JEFF VANSTEENBURG IOWA DEPARTMENT OF NATURAL RESOURCES Arsenic Removal/Reduction at the Point of Use in Small Water Systems

Definitions Point of Entry treatment (POE) is a treatment device applied to the drinking water entering a house or building for the purpose of reducing contaminants in the water distributed throughout the house or building.

Definitions Point of use treatment (POU) is a treatment device applied to a single tap or multiple taps, used for the purpose of reducing contaminants in drinking water at those taps, but is not intended to treat all of the water in the facility.

Safe Drinking Water Act Safe Drinking Water Act (SDWA) identifies POE and POU treatment units as potentially affordable technologies, but stipulates that the systems “shall be owned, controlled, and maintained by the public water system or by a person under contract with the Public Water Supply (PWS) to ensure proper operation and compliance…”

Small Public Water Supply Treatment Technologies (BAT) Activated alumina Coagulation/filtration Coagulation-assisted microfiltration Electrodialysis reversal Enhanced coagulation/filtration Enhanced lime softening Ion exchange

Small Public Water Supply Treatment Technologies (BAT) cont’d. Lime softening Oxidation/filtration Reverse osmosis All of these treatment technologies are effective, but are applied at a central treatment facility.

Three Most Common/Effective POU Treatment Technologies Activated alumina Ion exchange Reverse osmosis

Activated Alumina Aluminum hydroxide – dehydroxylated Used as a desiccant Highly porous Can be regenerated with sodium hydroxide, sulfuric acid, and/or alum Treat with sodium hydroxide then sulfuric acid; proper pretreatment of the beds is essential

Ion Exchange Anion resin is most common Resin needs to be regenerated Some resins are one-time use Water may need pretreatment

Reverse Osmosis Is effective in removing Arsenic V Arsenic III not as effective High volumes of reject water Need to send wastewater for appropriate treatment No chemical regeneration required

Iowa Department of Public Health Treatment Equipment Registration Iowa Department of Public Health (IDPH) rules require registration of water treatment equipment for sale to private well owners to meet the requirements of Iowa Code

Iowa Code Prohibits a person selling, leasing or renting, or advertising the sale, lease or rental of a water treatment system in Iowa, from making false or deceptive representations that the water treatment system will reduce the concentration of one or more contaminants in drinking water.

Registered Treatment Systems for Arsenic Removal 32 systems are registered to remove Arsenic V 7 are registered to remove Total Arsenic Registration ensures that the units have been tested in accordance with National Sanitation Foundation (NSF) Standards 53 and 58 Almost all of the units were reverse osmosis or reverse osmosis in combination with filtration or ion exchange

Treatment for the Private Well Owner There are a number of companies to choose from but, for the most part, the approved treatment of choice would be reverse osmosis. Consumers should be sure that the unit is registered and hold the seller responsible. Test pre and post-treatment. See for yourself that the unit is performing as promised.

What About Small Public Water Supplies? A public water supply is any system that serves an average of 25 people per day, 60 days out of the year (transient non-community). A system that would have an arsenic monitoring requirement would be a system that serves the same population for a minimum of 4 hours per day, 4 or more days per week, for 26 or more weeks per year (non-transient non-community PWS)

Community Water Supply A public supply that has at least 15 service connections used by year-round residents or regularly serves at least 25 year-round residents.

Use of Non-Centralized Treatment Devices Non-community PWS may be allowed to use POU devices to achieve compliance, provided there is no eminent health threat or that the use will not put a sensitive population at risk.

Non-centralized Treatment for Community PWS Community public water systems shall NOT use a POU or POE device to achieve permanent compliance with a maximum contaminant level (MCL) violation (IAC (3)).

Why POU/POE is Not Allowed for Community PWS Must protect the most vulnerable population All users must receive water that meets standards Units are within private residences and are hard to access for monitoring and maintenance Sampling for compliance purposes would be extremely difficult

Summary A variety of treatment technologies for small water systems to remove arsenic are available POU and POE treatment devices that remove arsenic are available Rules are in place to try and protect the consumer and to ensure that the treatment devices perform as advertised

Summary cont’d. POU and POE have a limited application for some public water supplies POU and POE are not allowed in Iowa community public water supplies to meet SDWA maximum contaminant levels requirements.