Water Quality Testing in RO Systems – MyronLMeters.com

Tweet Water quality testing is vital to the design of an efficient, cost-effective RO system, and is one of the best ways to preserve system life and performance. Using an accurate Total Dissolved Solids (TDS) measurement to assess the system load prevents costly mistakes up front. The TDS measurement gives users the information they need [...]

Water quality testing is vital to the design of an efficient, cost-effective RO system, and is one of the best ways to preserve system life and performance.

Using an accurate Total Dissolved Solids (TDS) measurement to assess the system load prevents costly mistakes up front. The TDS measurement gives users the information they need to determine whether or not pretreatment is required and the type of membrane/s to select. Ultrameter™ and ULTRAPEN PT1™ Series TDS instruments feature the unique ability to select from 3 industry standard solution models: 442 Natural Water™ NaCl; and KCl. Choosing the model that most closely matches the characteristics of source water yields measurements accurate enough to check and calibrate TDS monitor/controllers that can help alert to system failures, reducing downtime and increasing productivity. The same instruments provide a fast and accurate test for permeate TDS quality control. Measuring concentrate values and analyzing quality trends lets users accurately determine membrane usage according to the manufacturer’s specifications so they can budget consumption correctly. These daily measurements are invaluable in detecting problems with system performance where changes in the ionic concentration of post-filtration streams can indicate scaling or fouling. System maintenance is generally indicated if there is either a 10-15% drop in performance or permeate quality as measured by TDS.

Thin-film composite membranes degrade when exposed to chlorine. In systems where chlorine is used for microbiological control, the chlorine is usually removed by carbon adsorption or sodium bisulfite addition before membrane filtration. The presence of any chlorine in such systems will at best reduce the life of the membrane, thus, a target of 0 ppm free chlorine in the feedwater is desirable.

ORP gives the operator the total picture of all chemicals in solution that have oxidizing or reducing potential including chlorine, bromine, chloramines, chlorine dioxide, peracetic acid, iodine, ozone, etc. However, ORP can be used to monitor and control free chlorine in systems where chlorine is the only sanitizer used. ORP over +300 mV is generally considered undesirable for membranes. Check manufacturer’s specifications for tolerable ORP levels.

An inline ORP monitor/controller placed ahead of the RO unit to automatically monitor for trends and breakthroughs coupled with spot checks by a portable instrument will prevent equipment damage and failure. Myron L 720 Series II™ ORP monitor/controllers can be configured with bleed and feed switches as well as visible and audible alarms.

Ultrameter and ULTRAPEN portable handhelds are designed for fast field testing and are accurate enough to calibrate monitor/controllers. Our measurement methods are objective and have superior accuracy and convenience when compared to colorimetric methods where determination of equivalence points is subjective and can be skewed by colored or turbid solutions.

Monitoring pH of the source water will allow users to make adjustments that optimize the performance of antiscalants, corrosion inhibitors and anti-foulants. Using a 720 II Series Monitor/controller to maintain pH along with an Ultrameter Series or ULTRAPEN PT2™ handheld to spot check pH values will reduce consumption of costly chemicals and ensure their efficacy.

Most antiscalants used in chemical system maintenance specify a Langelier Saturation Index maximum value. Some chemical manufacturers and control systems develop their own proprietary methods for determining a saturation index based on solubility constants in a defined system. However, LSI is still used as the predominant scaling indicator because calcium carbonate is present in most water. Using a portable Ultrameter III 9PTKA™ provides a simple method for determining LSI to ensure the chemical matches the application.

The Ultrameter III 9PTKA computes LSI from independent titrations of alkalinity and hardness along with electrometric measurements of pH and temperature. Using the 9PTKA LSI calculator, alterations to the water chemistry can be determined to achieve the desired LSI. Usually, pH is the most practical adjustment. If above 7, acid additions are made to achieve the pH value in the target LSI. Injections are made well ahead of the RO unit to ensure proper mixing and avoid pH hotspots. A Myron L 720 Series II pH Monitor/controller will automatically detect and divert solution with pH outside the range of tolerance for the RO unit. ULTRAPEN PT2, TechPro II and Ultrameter Series instruments can be used to spot check and calibrate the monitor/controller as part of routine maintenance and to ensure uniform mixing.

Water hardness values indicate whether or not ion exchange beds are required in pretreatment. Checking hardness values directly after the softening process with the Ultrameter III 9PTKA ensures proper functioning and anticipates the regeneration schedule.

Alkalinity is not only important in its effect on the scaling tendency of solution, but on pH maintenance. Additions of lime are used to buffer pH during acid injection. Use a 9PTKA to measure alkalinity values for fast field analysis where other instrumentation is too cumbersome to be practical.

Though testing and monitoring pressure is a good way to evaluate system requirements and performance over time, measuring other water quality parameters can help pinpoint problems when troubleshooting. For example, if the pressure differential increases over the second stage, the most likely cause is scaling by insoluble salts. This means that any degradation in performance is likely due to the dissolved solids in the feed. Using a 9PTKA to evaluate LSI and calculate parameter adjustments is a simple way to troubleshoot a costly problem.

Myron L Meters saves you 10% on all Ultrameters and Ultrapens when you order online at MyronLMeters.com, where you can find the complete selection of Myron L meters, including the Ultrameter III 9PTKA.

Original story from International Filtration News V 32, no. 2

 

Myron L Meters Water Industry Resources – MyronLMeters.com

TweetSoon Myron L Meters will be adding a Water Industry Resources page to MyronLMeters.com.  The page will feature links to water industry events, water industry associations, and related technical resources.  Please look over our draft page below and  suggest anything we might be missing. Be sure to check back with us periodically for new features [...]

Soon Myron L Meters will be adding a Water Industry Resources page to MyronLMeters.com.  The page will feature links to water industry events, water industry associations, and related technical resources.  Please look over our draft page below and  suggest anything we might be missing. Be sure to check back with us periodically for new features and changes, including our upcoming Myron L Meters Users Forum.

Myron L Meters Water Industry Resources

 Blog

http://blog.myronlmeters.com/

 

Manuals and MSDS

http://www.myronlmeters.com/Articles.asp?ID=263

 

Video Channel

http://www.youtube.com/myronlmeters

 

Application Bulletins

https://www.myronlmeters.com/Articles.asp?ID=265

 

Users Group

 

Water Industry News

http://waterindustrynews.com/

 

Pinterest

http://pinterest.com/myronlmeters/boards/

 

Twitter

https://twitter.com/MyronLMeters

 

Water Science and Conservation

 

Water Conservation News - Science Daily

http://www.sciencedaily.com/news/earth_climate/water/

 

U.S. Department of the Interior | Bureau of Reclamation

http://www.usbr.gov/WaterSMART/

 

Environmental Protection Agency

http://www2.epa.gov/science-and-technology/water-science

 

Clean Water Network

http://www.cleanwaternetwork.org/

 

Soil and Water Conservation Society

http://www.swcs.org/

 

Partnership for Water Conservation

http://www.partners4water.org/

 

Nature Conservancy Conservation Gateway

http://www.conservationgateway.org/Pages/default.aspx

 

 

Water Products Suppliers

 

Pumps:                                  PulsafeederPumps

                                             http://www.pulsafeederpumps.com/

 

Storage Tanks:                       PeabodyStorageTanks

                                             http://www.peabodystoragetanks.com/Default.asp

 

Water Industry Events
Apr 14 – Apr 18, 2013

Miscellaneous | Miscellaneous

23th Annual Practical Membrane / Filtration & Separations Technologies Short Course

College Station, TX
Apr 16 – Apr 18, 2013

AWWA Section | Section Conference

New York Section 2013 Annual Conference

Saratoga Springs, NY
Apr 16 – Apr 18, 2013

Miscellaneous | Seminar

HEC-HMS

Chicago, IL
Apr 22 – Apr 24, 2013

AWWA | Seminar

SOLD OUT Financial Management Seminar, San Diego, California

San Diego, CA
Apr 23 – Apr 25, 2013

AWWA Section | Section Conference

Pennsylvania Section 2013 Annual Conference

Hershey, PA
Apr 25 – Apr 25, 2013

Miscellaneous | Miscellaneous

Native Landscape Design for Stormwater

Milwaukee, WI
Apr 29 – May 02, 2013

AWWA Section | Annual Meeting

Alaska Section 2013 Annual Conference

Anchorage, AK
May 01 – May 03, 2013

AWWA Section | Section Conference

Arizona Section 2013 Annual Conference

Glendale, AZ
May 06 – May 07, 2013

Miscellaneous | Miscellaneous

17th Annual Water Reuse & Desalination Research Conference

Phoenix, AZ
May 06 – May 08, 2013

Miscellaneous | Speciality Conferences

2013 ABPA Education Conference & Trade Show

Phoenix, AZ
May 06 – May 10, 2013

Miscellaneous | Miscellaneous

2013 West Regional Conference

Seattle, WA
May 07 – May 09, 2013

AWWA Section | Annual Meeting

Montana Section 2013 Annual Conference

Great Falls, MT
May 07 – May 07, 2013

Miscellaneous | Speciality Conferences

SCMA SWAT Training For Operators Workshop

Granbury, TX
May 08 – May 10, 2013

AWWA Section | Annual Meeting

Hawaii Section 2013 Annual Conference

Honolulu, HI

 

May 08 – May 10, 2013

AWWA Section | Section Conference

Pacific Northwest Section 2013 Annual Conference

Spokane, WA
May 08 – May 10, 2013

Miscellaneous | Seminar

Inspection and Assessment of Dams

Seattle, WA
May 09 – May 09, 2013

Miscellaneous | Miscellaneous

Watershed Planning – Putting the Pieces Together

Milwaukee, WI
May 09 – May 09, 2013

Miscellaneous | Miscellaneous

Smart Water for Smart Cities – A Workshop

Ellicot City, MD
May 09 – May 09, 2013

Miscellaneous | Speciality Conferences

SCMA I Scream, You Scream, We All Scream For Membranes Workshop

Tuttle, OK
May 16 – May 17, 2013

Miscellaneous | Annual Meeting

Water and Agriculture

Palos Verdes, CA
May 19 – May 22, 2013

AWWA Section | Section Conference

West Virginia Section 2013 Annual Conference

Daniels, WV
May 20 – May 20, 2013

Miscellaneous | Speciality Conferences

AMTA/SEDA Joint Technology Transfer Workshop “Application of Membrane Technologies in the Chesapeake Region”

Chesapeake, VA
May 21 – May 23, 2013

Miscellaneous | Miscellaneous

Appalachian Underground Corrosion Short Course (AUCSC 2013)

