August 2002: Volume 44, Number 8
Arsenic: Centrally Managed POU as a Compliance Method -- A Feasibility Study
by Angela Smith
The U.S. Environmental Protection Agency (USEPA) recently issued a national drinking water regulation, "Arsenic and Clarifications to Compliance and New Source Monitoring Rule" (Federal Register, Vol. 66, No. 14, Jan. 22, 2001, see: www.epa.gov/safewater/ars/arsenic_finalrule.pdf).
The new Arsenic Rule
This new rule will reduce the standard for arsenic in drinking water from 50 parts per billion (ppb) to 10 ppb. Over the next few years, each state will be required to enforce the new standard in communities that exceed 10 ppb, with compliance beginning in 2006. An estimated 4,100 small communities in the United States will be affected by the rule. NSF International has been awarded grants from the USEPA and the National Water Research Institute to demonstrate the feasibility of using point-of-use (POU) devices for meeting the drinking water standard in small communities (see Newsreel, this issue). The goal of the feasibility study is to document the cost factors, ability to have sustainable system maintenance, public acceptability and water quality compliance using POU water treatment.
Usually, a community that exceeds a new drinking water standard will install and manage a central treatment system to treat all of the water being produced to the new criteria. Such treatment systems are often cost prohibitive for small communities. In this project, only the water used for drinking and cooking would be treated in each home to comply with the new arsenic regulation. This approach offers the opportunity for a small community to reduce the arsenic in their drinking water and meet the new drinking water regulation at a much lower cost than would be possible by central treatment methods. A typical family of four uses several hundred gallons of water each day, but only a few quarts per person per day are consumed in drinking, cooking and making coffee, tea, reconstituted juices, etc. The information collected from this project will ultimately be used as a model that could be followed by hundreds of other small communities throughout the country to help them solve the same problem at much less cost than other, more expensive alternatives. Reducing the cost will ultimately result in more rapid compliance.
The POU method
This project will use a method called Centrally Managed Point-of-Use Treatment. It's a demonstration primarily of the operational and management aspects of achieving compliance using decentralized water treatment. It involves installing a POU drinking water system under the kitchen sink in each house, restaurant and appropriate businesses, schools, and other drinking water sources where consumption may occur. A new water tap will also be installed so the treated water from the POU system can be easily identified. The tap will be used for obtaining drinking water and water for cooking or preparing coffee or tea, reconstituted juices, or for making ice cubes.
The feasibility study is under way in a rural farm community north of Sacramento, Calif. California is one of several states faced with the issue of arsenic contamination in drinking water. The community involved in the study was chosen because it best fit the criteria (see Table 1) the project team outlined as important and high priority. In addition, there was enthusiastic support from the local leadership, as well as extensive support provided by the state, national organizations (Water Quality Association, National Rural Water Association, Association of State Drinking Water Administrators, American Water Works Association) and the California Rural Water Association. The community has about 25 ppb of arsenic in its water -- meeting the former standard of 50 ppb but clearly exceeding the new requirement of 10 ppb. Also, the number and types of connections offer different types of installation scenarios and represents a good example of a typical U.S. town.
Current status and timeline
Currently, NSF is coordinating the installation of the systems for each location in the community with a local service provider in the Sacramento area. The POU devices are being supplied by Kinetico Inc., of Newbury, Ohio, and rapid analytical kits for arsenic were supplied by Loveland, Colo.-based Hach Company and Industrial Test Systems, Inc., of Rock Hill, S.C. All of the POU treatment systems were to be installed by last month for the year-long study to commence. A high rate simulation test is being conducted to demonstrate the capability, effectiveness and performance of the system with the specific type of water found in the community. These tests will be completed and analyzed prior to the installations. The units selected for the study will also be certified to the appropriate ANSI/NSF standards, including the new procedure and criteria for arsenic reduction claims.
Initial system performance will be determined at the time of installation, and periodically thereafter during the course of the study. During periodic visits to the installations, the units will be inspected to ensure they're performing as expected and determine how much water each unit has treated. At the request of the USEPA, treatment cartridges will be replaced after six months.
After the project is completed in 2003, the treatment units will remain with the community. The community can, if it desires, continue to use the units and work out a process for servicing or replacing the units and cartridges when they have reached the end of their useful lives. The final report of the feasibility study will be issued at the end of next year and will include practical guidance on using POU as a standard compliance alternative.
Although this project is designed specifically for compliance with the arsenic standard, it will provide practical management information that would be applicable to numerous other standards that could be met in small communities using centrally managed POU or point-of-entry (POE) treatment systems
About the author
Angela Smith is a project coordinator at NSF International in the Environmental and Research Services Department. Smith has a bachelor's degree in environmental geology from the University of Michigan. She can be reached at (734) 913-5770 or email: email@example.com
Table 1. Considerations for Choosing an Arsenic Pilot Community
* It had to be a community that was not exceeding the old compliance rule: >50 ppb
* Didn't want the average arsenic level to be too low: <15 ppb
* Needed to have enough population to make data relevant, but not so many that cost considerations became prohibitive for companies donating equipment: ~100 connections
* Diversity in terms of age and variety of construction/architectural types in homes, businesses, schools, etc.
* Different kinds of equipment that would be representative of what was available and affordable on the market. (Other companies that volunteered to supply equipment include Culligan, Apyron, etc.)
* Positive attitude and cooperation of state and local authorities to the project.
* Availability of a service provider, or dealer, in the area that could be counted on to provide service and help with project monitoring.