stations S1 and S3. The COD levels are higher, with values of 500 mg O2/L or more. Also, the variability is clearly higher than at the industrial-type stations. No clear association between the variations at the two sites can be seen. A peak in COD was measured in the 14th day of the study at site S1 (1160 mg O2/L). Since S1 is a domestic type station, it is unlikely that some major discharge led to such a high variation of COD. Unfortunately, no other information exists that might indicate a possible cause for this increase.

3.3. Results for Dissolved Oxygen (DO)

The amount of DO, which represents the concentration of chemical or biological compounds that can be oxidized and that might have pollution potential, can affect a sum of processes that include re-aeration, transport, photosynthesis, respiration, nitrification, and decay of organic matter. Low DO concentrations can lead to impaired fish development and maturation, increased fish mortality, and underwater habitat degradation . No standards are given by Romanian or European Law for DO in wastewater. The DO values for the analyzed wastewater at all five sites are shown in Figure 4.

Figure 4




















Figure 4: Daily variation of DO at all sites.

Concentration of DO varies at all sampling sites and has values between 0.96 (at S2) and 11.33 (at S4) mg O2/L with a mean value of 6.39 mg O2/L. These are clearly higher than DO values measured, for instance, in surface natural waters in China, where the Taihu watershed had the lowest DO level (2.70 mg/L), while in other rivers DO varied from 3.14 to 3.36 mg O2/L [34]. On the other hand, such high values of DO (9.0 mg O2/L) could be found, for instance, in the Santa Cruz River , who argued that discharging industry and domestic wastewater induced serious organic pollution in rivers, since the decrease of DO was mainly caused by the decomposition of organic compounds. Extremely low DO content (DO < 2 mg O2/L) usually indicates the degradation of an aquatic system .

The DO levels vary similarly for all selected sampling sites. The DO levels cover a wide range, with a minimum value of 1.0 mg O2/L at S1 and S3 and a maximum value of 11.33 mg O2/L at S4. There is a drop in DO at all stations, observed is in the 8th day of the monitoring interval, which coincides with the day when a similar decrease in pH took place. The lowest values of DO are observed for S1, one of the two “domestic” stations. It is interesting to note that DO at S5 is low although the wastewater here comes only from industry sources.

3.4. Metals

The variation of Al+3, Fe+2, and Cd+2 concentrations in wastewater are shown in Figures 5, 6, and 7. Al+3 concentrations (Figure 5) were mostly within the 0.05–0.20 mg/L range at all the sampling sites. However, during the beginning and the end of the monitoring campaign, Al+3 concentration at station S2 is high (reaching even 0.65 mg/L), nonetheless below the limit imposed by the Romanian law, which is 5 mg/L . The fact that in the beginning of the time interval, the concentration of Al+3 is high at two neighboring stations (S1 and S2) suggests that some localized discharge affecting both runaway and waste water, might have happened in the southern part of the city, which led to the increase of Al+3concentration in the collected wastewater. This is supported by the fact that the concentration gradually decreases at S2.


Figure 5: Daily variation of Al at all sites.

Figure 5




















Figure 6: Daily variation of Fe at all sites.

Figure 6




















Figure 7: Daily variation of Cd at all sites.

Figure 7




















The variation of Fe+2 concentrations is shown in Figure 6. Fe+2 concentration is within the 0.07–0.4 mg/L interval, below 5.0 mg/L, which is the maximum accepted value of the Romanian law . Two higher values were observed at S2 and S4 (both with industrial component) during the third and fourth days of the monitoring campaign.

Besides Al+3 and Fe+2, concentrations of Cd+2 were determined and the variations at the five stations are shown in Figure 7. Cd+2 is a rare pollutant, originating from heavy industry. Leakages in the sewage systems can also lead to Cd+2. Except for two days, Cd+2 varies between 0.005 and 0.04 mg/L. The two high values of 0.11 mg/L were observed in the first and fourth days at S5, which collects industrial wastewater. However, Cd+2 concentrations do not exceed the maximum accepted values of the Romanian law [24] for the monitoring interval which is 0.2 mg/L.

3.5. Nutrients

Water systems are very vulnerable to nitrate pollution sources like septic systems, animal waste, commercial fertilizers, and decaying organic matter [37]. Important quantities of nutrients, which are impossible to be removed naturally, can be found in rivers and this leads to the eutrophication of natural water (like Danube River). As a result, an increase in the lifetime of pathogenic microorganisms is expected. Measurement of nutrient (different forms of nitrogen (N) or phosphorous (P)) variations in domestic wastewater is strongly needed in order to maintain the water quality of receptors [36]. Nitrogen by nitrate (Figure 8) and phosphorous by phosphate (Figure 9) are considered as representative for nutrients.

Figure 8: Daily variation of N-NO3 at all sites.

Figure 8



















Figure 9: Daily variation of P-PO4 at all sites.

Figure 9




















Figure 8 shows that N-NO3 concentrations vary, on the average, between 0 and 5.0 mg/L.

At all four stations with a domestic component, S1, S2, S3 and S4, the concentration of N-NO3 is low (between 0 and 1.5 mg/L) and the daily variation is relatively similar at all sites. Noticeable drops of the N-NO3 concentration are observed at all stations in the 8th day of the monitoring interval, coinciding with pH (Figure 2) and DO strong variations (Figure 4). This supports the conclusion that the heavy snowfall recorded at that period had an important impact on wastewater quality most likely due to the runoff joining the sewage system.

The behavior of N-NO3 clearly differs at station S5, which collects only industrial wastewater. Significantly higher values of N-NO3, ranging from 2.0 to 5.0 mg/L, were detected. However, the mean concentration of N-NO3 remained below the maximum concentration given by the Romanian law [24]. Obviously, if treatment stations have to be set up, the priority for this particular nutrient component should concentrate on stations where industrial wastewater is collected.

Another nutrient that was analyzed for our study was orthophosphate expressed by phosphorous. The P-PO4 concentration varies, on the average, between 1.0 and 6.0 mg/L (Figure 9). For this component, concentrations are higher at domestic stations, S1 and S3, than at the other three stations. P-PO4 is expected to increase in domestic wastewater because of food, more precisely meat, processing, washing, and so forth. The lowest values were observed at S5, which has a negligible domestic component. Peaks in the P-PO4 concentration are observed at S1. Interestingly enough, P-PO4 temporal variations correlated pretty well at stations S2, S4, and S5 (which collect industrial wastewater). Unlike most of the other analyzed compounds, for which the concentrations were within the accepted ranges, the maximum level of P-PO4 is exceeded at all five collectors. Both Romanian law  and the European law  stipulate 2.0 mg/L total phosphorous for 10000–100000 habitants, and for more than 100000 habitants (as in Galati City’s case) 1.0 mg/L total phosphorus. Interestingly, domestic stations seem to require more attention with respect to the quality of water then industrial stations.

Our results regarding the variation and levels of the analyzed parameters are grouped below as the following.(1)The values of pH are within the accepted range for Danube, and their daily variations are relatively similar for both domestic and mixed wastewater. Significantly smaller pH values were measured in the wastewater with a high industrial load. A clear minimum was observed at all sites in the 8th day of the monitoring period, when a heavy snowfall took place. One could speculate that the snowfall, which has an acidic character, might have affected the pH of the wastewater through “run off” phenomena. However, a clear connection cannot be established relying on one event only.(2)The COD level clearly depends on the type of wastewater. Higher values were observed for domestic wastewater, while “pure” industrial wastewater has the lowest COD. This might be explained by the fact that industrial wastewater benefits from some treatment before being discharged into the city sewage system. However, COD does exceed the maximum accepted values according to the Romanian law [24] at all sites thus additional treatment is required at all stations.(3)Concentrations of all analysed metals, Al+3, Cd+2 and Fe+2, are within the limit of the Romanian law. No association with the type of wastewater could be inferred. Isolated peaks could not be linked with any specific polluting factors, except for Cd+2, for which accidental concentration increases are observed for pure industrial wastewater.(4)The level of P-PO4, one of the two nutrients that were analyzed, was high at all stations; however, the highest concentrations are associated with domestic loads.(5)Opposingly, the N-NO3 level is the highest, by far, in wastewater with a high industrial contribution.

3.6. Possible Relationships between Various Parameters

The experimental results have shown that some parameters might be related and that their behavior greatly depends on the type of collected wastewater. Differences between the behavior of physico-chemical parameters at the domestic sites (S1 and S3), on one hand, and at the other sites, on the other, was observed. Pearson correlation coefficients have been calculated between all parameters at all the selected five sites and corresponding significances. Although most of correlations were not significant, some interesting connections between various parameters at sites with similar characteristics were revealed. Table 2 shows correlation coefficients between various parameters for all five stations. Significant correlations at different types of stations are denoted as follows: italicized fonts for domestic stations, boldface italicized fonts for the industrial station and boldface fonts for mixed stations.

Table 2





























Table 2: Correlation coefficients calculated for station S1 to S5. Significant correlations at each type of stations are identified as follows: boldface italicized fonts for industrial station (S5), italicized fonts for domestic stations (S1 and S3) and boldface fonts for mixed stations (S2 and S4).

An important relationship seems to exist between pH and N-NO3 at all stations except for the industrial wastewater collecting site, S5 (i.e., at all stations collecting wastewater resulting from domestic activities). Similarly, pH correlates well with DO at all stations except the industrial one.

COD correlates with two metals, Cd+2 and soluble Fe+2, which is expected [30], but only at S1 and S3, where the daily variations of the concentration for these two metals (Cd+2 and soluble Fe+2) were similar.

No conclusion can be drawn for the industrial wastewater collector that was analyzed, where both positive and negative correlations were observed. The lack of correlation between the two metals and COD at the industrial wastewater collectors suggests that other processes, that alter the chemical equilibrium between the two chemical compounds, must be taken into account. For example some metals are complexed by organic compounds that are present in the water and the pH values can influence these phenomena.

DO correlates with pH and N-NO3 at all four sampling stations with domestic component (S1–S4) but the relationship vanish at S5 (industrial). There is also a negative correlation between DO and Fe+2 and Cd+2 only for domestic wastewater, which is expected because of the natural oxidation of metals. The correlation vanishes at the other three stations which collect wastewater from industrial areas.

Heavy metals, Fe+2 and Cd+2 correlate only at domestic stations and no relationships can be defined to link the concentration of Al+3 with other components.

The P-PO4 variation is linked to the variation of soluble Fe+2 at the two stations that collect domestic wastewater. Interestingly, these two elements exist together in reductive domestic systems because these are dominated by proteins, lipids, degradation products. This relationship disappears at the other stations, where the industrial load is significant. The other metals, Al+3, seems to be linked with P-PO4at stations S5 and S2, which collect wastewater with the highest industrial load. No link is observed for the rest of stations and for Cd+2 which can be explained by a higher probability of iron (II) orthophosphate to form in wastewater compared to Al+3 or Cd+2 orthophosphates.