Morgantown, WV
May 22 – May 24, 2013

AWWA Section | Annual Meeting

Connecticut Section 2013 Annual Conference

Saratoga Springs, NY
May 30 – May 30, 2013

Miscellaneous | Miscellaneous

Water Law for Sustainable Management

Milwaukee, WI
Jun 09 – Jun 13, 2013

AWWA | Annual Meeting

2013 Annual Conference & Exposition

Denver, CO
Jun 24 – Jun 25, 2013

Miscellaneous | Speciality Conferences

2013 AWRA Summer Specialty Conference Environmental Flows

Hartford, CT
Jul 09 – Jul 10, 2013

AWWA | Speciality Conferences

NWMOA MBR Operator Training Workshop

Pendleton, OR
Aug 04 – Aug 04, 2013

Miscellaneous | Annual Meeting

Association of Clean Water Administrators

Sante Fe, NM
Sep 08 – Sep 12, 2013

Miscellaneous | Speciality Conferences

Dam Safety 2013

Providence, RI
Sep 09 – Sep 12, 2013

AWWA Section | Annual Meeting

Virginia Section 2013 Annual Conference

Richmond, VA
Sep 10 – Sep 13, 2013

AWWA Section | Section Conference

Michigan Section 2013 Annual Conference

Lansing, MI
Sep 11 – Sep 13, 2013

AWWA Section | Section Conference

Intermountain Section AWWA

Sun Valley, Idaho
Sep 15 – Sep 18, 2013

Miscellaneous | Symposium

North American Membrane Society 23rd Annual Meeting

Denver
Sep 15 – Sep 18, 2013

Miscellaneous | Symposium

28th Annual WateReuse Symposium

Denver, Colorado
Sep 15 – Sep 18, 2013

AWWA | Speciality Conferences

2013 DSS/Emergency Preparedness and Security Conf.

Itasca, IL
Sep 22 – Sep 25, 2013

Miscellaneous | Annual Meeting

World Congress 2013

Las Vegas, NV
Sep 23 – Sep 25, 2013

Miscellaneous | Annual Meeting

NWMOA 1st Annual Symposium – “Getting the Best from Your Membrane Treatment Plant”

Vancouver, WA
Sep 29 – Oct 03, 2013

Miscellaneous | Speciality Conferences

84th Annual Education and Business Conference

Kansas City, MO
Oct 01 – Oct 03, 2013

Miscellaneous | Speciality Conferences

NRWA WaterPro Conference

Seattle, WA
Oct 02 – Oct 04, 2013

Miscellaneous | Speciality Conferences

6th WaterSmart Innovations Conference and Exposition

Las Vegas, NV
Oct 13 – Oct 15, 2013

AWWA Section | Section Conference

Alabama-Mississippi Annual Conference

Tunica Resorts, MS
Nov 03 – Nov 07, 2013

AWWA | Speciality Conferences

2013 Water Quality Technology Conference

Long Beach, CA
Nov 04 – Nov 08, 2013

Miscellaneous | Miscellaneous

2013 Irrigation Show & Education Conference

Austin

 

 

Water Industry Associations

 

American Fisheries Society

2. The Chlorine Institute
3. Conservation International
4. Environmental Assessment Association
5. Environmental Council of the States
6. Environmental Law Institute
7. The Groundwater Foundation
8. Ground Water Protection Council
9. Institute of Professional Environmental Practice

10.Irrigation Association

11.NARUC Committee on Water

12.National Association of Conservation Districts

13.National Association of Counties

14.National Association of Environmental Professionals

15.National Association of Pipe Fabricators

16.National Association of Water Companies

17.National Council for Science and the Environment

18.National Drinking Water Clearinghouse

19.National Drought Mitigation Center

20.National Federation of Municipal Analysts

21.National Fire Protection Association

22.National Ground Water Association
National Institute for the Environment

23.National Institutes for Water Resources

24.National Rural Water Association

25.National Small Flows Clearinghouse

26.National Water Research Institute - Canada.

27.National Water Resources Association

28.Renewable Natural Resources Foundation

29.Soil and Water Conservation Society

30.State Water Resources Research Institutes

31.Water and Wastewater Equipment Manufacturers Association

 

 

American Filtration and Separations Society (AFS)
The premier organization in North America dedicated to R&D, problem solutions and technology transfer in fluid-particle separation for the benefit of industrial processes, individual health and a clean environment.

 

American Ground Water Trust is a nonprofit educational organization dedicated to promoting efficient and effective ground water management and provides educational information about ground water issues that are important to well owners.www.agwt.org

 

American Institute of Hydrology

 

American Public Works Association

 

American Society of Irrigation Consultants

 

American Water Resources Association

 

American Water Works Association (AWWA)

 

Association of Metropolitan Water Agencies

 

Association of Metropolitan Sewerage Agencies

 

Association of State Drinking Water Administrators

 

Association of State and Interstate Water Pollution Control Administrators

 

Association of Water Technologies

 

AWWA Research Foundation

California Water Operators Association (CWOA)
A professional association dedicated to helping water and wastewater operators in California thru education, public policy, wages, benefits, training.

Caribbean Water and Wastewater Association (CWWA)
The CWWA encourages the study, research and development in water supply and wastewater disposal, and the publication of the results of such work, so as to provide for appropriate and dynamic technological advances in the Caribbean.

Florida Water and Pollution Control Operators Association, Region 8
One of the leading water and wastewater professional training organizations in Florida for over 5,000 professionals that work in the public, private and government utilities.

Instrument Society of America (ISA)
The international society for measurement, control, instrumentation and automation.

 

International Bottled Water Association is the authoritative source of information about all types of bottled waters.

www.bottledwater.org

Regional Bottled Water Associations:
NEBWA – Northeastern Bottled Water Association
SEBWA – Southeastern Bottled Water Association
MABWA – Mid-America Bottled Water Association
CSBWA – Central States Bottled Water Association
NWBWA – Northwestern Bottled Water Association
CBWA – Canadian Bottled Water Association

International Private Water Association (IPWA)
Promoting private sector participation in water utilities.

The Irrigation Association (IA)
Formed more than 50 years ago to improve the products and practices used to manage water resources and to help shape the worldwide business environment of the irrigation industry.

Kentucky Water & Wastewater Operators Association (KWWOA)
A not-for-profit association organized in the fall of 1958.  The KWWOA was created by a group of operators from the drinking and wastewater industry.

Maine Lagoon Systems
The mission of the Maine Lagoon Systems website is to promote clean water resources through the enhanced communication of wastewater lagoon system operators in the state of Maine and beyond.

Maine Wastewater Control Association (MWCA)
An association of over 650 members consisting of municipal and industrial operators, consultants, students, and regulatory officials. The purpose is to facilitate communication of ideas and the preservation of Maine’s waterways.

Measurement, Control and Automation Association   (MCAA)

NAWC (National Association of Water Companies)

http://www.nawc.org/

 

National Ground Water Association (NGWA) is a trade association for ground water professionals including well drillers, pump installers, geologists and other scientists to promote responsible development, use and management of ground water resources. www.ngwa.org

 

National Institute for the Environment

 

National Institutes for Water Resources

 

National Rural Water Association
National Small Flows Clearinghouse
Helping America’s small communities meet their wastewater needs.

 

National Water Research Institute - Canada.

 

National Water Resources Association
Northeast Rural Water Association (NeRWA)
Started in 1982, a nonprofit association of water and wastewater systems in Massachusetts, New Hampshire, and Vermont. Among its many services, We offer training and onsite technical assistance to operators, managers, owners and boards.

South Carolina Rural Water Association (SCRWA)
Providing free training to water and wastewater operators in South Carolina, through cooperative agreements with NRWA and USEPA. Offering vendors opportunities to network with utility companies in our state. Offering utilities assistance with water & wastewater issues from an operational to a managerial level.

 

Water and Wastewater Equipment Manufacturers Association

http://www.wwema.org/

Water Design-Build Council (WDBC)
The Water Design-Build Council supports the development and rehabilitation of the nation’s municipal water and wastewater systems by using the design-build project delivery method.  Our mission is to promote best practices for design-build to facilitate productive and collaborative relationships between service providers and governments.

 

Water Education Foundation

 

Water Environment Federation (WEF)
Founded in 1928, the Water Environment Federation (WEF) is a not-for-profit technical and educational organization with members from varied disciplines who work toward the WEF vision of preservation and enhancement of the global water environment.

 

Water Environment Research Foundation

 

Water Environment WEB - Water Environment Federation

 

Water Industry Council

 

Water Organizations - [UWIN]

 

Water Quality Association (WQA)
A not-for-profit international trade association representing the residential, commercial, industrial, and small community water treatment industry. WQA maintains a close dialogue with other organizations representing different aspects of the water industry in order to best serve consumers, government officials, and industry members.

 

 

 

Regional Water Quality Associations:
EWQA – Eastern Water Quality Association
FWQA – Florida Water Quality Association
Missouri WQA – Missouri Water Quality Association
PWQA – Pacific Water Quality Association
TWQA – Texas Water Quality Association

 

 

 

Water Utility Benchmarking Association

 

The Watershed Management Council

 

Industry Publications:

Water Quality Products
www.wqpmag.com

Water Technology
www.watertechonline.com

Water Conditioning and Purification
www.wcponline.com

Food Processing Magazine
www.foodprocessing.com

ALN Magazine
www.alnmag.com

The Bottled Water Reporter
www.ibwa.org

 

Journal of Hydroinformatics

Journal of Water and Health

Journal of Water and Climate Change

Journal of Water Reuse and Desalination

Journal of Water Sanitation and Hygiene for Development

Journal of Water Supply: Research and Technology-AQUA

Hydrology Research

Water21

Water Asset Management International

Water Practice and Technology

Water Policy

Water Quality Research Journal of Canada

Water Research

Water Science and Technology

Water Science and Technology: Water Supply

 

Water Systems Council is a national nonprofit organization focused solely on household wells and small water well systems.

www.watersystemscouncil.org

Water Utility Management International

Water Intelligence Online
Government Information Sources

EPA Safe Drinking Water Act List of Primary and Secondary Contaminants, Health Effects, and Sources:

www.epa.gov/safewater/mcl.html

 

US Water Partnership: Department of State

http://www.state.gov/e/oes/rls/fs/2012/186581.htm

 

US Department of the Interior: Water Challenges

http://www.doi.gov/whatwedo/water/index.cfm

 

US Army Corps of Engineers: Water Resources Development

http://www.usace.army.mil/About/History/BriefHistoryoftheCorps/WaterResourcesDevelopment.aspx

 

Water Resources of the United States
http://water.usgs.gov

 

USGS Water Data for the Nation
http://waterdata.usgs.gov/nwis

 

National Water Quality Assessment Program
http://water.usgs.gov/nawqa/

 

US Bureau of Reclamation
http://www.usbr.gov

 

United States Environmental Protection Agency Water Resources
http://water.epa.gov

 

National Climatic Data Center
http://www.ncdc.noaa.gov/

 

National Water and Climate Center
http://www.wcc.nrcs.usda.gov/

 

US Drought Portal
http://www.drought.gov/drought/

 

CDC Healthy Water Portal
http://www.cdc.gov/healthywater/

 

 

Water Industry Training

 

Water Industry Whitepapers and Information

NAWC

http://www.nawc.org/knowledge-center/documents-and-publications/all-document.aspx

 

The Water and Wastewater Online Training Center is a virtual campus providing quality and targeted online training to meet the information needs of the water and wastewater treatment professional.

http://www.waterandwastewater.com/online_training/

 

Texas A&M Engineering Extension Service (Water and Wastewater)

http://www.teex.org/teex.cfm?pageid=EUprog&area=EU&templateid=1268

 

EPA Small Water Systems Training & Technical Assistance Grant

NO-COST EPA Safe Drinking Water Act Training

http://teexweb.tamu.edu/teex-third.cfm?area=EU&templateid=478

 

The Office of Water Programs at the California State University, Sacramento, College of Engineering and Computer Science provides distance learning courses for persons interested in the operation and maintenance of drinking water and wastewater facilities.

http://www.owp.csus.edu/courses/catalog.php

 

Kansas Basics Course for Small Public Drinking Water Systems

http://www.waterhelp.org/ks/kdhe/

 

WEF offers online education and webcasts here:

http://www.wef.org/onlineeducation/default.aspx

 

Water Industry Training Specialists are a California Corporation in the business of training and certifying Backflow Technicians and Cross-Connection Control Inspectors. 

https://www.backflowschool.com/

 

Environmental-Expert.com hosts several courses from different companies in industrial wastewater, water treatment, and environmental engineering.

http://www.environmental-expert.com/training/keyword-industrial-wastewater-182

 

Plumbing Engineer

http://www.plumbingengineer.com/white.php

 

Bitpipe.com

http://www.bitpipe.com/tlist/Utilities-Industry.html

 

Water-Technology.net

http://www.water-technology.net/downloads/whitepapers/

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Pool Draining Tips to Protect Water Quality – MyronLMeters.com

TweetMyronLMeters.com has the most advanced lineup of pool analysis meters for the professional pool maintenance technician from the Ultrapen to the PoolPro PS9. Pool Draining Tips to Protect Water Quality With summer right around the corner, many swimming pool owners will be readying their swimming pools in anticipation of the season’s heat. As part of [...]

