By P. “Regu” Regunathan, Ph.D., and Joseph F. Harrison, P.E., CWS-VI

Summary: Recently, POU treatment was touted as a feasible approach to meeting the new arsenic MCL by the USEPA. This has opened the door to many opportunities for the water treatment industry. Three studies are currently in progress that will go a long way in determining what approaches fit best for small system consumers.


Point-of-use/point-of-entry (POU/POE) devices are used for reducing contaminants in drinking water. Traditionally, aesthetic improvement of water, such as reducing chlorine, choloramines, total dissolved solids (TDS) and several trace organics, has been the main focus of this market segment. Still, that focus has been changing toward addressing low levels of health-related contaminants—reduced by POU units—that include lead, protozoan cysts, trihalomethanes, and many different organic compounds. Recently, several manufacturers have pursued arsenic reduction with POU devices.

Traditional POU units have been made available to consumers through water treatment dealers, distributors, mass merchandisers and discount department stores. Consumers seek these devices voluntarily based on an understanding of their needs and desires to improve the taste of drinking water and/or to reduce trace contaminants that may be present in their water supplies.

New opportunities and requirements
In 1996, the Safe Drinking Water Act (SDWA) was amended to allow public water systems to install POU or POE devices to achieve compliance with National Primary Drinking Water Regulations (NPDWRs) as determined by the U.S. Environmental Protection Agency (USEPA). These amendments regulate the use and operation of POU/POE to achieve compliance with a maximum contaminant level (MCL) standards as follows:

  • POU treatment may not be used for compliance with microbial MCL requirements,
  • POU and POE units must be owned, controlled and maintained by the water system or by a dealer hired by the water system; responsibility for operation and maintenance of the system stays with the water system in either case,
  • The units used must have mechanical warnings incorporated to notify customers of operational problems, if any; i.e., alarm, light or shut-off mechanisms must be part of each POU/POE system, and
  • POU units selected must have been independently tested and certified per the protocols of product standards issued, if any, by the American National Standards Institute (ANSI).

The USEPA, based on these amendments, recently acknowledged the use of POU for decentralized water treatment by public water systems as a means of complying with the new arsenic standard of 10 parts per billion, or ppb (see Newsreel this issue). This arsenic MCL, which was lowered from the previous 50 ppb, is expected to impact more than 3,000 small communities around the country, and the cost of achieving compliance by central treatment is likely to be too high for many of these communities. It has been projected that POU devices, which would treat only drinking water, installed in each household of these communities may be less costly and more affordable for these systems.

New challenges
To successfully implement a POU strategy, however, four logistical challenges must be met:

  1. Regular and routine access to the treatment units inside the houses must be ensured. Local ordinances may be needed assuring such access and agreement to use these devices by all homeowners.
  2. New procedures for installation, maintenance and management of the home units by the water system of the community or the commercial service provider under contract may have to be developed.
  3. Monitoring and compliance requirements that fit the needs of such decentralized treatment approach need to be fully defined.
  4. Focused procedures aimed at public outreach and participation in this new approach will have to be developed.

The USEPA has issued two guidance documents to specifically discuss the centrally managed POU compliance strategy. The first one, released last March, discusses and analyzes the implementation issues. Meanwhile, the second one released three months later, “Draft Guidance for Implementing a Point-of-Use or Point-of-Entry Treatment Strategy for Compliance with the Safe Drinking Water Act,” discusses in more detail the issues related to access, ordinance, ANSI standards, certification issues and monitoring approaches.

Three different projects are now under way to demonstrate field feasibility of POU approaches for compliance with the standard and answer, in practical terms, the questions related to access, public education, participation, maintenance, monitoring, and costs associated with different tasks. The American Water Works Association Research Foundation (AWWARF) has funded two of these projects and the other has been funded by the USEPA.

Demonstration studies
1. AWWARF Projet #2730—Point-of-Use/Point-of-Entry Implementation Feasibility Study for Arsenic Treatment:

The project was awarded to Nara-simhan Consulting Services, of Phoenix. The study evaluates some of the most promising POU and POE treatment alternatives for arsenic removal including reverse osmosis (RO) and adsorption to iron-alumina and granular ferric hydroxide media. These technologies have been evaluated in several locations, namely, Stage Coach, Nev.; Carson City, Nev.; Unity, Maine; Sun City West, Ariz., and Metro Water, of Tucson, Ariz., over periods ranging from three to six months. The POU and POE units were operated under continuous and intermittent conditions. The intermittent operation was performed to simulate the actual use in homes. In addition to arsenic, other parameters monitored in the treated water included TDS, silica, hardness and heterotrophic plate counts (HPC).

This part of the study has shown consistent removal of arsenic and TDS by the POU RO devices with consistent fluxes being maintained even after operation of six to eight weeks. The run lengths on the POU and POE adsorption systems have been long, but also dependent on the pH of the raw water and presence of other interfering ions such as silica.