Positive correlations can also be seen between P-PO4 and COD for all sampling sites except S1, where the relationship is still positive but less significant. The other nutrient, N-NO3, is anticorrelated with COD but only at S3 and is well correlated with pH and DO at all four stations with domestic component. The only exception is station S5, which collects mostly industrial wastewater.

Concluding, positive correlations were observed between the following parameters.(1)pH and N-NO3 everywhere except “purely” industrial water.(2)COD and soluble Fe+2 at domestic stations.(3)DO and pH, on the one hand, and DO and N-NO3 at domestic stations.(4)P-PO4 and soluble Fe+2 at domestic stations.(5)P-PO4 and COD everywhere, which, taking into account the high level of P-PO4 at domestic stations, might suggest that one important contributor to water quality degradation are household discharges.(6)Al+3 and P-PO4.

4. Conclusions

In the present paper we have analyzed the daily variation of several physico-chemical parameters of the wastewater (pH, COD, DO, Al+3, Fe+2, Cd+2, N-NO3, and P-PO4) at five collectors that have been characterized as domestic, industrial and mixed, according to the type of collecting area. Different results have been obtained for domestic and industrial wastewater. Most of the chemical parameters are within accepted ranges. Nevertheless, their values as well as their behavior depend significantly on the type of collected wastewater.

The overall conclusion is that wastewater with a high domestic load has the highest negative impact on water quality in a river. On the other hand, industrial wastewater brings an important nutrient load, with potentially negative effect on the basins where it is discharged. Our results suggested that meteorological factors (snow) might modify some characteristics of wastewater, but a clear connection cannot be established relying on one event only.

Significantly smaller pH values were measured in the wastewater with a high industrial load. The COD level clearly depends on the type of wastewater. Higher values were observed for wastewater with domestic sources, while “pure” industrial wastewater has the lowest COD. This might be explained by the fact that industrial wastewater benefits from some treatment before being discharged into the city sewage system. COD does exceed the maximum accepted values according to the Romanian law at all sites thus additional treatment is required at all stations. Accidental increases of Cd+2 concentrations are observed for pure industrial wastewater. The highest concentrations of P-PO4 are associated with domestic loads. Opposing, the N-NO3 level is clearly the highest in wastewater with a high industrial contribution.

Correlation analysis has been used in order to identify possible relationships between various parameters for wastewater of similar origin.

Positive correlations between various physico-chemical parameters exist for the domestic wastewater (DO, pH and N-NO3, on the one hand, and P-PO4, COD and soluble Fe+2, on the other hand). Except for two cases, these relationships break when the industrial load is high. Some of the existing correlations are expected as discussed above, thus any removal treatment should be differentiated according to the type of collector, before discharging it into the natural receptors in order to be costly efficient. Correlations between DO and COD and nutrient load suggest that the most important threat for natural basins in the studied area, are domestic sources for the wastewater.

The different percentages of industrial and domestic collected wastewater vary at each station, which has a clear impact on concentrations of the selected chemical components. Our results show that domestic wastewater has a higher negative impact on water quality than wastewater with a high industrial load, which, surprisingly, seems to be cleaner. This might be related to the fact that most industries are forced, by law, to apply a pretreatment before discharging wastewater into the city sewage system. Industrial wastewater affects the nutrient content of natural water basins. Although the time period was relatively short, our study identified specific requirements of chemical treatment at each station. An efficient treatment plan should take into account the type of wastewater to be processed at each station. Results presented here are linked with another research topic assessing the level of water quality in the lower basin of the Danube before and after implementing the complete biochemical treatment plants.


The work of Catalin Trif was supported by Project SOP HRD-EFICIENT 61445/2009.

Copyright © 2012 Paula Popa et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited – original found here:



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Application Bulletin: POOL & SPA Water –

Posted by 31 Jan, 2013

Tweet                 Anyone responsible for operating and maintaining a swimming pool or spa has to test, monitor, and control complex, interdependent chemical factors that affect the quality of water. Additionally, aquatic facilities operators must be familiar with all laws, regulations, and guidelines governing what these parameters should be. […]










Anyone responsible for operating and maintaining a swimming pool or spa has to test, monitor, and control complex, interdependent chemical factors that affect the quality of water. Additionally, aquatic facilities operators must be familiar with all laws, regulations, and guidelines governing what these parameters should be.

Why? Because the worst breeding ground for any kind of microorganism is a warm (enough) stagnant pool of water. People plus stagnant water equals morbid illness. That’s why pools have to be circulated, filtered, and sanitized –  with any number of chemicals or methods, but most frequently with chlorine compounds. However, adding chemicals that kill the bad microorganisms can also make the water uncomfortable, and in some cases unsafe, for swimmers. Additionally, if all the chemical factors of the water are not controlled, the very structures and equipment that hold the water and keep it clean are ruined.

So the pool professional must perform a delicate balancing act with all the factors that affect both the health and comfort of bathers and the equipment and structures that support this. Both water balance – or mineral saturation control – and sanitizer levels must constantly be maintained. This is achieved by measuring pertinent water quality factors and adding chemicals or water to keep the factors within acceptable parameters.


Water is constantly changing. Anything and everything directly and indirectly affects the relationship of its chemical parameters to each other: sunlight, wind, rain, oil, dirt, cosmetics, other bodily wastes, and any chemicals you add to it. Balanced water not only keeps swimmers comfortable, but also protects the pool shell, plumbing, and all other related equipment from damage by etching or build-up and stains.

The pool professional is already well acquainted with pH, Total Alkalinity (TA), and Calcium Hardness (CH); along with Total Dissolved Solids (TDS) and Temperature, these are the factors that influence water balance. Water that is in balance is neither aggressive nor oversaturated. Aggressive water lacks sufficient calcium to saturate the water, so it is hungry for more. It will eat anything it comes into contact with to fill its need, including the walls of your pool or spa or the equipment it touches. Over-saturated water cannot hold any more minerals, so dissolved minerals come out of solution and form scale on pool and equipment surfaces.

The pH of pool water is critical to the effectiveness of the sanitizer as well as the water balance. pH is determined by the concentration of Hydrogen ions in a specific volume of water. It is measured on a scale of 0-14, 0-7 being acidic and 7-14 being basic.

You must maintain the pH of the water at a level that assures the sanitizer works effectively and at the same time protects the pool shell and equipment from corrosion or scaling and the bathers from discomfort or irritation. If the pH is too high, the water is out of balance, and the sanitizer’s ability to work decreases. More and more sanitizer is then needed to maintain the proper level to kill off germs. Additionally, pH profoundly affects what and how much chemical must be added to control the balance. A pH of between 7.2 – 7.6 is desirable in most cases.*

As one of the most important pool water balance and sanitation factors, pH should be checked hourly in most commercial pools.* Even if you have an automatic chemical monitor/controller on your system, you need to double- check its readings with an independent pH test. With salt- water pools, pH level goes up fast, so you need to check it more often. Tests are available that require reagents and subjective evaluation of color depth and hue to judge their pH. But different users interpret these tests differently, and results can vary wildly. The PooLPRo and ULTRAPEN PT2 give instant lab-accurate, precise, easy-to-use, objective pH measurements, invaluable in correctly determining what and how much chemical to add to maintain water balance and effective sanitizer residuals.

Total Alkalinity (TA) is the sum of all the alkaline minerals in the water, primarily in bicarbonate form in swimming pools, but also as sodium, calcium, magnesium, and potassium carbonates and hydroxides, and affects pH directly through buffering. The greater the Total Alkalinity, the more stable the pH. In general, TA should be maintained at 80 – 120 parts per million (ppm) for concrete pools to keep the pH stable.* Maintaining a low TA not only causes pH bounce, but also corrosion and staining of pool walls and eye irritation. Maintaining a high TA causes overstabilization of the water, creating high acid demands, formation of bicarbonate scale, and may result in the formation of white carbonate particles (suspended solids), which clouds the water. Reducing TA requires huge amounts of effort. So the best solution to TA problems is prevention through close monitoring and controlling. The PoolPro PS9 Titration Kit features an in-cell conductometric titration for determining alkalinity.

 Calcium Hardness (CH) is the other water balance parameter pool professionals are most familiar with. CH represents the calcium content of the water and is measured in parts per million. Low CH combined with a low pH and low TA significantly increases corrosivity of water. Under these conditions, the solubility of calcium carbonate also increases. Because calcium carbonate is a major component of both plaster and marcite, these types of pool finishes will deteriorate quickly. Low CH also leads to corrosion of metal components in the pool plant, particularly in heat exchangers. Calcium carbonate usually provides a protective film on the surface of copper heat exchangers and heat sinks, but does not adversely affect the heating process. Without this protective layer, heat exchangers and associated parts can be destroyed prematurely. At the other extreme, high CH can lead to the precipitation of calcium carbonate from solution, resulting in cloudy water, the staining of structures and scaling of equipment. The recommended range for most pools is 200 – 400 ppm.* Calcium hardness should be tested at least monthly. The PoolPro  PS9 Titration Kit features an in-cell conductometric titration for determining hardness.

Total Dissolved Solids (TDS) is the sum of all solids dissolved in water. If all the water in a swimming pool was allowed to evaporate, TDS would be what was left on the bottom of the pool – like the white deposits left in a boiling pot after all the water has evaporated. Some of this dissolved material includes hardness, alkalinity, cyanuric acid, chlorides, bromides, and algaecides. TDS also includes bather wastes, such as perspiration, urine, and others. TDS is often confused with Total Suspended Solids (TSS). But TDS has no bearing on the turbidity, or cloudiness, of the water, as all the solids are truly in solution. It is TSS, or undissolved, suspended solids, present in or that precipitate out of the water that make the water cloudy.

High TDS levels do affect chlorine efficiency, algae growth, and aggressive water, but only minimally. TDS levels have the greatest bearing on bather comfort and water taste – a critical concern for commercial pool operators. At levels of over 5,000 ppm, people can taste it. At over 10,000 ppm bather towels are scratchy and mineral salts accumulate around the pool and equipment. Still some seawater pools comfortably operate with TDS levels of 32,000 ppm or more.

As methods of sanitization have changed, high TDS levels have become more and more of a problem. The best course of action is to monitor and control TDS by measuring levels and periodically draining and replacing some of your mature water with new, lower TDS tap water. This is a better option than waiting until you must drain and refill your pool, which is not allowed in some areas where water conservation is required by law. However, you can also decrease TDS with desalinization equipment as long as you compensate with Calcium Hardness. (Do not adjust water balance by moving pH beyond 7.8.)*

Regardless, you do need to measure and compensate for TDS to get the most precise saturation index and adjust your pH and Calcium Hardness levels accordingly. It is generally recommended that you adjust for TDS levels by subtracting one tenth of a saturation index unit (.1) for every 1,000 ppm TDS over 1,000 to keep your water properly balanced. When TDS levels exceed 5,000 ppm, it is recommended that you subtract half of a tenth, or one twentieth of unit (.05) per 1,000 ppm.* And as the TDS approaches that of seawater, the effect is negligible.