MyronLMeters.com has the most advanced lineup of pool analysis meters for the professional pool maintenance technician from the Ultrapen to the PoolPro PS9.

Pool Draining Tips to Protect Water Quality

With summer right around the corner, many swimming pool owners will be readying their swimming pools in anticipation of the season’s heat. As part of this process, some pool owners like to drain old swimming pool water which has been sitting all winter. Though not a necessary task, the following tips are provided for you to properly drain pool water in order to protect the water resources in your community.

Whenever possible, it is best to drain your pool onto your landscape. This recycles your pool water, conserves irrigation water, and avoids the environmental risks associated with draining your pool to the street. Before draining your pool water to the street or to your landscape, be sure to follow the guidelines outlined below.

While draining pool water to the street is a common practice, it can prove harmful to the environment if the pool owner does not properly plan and prepare prior to draining. When pool water is drained to the street, it can carry other pollutants such as oil, grease, sediment, bacteria and trash down the storm drain and into the nearest creek, river, or the ocean. Swimming pool water also often contains harmful additives and chemicals. If the water is not properly treated to remove these pollutants prior to draining, they can cause further damage to the health of our waterways and to the plants and animals that live there.

Also, prior to draining to the street, residents are asked to sweep the curb and gutter between the discharge point from their yard to the storm drain down hill from their home. This will remove any pollutants from the gutter that may be carried up by the drained pool water to the storm drain.

For chlorine pools, chlorine levels must be lowered to less than 1 part per million prior to draining. This can be done naturally, by simply allowing the pool water to sit in the sun for a minimum of three days. Alternatively, de-chlorination kits can be purchased at home supply stores at a very reasonable cost. These kits have the tools you need to reach the appropriate chlorine levels before draining your pool to the curb and gutter.

Some people have salt water pool systems which may be preferred due to the lower amount of chemicals required for their operation. However, these pools must not be drained to the storm drain system due to their high salt content relative to the fresh water systems they drain into. Total dissolved solids (TDS) must be below 500 parts per million in order to drain into the street.

“Green pools,” which are pools in which algae is growing, also must not be drained to the street. In these instances, algae must first be killed and removed. This is usually done by chlorinating the swimming pool until the algae is gone, then lowering chlorine to the allowable discharge level. Cartridge filters or diatomaceous earth (DE) filters should be rinsed onto a pervious surface such as landscaped areas or grass. While DE is actually beneficial in your garden, it can build up in storm drains and clog them. DE residues can be scooped up and simply thrown in the trash or put to use fending off worms in your garden.

For more information on how to reach acceptable chemical and TDS levels, call your pool maintenance specialist.

If you are a pool maintenance specialist, consider the PoolPro PS9TKA from MyronLMeters.com – the most advanced and comprehensive pool water analysis meter on the market.

 

 

 

 

 

 

 

 

 

Pool Pro PS9TK

Measures 9 Parameters: Conductivity, Mineral/Salts, TDS, Alkalinity, Hardness, LSI, pH, ORP/Free Chlorine, Temperature
LSI Calculator for hypothetical water balance calculations
Wireless data transfer capability with bluDock option
Auto-ranging delivers increased resolution across diverse applications
Adjustable Temperature Compensation and Cond/TDS conversion ratios for user-defined solutions
Nonvolatile memory of up to 100 readings for stored data protection
Date & time stamp makes record-keeping easy
pH calibration prompts alert you when maintenance is required
Auto-off minimizes energy consumption
Low battery indicator
(Includes instrument with case and solutions)

Peat Water Treatment Using Combination of Cationic Surfactant Modified Zeolite, Granular Activated Carbon, and Limestone

Tweet MyronLMeters.com attempts to provide its customers with the latest in water quality research and industry updates. Find more at https://www.myronlmeters.com/. Abstract This research was conducted essentially to treat fresh peat water using a series of adsorbents. Initially, the characterization of peat water was determined and five parameters, including pH, colour, COD, turbidity, and iron ion [...]

 

The serial sequence arrangements of adsorbents were conducted as shown in Figure 1 below. Effluent samples were collected at various time intervals, whilst maintaining room temperature, and analysed.

 

 

 

The pH of the system exerts profound influence on the adsorptive uptake of adsorbate molecules presumably due to its influence on the surface properties of the adsorbent and ionization or dissociation of the adsorbate molecule. Figure 2(b) represents the percentage removal of natural zeolite and CSMZ where they reach optimum efficiency in removing organic compound (COD) at pH 2 with efficiency of 53% and 60% respectively. Meanwhile, the highest percentage removal of COD for GAC was achieved at pH 4 with efficiency obtained about 61%. Identical trends in colour removal were exhibited in percentage removal of COD for natural zeolite, CSMZ and GAC. In fact, this result also reveals that GAC has the highest percentage removal among natural zeolite and CSMZ yet optimum in difference pH solution. Neutralization mechanism occurs in low pH makes color removal, COD removal and Turbidity removals at pH 2 are higher for most of absorbents in this process.

 

Figure 3(a) displays the relationship between the amount of adsorbent mass (dosage) and adsorption efficiency for natural zeolite and CSMZ in terms of removing colour. The colour removal of peat water increased from about 25% to 52% with increasing adsorbent dosage of natural zeolite from 0.5 g to 3.5 g whereas for CSMZ, removal percentage increased from 41% to 53% with increasing adsorbent dosage from 0.5 g to 2.0 g. However, further increase in adsorbent dosage to 5.0 g only led to slight degradation of removal efficiency to 50% and 41% for natural zeolite and CSMZ respectively. This degradation with further increases in adsorbent dosage was due to the unsaturated adsorption active sites during the adsorption process since the adsorbates in the vessel were only shaken for 20 minutes (insufficient time). Besides, modification of zeolite by cationic surfactant had proven to have better colour removal as presented in the graph.

The results from Figure 4(b) indicated that increasing the GAC dosage would increase the efficiency in removing COD respectively. The optimum dosage was recorded at 3.0 g with 72% of removal efficiency. Meanwhile, increasing the dosage above 3.0 g exhibited a slight decrease in removal efficiency with 67% to 61% for COD removal. A better result in removing COD was also shown by GAC compared to the natural zeolite and CSMZ.

 

On the second running, the column was packed with CSMZ (1st layer), limestone (2nd layer), and GAC (3rd layer) as presented in Figure 5(b). The removal percentages of colour, COD, turbidity, and iron ion were noticed after 1 hour to be 52%, 49%, 71%, and 30% respectively. The time of contact between adsorbate and adsorbent is proven to play an important role during the uptake of pollutants from peat water samples by adsorption process. In addition, the development of charge on the adsorbent surface was governed by contact time and hence the efficiency and feasibility of an adsorbent for its use in water pollution control can also be predicted by the time taken to attain its equilibrium (Sharma, 2003). Removal efficiency of 90% for colour, 81% for COD, 91% for turbidity, and 57% for iron ion were obtained at 24 hours of contact time.

References

 

Paune, F., Caixach, J., Espadaler, I., Om, J., & Riveraet, J. (1998). Assessment on the removal of organic chemicals from raw and drinking water at a Llobregat river water works plant using GAC. Water Research, 32(11), 3313-3324. http://dx.doi.org/10.1016/S0043-1354(98)00108-0

Rieley, J. O. (1992). The ecology of tropical peatswamp forest ± a South-east Asian perspective. In Tropical Peat, Proceedings of International Symposium on Tropical Peatland, Kuching, Sarawak, Malaysia, 6±10 May 1991

(B.Y.  Aminuddin, ed.) pp.  244±54. Kuching, Malaysia:  Malaysia  Agricultural Research  Development Institute & Department of Agriculture, Sarawak, Malaysia

Syafalni, S., Abustan, I., Dahlan, I., & Wah, C. K. (2012b). Treatment of Dye wastewater Using Granular Activated Carbon and  Zeolite  Filter. Modern Applied Science,  6(2), 37-51. http://dx.doi.org/10.5539/mas.v6n2p37

Syafalni, S., Abustan, I., Zakaria, S. N. F., & Zawawi, M. H. (2012a). Raw water treatment using bentonite-chitosan as a coagulant. Water Science & Technology: Water Supply, 12(4), 480-488. http://dx.doi.org/10.2166/ws.2012.016

Torresdey, J. L., Tang, L., & Salvador, J. M. (1996). Copper adsorption by esterified and unesterified fractions of sphagnum peat moss and its different humic substances. Journal of Hazardous Materials, 48,  191-206. http://dx.doi.org/10.1016/0304-3894(95)00156-5

World Wildlife Fund (WWF) Malaysia. (2004). The importance of rivers.