The next stage in the study includes 20 units installed in homes in three of these communities and monitored for their performance during normal use by residents. These would include both POU RO and adsorptive media-based units.

Costs for POU RO and POU adsorption are also being developed by researchers in the project, obtaining individual quotations for significant cost items such as housings, membrane elements/adsorption media, and bladder or storage tanks. The treatment costs for POU have been compared with those of POE treatment and are found to be lower in capital and operational costs for small water systems.

The replacement frequency for media and/or membranes will be determined based on the findings of the field POU/POE tests, consultations with manufacturers, and professional judgment. The findings of this study will be useful for systems that are both impacted by the new arsenic MCL and considering POU/POE treatment approaches. A paper is expected to be presented as a progress report of this study at the 2002 AWWA Water Quality Technology Conference on Nov. 10-13.

2. Project funded by USEPA’s Office of Ground Water and Drinking Water and the National Water Research Institute of Fountain Valley, Calif.:

The award was made to NSF International with significant roles involving J. Cotruvo Associates, Regunathan & Associates, and the National Rural Water Association. After a nationwide search, a community of 125 connections and 400 persons in northern California was selected as the demonstration site.

During July/August 2002, commercial POU water treatment devices using activated alumina-based adsorbents were installed at the kitchen sinks in each home, commercial establishments, and on school water fountains. These units have already been tested per the protocols in ANSI/NSF Standard 53 for health effects. They were also tested using water in the community on an accelerated basis to verify their effectiveness locally.

In many respects, new ground is being broken and the numerous technical, operational, management and legal issues must be resolved. Key elements to be examined in the demonstration are:

  • Procedures for installation, maintenance and management of the home units by a community and the commercial service provider under contract to the community,
  • Monitoring unit performance using inexpensive test kits,
  • The useful life and replacement frequency of the treatment cartridges,
  • Certified laboratory compliance analysis requirements,
  • Access to residences for service and compliance monitoring,
  • Community oversight responsibilities,
  • Quantification of capital and operation and maintenance (O&M) costs, and many others.

Another area of particular significance is the perception of the consumers of this unusual compliance practice—and their willingness to utilize it.

The systems in the home will be run for 12 months. It’s expected the result will be a detailed practical operational “cookbook” that will provide all information needed by a small community to determine whether or not to select a decentralized POU compliance system, as well as what would need to be known to assure successful sustainable operation.

3. AWWARF Project #2671—Comparison of Conventional and Unconventional Approaches for the Provision of Water:

Stratus Consulting, of Boulder, Colo., has been awarded this research contract. NCS Consulting Services and J. Cotruvo Associates along with Joe Drago, of Kennedy Jenks, and Regunathan & Associates are significant contributors to this study.

This study is aimed at looking at the broad aspect of providing high quality drinking water to consumers by the community water system using conventional and unconventional approaches. The different approaches to be examined include central treatment, POU/POE treatment either for compliance or supplementary purposes, as well as—for similar purposes—bottled water, neighborhood treatment systems, dual distribution and water reuse.
The first phase of this study evaluated several types of POU devices in two large communities, Los Angeles and Contra Costa Water Districts in California. Devices being evaluated are POU RO, POU carbon, POU UV-carbon, POU arsenic media, and faucet-attached carbon filters. These were monitored for effectiveness in reducing several parameters over the last six months and will continue as such for six more months. At the end of this phase, feasibility of this option for compliance or as a supplementary treatment will be examined and reported.

The second phase of the study is to look at the evolving regulatory issues in the future and discuss the possibility of combining several different conventional and unconventional approaches to provide the best quality water to the consumer in an economical manner.

Conclusion
The USEPA’s identification of POU treatment as an acceptable approach for compliance with the arsenic MCL has opened a new opportunity for manufacturers, dealers, certifiers and other service providers of the POU industry. Three independent studies can provide the industry, regulators and the community water systems valuable information to provide good quality water to the consumers at an affordable cost.

About the authors
Dr. “Regu” P. Regunathan has been involved in the water industry for over 34 years. He was the president of Everpure Inc. and vice president of Science & Technology at Culligan prior to retiring and starting a consulting company, Regunathan & Associates in 1999. Regunathan earned his doctorate degree in environmental engineering from Iowa State University. He currently serves as a consultant to NSF International, and consults on technical matters to the Water Quality Association. He can be reached at (630) 653-0387 or email: regu5@aol.com

Joseph F. Harrison is technical director for the Water Quality Association, which is based in Lisle, Ill. He’s a registered professional engineer and holds the WQA’s highest certification, Certified Water Specialist, Level 6. Before joining the WQA in 1990, he was chief of the Safe Drinking Water Branch of  the USEPA’s Region V Office in Chicago.

He holds a bachelor’s degree in civil engineering from Wisconsin State University and a master’s degree in water resources management from the University of Wisconsin. Harrison can be reached at (630) 505-0160, (630) 505-9637 (fax) or email: jharrison@mail.wqa.org

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