Hot tubs and spas have a more significant problem with TDS levels than pools. Because the bather load is relatively higher, more chemicals are added for superchlorination and sudsing along with a higher concentration of bather wastes. The increased electrical conductance that high TDS water promotes can also result in electrolysis or galvanic corrosion. Every hot water pool operator should consider a TDS analyzer as a standard piece of equipment.

A TDS analyzer is required to balance the water of any pool or spa in the most precise way. PoolPro, PoolMeter and ULTRAPEN PT1 instantly display accurate TDS levels giving you the information you need to take corrective action before TDS gets out of hand.

Temperature is the last and least significant factor in maintaining water balance. As temperature increases, the water balance tends to become more basic and scale- producing. Calcium carbonate becomes less soluble, causing it to precipitate out of solution. As temperature drops, water becomes more corrosive.

 In addition to helping determine water balance, temperature also affects bather comfort, evaporation, chlorination, and algae growth (warmer temperatures encourage growth). Myron L’s PooLPRo also precisely measures temperature to one tenth of a degree at the same time any other parameter is measured.

In the pool and spa industry water balance is calculated using the Langelier Saturation Index (LSI) formula:

SI = (pH + TF + CF + AF ) – 12.1


PH = pH value

TF = 0.0117 x Temperature value – 0.4116 CF = 0.4341 x ln(Hardness value) – 0.3926 AF = 0.4341 x ln(Alkalinity value) – 0.0074

The following is a general industry guideline for interpreting LSI values:

•   An index between -0.5 and +0.5 is acceptable pool water.

  • An index of more than +0.5 is scale-forming.
  • An index below -0.5 is corrosive.

pH, Total Alkalinity, and Calcium Hardness are the largest contributors to water balance. Pool water will often be balanced if these factors are kept within the recommended ranges.

The PoolPro PS9 Titration Kit features an LSI function that steps you through alkalinity & hardness titrations and pH & temperature measurements to quickly and accurately determine LSI. An LSI calculator allows you to manipulate pH, alkalinity, hardness and temperature values in the equation to determine water balance adjustments on the spot.


The most immediate concern of anyone monitoring and maintaining a pool is the effectiveness of the sanitizer – the germ-killer. There are many types of sanitizers, the most common being chlorine in swimming pools and bromine in hot tubs and spas. The effectiveness of the sanitizer is directly related to the pH and, to a lesser degree, the other factors influencing water balance.

To have true chemical control, you need to monitor both the sanitizer residual and the pH and use that information to chemically treat the water. To check chlorine residual, free chlorine measurements are made. For automatic chlorine dosing systems, ORP must also be monitored to ensure proper functioning.

Free Chlorine is the amount of chlorine available as hypochlorous acid (HOCl-) and hypochlorite ion (OCl-), the concentrations of which are directly dependent on pH and temperature. pH is maintained at the level of greatest concentration of HOCl- because hypochlorous acid is a much more powerful sanitizer than hypochlorite ion. Free chlorine testing is usually required before and after opening of commercial pools. Samples should be taken at various locations to ensure even distribution. Residual levels are generally kept between 1-2 mg/L or ppm.* PooLPRo V.4.03 and later features the ability to measure ppm free chlorine in pools and spas sanitized by chlorine only. With this feature PoolPro can measure a dynamic range of chlorine concentrations wider than that of a colorimetric test kit with a greater degree of accuracy.

ORP stands for Oxidation Reduction Potential (or REDOX ) of the water and is measured in millivolts (mV). The higher the ORP, the greater the killing power of all sanitizers, not just free chlorine, in the water. ORP is the only practical method available to monitor sanitizer effectiveness. Thus, every true system of automatic chemical control depends on ORP to work.

The required ORP for disinfection will vary slightly between disinfecting systems and is also dependent on the basic water supply potential, which must be assessed and taken into account when the control system is initialized. 650 mV to 700 – 750 mV is generally considered ideal.*

Electronic controllers can  be inaccurate and inconsistent when confronted with certain unique water qualities, so it is critical to perform manual testing with separate instrumentation. For automatic control dosing, it is generally recommended that you manually test pH and ORP prior to opening and then once during the day to confirm automatic readings.*

Samples for confirming automatic control dosing should be taken from a sample tap strategically located on the return line as close as possible to the probes in accordance with the manufacturer’s instructions. If manual and automatic readings consistently move further apart or closer together, you should investigate the reason for the difference.*

ORP readings can only be obtained with an electronic instrument. PoolPro provides the fastest, most precise, easy-to-use method of obtaining ORP readings to check the effectiveness of the sanitizer in any pool or spa. This is the best way to determine how safe your water is at any given moment.


A relatively new development, saltwater pools use regular salt, sodium chloride, to form chlorine with an electrical current much in the same way liquid bleach is made. As chlorine – the sanitizer – is made from the salt in the water, it is critical to maintain the salt concentration at the appropriate levels to produce an adequate level of sanitizer. It is even more important to test water parameters frequently in these types of pools and spas, as saltwater does not have the ability to respond adequately to shock loadings (superchlorination treatments).

Most saltwater chlorinators require a 2,500 – 3,000 ppm salt concentration in the water (though some may require as high as 5,000-7,000 ppm).* This can barely be tasted, but provides enough salt for the system to produce the chlorine needed to sanitize the water.

(It is important to have a good stabilizer level – 30 – 50 ppm* – in the pool, or the sunlight will burn up the chlorine. Without it, the saltwater system may not be able to keep up with the demand regardless of salt concentration.)

Taste and salt shortages are of little concern to seawater systems that maintain an average of 32,000 ppm. In these high-salt environments, you need to beware of corrosion to system components that can distort salt level and other parameter readings.

Additionally, incorrect salt concentration readings can occur in any saltwater system. The monitoring/controlling components can and do fail or become scaled— sometimes giving a false low salt reading. Thus, you must test manually for salt concentration with separate instrumentation before adding salt.

You must also test salt concentration manually with separate instrumentation to re-calibrate your system. This is critical to system functioning and production of required chlorine. Both the PoolPro and PT1 conveniently test for salt concentration at the press of a button as a check against automatic controller systems that may have disabled equipment or need to be re-calibrated.

Though no one instrument or method can be used to determine ALL of the factors that affect the comfort and sanitation of pool and spa water, PoolPro is a comprehensive water testing instrument that is reliable durable, easy-to-use and easy-to-maintain and calibrate. As a pool professional, a PoolPro will not only simplify your life, it will save you time and money.


Data handling should be done objectively, and data recorded in a common format in the most accurate way. Also, data should be stored in more than one permanent location and made available for future analysis. Most municipalities require commercial aquatic facilities to keep permanent records on site and available for inspection at any time.

PoolPro makes it easy to comply with record keeping requirements. The PoolPro is an objective means to test free chlorine, ORP, pH, TDS, temperature and the mineral/salt content of any pool or spa. You just rinse and fill the cell cup by submerging the waterproof unit and press the button of the parameter you wish to measure. You immediately get a standard, numerical digital readout –  no interpretation required – eliminating all subjectivity. And model PS9TK features the added ability to perform in-cell conductometric titrations for Alkalinity, Hardness and LSI on the spot. Up to 100 date-time-stamped readings can be stored in memory and then later transferred directly to a computer wirelessly using the bluDock™ accessory package. Simply pair the bluDock with your computer, then open the U2CI software application to download data. The user never touches the data, reducing the potential for human error in transcription. The data can then be imported into any program necessary for record-keeping and analysis. The bluDock is a quick and easy way to keep records that comply with governing standards.*

*Consult your governing bodies for specific testing, chemical concentrations, and all other guidelines and requirements. The ranges and methods suggested here are meant as general examples.

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The Septage Management System of the Baliwag Water District, Philippines –

Posted by 23 Jan, 2013

TweetThe Municipality of Baliwag is located in the Province of Bulacan in the Philippines, just about an hour’s drive north of Metro Manila. The urban LGU has a population of over 160,000 and is the financial, commercial, and educational center of the Province of Bulacan, with the majority of these residents receiving their water supply – and soon their sanitation – […]

The Municipality of Baliwag is located in the Province of Bulacan in the Philippines, just about an hour’s drive north of Metro Manila. The urban LGU has a population of over 160,000 and is the financial, commercial, and educational center of the Province of Bulacan, with the majority of these residents receiving their water supply – and soon their sanitation – from the Baliwag Water District (BWD).

The BWD, like other water districts in the Philippines, is a government owned and controlled corporation (GOCC) focused on providing water and sanitation service on a baliwag1.JPGcost-recovery basis. Water districts around the country are coordinated by the Local Water Utilities Administration (LWUA), a unique GOCC itself that is tasked to promote and oversee the development of WatSan systems outside of the Metro Manila area.

In the Philippines, sewerage is rare / mainly non-existent outside of the Metro Manila area, with most residents in urban areas relying on septic tanks, most of which – in absence of any formal sanitation program – are often poorly designed and rarely desludged. This results in widespread groundwater contamination and polluted rivers from the discharges of septic tank effluent directly to drainage canals.

Awareness is rapidly rising around the country about the seriousness of this sanitation problem though, and a wide variety of both donor-driven and locally-driven sanitation programs are now underway, including a variety of septage management programs. However, to date, these existing septage management programs have been undertaken by the LGU/private sector (e.g. in San Fernando City, La Union), by an LGU-water district partnership (e.g. in Dumaguete City, Negros Oriental), or by a mainly private sector ‘build-operate-transfer’ style of arrangement (e.g. the programs of Manila Water Company Inc. & Maynilad Water Services Inc. in the Metro Manila area).

baliwag2.JPGThe BWD, though, decided to try a different arrangement with its new septage management program: one led entirely by the water district, with very little LGU/government collaboration. The BWD, led by its dynamic and learned General Manager since 1995, Mr Artemio Baylosis, has rapidly grown from an insignificant, 1000-connection provider to the significant and respected provider it is today, ISO-9001 certified and with over 25,000 connections accounting for about 80% of the total population of Baliwag, which is better coverage than many other water districts in other urban areas around the country.

Through the initiative of Mr Baylosis and the BWD team, the BWD, in 2008, secured the support of the USAID-funded Philippine Water Revolving Fund (PWRF) to fund a feasibility study on septage management for the water district. From the data and analysis gathered by this study, the BWD was then able to pursue their own program without any further donor assistance, the planning for which began in 2009.