Wosten, J. H. M., Clymans, E., Page, S. E., Rieley, J. O., & Limin, S. H. (2008). Peat- Water interrelationships in a          Tropical Peatland Ecosystem in Southeast Asia. Catena, 73, 212-224. http://dx.doi.org/10.1016/j.catena.2007.07.010

Zhang, P., Tao, X., Li, Z., & Bowman, R. S. (2002). Enhanced Perchloroethylene Reduction in Column Systems Using Surfactant Modified Zeolite/zero-valent Iron Pellets. Environmental Science and Technology, 36, 3597-3603. http://dx.doi.org/10.1021/es015816u

Modern Applied  Science;  Vol.  7,  No.  2;  2013

ISSN 1913-1844     E-ISSN 1913-1852

Published by Canadian Center of Science and Education

S. Syafalni1, Ismail Abustan1, Aderiza Brahmana1, Siti Nor Farhana Zakaria1 & Rohana Abdullah1

1 School of Civil Engineering, Engineering Campus, Universiti Sains Malaysia, Nibong Tebal, Penang, Malaysia. Correspondence:  S. Syafalni,  School of Civil Engineering, Engineering Campus,  Universiti Sains Malaysia,

Nibong Tebal 14300, Penang, Malaysia. E-mail: cesyafalni@eng.usm.my

Received: December 3, 2012        Accepted: January 14, 2013        Online Published: January 22, 2013 doi:10.5539/mas.v7n2p39                                                     URL: http://dx.doi.org/10.5539/mas.v7n2p39

Shared via Creative Commons Attribution 3.0 Unported license

 

Conductivity as alternative measurement for WWTP inflow dynamics – MyronLMeters.com

Tweet Myron L Meters Myron L Meters sells the most accurate, reliable conductivity instruments in the water treatment industry.  You can find some of our most popular meters here: http://www.myronlmeters.com/SearchResults.asp?Search=conductivity&x=-1345&y=-145 Introduction Along with the development of  more and more complex integrated models for urban water systems the need of sufficient  data  bases grows as well. [...]

This poster presents a method regarding the possibility of substituting an online ammonia measurement by conductivity measurements in the inflow of a Waste Water Treatment Plant . The aim was the description of the dynamics in wet weather flow through storm water events for modelling purposes.

The conductivity of an aqueous solution is the measure of its ability to conduct electricity. Responsible for that phenomenon are ions of dissolved salts. In natural and drinking water these are mainly carbonates, chlorides and sulphates of calcium, magnesium, sodium and potassium. Conducted experiences and measurements in combined sewers showed a relation between conductivity in Waste Water Treatment Plant inflow and the concentration of dissolved components, e.g. ammonia, in case of rainfall events. The data for different 3 Waste Water Treatment Plant are shown in Figure 1. Rainwater has nearly no ions that cause conductivity to be measured. Therefore, diluted wastewater flowing into the Waste Water Treatment Plant can be detected by a conductivity probe. The measure and quality of linear regression between ammonia concentration and conductivity can be found in Table 1 for all data from Figure 1.

Material and Methods

With this knowledge a simple regression-based inflow model for use in activated sludge modelling of Waste Water Treatment Plant was defined to use conductivity beside available composite samples as a measure for dynamics in ammonia concentration as one of the most dynamic measure.

Results and Discussion

For one of the considered Waste Water Treatment Plants (WWTP) the resulting quality for the inflow model is shown in Figure 2 for a time series of a week.

Furthermore, the inflow model was used as a source for a retention tank model at the inlet of another Waste Water Treatment Plant to describe the impact of different management strategies (storage or flow through) on receiving water and Waste Water Treatment Plant (Figure 3).

A long-term modelling of 9 storm water events was used to show the predictive capacity of the model. The regression parameters were fitted by an optimisation routine to get best fit for all concentrations (also for COD, not presented here). Figure 3 shows the fit for all events. A good prediction of dynamics and absolute values for ammonia can be seen.

The results of different Goodness-of-fit measures are summarized in Table 2 for both presented WWTP inflows. Especially the values for the modified Coefficient of Efficiency, as a well-known and used measure for model quality in hydrological sciences, show the degree of predicting of the used method and the usability of conductivity for description of influent dynamics to Waste Water Treatment Plant in storm water cases.

 Conclusions

This simple and easy-to-use method is well suited for implementation in Waste Water Treatment Plant models to describe the inflow dynamics regarding a more realistic behavior e.g. for optimization of process control.

by Markus Ahnert*, Norbert Günther*, Volker Kuehn*, University of Dresden 

References
Ahnert, M., Blumensaat, F., Langergraber, G., Alex, J., Woerner, D., Frehmann, T., Halft, N., Hobus, I., Plattes, M., Spering, V. und Winkler, S. (2007), Goodness-of-fit measures for numerical modelling in urban water management – a summary to support practical applications., paper presented at 10th IWA Specialised Conference on “Design, Operation and Economics of Large Wastewater Treatment Plants”, 9-13 September 2007, Vienna, Austria, 9-13 September 2007.

Nash, J. E. und Sutcliffe, J. V. (1970), River flow forecasting through conceptual models part I – A discussion of principles, Journal of Hydrology, 10, 282.

 

The thermal conductivity enhancement of nanofluids – MyronLMeters.com

TweetThe thermal conductivity enhancement of nanofluids  Abstract Increasing interests have been paid to nanofluids because of the intriguing heat transfer enhancement performances presented by this kind of promising heat transfer media. We produced a series of nanofluids and measured their thermal conductivities. In this article, we discussed the measurements and the enhancements of the thermal [...]

The thermal conductivity enhancement of nanofluids

 Abstract

Increasing interests have been paid to nanofluids because of the intriguing heat transfer enhancement performances presented by this kind of promising heat transfer media. We produced a series of nanofluids and measured their thermal conductivities. In this article, we discussed the measurements and the enhancements of the thermal conductivity of a variety of nanofluids. The base fluids used included those that are most employed heat transfer fluids, such as deionized water (DW), ethylene glycol (EG), glycerol, silicone oil, and the binary mixture of DW and EG. Various nanoparticles (NPs) involving Al₂O₃ NPs with different sizes, SiC NPs with different shapes, MgO NPs, ZnO NPs, SiO₂ NPs, Fe₃O₄ NPs, TiO₂ NPs, diamond NPs, and carbon nanotubes with different pretreatments were used as additives. Our findings demonstrated that the thermal conductivity enhancements of nanofluids could be influenced by multi-faceted factors including the volume fraction of the dispersed NPs, the tested temperature, the thermal conductivity of the base fluid, the size of the dispersed NPs, the pretreatment process, and the additives of the fluids. The thermal transport mechanisms in nanofluids were further discussed, and the promising approaches for optimizing the thermal conductivity of nanofluids have been proposed.

More efficient heat transfer systems are increasingly preferred because of the accelerating miniaturization, on the one hand, and the ever-increasing heat flux, on the other. In many industrial processes, including power generation, chemical processes, heating or cooling processes, and microelectronics, heat transfer fluids such as water, mineral oil, and ethylene glycol always play vital roles. The poor heat transfer properties of these common fluids compared to most solids is a primary obstacle to the high compactness and effectiveness of heat exchangers[1]. An innovative way of improving the thermal conductivities of working media is to suspend ultrafine metallic or nonmetallic solid powders in traditional fluids since the thermal conductivities of most solid materials are higher than those of liquids. A novel kind of heat transfer enhancement fluid, the so-called nanofluid, has been proposed to meet the demands [2].

“Nanofluid” is an eye-catching word in the heat transfer community nowadays. The thermal properties, including thermal conductivity, viscosity, specific heat, convective heat transfer coefficient, and critical heat flux have been studied extensively. Several elaborate and comprehensive review articles and books have addressed thermal transport properties of nanofluids [1,3-6]. Among all these properties, thermal conductivity is the first referred one, and it is believed to be the most important parameter responsible for the enhanced heat transfer. Investigations on the thermal conductivity of nanofluids have been drawing the greatest attention of the researchers. A variety of physical and chemical factors, including the volume fraction, the size, the shape, and the species of the nanoparticles (NPs), pH value and temperature of the fluids, the Brownian motion of the NPs, and the aggregation of the NPs, have been proposed to play their respective roles on the heat transfer characteristics of nanofluids [7-19]. Extensive efforts have been made to improve the thermal conductivity of nanofluids [7-19] and to elucidate the thermal transport mechanisms in nanofluids [20-23].

The authors have carried out a series of studies on the heat transfer enhancement performance of nanofluids. A variety of nanofluids have been produced by the one- or two-step method. The base fluids used include deionized water (DW), ethylene glycol (EG), glycerol, silicone oil, and the binary mixture of DW and EG (DW-EG). Al₂O₃ NPs with different sizes, SiC NPs with different shapes, MgO NPs, ZnO NPs, SiO₂ NPs, Fe₃O₄ NPs, TiO₂ NPs, diamond NPs (DNPs), and carbon nanotubes (CNTs) with different pretreatments have been used as additives. The thermal conductivities of these nanofluids have been measured by transient hot wire (THW) method or short hot wire (SHW) technique. In this article, the experimental results that elucidate the influencing factors for thermal conductivity enhancement of nanofluids are presented. The thermal transport mechanisms in nanofluids and promising approaches for optimizing the thermal conductivity of nanofluids are further presented.

Two techniques have been applied to prepare nanofluids in our studies: two- and one-step techniques. Most of the studied nanofluids were prepared by the two-step technique. During the procedure of two-step technique, the dispersed NPs were prepared by chemical or physical methods first, and then the NPs were added into a specified base fluid, with or without pretreatment and surfactant based on the need. In the preparation of nanofluids containing metallic NPs, one-step technique was employed.

The process was quite simple in the preparation of nanofluids containing oxide NPs like Al₂O₃, ZnO, MgO, TiO₂, and SiO₂ NPs. The NPs were obtained commercially and were dispersed into a base fluid in a mixing container. The NPs were deagglomerated by intensive ultrasonication after being mixed with the base fluid, and then the suspensions were homogenized by magnetic force agitation.

Two-step method was used to prepare graphene nanofluids. The first step was to prepare graphene nanosheets. Functionalized graphene was gained through a modified Hummers method as described elsewhere [24]. Graphene nanosheets were obtained by exfoliation of graphite in anhydrous ethanol. The product was a loose brown powder, and it had good hydrophilic nature. The graphene nanosheets could be dispersed well in polar solvents, like DW and EG, without the use of surfactant. For liquid paraffin (LP)-based nanofluid, oleylamine was used as the surfactant. The fixed quality of graphene nanosheets with different volume fractions was dispersed in the base fluids.

Severe aggregation always takes place in the as-prepared CNTs (pristine CNTs: PCNTs) because of the non-reactive surfaces, intrinsic Von der Waals forces, and very large specific surface areas, and aspect ratios [25]. In CNT nanofluid preparations, surfactant addition is an effective way to enhance the dispersibility of CNTs [26-28]. However, surfactant molecules attaching on the surfaces of CNTs may enlarge the thermal resistance between the CNTs and the base fluid [29], which limits the enhancement of the effective thermal conductivity. The steps involved in the preparation of surfactant-free CNT nanofluids include (1) disentangling the nanotube entanglement and introducing hydrophilic functional groups on the surfaces of the nanotubes by chemical treatments; (2) cutting the treated CNTs (TCNTs) to optimal length by ball milling; and (3) dispersing the treated and cut CNTs into base fluids. CNTs including single-walled CNTs (SWNTs), double-walled CNTs (DWNTs), and multi-walled CNTs (MWNTs) were obtained commercially. Two chemical routes for treating CNTs were used for this study. One is oxidation with concentrated acid, and the other is mechanochemical reaction with potassium hydroxide (KOH). The detailed treatment processes have been described elsewhere [8,30].

Phase transfer method was used to prepare stable kerosene-based Fe₃O₄ magnetic nanofluid. The first step is to synthesize Fe₃O₄ NPs in water by coprecipitation. Oleic acid was added to modify the NPs. When kerosene is added to the mixture with slow stirring, the phase transfer process took place spontaneously. There was a distinct phase interface between the aqueous and kerosene. After the removal of the aqueous phase using a pipette, the kerosene-based Fe₃O₄ nanofluid was obtained [31].

Nanofluids containing copper NPs were prepared using direct chemical reduction method. Stable nanofluids were obtained with the addition of poly(vinylpyrrolidone) (PVP). The diameters of copper NPs prepared by chemical reduction procedure are in the range of 5-10 nm, and copper NPs disperse well with no clear aggregation [32].

Surface modification is always used to enhance the dispersibility of NPs in the preparation of nanofluids. For example, diamond NPs (DNPs) were purified and surface modified by acid mixtures of perchloric acid, nitric acid and hydrochloric acid according to the literature [33] before being dispersed into the base fluids. SiC NPs were heated in air to remove the excess free carbon and their surfaces modified to enhance their dispersibility.

Inconsistent experimental results and controversial arguments arise unceasingly from different groups conducting research on nanofluids, indicating the complexity of the thermal transport in nanofluids. Through an investigation, a large degree of randomness and scatter have been observed in the experimental data published in the open literature. Given the inconsistency in the data, it is impossible to develop a convincing and comprehensive physical-based model that can predict all the trends. To clarify the suspicion on the scattered and wide-ranging experimental results of the thermal conductivity obtained by different groups, it is preferred to screen the measurement technique and procedure to guarantee the accuracy of the obtained results.

Several researchers observed the “time-dependent characteristic” of thermal conductivity [34-36], that is to say, thermal conductivity was the highest right after nanofluid preparation, and then it decreased considerably with elapsed time. We believe that the “time-dependent characteristic” does not represent the essence of thermal conduction capability of nanofluids. The following two factors may account for this phenomenon. The first one is the motion of the remained particle caused by the agitation during the nanofluid preparation. To make a nanofluid homogeneous and long-term stable, it is always subjected to intensive agitation including magnetic stirring and sonication to destroy the aggregation of the suspended NPs. In very short time after nanofluid preparation, the NPs still keep moving in the base fluid (different from Brownian motion). The motion of the remained particle would cause convection and enhance the energy transport in the nanofluids. Second, when a nanofluid is subjected to long-time sonication, its temperature would be increased. The temperature goes down gradually to the surrounding temperature (thermal conductivity measurement temperature). In very short time after the sonication stops, the process has been remaining. Although the temperature decrease is not severe, the thermal conductivity obtained is very sensitive to the temperature decrease when the transient hot-wire technique is used to measured the thermal conductivity. In our measurements, this phenomenon would be observed. When measuring the thermal conductivity at an unequilibrium state, it was found that the measured data might be very different for a nanofluid even at a specific temperature (see 25°C) if the process to reach this temperature is different. If the temperature is increasing, then the datum obtained of the thermal conductivity would be lower than the true value. While the temperature is decreasing, the datum obtained of the thermal conductivity would be higher than the true value. Therefore, keeping a nanofluid stable and initial equilibrium is very important to obtain accurate thermal conductivity data in measurements.

A transient short hot-wire method was used to measure the thermal conductivities of the base fluids (k₀) and the nanofluids (k). The detailed measurement principle, procedure, and error analysis have been described in [37]. In our measurements, a platinum wire with a diameter of 50 μm was used for the hot wire, and it served both as a heating unit and as an electrical resistance thermometer. The platinum wire was coated with an insulation layer of 7-μm thickness. Initially the platinum wire immersed in media was kept at equilibrium with the surroundings. When a regulation voltage was supplied to initiate the measurement, the electrical resistance of the wire changed proportionally with the rise in temperature. The thermal conductivity was calculated from the slope of the rise in the wire’s temperature against the logarithmic time interval. The uncertainty of this measurement is estimated to be within ± 1.0%. A temperature-controlled bath was used to maintain different temperatures of the nanofluids. Instead of monitoring the temperature of the bath, a thermocouple was positioned inside the sample to monitor the temperature on the spot. When the temperature of the sample reached a steady value, the authors waited for further 20 min to make sure that the initial state is at equilibrium. At every tested temperature, measurements were made three times and the average values were taken as the final results. A 20-min interval was needed between two successive measurements. After the above-mentioned careful check on the measurement condition and procedure, the authors could gain confidence on the experimental results.

In the experiment of the study, it was found that the thermal conductivity enhancements of nanofluids might be influenced by multi-faceted factors including the volume fraction of the dispersed NPs, the tested temperature, the thermal conductivity of the base fluid, the size of the dispersed NPs, the pretreatment process, and the additives of the fluids. The effects of these factors are presented in this section.

Particle loading

The idea of nanofluid application originated from the fact that the thermal conductivity of a solid is much higher than that of a liquid. For example, the thermal conductivity of the most used conventional heat transfer fluid, water, is about 0.6 W/m · K at room temperature, while that of copper is higher than 400 W/m · K. Therefore, particle loading would be the chief factor that influences the thermal transport in nanofluids. As expected, the thermal conductivities of the nanofluids have been increased over that of the base fluid with the addition of a small amount of NPs. Figure 1 shows the enhanced thermal conductivity ratios of the nanofluids with NPs at different volume fractions [7,8,38-42]. (k - k₀)/k₀ and φ refer to the thermal conductivity enhancement ratio of nanofluids and the volume fraction of NPs, respectively, in this article. Figure1a presents oxide nanofluids, while Figure 1b presents nonoxide nanofluids. The results show that all the nanofluids have noticeable higher thermal conductivities than the base fluid without NPs. In general, the thermal conductivity enhancement increases monotonously with the volume fraction. For the graphene nanofluid with a volume fraction of 0.05, the thermal conductivity can be enhanced by more than 60.0%. There is an approximate linear relationship between the thermal conductivity enhancement ratios and the volume fraction of graphene nanosheets. The nanofluids containing graphene nanosheets show larger thermal conductivity enhancement than those containing oxide NPs. It demonstrates that graphene nanosheet is a good additive to enhance the thermal conductivity of base fluid. However, the enhancement ratios of nanofluids containing graphene nanosheets are less than those of CNTs with the same loading. Many factors have direct influence on the thermal conductivity of the nanofluid. One of the important factors is the crystal structure of the inclusion in the nanofluid. Graphene is a one-atom-thick planar sheet of sp²-bonded carbon atoms that are densely packed in a honeycomb crystal lattice. The perfect structure of graphene is damaged when graphite is chemically oxidized by treatment with strong oxidants. There is no doubt that the high thermal conductivity is diminished by defects, and the defects have direct influence on the heat transport along the 2-D structure.

Figure 1. Thermal conductivity enhancement ratios of the nanofluids as a function of nanoparticle loading. (a) Oxide nanofluids: MgO-EG [38]; Al₂O₃-EG [7]; ZnO-EG [39]; (b) Nonoxide nanofluids: CNT-EG [8]; DNP-EG [40]; Graphene-EG [41]; Cu-EG [42].

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Temperature

Some studies have demonstrated that the temperature has a great effect on the enhancement of the thermal conductivity for nanofluids. However, there is considerable disagreement in the literature with respect to the temperature dependence of their thermal conductivity. For example, Das et al. reported strong temperature-depended thermal conductivity for water-based Al₂O₃ and CuO nanofluids [43]. The thermal conductivity enhancements of nanofluids containing Bi₂Te₃nanorods in FC72 and in oil had been experimentally found to decrease with increasing temperature [44]. Micael et al. measured the thermal conductivities of EG-based Al₂O₃ nanofluids at temperatures ranging from 298 to 411 K. A maximum in the thermal conductivity was observed at all mass fractions of NPs [45].

Figure 2 shows our measured temperature-depended thermal conductivity enhancements of nanofluids [8,38-42]. For EG-based nanofluids containing MgO, ZnO, SiO₂, and graphene NPs, the thermal conductivity enhancements almost remain constant when the tested temperature changes (see Figure 2a), which means that the thermal conductivity of the nanofluid tracks the thermal conductivities of the base liquid in the experimented temperature range of this study. The thermal conductivity enhancements of DW-EG-based nanofluids containing MgO, ZnO, SiO₂, Al₂O₃, Fe₂O₃, TiO₂, and graphene NPs also appear to have the same behavior. It was further found that kerosene-based Fe₃O₄ nanofluids presented temperature-independent thermal conductivity enhancements. Patel et al. [46] reported that the thermal conductivity enhancement ratios of Cu nanofluids are enhanced considerably when the temperature increases. The experimental results of this study shown in Figure 2b demonstrated similar tendency. At 10°C, the thermal conductivity enhancement of EG based Cu nanofluid with 0.5% nanoparticle loading is less than 15.0%. When the temperature is increased to 60°C, the enhancement reaches as large as 46.0%. Brownian motion of the NPs has been proposed as the dominant factor for this phenomenon. For the EG-based CNT nanofluids, cylindrical nanotubes with large aspect ratios were used as additions. The effect of Brownian motion will be negligible. Typical conduction-based models will give (k - k₀)/k₀, independent of the temperature. However, results shown in Figure 2b illustrate that (k - k₀)/k₀increases, though not drastically, with the temperature. CNT aggregation kinetics may contribute to the observed differences [21]. It is worthy of bearing in mind that the temperatures of the base fluid and the nanofluid should be the same when compared with the thermal conductivities between them. Comparison of the thermal conductivities between the nanofluid at one temperature and the base at another one is meaningless.

Figure 2. Thermal conductivity enhancement varying with the tested temperatures. (a) Oxide nanofluids: MgO-EG [38]; ZnO-EG[39]; Graphene-EG [41]; (b) Nonoxide nanofluids: Cu-EG [42]; CNT-EG[8]; DNP-EG [40].

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Base fluid

Figure 3 shows the relation between the enhanced thermal conductivity ratios of the nanofluids and the thermal conductivities of the base fluids [7,8,40,41]. It is clearly seen that no matter what kind of nanoparticle was used, the thermal conductivity enhancement decreases with an increase in the thermal conductivity of the base fluid. For pump oil (PO)-based Al₂O₃ nanofluid with 5.0% nanoparticle loading, the thermal conductivity can be enhanced by more than 38% compared to that of PO. When the base fluid is substituted with water, the thermal conductivity enhancement achieved is only about 22.0% [7]. A greater dramatic improvement in thermal conductivity of CNT nanofluid is seen for a base fluid with lower thermal conductivity. At 1.0% nanoparticle loading, the thermal conductivity enhancements are 19.6, 12.7, and 7.0% for CNT nanofluids in decene, EG, and DW, respectively. No matter what kind of base fluid is used, the thermal conductivity enhancement of CNT nanofluids is much higher than that for Al₂O₃ nanoparticle suspensions [8] at the same volume fraction. The reason would lie in the substantial difference in thermal conductivity and morphology between alumina nanoparticle and carbon nanotube.

Figure 3. Thermal conductivity enhancement ratios as a function of the thermal conductivities of the base fluids: Al2O3 NFs [7]; CNT NFs [8]; Graphene NFs [41]; DNP NFs [40].