The next step after the feasibility study was to ensure a suitable regulatory environment for the program. The BWD worked with the local government of Baliwag to help them pass an ordinance in 2009 that allowed the establishment of the BWD septage and (future) sewerage management program. This was not a particularly comprehensive nor proactive ordinance for the LGU, but was sufficient to allow the BWD to be proactive on their own initiative. In addition, the BWD and LGU signed an MoA in 2010 to provide further details on the sharing of responsibilities for the septage management program. Most of these responsibilities were taken on by the BWD, with the LGU simply in charge of levying fines where necessary and in supporting the outreach efforts of the BWD about the program.

The BWD then required a source of funds to manage this program. Rather than rely on donor assistance, the BWD simply secured a 60M Peso (~$1.5M USD) loan from thebaliwag3.JPG Philippine National Bank, with a 10-year repayment period and 7% interest.

With these funds, the BWD could then launch into the program planning and consultations. They conducted a thorough public information drive across the entire LGU, to discuss and seek feedback on the program’s legality, guidelines, and proposed tariff structure. During this time, the BWD also engaged in a ‘Water Operators Partnership’, through the USAID-sponsored Waterlinks program, which linked them up with Indah Water Company in Malaysia, for joint trainings, site visits, and consultations on technical aspects of Indah’s already successful program.

Through this, the BWD was able to design their program to incorporate elements already proven to be successful, and build off of the unsuccessful elements of other programs. On desludging, the BWD decided to split their service area into 5 zones, with the goal of desludging one zone each year, so as to achieve a regular, once-every-5-years desludging cycle for its customers. However, they also do not plan on charging any additional fees if customers want to avail of additional desludgings within this 5-year period; if they desire 2 or 3 desludgings during this time, the BWD hopes to be able to do this for them without any additional fee.

baliwag4.JPGThe BWD is able to make this offer because, unlike a private company, they do not need to make a profit, only to recover their costs. This also allows them to offer a low water tariff, with the subsidised price of the first 10 cubic meters at only ~145 Pesos (just over $3USD), with average monthly water consumption in the community at approximately 20 cubic meters. And because of their 80% water supply coverage, they thus decided to use this water tariff as the basis for financing their septage management costs. Their financial models determined that a fixed charge of 10% of the user’s total water bill would collect enough to recover the costs. Thus, the previously mentioned 145 Peso bill, as of June 2012, became a 160 Peso bill. The community was consulted on this tariff structure and were agreeable to it. So far, as of Dec. 2012, no one has complained about the new fee, even though the desludging service has not yet begun.

In addition to the desludging service that the BWD will offer, they also plan on taking responsibility for enforcing properly-designed septic tanks in the LGU, both for old tanks and new constructions. For the former, they hope to inspire maintenance/upgrading via consultation with customers and fines if necessary, while for the latter, they plan on visiting new construction sites to ensure that the septic tanks are properly designed. They have also already begun collecting data on every septic tank of their customers. Currently, they have just noted the number of household users of the tank and its general location on the property (e.g. on the left side / right side / inside / etc.), but they soon hope to begin mapping each of these tanks into their GIS/GPS database, for easy reference and route planning for desludging. Properly-designed septic tanks (i.e. 2 or 3 chambers and sealed at the bottom) are important, since many of the country’s existing tanks are sized too small for their daily flow rate and are not sealed at the bottom, resulting in widespread groundwater pollution.

A problem that has faced previous septage management programs is that of availment rates. Even if customers are paying (e.g. through the water tariff) for the desludging service, availment rates of this service have often been as low as 50%, due mainly to the desludgers’ rules about the lifting of the septic tank lid. In previous programs, the desludger required residents to lift the septic tank lid if they wanted to avail of the service (to avoid any liability related to potentially damaging the lid), but this was often complicated by the fact that many septic tanks here are built without a lid and/or are built in a difficult-to-access location, such as under the kitchen.

Learning from this, the BWD will try a different approach. In the first 5-year cycle, the BWD will lift all of the lids themselves, a day or two in advance of the planned baliwag5.JPGdesludging, and if there is no lid, the BWD will drill one themselves by breaking a hole through the floor. Then, in the second 5-year cycle, the customers will be responsible for lifting their own lids. They are not concerned about liability, as their activities are supported by the LGU’s ordinance, though it remains to be seen whether this will be enough to prevent any complaints on potential damage. If successful, though, this approach could greatly increase availment rates, and thus greatly reduce the amount of ground/surface water pollution from overflowing septic tanks.

Turning now to the technology, the BWD purchased two, 5 cubic meter desludging trucks (at a cost of 17.4M Pesos (~$420,000 USD), which they hope to run at 3 loads per day, 5 days per week. These trucks will bring the septage to the new septage treatment plant (SpTP), which is currently under construction in the LGU. The BWD purchased the land for this plant itself, even though the LGU is supposed to be legally obligated to provide it, thus showing the BWD’s desire to do it themselves. The construction of their SpTP and the office / laboratory building that will rise beside it were contracted out to two different local engineering companies. The SpTP will have a capacity of 30 cubic meters per day and will cost 32.7M Pesos (~$800,000 USD) to build. In addition to their regular desludging, the BWD also hopes that this capacity will allow the acceptance of some septage from neighboring LGUs or from small private desludgers, with a tipping fee applied. In theory, the site could also be upgraded to accept sewage one day, as they chose a location in a lower elevation area as compared with the rest of the LGU. The site is also strategically located in terms of odor – it is beside a smelly pig farm and duck farm, so it is unlikely that these neighbors will complain about odors from the plant!

baliwag6.JPGThe SpTP uses a highly mechanised technology package, which was chosen by the BWD so as to minimise the exposure of its staff to raw septage, even though this option is more expensive than a less mechanised version. Their technology process is as follows:

1) Macerator and/or bar screen – These will be able to run in series or parallel. The use of the macerator will depend on how much electricity it consumes.
2) A joint garbage screen / sand screen / FOG (fats/oils/grease) screen unit
3) Holding tank (with mixer) – 2 tanks, each with 2 days of holding time
4) Pump line, with cationic polymer injection, leading to the dewatering screw press (solids from this and the aforemention garbage / sand will fall into a pickup truck)
5) Equalisation Tank
6) Sequencing Batch Reactor (SBR) (Consisting of: a – Equalisation tank {aerobic} , b – SBR {aerobic} , c – Chlorine contact tank (Cl will drip in in liquid form), d – Effluent holding tank -> Discharge to storm drain. e – Sludge from tank B will get pumped to a sludge digestion tank, for further holding time, which will overflow back into tank A)

The aerobic portions are serviced by 2 blower motors. The site will also have 2 big water tanks for drinking water and recycled/rain water for use on site. The effluent can also be recirculated after the screw press back into the holding tank if so desired for further treatment time. The biosolids/sludge from this SpTP will be composted for local use around the LGU.


As of this writing (Dec. 2012), construction of the SpTP was nearly complete, with testing and commissioning to follow from Jan. to Aug. 2013, with the goal of project turn over and full operation by Sept. 2013. Even though it has not yet begun, the innovative design being used here by the BWD is already being mimicked by neighboring water districts in their septage planning, and it thus stands to serve as a model for water district-led septage management in the Philippines, with its lessons being applicable to septage management programs around the world as well. now features one-week direct shipping to the Philippines. Shipping one Ultrameter III 9P to the Philippines costs only $35 plus taxes and duties.



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Recent Papers in Water Treatment for Small/Decentralized Systems –

Posted by 12 Jan, 2013

TweetRecent Papers in Water Treatment for Small/Decentralized Systems Content Table Recent Papers in Water Treatment for Small/Decentralized Systems  Turbidity and chlorine demand reduction using locally available physical water clarification mechanisms before household chlorination in developing countries Appropriate wastewater treatment systems for developing countries: criteria and indictor assessment in Thailand A new paradigm for low-cost urban […]

Recent Papers in Water Treatment for Small/Decentralized Systems

Content Table

Turbidity and chlorine demand reduction using locally available physical water clarification mechanisms before household chlorination in developing countries

Journal of Water and Health Vol 07 No 3 pp 497–506 © IWA Publishing 2009 doi:10.2166/wh.2009.071

Link to Summary Page

Nadine Kotlarz, Daniele Lantagne, Kelsey Preston and Kristen Jellison

Department of Civil and Environmental Engineering, Lehigh University, 13 East Packer Avenue, Bethlehem, PA 18015, USA
Enteric Diseases Epidemiology Branch, US Centers for Disease Control and Prevention, 1600 Clifton Road, MS-A38, Atlanta, GA 30333, USA Tel.:             +1 404 639 0231       Fax: +1 404 639 2205 E-mail:


Over 1.1 billion people in the world lack access to improved drinking water. Diarrhoeal and other waterborne diseases cause an estimated 1.9 million deaths per year. The Safe Water System (SWS) is a proven household water treatment intervention that reduces diarrhoeal disease incidence among users in developing countries. Turbid waters pose a particular challenge to implementation of SWS programmes; although research shows that a 3.75 mg l-1 sodium hypochlorite dose effectively treats turbid waters, users sometimes object to the strong chlorine taste and prefer to drink water that is more aesthetically pleasing. This study investigated the efficacy of three locally available water clarification mechanisms—cloth filtration, settling/decanting and sand filtration—to reduce turbidity and chlorine demand at turbidities of 10, 30, 70, 100 and 300 NTU. All three mechanisms reduced turbidity (cloth filtration -1–60%, settling/decanting 78–88% and sand filtration 57–99%). Sand filtration (P=0.002) and settling/decanting (P=0.004), but not cloth filtration (P=0.30), were effective at reducing chlorine demand compared with controls. Recommendations for implementing organizations based on these results are discussed.

Appropriate wastewater treatment systems for developing countries: criteria and indictor assessment in Thailand

Water Science & Technology—WST Vol 59 No 9 pp 1873–1884 © IWA Publishing 2009 doi:10.2166/wst.2009.215

Link to Summary Page

W. Singhirunnusorn and M. K. Stenstrom

Faculty of Environment and Resource Studies, Mahasarakham University, Kantharawichai District, Maha Sarakham Province 44150, Thailand E-mail:
Department of Civil and Environmental Engineering, UCLA, Los Angeles CA 90095, USA E-mail:


This paper presents a comprehensive approach with factors to select appropriate wastewater treatment systems in developing countries in general and Thailand in particular. Instead of focusing merely on the technical dimensions, the study integrates the social, economic, and environmental concerns to develop a set of criteria and indicators (C&I) useful for evaluating appropriate system alternatives. The paper identifies seven elements crucial for technical selection: reliability, simplicity, efficiency, land requirement, affordability, social acceptability, and sustainability. Variables are organized into three hierarchical elements, namely: principles, criteria, and indicators. The study utilizes a mail survey to obtain information from Thai experts—academicians, practitioners, and government officials—to evaluate the C&I list. Responses were received from 33 experts on two multi-criteria analysis inquiries—ranking and rating—to obtain evaluative judgments. Results show that reliability, affordability, and efficiency are among the most important elements, followed by sustainability and social acceptability. Land requirement and simplicity are low in priority with relatively inferior weighting. A number of criteria are then developed to match the contextual environment of each particular condition. A total of 14 criteria are identified which comprised 64 indicators. Unimportant criteria and indicators are discarded after careful consideration, since some of the indicators are local or site specific.

A new paradigm for low-cost urban water supplies and sanitation in developing countries

Water Policy Vol 10 No 2 pp 119–129 © IWA Publishing 2008 doi:10.2166/wp.2008.034

Link to Summary Page

Duncan Maraa and Graham Alabasterb

aCorresponding author. School of Civil Engineering, University of Leeds, Leeds LS2 9JT UK. Fax: +44-113-343-2243 E-mail:
bUnited Nations Human Settlements Programme, PO Box 30300, Nairobi, Kenya


To achieve the Millennium Development Goals for urban water supply and sanitation ~300,000 and ~400,000 people will have to be provided with an adequate water supply and adequate sanitation, respectively, every day during 2001–2015. The provision of urban water supply and sanitation services for these numbers of people necessitates action not only on an unprecedented scale, but also in a radically new way as “more of the same” is unlikely to achieve these goals. A “new paradigm” is proposed for low-cost urban water supply and sanitation, as follows: water supply and sanitation provision in urban areas and large villages should be to groups of households, not to individual households. Groups of households would form (even be required to form, or pay more if they do not) water and sanitation cooperatives. There would be standpipe and yard-tap cooperatives served by community-managed sanitation blocks, on-site sanitation systems or condominial sewerage, depending on space availability and costs and, for non-poor households, in-house multiple-tap cooperatives served by condominial sewerage or, in low-density areas, by septic tanks with on-site effluent disposal. Very poor households (those unable to afford to form standpipe cooperatives) would be served by community-managed standpipes and sanitation blocks.

Faecal bacterial indicators removal in various wastewater treatment plants located in Almendares River watershed (Cuba)

Water Science & Technology—WST Vol 58 No 4 pp 773–779 © IWA Publishing 2008 doi:10.2166/wst.2008.440

Link to Summary Page

Tamara Garcia-Armisen, Josué Prats, Yociel Marrero and Pierre Servais

Ecologie des Systèmes Aquatiques, Université Libre de Bruxelles, Brussels, Belgium *Present address: MINT, Vrije Universiteit Brussel, Building E, Pleinlaan 2, 1050, Brussels, Belgium Tel.:            +3226291918       E-mail:
Dpto. de Microbiología, Facultad de Biología, Universidad de La Habana, La Habana, Cuba
Instituto Superior Politécnico José Antonio Echeverría, La Habana, Cuba


The Almendares River, located in Havana city, receives the wastewaters of more than 200,000 inhabitants. The high abundance of faecal bacterial indicators (FBIs) in the downstream stretch of the river reflects the very poor microbiological water quality. In this zone, the Almendares water is used for irrigation of urban agriculture and recreational activities although the microbiological standards for these uses are not met. Improvement of wastewater treatment is absolutely required to protect the population against health risk. This paper compares the removal of FBIs in three wastewater treatment plants (WWTPs) located in this watershed: a conventional facility using trickling filters, a constructed wetland (CW) and a solar aquatic system (SAS). The results indicate better removal efficiency in the two natural systems (CW and SAS) for all the measured parameters (suspended matters, biological oxygen demand, total coliforms, E. coli and enterococci). Removals of the FBIs were around two log units higher in both natural systems than in the conventional one. A longitudinal profile of the microbiological quality of the river illustrates the negative impact of the large conventional WWTP. This case study confirms the usefulness of small and natural WWTPs for tropical developing countries, even in urban and periurban areas.

Treatment of low and medium strength sewage in a lab-scale gradual concentric chambers (GCC) reactor

Water Science & Technology—WST Vol 57 No 8 pp 1155–1160 © IWA Publishing 2008 doi:10.2166/wst.2008.093

Link to Summary Page

L. Mendoza, M. Carballa, L. Zhang and W. Verstraete

Experimental Reproduction Centre (CEYSA), Agricultural Faculty, Technical University of Cotopaxi, Latacunga, Ecuador E-mail:
Laboratory of Microbial Ecology and Technology (LabMET), Ghent University, Coupure Links 653, B-9000, Ghent, Belgium E-mail:;;


One of the major challenges of anaerobic technology is its applicability for low strength wastewaters, such as sewage. The lab-scale design and performance of a novel Gradual Concentric Chambers (GCC) reactor treating low (165±24 mg COD/L) and medium strength (550 mg COD/L) domestic wastewaters were studied. Experimental data were collected to evaluate the influence of chemical oxygen demand (COD) concentrations in the influent and the hydraulic retention time (HRT) on the performance of the GCC reactor. Two reactors (R1 and R2), integrating anaerobic and aerobic processes, were studied at ambient (26°C) and mesophilic (35°C) temperature, respectively. The highest COD removal efficiency (94%) was obtained when treating medium strength wastewater at an organic loading rate (OLR) of 1.9 g COD/L·d (HRT = 4 h). The COD levels in the final effluent were around 36 mg/L. For the low strength domestic wastewater, a highest removal efficiency of 85% was observed, producing a final effluent with 22 mg COD/L. Changes in the nutrient concentration levels were followed for both reactors.

Use of modelling for optimization and upgrade of a tropical wastewater treatment plant in a developing country

Water Science & Technology Vol 56 No 7 pp 21–31 © IWA Publishing 2007 doi:10.2166/wst.2007.675

Link to Summary Page

D. Brdjanovic*, M. Mithaiwala** , M.S. Moussa*** , G. Amy* and M.C.M. van Loosdrecht**** 

*Department of Urban Water and Sanitation, UNESCO-IHE Institute for Water Education, Westvest 7, PO Box 3015, 2061 DA , Delft, The Netherlands (E-mail:
**Drainage Department, Surat Municipal Corporation, Muglisara, Surat , Gujarat, 395003, India (Email:
***Civil Engineering Department, Faculty of Engineering Mataria, Helwan , University, Egypt (Email:
****Department of Biochemical Engineering, Delft University of Technology, Julianalaan 67, 2628 BC , Delft, The Netherlands (Email:


This paper presents results of a novel application of coupling the Activated Sludge Model No. 3 (ASM3) and the Anaerobic Digestion Model No.1 (ADM1) to assess a tropical wastewater treatment plant in a developing country (Surat, India). In general, the coupled model was very capable of predicting current plant operation. The model proved to be a useful tool in investigating various scenarios for optimising treatment performance under present conditions and examination of upgrade options to meet stricter and upcoming effluent discharge criteria regarding N removal. It appears that use of plant-wide modelling of wastewater treatment plants is a promising approach towards addressing often complex interactions within the plant itself. It can also create an enabling environment for the implementations of the novel side processes for treatment of nutrient-rich, side-streams (reject water) from sludge treatment.

Ceramic silver-impregnated pot filters for household drinking water treatment in developing countries: material characterization and performance study

Water Science & Technology: Water Supply Vol 7 No 5-6 pp 9–17 © IWA Publishing 2007 doi:10.2166/ws.2007.142

Link to Summary Page

D. van Halem*, S.G.J. Heijman* , A.I.A. Soppe** , J.C. van Dijk* and G.L. Amy*** 

*Delft University of Technology, Stevinweg 1, 2628 CN , Delft, The Netherlands (E-mail:;
**Delft University of Technology & Kiwa Water Research, Groningenhaven 7, 3433 PE , Nieuwegein, The Netherlands (E-mail:
***Aqua for All Foundation, Groningenhaven 7, 3433 PE , Nieuwegein, The Netherlands (E-mail:
****UNESCO-IHE Institute for Water Education, Westvest 7, 2611 AX , Delft, The Netherlands (E-mail:


The ceramic silver-impregnated pot filter (CSF) is a low-cost drinking water treatment system currently produced in many factories worldwide. The objective of this study is to gather performance data to provide a scientific basis for organisations to safely scale-up and implement the CSF technology. Filters from three production locations are included in this study: Cambodia, Ghana and Nicaragua. The microstructure of the filter material was studied using mercury intrusion porosimetry and bubble-point tests. Effective pores were measured with a mean of 40 mm, which is larger than many pathogenic microorganisms. The removal efficiency of these microorganisms was measured by using indicator organisms; total coliforms naturally present in canal water, sulphite reducing Clostridium spores, E.coli K12 and MS2 bacteriophages. The removal of these organisms was monitored during a long-term study of several months in the laboratory. Ceramic silver impregnated pot filters successfully removed total coliforms and sulphite reducing Clostridium spores. High concentrations of Escherichia coli K12 were also removed, with log(10) reduction values consistently higher than 2. MS2 bacteriophages were only partially removed from the water, with significantly better results for filters without an impregnation of colloidal silver. During this study the main deficiency of the filter system proved to be the low water production; after 12 weeks of use all filter discharges were below 0.5 Lh-1, which is insufficient to provide drinking water for a family

Ceramic membranes for direct river water treatment applying coagulation and microfiltration

Water Science & Technology: Water Supply Vol 6 No 4 pp 89–98 © IWA Publishing 2006 doi:10.2166/ws.2006.906

Link to Summary Page

A. Loi-Brügger*, S. Panglisch*, P. Buchta*, K. Hattori**, H. Yonekawa**, Y. Tomita** and R. Gimbel*,***

*IWW Water Center, Moritzstr. 26, 45476 Mülheim, , Germany (E-mail:
**NGK Insulators Ltd., 2-56 Suda-cho, Nagoya, Aichi, , 467-8530, Japan (E-mail:
***Institut für Energie- und Umweltverfahrenstechnik, Universität Duisburg-Essen Bismarckstr. 90, 47057 Duisburg, , Germany (E-mail:


A new ceramic membrane has been designed by NGK Insulators Ltd., Japan, to compete in the drinking water treatment market. The IWW Water Centre, Germany, investigated the operational performance and economical feasibility of this ceramic membrane in a one year pilot study of direct river water treatment with the hybrid process of coagulation and microfiltration. The aim of this study was to investigate flux, recovery, and DOC retention performance and to determine optimum operating conditions of NGK’s ceramic membrane filtration system with special regards to economical aspects. Temporarily, the performance of the ceramic membrane was challenged under adverse conditions. During pilot plant operation river water with turbidities between 3 and 100 FNU was treated. Membrane flux was increased stepwise from 80–300 l/m2h resulting in recoveries between 95.9 and 98.9%. A DOC removal between about 20–35% was achieved. The pilot study and the subsequent economical evaluation showed the potential to provide a reliable and cost competitive process option for water treatment. The robustness of the ceramic membrane filtration process makes it attractive for a broad range of water treatment applications and, due to low maintenance requirements, also suitable for drinking water treatment in developing countries.