Particle size

Figure 4 presents the thermal conductivity enhancement of the nanofluids as a function of the specific surface area (SSA) of the suspended particles [7]. It is seen that the thermal conductivity enhancement increases first, and then decreases with an increase in the SSA, with the largest thermal conductivity at a particle SSA of 25 m² · g^-1. We ascribe the thermal conductivity change behavior to twofold factors. First, as particle size decreases, the SSA of the particle increases proportionally. Heat transfer between the particle and the fluid takes place at the particle-fluid interface. Therefore, a dramatic enhancement in thermal conductivity is expected because a reduction in particle size can result in large interfacial area. Second, the mean free path in polycrystalline Al₂O₃ is estimated to be around 35 nm, which is comparable to the size of the particle that was used. The intrinsic thermal conductivity of nanosized Al₂O₃ particle may be reduced compared to that of bulk Al₂O₃ due to the scattering of the primary carriers of energy (phonon) at the particle boundary. It is expected that the suspension’s thermal conductivity is reduced with an increase in the SSA. Therefore, for a suspension containing NPs at a particle size much different from the mean free path, the thermal conductivity increases when the particle size decreases because the first factor is dominant. However, when the size of the dispersed NPs is close to or smaller than the mean free path, the second factor will govern the mechanism of the thermal conductivity behavior of the suspension.

Figure 4. Enhanced thermal conductivity ratios as a function of the SSAs: Al2O3-EG [7]; Al2O3-PO [7].

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Figure 5 depicts the thermal conductivity enhancements of nanofluids containing CNTs with different sizes [47]. The base fluid is DW, and the volume fraction of the CNTs is 0.0054. It is observed from Figure 5 that the thermal conductivity enhancements show differences among these three kinds of nanofluids containing SWNTs, DWNTs, and MWNTs as the volume fraction of CNTs is the same. Two influencing factors may be addressed. The first one is the intrinsic heat transfer performance of the CNTs. It is reported that the thermal conductivity of CNTs decreases with an increase in the number of the nanotube layer. The tendency of the thermal conductivity enhancement of the obtained CNT nanofluids accords with that of the heat transfer performance of the three kinds of CNTs. The second one is the alignment of the liquid molecules on the surface of CNTs. There are greater number of water molecules close to the surfaces of CNTs with smaller diameter due to the larger SSA if the volume fractions of CNTs are the same. These water molecules can form an interfacial layer structure on the CNT surfaces, increasing the thermal conductivity of the nanofluid [47].

Figure 5. Thermal conductivity enhancements of nanofluids containing CNTs with different sizes: SWNT-DW [47]; DWNT-DW[47]; MWNT-DW [47].

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Pretreatment

In the preparation of nanofluids, solid additives are always subjected to various pretreatment procedures. The initial incentive is to tailor the surfaces of the NPs to enhance their dispersibility, thereby to enhance the stability of the nanofluids. The morphologies would be significantly changed when CNTs were subjected to chemical or mechanical treatments. Theoretical research into the thermal conductivity of composites containing cylindrical inclusions has demonstrated that the morphologies, including the aspect ratio, have influence on the effective thermal conductivity of the composites. Therefore, it can be expected that the thermal conductivity of CNT contained nanofluids would be affected by the pretreatment process.

Figure 6 shows the dependence of the thermal conductivity enhancement on the ball milling time of CNTs suspended in the nanofluids [48]. From theoretical prediction, the thermal conductivity of a composite increases with the aspect ratio of the included solid particles [49-51]. Intuition suggests that increasing the milling time should therefore decrease (k - k₀)/k₀ because of the reduced aspect ratio. Figure 6, however, shows clear peak and valley values in the thermal conductivity enhancement with respect to the milling time for all the studied CNT loadings. For nanofluid at a volume fraction of 0.01, the thermal conductivity enhancements present a peak value of 27.5% and a valley value of 10.4% when the milling times are 10 and 28 h, respectively. The maximal enhancement is intriguingly more than two and half times as the minimal one. Interestingly, when further increased the milling time from 28 to 38 h, (k - k₀)/k₀ increases from the valley value of 10.4 to 12.8%. Though the increment is not pronounced, it illustrates a difference in tendency from that in the milling time range from 10 to 28 h. Temperature-dependent thermal conductivity enhancement data further indicate that, at all the measured temperatures, nanofluid with CNTs milled for 10 h has the largest increment in thermal conductivity. Glory et al. [52] reported that the enhancement of the thermal conductivity noticeably increases when the nanotube aspect ratio increases. However, the thermal conductivity enhancement behavior of our CNT nanofluid is very different and cannot be explained only by the effect of the aspect ratio.

Figure 6. Dependence of the thermal conductivity enhancement on the ball milling time of CNTs suspended in the nanofluids [48].

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The above results suggest other dominant factors that have the influence over the thermal conductivity of the CNT nanofluids. The authors proposed that the nonstraightness and the aggregation would play significantly roles. As is known, the walls of CNTs have similar structure of graphene sheet, and the thermal conductivity of CNTs shows greatly anisotropic behavior. Heat transports substantially quicker through axial direction than through radial direction [53]. For a nonstraight CNT, the high thermal anisotropy of CNTs induces a unique property that individual CNTs are nearly perfect one-dimensional thermal passages with negligibly small heat flux losses during long distance heat conductions [54]. For a nonstraight CNT with length L under a two-end temperature difference, the heat flux q goes through a curled passage. This CNT can be regarded as an equivalent straight thermal passage with a distance of L^e. The same heat flux q is conducted between the two ends of this straight passage. Obviously, the equivalent length L^e depends on the curvature of the actual nanotube in the nanofluid. A concept, straightness ratio η (η = L^e/L), can be adopted to describe the straightness of a curled CNT. The lowest straightness ratio arises when a suspended nanotube forms ring closure [55].

When subjected to ball milling, CNTs were broken and cut short with appropriate average length. The straightness ratio was significantly increased and heat transports more effectively through the CNTs and across the interfaces between the CNT tips and the base fluid, resulting in the highest thermal conductivity enhancement in a nanofluid containing CNTs milled for 10 h. For nanofluids containing relatively straight nanotubes, the influence of the aspect ratio will surpass that of straightness ratio. Therefore, by further treatment on nanotubes with relatively high straightness ratio, the excessive deterioration of the aspect ratio would decrease the thermal conductivity of nanofluids, causing (k - k₀)/k₀ decrease from 10 to 28 h. Recent theoretical analysis has revealed that the aggregation of nanoparticle plays a significant role in deciding (k - k₀)/k₀ [21]. Percolation effects in the aggregates, as highly conducting nanotubes touch each other in the aggregate, help in increasing the thermal conductivity. Our experiments demonstrate that aggregates are the dominant appearance of CNTs when the ball-milling time is increased to 38 h. The aggregation accounts for the increment of thermal conductivity enhancement when the ball-milling time is increased from 28 to 38 h. This result implies that the positive influence of the aggregation surpasses the negative influence of the aspect ratio deterioration.

pH value

For some nanofluids, the pH values of the suspensions have direct effects on the thermal conductivity enhancement. Figure 7 presents the thermal conductivity enhancement ratios at different pH values [7,40]. The results show that the enhanced thermal conductivity increases with an increase in the difference between the pH value of aqueous suspension and the isoelectric point of Al₂O₃ particle [7]. When the NPs are dispersed into a base fluid, the overall behavior of the particle-fluid interaction depends on the properties of the particle surface. For Al₂O₃ particles, the isoelectric point (pH_iep) is determined to be 9.2, i.e., the repulsive forces among Al₂O₃ particles is zero, and Al₂O₃ particles will coagulate together under this pH value. Therefore, when pH value is equal or close to 9.2, Al₂O₃ particle suspension is unstable according to DLVO theory [56]. The hydration forces among particles increase with the increasing difference of the pH value of a suspension from the pH_iep, which results in the enhanced mobility of NPs in the suspension. The microscopic motions of the particles cause micro-convection that enhances the heat transport process. Wensel’s study showed that the thermal conductivity of nanofluids containing oxide NPs and CNTs with very low percentage loading decreased when the pH value is shifted from 7 to 11.45 under the influence of a strong outside magnetic field [14].

Figure 7. Thermal conductivity enhancement ratios at different pH values: Al2O3-DW [7]; DNP-EG [40].

 

 

 

 

 

 

 

 

 

 

 

 

 

 

For DNP-EG nanofluids, it is observed from Figure 7 that the thermal conductivity enhancement increases with pH values in the range of 7.0-8.0. When pH value is above 8.0, there is no obvious relationship between pH value and the thermal conductivity enhancement. In our opinion, the influence of pH value on thermal conductivity is that pH value has a direct effect on the stability of nanofluids. When pH value is below 8.5, the suspension is not very stable, and DNPs are easy to form aggregations. The alkalinity of the solution is helpful to the dispersion and the stability of the nanofluids. In order to verify the above statement, the influence of settlement time on the thermal conductivity enhancement was further investigated. It is found that the thermal conductivity enhancement decreases with elapsed time for DNP-EG nanofluid when pH is 7.0. However, for the stable DNP-EG nanofluids with pH of 8.5, there is no obvious thermal conductivity decrease for 6 months [40].

Surfactant addition

Surfactant addition is an effective way to enhance the stability of nanofluids. Kim’s study revealed that the thermal conductivity decreased rapidly for the instable nanofluids without surfactants after preparation. However, no obvious changes in the thermal conductivity of the nanofluids with sodium dodecyl sulfate (SDS) as surfactant were observed even after 5-h settlement [57]. Assael et al. investigated the thermal conductivities of the aqueous suspension of CNTs. When Sodium dodecyl sulfate (SDS) was employed as the dispersant, the maximum thermal conductivity enhancement obtained was 38.0% for a nanofluid with 0.6 vol% CNT loadings [58]. When the surfactant is substituted with hexadecyltrimethyl ammonium bromide (CTAB), the maximum thermal conductivity enhancement obtained was 34.0% for same fraction of CNT loading [26]. Liu et al. reported that the thermal conductivity of carbon nanotube-synthetic engine oil suspensions is higher compared with that of same suspensions without the addition of surfactant. The presence of surfactant as stabilizer has positive effect on the carbon nanotube-synthetic engine oil suspensions[59].

We used cationic gemini surfactants (12-3(4,6)-12,2Br^-1) to stabilize water-based MWNT nanofluids. These surfactants were prepared following the process described in [60]. Figure 8presents the thermal conductivity enhancement ratios of the CNT-contained nanofluids with different surfactant concentrations. The volume fraction of the dispersed CNTs is 0.1%. The critical micelle concentration of 12-3-12, 2Br^-1 is reported as 9.6 ± 0.3 × 10^-4 mol/l [61]. Ten times critical micelle concentration of 12-3-12, 2Br^-1 is 0.6 wt%. Solutions of 12-3-12, 2Br^-1 with different concentrations (0.6, 1.8, and 3.6 wt% at room temperature) were selected to prepare CNT nanofluids. It is observed that at all the measured temperatures the thermal conductivity enhancement decreases with the surfactant addition. The surfactant added in the nanofluids acts as stabilizer which improves the stability of the CNT nanofluids. However, excess surfactant addition might hinder the improvement of the thermal conductivity enhancement of the nanofluids.