Related Publications

Public Private Partnerships in the Water Sector – Cledan Mandri-Perrott and David Stiggers
Publication Date: Mar 2013 – ISBN – 9781843393207

Designing Wastewater Systems According to Local Conditions – David M Robbins
Publication Date: Jan 2014 – ISBN – 9781780404769

Water Services Management and Governance – Tapio Katko, Petri S. Juuti, and Klaas Schwartz
Publication Date: Oct 2012 – ISBN – 9781780400228

Meeting the Challenge of Financing Water and Sanitation – Organisation for Economic Co-Operation and Development (OECD)
Publication Date: Nov 2011 – ISBN – 9781780400327

OECD Water Resources and Sanitation Set – Organisation for Economic Co-Operation and Development (OECD)
Publication Date: Nov 2011 – ISBN – 9781780400570

OECD Water Policy and Finance Set – Organisation for Economic Co-Operation and Development (OECD)
Publication Date: Nov 2011 – ISBN – 9781780400563 now ships to over 220 countries.


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Reusing Greywater –

Posted by 15 Dec, 2012

TweetGreywater is water from your bathroom sinks, showers, tubs, and washing machines. It is not water that has come into contact with feces, either from the toilet or from washing diapers. Greywater may contain traces of dirt, food, grease, hair, and certain household cleaning products. While greywater may look “dirty,” it is a safe and […]

Greywater is water from your bathroom sinks, showers, tubs, and washing machines. It is not water that has come into contact with feces, either from the toilet or from washing diapers.

Greywater may contain traces of dirt, food, grease, hair, and certain household cleaning products. While greywater may look “dirty,” it is a safe and even beneficial source of irrigation water in a yard. If released into rivers, lakes, or estuaries, the nutrients in greywater become pollutants, but to plants, they are valuable fertilizer. Aside from the obvious benefits of saving water (and money on your water bill), reusing your greywater keeps it out of the sewer or septic system, thereby reducing the chance that it will pollute local water bodies. Reusing greywater for irrigation reconnects urban residents and our backyard gardens to the natural water cycle.

The easiest way to use greywater is to pipe it directly outside and use it to water ornamental plants or fruit trees. Greywater can be used directly on vegetables as long as it doesn’t touch edible parts of the plants. In any greywater system, it is essential to put nothing toxic down the drain–no bleach, no dye, no bath salts, no cleanser, no shampoo with unpronounceable ingredients, and no products containing boron, which is toxic to plants. It is crucial to use all-natural, biodegradable soaps whose ingredients do not harm plants. Most powdered detergent, and some liquid detergent, is sodium based, but sodium can keep seeds from sprouting and destroy the structure of clay soils. Choose salt-free liquid soaps. While you’re at it, watch out for your own health: “natural” body products often contain substances toxic to humans, including parabens, stearalkonium chloride, phenoxyethanol, polyethelene glycol (PEG), and synthetic fragrances.

For residential greywater systems simple designs are best. With simple systems you are not able to send greywater into an existing drip irrigation system, but must shape your landscape to allow water to infiltrate the soil. We recommend simple, low-tech systems that use gravity instead of pumps. We prefer irrigation systems that are designed to avoid clogging, rather than relying on filters and drip irrigation.

Greywater reuse can increase the productivity of sustainable backyard ecosystems that produce food, clean water, and shelter wildlife. Such systems recover valuable “waste” products–greywater, household compost, and humanure–and reconnect their human inhabitants to ecological cycles. Appropriate technologies for food production, water, and sanitation in the industrialized world can replace the cultural misconception of “wastewater” with the possibility of a life-generating water culture.

More complex systems are best suited for multi-family, commercial, and industrial scale systems. These systems can treat and reuse large volumes of water, and play a role in water conservation in dense urban housing developments, food processing and manufacturing facilities, schools, universities, and public buildings. Because complex systems rely on pumps and filtration systems, they are often designed by an engineer, are expensive to install and may require regular maintenance.

Basic Greywater Guidelines

Greywater is different from fresh water and requires different guidelines for it to be reused.
1. Don’t store greywater (more than 24 hours). If you store greywater the nutrients in it will start to break down, creating bad odors.
2. Minimize contact with greywater. Greywater could potentially contain a pathogen if an infected person’s feces got into the water, so your system should be designed for the water to soak into the ground and not be available for people or animals to drink.
3. Infiltrate greywater into the ground, don’t allow it to pool up or run off (knowing how well water drains into your soil (or the soil percolation rate of your soil) will help with proper design. Pooling greywater can provide mosquito breeding grounds, as well as a place for human contact with greywater.
4. Keep your system as simple as possible, avoid pumps, avoid filters that need upkeep. Simple systems last longer, require less maintenance, require less energy and cost less money.
5. Install a 3-way valve for easy switching between the greywater system and the sewer/septic.
6. Match the amount of greywater your plants will receive with their irrigation needs.

Types of simple systems

From the Washing Machine

Washing machines are typically the easiest source of greywater to reuse because greywater can be diverted without cutting into existing plumbing. Each machine has an internal pump that automatically pumps out the water- you can use that to your advantage to pump the greywater directly to your plants.

Laundry Drum

Drum should be strapped to wall for safety.







An example of a laundry drum system.

If you don’t want  to invest much money in the system (maybe you are a renter), or have a lot of hardscape (concrete/patio) between your house and the area to irrigate, try a laundry drum system.

Wash water is pumped into a “drum,” a large barrel or temporary storage called a surge tank. At the bottom of the drum the water drains out into a hose that is moved around the yard to irrigate. This is the cheapest and easiest system to install, but requires constant moving of the hose for it to be effective at irrigating.

Laundry to Landscape (aka drumless laundry)

The laundry to landscape system gives you flexibility in what plants you’re able irrigate and takes very little maintenance.

In this system, the hose leaving the washing machine is attached to a valve that allows for easy switching between the greywater system and the sewer. The greywater goes to 1″ irrigation line with outlets sending water to specific plants. This system is low cost, easy to install, and gives huge flexibility for irrigation. In most situations this is the number one place to start when choosing a greywater system.

From the Shower

Showers are a great source of greywater- they usually produce a lot of relatively clean water. To have a simple, effective shower system you will want a gravity-based system (no pump). If your yard is located uphill from the house, then you’ll need to have a pumped system.

Branched Drain:

Greywater in this system flows through standard (1 1/2″ size) drainage pipe, by gravity, always sloping downward at 2% slope, or 1/4 inch drop for every foot traveled horizontally, and the water is divided up into smaller and smaller quantities using a plumbing fitting that splits the flow. The final outlet of each branch flows into a mulched basin, usually to irrigate the root zone of trees or other large perennials. Branched drain systems are time consuming to install, but once finished require very little maintenance and work well for the long term.






An example of a branched drain system .

From the Sinks

Kitchen sinks are the source of a fair amount of water, usually very high in organic matter (food, grease, etc.). Kitchen sinks are not allowed under many greywater codes, but are allowed in some states, like Montana. This water will clog many kinds of systems. To avoid clogging, we recommend branched drains to large mulch basins. Much less water passes through bathroom sinks. If combined with the shower water it will fall under the shower system, if used alone, it can be drained to a single large plant, or have the flow split to irrigate two or three plants.

Constructed Wetlands







Wetland planter ecologically disposes greywater from an office with no sewer hookup.

If you produce more greywater than you need for irrigation, a constructed wetland can be incorporated into your system to “ecologically dispose” of some of the greywater. Wetlands absorb nutrients and filter particles from greywater, enabling it to be stored or sent through a properly designed drip irrigation system (a sand filter and pump will also be needed- this costs more money). Greywater is also a good source of irrigation for beautiful, water loving wetland plants. If you live near a natural waterway, a wetland can protect the creek from nutrient pollution that untreated greywater would provide. If you live in an arid climate, or are trying to reduce your fresh water use, we don’t recommend incorporating wetlands into greywater systems as they use up a lot of the water which could otherwise be used for irrigation.

Pumped Systems

If you can’t use gravity to transport the greywater (your yard is sloped uphill, or it’s flat and the plants are far away) you will need a “drum with effluent pump” system. The water flows into a large (usually 50 gallon) plastic drum that is either buried or located at ground level. In the drum a pump pushes the water out through irrigation lines (no emitters) to the landscape. Pumps add cost, use electricity, and will break, so avoid this if you can.

Indoor Greywater use

In most residential situations it is much simpler and more economical to utilize greywater outside, and not create a system that treats the water for indoor use. The exceptions are in houses that have high water use and minimal outdoor irrigation, and for larger buildings like apartments.

There are also very simple ways to reuse greywater inside that are not a “greywater system”. Buckets can catch greywater and clear water, the water wasted while warming up a shower. These buckets can be used to “bucket flush” a toilet, or carried outside. There are also simple designs like Sink Positive, and more complicated systems like the Brac system. Earthships have an interesting system that reuse greywater inside with greenhouse wetlands.

Plants and Greywater







Kiwi fruit irrigated with greywater

Low tech, simple greywater systems are best suited to specific, large plants. Use them to water trees, bushes, berry patches, shrubs, and large annuals. It’s much more difficult to water lots of small plants that are spread out over a large area (like a lawn or flower bed).

Greywater Policy

Greywater policies differ state to state. The best policy is from the state of Arizona. They have greywater guidelines to educate residents on how to build simple, safe, efficient, greywater irrigation systems. If people follow the guidelines their systems falls under a general permit and is automatically “legal”, that is, the residents don’t have to apply or pay for any permits or inspections.

California had the first greywater code in the nation, but it had been very restrictive and usually made it unfeasible for people to afford installing a permitted system. Because of this the vast majority of systems in California are unpermitted. Using data from a study done by the soap industry, Art Ludwig estimates that for every permit given in the past 20 years, there were 8,000 unpermitted systems built. In 2009 California changed its code, making it much easier for people to build simple, low cost systems legally.

Some states have no greywater policy and don’t give permits at all, while other states give experimental permits for systems on a case-by-case basis.