Figure 8. Thermal conductivity enhancement ratios with different surfactant concentrations.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The effect of the structures of cationic gemini surfactant molecules on the thermal conductivity enhancement is shown in Figure 9. The fractions of the dispersed CNTs and the cationic gemini surfactants is 0.1 vol% and 0.6 wt%, respectively. The spacer chain length of the cationic gemini surfactant increase from 3 methylenes to 6 methylenes. It is seen that the thermal conductivity enhancement ratio increases with the decrease of spacer chain length of cationic gemini surfactant. Zeta potential analysis indicates that the CNT nanofluids stabilized by gemini surfactant with short spacer chain length have better stabilities. Increase of spacer chain length of surfactant might give rise to sediments of CNTs in the nanofluids, resulting in the decrease of thermal conductivity enhancement of the nanofluids.

Figure 9. Effect of surfactant structures on the thermal conductivity enhancement ratio.

Nanofluids have great potential for heat transfer enhancement and are highly suited to application in practical heat transfer processes. This provides promising ways for engineers to develop highly compact and effective heat transfer equipments. More and more researchers have paid their attention to this exciting field. When addressing the thermal conductivity of nanofluids, it is foremost important to guarantee the accuracy in the measurement of the thermal conductivity of nanofluids. Two aspects should be considered. The first one is to prepare homogeneous and long-term stable nanofluids. The second one is to keep the initial equilibrium before measuring the thermal conductivity. In general, the thermal conductivity enhancement increases monotonously with the particle loading. The effect of temperature on the thermal conductivity enhancement ratio is somewhat different for different nanofluids. It is very important to note that the temperatures of the base fluid and the nanofluid should be the same while comparing the thermal conductivities between them. With an increase in the thermal conductivity of the base fluid, the thermal conductivity enhancement ratio decreases. Considering the effect of the size of the inclusion, there exists an optimal value for alumina nanofluids, while for the CNT nanofluid, the thermal conductivity increases with a decrease of the average diameter of the included CNTs. The thermal characteristics of nanofluids might be manipulated by means of controlling the morphology of the inclusions, which also provide a promising way to conduct investigation on the mechanism of heat transfer in nanofluids. The additives like acid, base, or surfactant play considerable roles on the thermal conductivity enhancement of nanofluids.

CNTs: carbon nanotubes; DNPs: diamond NPs; DW: deionized water; DWNTs: double-walled CNTs; EG: ethylene glycol; KOH: potassium hydroxide; LP: liquid paraffin; MWNTs: multi-walled CNTs; NPs: nanoparticles; PVP: poly(vinylpyrrolidone); SDS: sodium dodecyl sulfate; SHW: short hot wire; SSA: specific surface area; SWNTs: single-walled CNTs; THW: transient hot wire; TCNTs: treated CNTs.

The authors declare that they have no competing interests.

HQ supervised and participated all the studies. He wrote this paper. WY carried out the studies on the nanofluids containing copper nanoparticles, graphene, diamond nanoparticles, and several kinds of oxide nanoparticles. YL carried out the studies on the nanofluids containing other oxide nanoparticles. LF carried out the studies on the nanofluids containing carbon nanotubes.

This study was supported by the National Science Foundation of China (50876058), Program for New Century Excellent Talents in University (NCET-10-883), and the Program for Professor of Special Appointment (Eastern Scholar) at Shanghai Institutions of Higher Learning.

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Huaqing Xie^*, Wei Yu, Yang Li and Lifei Chen

• *Corresponding author: Huaqing Xie hqxie@eed.sspu.cn

Author Affiliations

School of Urban Development and Environmental Engineering, Shanghai Second Polytechnic University, Shanghai 201209, China

For all author emails, please log on.

Nanoscale Research Letters 2011, 6:124 doi:10.1186/1556-276X-6-124

The electronic version of this article is the complete one and can be found online at:http://www.nanoscalereslett.com/content/6/1/124

 

Received:	3 September 2010
Accepted:	9 February 2011
Published:	9 February 2011

 

© 2011 Xie et al; licensee Springer.

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Testing Hydroponics System’s Nutrient Solution – MyronLMeters.com

TDS meter

Whether or not you’re a newcomer to hydroponic growing, keeping your hydroponic system’s nutrient solution properly balanced with a satisfactory nutrient concentration can be tough. Regular testing of one’s t solution is required if you want to keep the hydroponic system balanced and your plants healthy and growing. The simplest way to keep your nutrient solution balanced is via testing. You must check your solution’s pH level and nutrient concentration no less than every couple of days. To be able to try out your solution you need a few basic devices. You need to get a trusted pH tester and either an overall total Dissolved Solids (TDS) meter or perhaps a Conductivity (EC) meter.

pH tester

It is generally agreed that the pH of one’s nutrient solution should be kept slightly acidic using a pH range of 5.5-6.0. You will find exceptions for this generalization. If you are unsure what are the best pH range is for the plants you might be growing, there are many resources open to guide you. You can find three basic means of testing pH. The least expensive technique is paper testing strips. They’re simple to use but could be difficult to learn. Typically the most popular testing way is liquid test kits. This method is extremely accurate and easier to see than paper testing strips but it is also more expensive. An electronic digital pH meter may be the last available option. Digital pH meters are available in various shapes, sizes, and price ranges. The benefit of an electronic pH meter is that it can be really user friendly, fast, and accurate. However, they are the most costly of the testing options, they can break easily, plus they has to be calibrated frequently if you’d like them to remain accurate.

TDS tester

Both conductivity meters and TDS meters are used to look at the strength, or concentration, of your hydroponic nutrient solution. Even though it is crucial that you know the concentration of your solution, this is because measurements ought to be used being a guideline only. EC meters will almost always be measured much the same way. Two sensors they fit within the solution being tested along with a little bit of electricity is emitted by one sensor and received by the other sensor. How well the electricity travels is then based on the EC meter. The harder electricity conducted, the greater the power of solids in the solution. A TDS meter uses the EC after which calculates the amount of solids inside the solution according to among three conversion factors. Considering that the TDS is dependant on a calculation, it really is only a quote of solids in the nutrient solution.

With this particular basic comprehension of the main difference between TDS and conductivity meters you can determine which measurement process is best for you. When you use a packaged nutrient solution, browse the product label to learn which kind of meter the maker recommends. In the event the manufacturer recommends a TDS, they’ll also inform you which conversion step to use as well as the recommended concentration range for his or her product. If you use a homemade nutrient solution plus a TDS meter, a great general guideline is to keep your TDS between 800 and 1200 ppm (ppm). If you work with an EC meter to test your homemade nutrient solution, a good range is 1.0 to 3.0 mS/cm (milisiemens per centimeter).

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Microporous Silica Based Membranes for Desalination – MyronLMeters.com

Tweet Microporous Silica Based Membranes for Desalination  Abstract: This review provides a global overview of microporous silica based membranes for desalination via pervaporation with a focus on membrane synthesis and processing, transport mechanisms and current state of the art membrane performance. Most importantly, the recent development and novel concepts for improving the hydro-stability and separating [...]

• 1.  Introduction

Figure  1. Schematic  representation of  transport mechanism  through a  membrane via

Figure 2. Pervaporation (PV) processes in various operational arrangements.

 

4.  Novel Silica Based Membranes in Desalination

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2. Blanco Gálvez, J.; García-Rodríguez, L.; Martín-Mateos, I. Seawater desalination by an innovative solar-powered membrane distillation system: The medesol project. Desalination 2009, 246, 567–576.
3. Blanco, J.; Malato, S.; Fernández-Ibañez, P.; Alarcón, D.; Gernjak, W.; Maldonado, M.I. Review of feasible solar energy applications to water processes. Renew. Sustain. Energy Rev. 2009, 13, 1437–1445.
4. Chen, T.-C.; Ho, C.-D. Immediate assisted solar direct contact membrane distillation in saline water desalination. J. Membr. Sci. 2010, 358, 122–130.
5. Mericq, J.-P.; Laborie, S.; Cabassud, C. Evaluation of systems  coupling  vacuum membrane distillation and solar energy for seawater desalination. Chem. Eng. J. 2011, 166, 596–606.
6. Tang, C.Y.; Chong, T.H.; Fane, A.G. Colloidal interactions and fouling of nf and ro membranes: A review. Adv. Colloid Interface Sci. 2011, 164, 126–143.

Muthia Elma, Christelle Yacou, David K. Wang, Simon Smart and João C. Diniz da Costa *

Films and Inorganic Membrane Laboratory, School of Chemical Engineering, The University of Queensland, Brisbane, Queensland 4072, Australia; E-Mails: m.elma@uq.edu.au (M.E.); c.yacou@uq.edu.au (C.Y.); d.wang1@uq.edu.au (D.K.W.); s.smart@uq.edu.au (S.S.)

*  Author to whom correspondence should be addressed; E-Mail: j.dacosta@eng.uq.edu.au; Tel.: +62-7-33656960; Fax: +62-7-33654199.

© 2012 by the authors; licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution license (http://creativecommons.org/licenses/by/3.0/).

Testing Fountain Solution Conductivity – MyronLMeters.com

Tweet WHY TEST FOUNTAIN SOLUTIONS? Accurate fountain (dampening) solution concentration control is essential for consistent, high-quality results in lithography. Low concentration can cause drying on the non-image area of the plate resulting in tinting, scumming, blanket piling, etc. High concentrations, on the other hand, bring about over-emulsification of the ink. This results in weakening of [...]

 

 

 

Sustainability in Water Supply – MyronLMeters.com

TweetSustainability in Water Supply Sustainable water systems should provide adequate water quantity and appropriate water quality for a given need, without compromising the future ability to provide this capacity and quality. Water systems in the realm of sustainable development may not literally include the use of water, but include systems where the use of water [...]

Sustainability in Water Supply

Sustainable water systems should provide adequate water quantity and appropriate water quality for a given need, without compromising the future ability to provide this capacity and quality. Water systems in the realm of sustainable development may not literally include the use of water, but include systems where the use of water has traditionally been required. Examples include waterless toilets and waterless car washes, whose use helps to alleviate water stress and secure a sustainable water supply.

Accessing the sustainability features in water supply, that is to say, the three-fold goals of economic feasibility, social responsibility and environmental integrity, is linked to the purpose of water use. Sometimes, these purposes compete when resources are limited; for example, water needed to meet the demands of an increasingly urban population and those needs of rural agriculture. Water is used (1) for drinking as a survival necessity, (2) in industrial operations (energy production, manufacturing of goods, etc.), (3) domestic applications (cooking, cleaning, bathing, sanitation), and (4) agriculture. Sustainable water supply is a component of integrated water resource management, the practice of bringing together multiple stakeholders with various viewpoints in order to determine how water should best be managed. In order to decide if a water system is sustainable, various economical, social and ecological considerations must be considered.

Surface water

Surface freshwater is unfortunately limited and unequally distributed in the world. Almost 50% of the world’s lakes are located in Canada alone (UNEP, 2002). In addition, pollution from various activities leads to surface water that is not drinking quality. Therefore, treatment systems (either large scale or at the household level) must be put in place.