Images and information by Greywater Action used above are licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License., original found here:

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Using Rainwater –

Posted by 13 Nov, 2012

Tweet Using Rainwater Those of us who live in cities and towns, and eat food grown on industrial farms, depend on imported water for daily survival. Our water travels hundreds of miles to reach us. It is powered by mountain-leveling coal, mega-dam hydro-power, and nuclear power. The infrastructure that brings us this water costs billions […]

Using Rainwater

Those of us who live in cities and towns, and eat food grown on industrial farms, depend on imported water for daily survival. Our water travels hundreds of miles to reach us. It is powered by mountain-leveling coal, mega-dam hydro-power, and nuclear power. The infrastructure that brings us this water costs billions of dollars in public tax money and household utility bills.
Harvesting rainwater can reduce our need for water transport systems that threaten the health of the water cycle and our local environments. Ironically, water use is often highest in the places where rain falls the least. But whether you live in the damp Pacific Northwest, the arid Mojave desert, the thunderstorm Midwest, or beyond, you depend on problematic water infrastructures.

Rainwater harvesting is one strategy to reduce domestic water use. Harvesting rainwater and dozens of other green household practices can bring us greater sustainability. Growing plants that shade and installing insulated windows can reduce energy use. Increasing home food production reduces demand for wasteful water use in industrial fields. Above all, rainwater harvesting increases quality of life: ours, and that of life around the world.
In arid climates and places with salty irrigation water, rainwater flushes salts and chemicals out, increasing health and soil vitality.
Design landscape to welcome the rain

On any house lot, there are three potential ways to harvest the rain: direct rainfall, street harvesting, and roof harvesting.
The easiest rainwater source is that which falls on the yard. Proper placement of plants, trees, and water sources can turn your yard into a water efficient system. Shape the surface of the soil to slow down runoff, raise paths and patios, and sink all planting areas to capture the flow. Choose plants–primarily natives–that can absorb and hold water in their root systems, or pass it down to the water table. This way, rainwater doesn’t run off into the street, where it would be swept away with motor oil, into the sewer system or discharged directly into a local waterway.

The second source of rainwater is the street. Streets aren’t flat; they are graded so that water flows to the curb, down the block to a gutter and into a storm drain. In cities like San Francisco and Portland, storm drains are connected to the sewage treatment plant, and heavy rains cause the sewer plant to overflow raw and partially treated sewer into the bay or river. Other cities connect storm drains to underground creeks, and the polluted water runs straight into the bay or nearby river. By cutting curbs and digging sunken basins into the “right-of way” or “parking strip” area of the sidewalk, you can turn street rainwater from a problem to a resource. Diverted rain that falls on streets can nourish plants, protect creeks, and contribute to cleaner cities.

Store the rain- cisterns and rain barrels
The third source of rainwater is the roof. Even in areas with low rainfall this is an easy way to harvest rainwater.
For example, the roof of a 1,000 square foot house can collect around 600 gallons per ONE inch of rain! In an average year with 12 inches of rain in Los Angeles, that small roof could collect 7,200 gallons.

The rain catchment system
A water catchment system for roof rainwater is simple, and can store water for outdoor irrigation.
200 gallons of storage tucked next to a garage
• Gutters: Roof water gathers in the gutters and runs to a pipe towards the tank.
• “First Flush”: The first rain of the year is the dirtiest as it cleans the roof. This water is directed away from the tank in a “first flush system” and the subsequent water continues to the tank.
• Screen: The rainwater goes through a screen to remove leaves and debris, and then funnels into the top of the covered tank.
• Storage: The tank is dark, to prevent algea from growing, and screened, to prevent mosquitoes from entering.
• Irrigation: A hose attachment is located near the bottom for irrigation.

Rain barrels are a popular way to begin rainwater harvesting, especially in urban areas; they are low cost, and can be installed along houses, under decks, or in other unused spaces.
There is a huge range of options for cisterns, large single storage tanks. They can be made from plastic, ferrocement, metal, or fiberglass, ranging in size from 50 gallons to tens of thousands of gallons.

Indoor use

Ceramic drinking water filter: This highly-effective, passive filter removes pollutants and pathogens including viruses from drinking water.
In Australia, rainwater cisterns supply potable water to thousands of homes. In the US, it’s becoming more common for people to use rainwater indoors for non-potable uses. These systems can reduce or eliminate use of municipal or well water during the rainy season, when outdoor irrigation is unnecessary. Most household rainwater systems use a pump and pressure tank to pressurize water. Many states do not have codes covering indoor rainwater use, and people seeking permits may be required to filter and disinfect the water, increasing system cost and complexity. However, EPA and other research has shown that rainwater harvested using a “first flush” system and protected from light is safe to use for bathing and other household use. Filtering only the small amount of water used for drinking with passive filters such as the ceramic filter shown at left, or with slow sand filters, greatly reduces system cost, and offers an affordable solution for people needing clean drinking water.

Information from shared via Creative Commons Attribution-ShareAlike 3.0 Unported (CC BY-SA 3.0)

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Environmental Applications Bulletin –

Posted by 4 Oct, 2012

TweetEnvironmental Applications Keeping the water in our lakes, rivers, and streams clean requires monitoring of water quality at many points as it gradually makes its way from its source to our oceans. Over the years ever-increasing environmental concerns and regulations have heightened the need for increased diligence and tighter restrictions on wastewater quality. Control of […]

Environmental Applications
Keeping the water in our lakes, rivers, and streams clean requires monitoring of water quality at many points as it gradually makes its way from its source to our oceans. Over the years ever-increasing environmental concerns and regulations have heightened the need for increased diligence and tighter restrictions on wastewater quality. Control of water pollution was once concerned mainly with treating wastewater before it was discharged from a manufacturing facility into the nation’s waterways. Today, in many cases, there are restrictions on wastewater that is discharged to city sewer systems or to other publicly owned treatment facilities. Many jurisdictions even restrict or regulate the runoff of storm water — affecting not only industrial and commercial land, but also residential properties as well.

In its simplest form, water pollution management requires impoundment of storm water runoff for a specified period of time before being discharged. Normally, a few simple tests such as pH and suspended solids must be checked to verify compliance before release. If water is used in any way prior to discharge, then the monitoring requirements can expand significantly. For example, if the water is used for once-through cooling, testing may include temperature, pH, total dissolved solids (TDS), chemical oxygen demand (COD), and biochemical oxygen demand (BOD), to name a few.

Once water is used in a process, some form of treatment is often required before it can be discharged to a public waterway. If wastewater is discharged to a city sewer or publicly owned facility, and treatment is required, the quality is often measured and the cost is based not only on the quantity discharged, but also the amount of treatment required. As a minimum requirement suspended solids must be removed. Filtering or using clarifiers often accomplishes such removal. Monitoring consists of measuring total suspended solids (TSS) or turbidity.

If inorganic materials have been introduced into the water, their concentration must be reduced to an acceptable level. Inorganics, such as heavy metals, typically are removed by raising the pH to form insoluble metal oxides or metal hydroxides. The precipitated contaminants are filtered or settled out. Afterward, the pH must be adjusted back into a “normal” range, which often requires continuous monitoring of pH.

Organic materials by far require the most extensive treatment. Many different methods have been devised to convert soluble organic compounds into insoluble inorganic matter. Most of these involve some form of biological oxidation treatment. Bacteria are used to metabolize the organic materials into carbon dioxide and solids, which can be easily removed. To insure that these processes work smoothly and efficiently requires regular monitoring of the health of the biological organisms. The level of food (organic material), nutrients (nitrogen and phosphorous), dissolved oxygen, and pH are some of the parameters that must be controlled. After bio-oxidation the wastewater is filtered or clarified. Often the final effluent is treated with an oxidizing compound such as chlorine to kill any remaining bacterial agents, but any excess oxidant normally must be removed prior to discharge. Oxidation Reduction Potential (ORP)/Redox is ideal for monitoring the level of oxidants before and after removal. The final effluent stream must be monitored to make sure it meets all regulatory requirements.

The monitoring of wastewater pollution does not end there. Scientists are continuously testing water in streams, ground water, lakes, lagoons, and other bodies of water to determine if and what effects any remaining contamination is having on the receiving waters and its associated aquatic life. Measurements may include pH, conductivity, TDS, temperature, dissolved oxygen, TSS and organic levels (COD and BOD).

Environmental testing is not limited to monitoring of wastewater systems. Control of air emissions often includes gas-cleaning systems that involve the use of water. Wet scrubbers and wet electrostatic precipitators are included in this group. A flue gas desulfurization (FGD) system is one type of wet scrubber that uses slurry of lime, limestone, or other caustic material to react with sulfur compounds in the flue gas. The key to reliable operation of these units is proper monitoring of solids levels and pH. After use, the water in these systems must be treated or added to other wastewater from the plant, where it is treated by one of the methods previously discussed.
With proper monitoring, systems that maintain cleaner air and water can be operated efficiently and effectively. Such operation will go a long way toward maintaining a cleaner environment for future generations.

Myron L Meters offers a full line of handheld instruments and in-line monitor/controllers that can be used to measure or monitor many of the parameters previously mentioned. The following table lists some of the model numbers for measuring, monitoring, or controlling pH, conductivity, TDS and ORP. For additional information, please refer to our data sheets or Ask An Expert at

Note: When using a monitor/controller to measure pH in streams that contain heavy metals, sulfides, or other materials that react with silver, Myron L Meters recommends using a double junction pH sensor with a potassium nitrate (KNO3) reference gel to avoid fouling the silver electrode. See our 720II Sensor Selection Guide for pH and ORP Monitor/controllers for more information.
Recommended handheld:

Ultrameter II 6P






Multi-Parameter: Conductivity, TDS, Resistivity, pH, ORP, Temperature, Free Chlorine (FCE)
+/-1% Accuracy of Reading
Memory Storage: Save up to 100 samples w/ Date & Time stamp
Wireless Download Module Optional


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Buying and Using a pH Meter for Food Processing –

Posted by 2 Oct, 2012

TweetWhat is pH and why do I need to measure it? pH measures the amount of acidity or alkalinity in a food or solution using a numerical scale between  1 and 14. A pH value of 1 is most acidic, a pH value of 7 is neutral, and values above 7 are referred to as […]

What is pH and why do I need to measure it?

pH measures the amount of acidity or alkalinity in a food or solution using a numerical scale between  1 and 14. A pH value of 1 is most acidic, a pH value of 7 is neutral, and values above 7 are referred to as basic or alkaline. Acidified foods have a pH value less than or equal to 4.6. The proper pH of a canned food product can be critical to ensuring the safety of the product. It is very important that pH testing be done correctly and accurately.

How is pH measured?

If you process acidified foods, you will be required to monitor the pH of the product that you produce. Depending on the pH of the product, you may be able to use paper pH strips (often referred to as litmus paper), or required to use a pH meter. Paper strips that measure pH rely on a color change in the paper to indicate product pH. Paper strips can be used to measure pH if the product pH is less than 4.0. Paper strips are an inexpensive way to test pH, but can be inaccurate or difficult to read. A pH meter measures the amount of hydrogen-ion (acid) in solution using a glass electrode immersed in the solution. A pH meter must be used when product pH is greater than, or equal to, 4.0. If you are canning acidified foods, accurately monitoring and recording the product pH is key to knowing that you are selling a safe product.

What is equilibrium pH?

Equilibrium pH is the pH of a food product after the added acid has reached throughout the food; the pH of the acid brine and the food that have equilibrated.  When you monitor pH as part of process monitoring, it is the equilibrium pH that you are measuring. For a proper pH reading, you should test the pH of the product roughly 24 hours after processing, once the jars have cooled to room temperature and stabilized. Do not take the pH of a product just before or right after canning because it will not be an accurate measure of the equilibrium pH.

What should I look for if I need to purchase a pH meter?

If you are required to check your product pH with a meter, there are several things to consider.

Accuracy. Accuracy is listed as a range of +0.XX pH units. This means that the meter may read so many pH units above or below the actual pH of the product. Purchase a pH meter with an accuracy of +0.02 units or better. For instance, a pH meter with an accuracy of

+0.01 is a good choice. A pH meter with an accuracy of +0.10 is not a good choice, it is not accurate enough for all products.


All pH meters must be calibrated (checked against a known standard) to assure accuracy. Standards are colored liquids of known pH. Buy a meter that uses at least a 2-point calibration; for acidified foods you will calibrate your meter with pH 4.0 and 7.0 buffers.

Electrode. The electrode is the part of the instrument that is immersed in solution. When considering which pH meter to purchase, consider the cost of replacement electrodes. Some  electrodes  have  special  non-clog  tips  and  these  may  be  useful  is  you  will  be measuring the pH of foods that are not easily blended.

Temperature. pH readings are affected by temperature. In order to get an accurate reading, the pH meter must be calibrated at the same temperature as the samples being tested. More expensive meters will compensate for variations in sample temperature (too warm or too cold). Myron L meters have automatic temperature compensation. If you can afford a meter with this feature, it’s nice to have.

What should I buy?

The cost of a pH meter ranges from under $100 to well over $500.  As a starting point, there are several styles that small food and beverage processors currently use.

Testing the Equilibrium pH of an Acidified Food Product

1.   Open one jar and take a representative sample of your food product once it has cooled, usually 12 to 24 hours after processing. You should sample each batch. Heating will drive the acid into your food product; sampling after processing (and cooling) will give you an accurate reading of the equilibrium pH.

2.   Strain the solids, draining out the liquid (brine) from the jar. Place the strained solids into a blender.

3.   Blend the product, adding distilled water if necessary, to produce a slurry. Added distilled water will not change the pH of the product and will allow for effective blending. You can purchase distilled water at many grocery stores or drug stores.

4.   Use a calibrated pH meter to measure pH.

The pH meter must be calibrated using at least 2-point calibration with pH 4.0 and 7.0 buffers. Myron L Meters recommends a three point calibration.

The pH meter must be calibrated each day that you use it. A pH meter must be used to monitor the pH of foods with an equilibrium pH greater than 4.0.

5.   Record the results in your batch log.

*Myron L meters are used by Tyson, Sara Lee, Gordon Food Service, Better Baked Foods, Schreiber Foods, Homestead Slow Foods, and others in the food

processing industry.

These are our two most popular handheld pH meters:

Ultrapen PT2




ULTRAPEN PT2 pH and Temperature Pen

Accuracy of +/- 0.01 pH

Reliable Repeatable Results

Easy Calibration

Automatic Temperature Compensation

Measures Temperature

Durable, Fully Potted Circuitry


Comes with 2oz bottle of pH Storage Solution








Ultrameter II – 6PII

Multi-Parameter: Conductivity, TDS, Resistivity, pH, ORP, Temperature, Free Chlorine (FCE)

+/-1% Accuracy of Reading

Memory Storage: Save up to 100 samples w/ Date & Time stamp

Wireless Download Module Optional



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The Ultrameter II 6P in Ghana

Posted by 14 Aug, 2012

Tweet KatherineAlfredo uses the Ultrameter II to record and analyze data in Ghana to develop a cost-effective solution for fluoride removal. The task of providing safe drinking water to the inhabitants of rural Ghana is a daunting one. Though Ghana has achieved government stability and fostered economic development over the past decade, just 71% of […]

KatherineAlfredo uses the Ultrameter II to record and analyze data in Ghana to develop a cost-effective solution for fluoride removal.

The task of providing safe drinking water to the inhabitants of rural Ghana is a daunting one. Though Ghana has achieved government stability and fostered economic development over the past decade, just 71% of the rural population has access to improved water for drinking and sanitation, and groundwater demand is projected to increase by 69% by the year 2020.

In rural areas, groundwater is plentiful, but natural geographic contamination by inorganic contaminants like iron, manganese and fluoride render government-sponsored boreholes useless. Fluoride in the upper-east, upper-west and northern regions of Ghana often exceeds the general World Health Organization recommended limit of 1.5 mg/L.

The effects of excess fluoride consumption are serious. Mottling of tooth enamel in children progresses to structural damage to teeth. As daily fluoride intake increases, skeletal fluorosis, weight-loss, thyroid dysfunction, kidney failure and eventually death result; therefore, hand pumps in contaminated locations are capped or abandoned. This comes at a high cost to the community members and government sponsors.

Impoverished rural communities cannot afford to waste effort and funding on further drilling of boreholes contaminated by fluorides, but they do not have the resources to determine the extent and location of the contamination. Testing and mapping is needed to guide future efforts. It is this need that inspired Katherine Alfredo, a graduate student at the University of Texas at Austin, to propose a project for a Fulbright Fellowship.

Mapping Fluoride

The purpose of the fellowship was to map the extent of the fluoride concentration in the Bongo District of the Upper Eastern Region for use by local authorities and eventually use the data collected in the development of a cost-effective defluoridation filter for existing capped wells.

Alfredo began her research by observing and recording local water usage habits. She conducted borehole water usage counts on centrally and noncentrally located borehole sites tracking the quantity of water collected daily. Coupling this data with familial compound water usage surveys, Alfredo was able to begin understanding the volumetric demand placed on each borehole daily and how that volume translates to the household level.

Along with the quantity studies, 286 boreholes throughout the Bongo District were visited between January and March 2009 with the help of local guides using a bicycle for transportation.

At each borehole, GPS data and borehole identity information were collected. When no borehole identity number was present, the identity number of the pump was recorded; if that was unavailable, an identity was created for logging purposes. A 1-L sample of water was retrieved for testing and used for all of the water quality tests.

An aliquot of the sample water was placed in an Ultrameter II 6P to measure pH, ORP, conductivity, total dissolved solids (TDS) and temperature.

Alfredo found the Ultrameter II to be an ideal tool for her work. “I was so impressed with the Ultrameter II and its ability to hold a calibration,” she said. “This one fact not only made my sampling progression quicker, but it also saved me from carrying more than 100 mL of each calibration fluid with me on any given day, given the fact that I performed all of my sampling via bicycle, carrying all the equipment on the bicycle as well, was something of extreme importance to me.”

The Ultrameter II utilizes a KCl gel-filled pH sensor for accurate electrometric pH readings within ±0.01 pH. The pH levels of the water were of specific importance to Alfredo’s research of adsorbing fluoride on aluminum-based adsorbents. This is because the amount of fluoride an adsorbent is able to absorb is directly related to the pH of the water. The ideal pH for removal of fluoride by activated alumina from raw water, for example, is 5.5.

Conductivity readings from the Ultrameter II were within ±0.01 mV achieved through an advanced design 4-electrode conductivity cell. These readings will be used to simulate influent water containing excessive levels of fluoride in Alfredo’s laboratory. Using Bongo as a design test case, she plans to adjust the ionic strength of her synthetic influent to reflect that seen in the Bongo District.

Solution temperature measured by means of thermistor was logged automatically by the Ultrameter II with each parameter measured. Fluctuations in temperature will be studied to see how temperature affects fluoride removal.

TDS readings were used as a quality indicator of water as it is dispensed from a borehole. The amount of all dissolved solids is important in determining the potential for interference and competition for adsorption sites on the aluminum adsorbents. Preventing any ions from competing for active sites on alumina surfaces will greatly increase the efficiency of filtration. ORP readings gave a good indication of the general biological activity in the water.

Additional testing was performed using two 2-mL tubes filled with sample water to measure nitrate/nitrite and ammonia using test strips. In another 2-mL tube, a 1:1 dilution of the sample was created using distilled water to measure alkalinity using test strips. Using a 0.45-micron filter, a 30- or 60-mL sterile plastic bottle was completely filled for fluoride concentration testing later in the laboratory and was labeled with a sample ID number that was later used to correlate borehole data with water quality information.

Finally, sample time, the date and basic notes on the state of the borehole construction and surroundings were logged in the logbook. Fluoride concentrations were measured using an ion selective electrode typically within 72 hours of collection.

Each capped borehole, new borehole or nonfunctional borehole that was visited had its corresponding borehole identity (actual or created) recorded in a handheld GPS device. After each governance was covered, eight capped boreholes (due to elevated fluoride levels—not broken parts) were chosen for water quality testing to be compared to the nearby functional boreholes. For each capped borehole, additional information corresponding to the total depth of the borehole and depth to the water surface were collected.

An undisturbed sample was retrieved using a point source bailer 15 ft from the bottom of the borehole under the assumption that at this level the aquifer would be flowing through the screened interval. Water quality information and the samples were collected using the same methodology as that for functional boreholes.

Using GIS, a base map of the Bongo District was created and the sample identity number, borehole identity, latitude, longitude, measured fluoride concentration (mg/L) and pH were uploaded for each borehole tested. Using the interpolation tools in GIS, an inverse distance weighted interpolation was performed on the fluoride concentration borehole data to approximate the concentrations throughout the aquifer. This data will be correlated to the geologic and drainage information for the area during the next phase of research.

At the time of Alfredo’s departure, she had reported the pH and fluoride concentration of each well to the two water and sanitation government agencies in the Bongo area—the Community Water and Sanitation Agency and the Bongo District Assembly Water and Sanitation Team.

Alfredo continues to analyze data recorded in Ghana and experiment with cost-effective solutions for fluoride removal in rural communities.

More about the Ultrameter II here:

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Forest Byproducts, Shells May Be Key to Removing Radioactive Contaminants from Drinking Water

Posted by 26 Apr, 2011

Tweet ScienceDaily (Apr. 15, 2011) — A combination of forest byproducts and crustacean shells may be the key to removing radioactive materials from drinking water, researchers from North Carolina State University have found. Complete story below:   There’s always more at


ScienceDaily (Apr. 15, 2011) — A combination of forest byproducts and crustacean shells may be the key to removing radioactive materials from drinking water, researchers from North Carolina State University have found.

Complete story below:


There’s always more at

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