Structures such as dams may be used to impound water for consumption. Dams can be used for power generation, water supply, irrigation, flood prevention, water diversion, navigation, etc. If properly designed and constructed, dams can help provide a sustainable water supply. The design should consider peak flood flows (historical and projected for climate change), earthquake faults, soil permeability, slope stability and erosion, silting, wetlands, water table, human impacts, ecological impacts (including wildlife), compensation for resettlement, and other site characteristics. There are various challenges that large-scale dam projects may present to sustainability: negative environmental impacts on wildlife habitats, fish migration, water flow and quality, and socioeconomic impacts resulting from resettled local communities. A sustainability impact assessment should therefore be performed to determine the environmental, economic and social consequences of the construction.

Groundwater

Groundwater accounts for greater than 50% of global freshwater; thus, it is critical for potable water (Lozan et al, 2007). Groundwater can be a sustainable water supply source if the total amount of water entering, leaving, and being stored in the system is conserved. There are three main factors which determine the source and amount of water flowing through a groundwater system: precipitation, location of streams and other surface-water bodies, and evapotranspiration rate; it is thus not possible to generalize a sustainable withdrawal or pumping rate for groundwater (USGS, 1999). Unsustainable groundwater use results in water-level decline, reduced streamflow, and low water quality, jeopardizing the livelihood of effected communities. Various practices of sustainable groundwater supply include changing rates or spatial patterns of ground-water pumpage, increasing recharge to the ground-water system, decreasing discharge from the groundwater system, and changing the volume of groundwater in storage at different time scales (USGS, 1999). A long-term vision is necessary when extracting groundwater since the effects of its development can take years before becoming apparent. It is important to integrate groundwater supply within adequate land planning and sustainable urban drainage systems.

Rainwater Harvesting

Collecting water from precipitation is one of the most sustainable sources of water supply since it has inherent barriers to the risk of over-exploitation found in surface and groundwater sources, and directly provides drinking water quality. However, rainwater harvesting systems must be properly designed and maintained in order to collect water efficiently, prevent contamination and use sustainable treatment systems in case the water is contaminated. A number of drinking water treatments exist at point-of-use, each with advantages and disadvantages. These include solar treatment, boiling, using filters, chlorination, combined methods such as filtration and chlorination, flocculation and chlorination. Although technically given the Earth’s surface and precipitation, rainwater harvesting can meet global water demand, the solution can most practically be a supplement to sustainable water supply systems given a level of uncertainty (especially with climate change), and competing land-use applications.

Reclaimed Water

Reclaimed water, or water recycled from human use, can also be a sustainable source of water supply. It is an important solution to reduce stress on primary water resources such as surface and groundwater. There are both centralized and decentralized systems which include greywater recycling systems and the use of microporous membranes. Reclaimed water must be treated to provide the appropriate quality for a given application (irrigation, industry use, etc.). It is often most efficient to separate greywater from blackwater, thereby using the two water streams for different uses. Greywater comes from domestic activities such as washing, whereas blackwater contains human waste. The characteristics of the two wastestreams thus differ.

Desalinization

Desalinisation has the potential to provide an adequate water quantity to those regions that are freshwater poor, including small island states. However, the energy demands of reverse osmosis, a widely-used procedure used to remove salt from water, are a challenge to the adaptation of this technology as a sustainable one. The costs of desalination average around 0.81 USD per cubic meter compared to roughly 0.16 USD per cubic meter from other supply sources (USGS, 2010). If desalination can be provided with renewable energies and efficient technologies, the sustainable features of this supply source would increase. Currently, desalination increases operational costs because of the needed energy (and also carbon dioxide emissions); this in turn raises the cost of the final product. In addition, desalination plants can have negative impacts on marine life, and cause water pollution due to the chemicals used to treat water and the discharge of brine.

Bottled Water

Bottled water is a 21st century phenomenon whereby mostly private companies provide potable water in a bottle for a cost. In some areas, bottled water is the only reliable source of safe drinking water. However, often in these same locations, the cost is prohibitively expensive for the local population to use in a sustainable manner. Bottled water is not considered an “improved drinking water source” when it is the only potable source available (UN, 2010). When sustainability metrics are used to access bottled water, it falls short in many situations of being a sustainable water supply. Economic costs, pollution associated with its manufacturing (plastic, energy, etc.) and transportation, as well as extra water use, makes bottled water an unsustainable water supply system for many regions and for many brands. It takes 3-4 liters of water to make less than 1 liter of bottled water (Pacific Institute, 2008).

Potable Water

Potable water requires some of the strictest standards of quality in terms of bacteriological and chemical pollutants. These standards are often governed by national governments; international recommendations can be found from the World Health Organization (http://www.who.int/water_sanitation_health/dwq/guidelines/en/index.html). Drinking water must be freshwater and should be free of pathogens and free of harmful chemicals.

Water in Industry

Water is used in just about every industry. Industrial water withdrawls represent 22% of total global water use (significant regional differences). Its use is notable for manufacturing, processing, washing, diluting, cooling, transporting substances, sanitation needs within a facility, incorporating water into a final product, etc. (USGS, 2010). The food, paper, chemicals, refined petroleum, and primary metal industries use large amounts of water (USGS, 2010). A sustainable water supply in industry involves limiting water use through efficient appliances and methods adapted to the particular industry. Rainwater harvesting on-site (including the creation of large pond-like structures), as well as recycling water in industrial processes, can provide a sustainable water supply for industry without straining municipal water supplies. Industry releases organic water pollutants, heavy metals, solvents, toxic sludge, and other wastes into water supply sources. Industry thus has a dual responsibility for internal sustainable water supply and the protection of external water supply sources.

Water in Agriculture

Agriculture uses the largest amount of freshwater on a global scale. It represents roughly 70% of all water withdrawal worldwide, with various regional differences. In the United States, for example, agriculture accounts for over 80% of water consumption (USDA, 2010). The productivity of irrigated land is approximately three times greater than that of rain-fed land (FAO, 2010). Thus, irrigation is an important factor for sustainable agriculture systems. In addition, global food production is expected to increase by 60% from 2000 to 2030, creating a 14% increase in water demand for irrigation (UN, 2005). Agriculture is also responsible for some of the surface and groundwater degradation because of run-off (chemical and erosion-based). It thus has a dual role in sustainable water supply: (1) using water efficiently for irrigation and (2) protecting surface and groundwater supply sources. Techniques for sustainable water supply in agriculture include organic farming practices which limit substances that would contaminate water, efficient water delivery, micro-irrigation systems, adapted water lifting technologies, zero tillage, rainwater harvesting, runoff farming, and drip irrigation (efficient method that allows water to drip slowly to plant roots by using pipes, valves, tubes and emitters).

Domestic Water Uses

The average household needs an estimated 20-50 liters of water per person per day, depending on various assumptions and practices (Gleick, 1996). Reducing water use through waterless toilets, water efficient appliances, and water quantity monitoring, is an important part of sustainability for domestic water supply. Efficient piping systems that are leak-free and well insulated provide a network that is reliable and help to limit water waste. The aforementioned potable water supply sources, with their sustainability features and sustainability challenges, are all relevant to other domestic uses. Since water quality standards are not as strict for household uses as for drinking, there is more flexibility when considering sustainable domestic water supply (including the potential for reclaimed water use).

Conclusions

A water supply system will be sustainable only if it promotes efficiencies in both the supply and the demand sides. Initiatives to meet demand for water supply will be sustainable if they prioritize measures to avoid water waste. Avoiding wastage will contribute to reducing water consumption and, consequently, to delaying the need for new resources.
On the supply side, it is fundamental to enhance operation and maintenance capabilities of water utilities, reducing non-revenue water (NRW), leakages, and energy use, as well as improving the capacity of the workforce to understand and operate the system. It is also necessary to ensure cost-recovery through a fair tariff system and “intelligent” investment planning. In addition, all alternatives to increase the water supply must be analysed considering the entire life cycle.

On the demand side, the adoption of water efficient technology can considerably reduce water consumption. Investments in less water intensive industrial processes and more efficient buildings lead to a more sustainable water supply. Concrete possibilities of economic savings, social benefits (such as the involvement of different sectors of society to reach a common objective, environmental awareness of the population, etc.) and a range of environmental gains make the adoption of water efficient technologies viable.
Sustainable water supply involves a sequence of combined actions and not isolated strategies. It depends on the individual’s willingness to save water, governmental regulations, changes in the building industry, industrial processes reformulation, land occupation, etc. The challenge is to create mechanisms of regulation, incentives and affordability to ensure the sustainability of the system.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

References

Food and Agriculture Organization of the United Nations (FAO). (2010). Water Use in Agriculture. Retrieved from http://www.fao.org/ag/magazine/0511sp2.htm

Gleick, Peter H. (1996). Basic Water Requirements for Human Activities: Meeting Basic Needs.” Water International 21, 2: 83-92.

US Geological Survey. (2010). Industrial Water Use. Retrieved from http://ga.water.usgs.gov/edu/wuin.html

United States Department of Agriculture. (2010). Irrigation and Water Use. Retrieved from http://www.ers.usda.gov/Briefing/WaterUse/

Lozan, Grassl, et al. (2007). The water problem of our Earth: From climate and the water cycle to the human right for water.

UN Water for Life Decade. (2005). United Nations Department of Public Information (32948—DPI/2378—September 2005—10M).

UNEP. (2002). Vital Water Graphics: An Overview of the State of the World’s Fresh and Marine Waters. Retrieved from http://www.unep.org/dewa/assessments/ecosystems/water/vitalwater/.

Pacific Institute. Water Content of Things. The World’s Water 2008-2009.

United Nations (WHO and UNICEF). (2010). Progress on Sanitation and Drinking Water Update 2010. Retrieved from http://www.unicef.org/media/files/JMP-2010Final.pdf.

USGS. (2010). Thirsty? How ’bout a cool, refreshing cup of seawater? Retrieved from http://ga.water.usgs.gov/edu/drinkseawater.html.

USGS. (1999). Sustainability of Ground-Water Resources. Retrieved from http://pubs.usgs.gov/circ/circ1186/pdf/circ1186.pdf.

Waite, Marilyn. (2010). Sustainable Water Resources in the Built Environment. IWA Publishing: London.

Resources

Many of the issues in this article are covered in the book, Sustainable Water Resources in the Built Environment, published in 2010, written by Marilyn Waite.

Sustainable Water Resources in the Built Environment covers elements of water engineering and policy making in the sustainable construction of buildings with a focus on case studies from Panama and Kenya. It provides comprehensive information based on case studies, experimental data, interviews, and in-depth research.

The book focuses on the water aspects of sustainable construction in less economically developed environments. It covers the importance of sustainable construction in developing country contexts with particular reference to what is meant by the water and wastewater aspects of sustainable buildings, the layout, climate, and culture of sites, the water quality tests performed and results obtained, the design of rainwater harvesting systems and policy considerations.

The book is a useful resource for practitioners in the field working on the water aspects of sustainable construction (international aid agencies, engineering firms working in developing contexts, intergovernmental organizations and NGOs). It is also useful as a text for water and sanitation practices in developing countries.

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