Technologies and Costs for Removal of Arsenic From Drinking Water

5.0 POINT-OF-ENTRY/POINT-OF-USE TREATMENT OPTIONS5.1 INTRODUCTIONCentralized treatment is not always a feasible treatment option, for example, in areas whereeach home has a private well or where centralized treatment is cost prohibitive. In these instances,point-of-entry (POE) and point-of-use (POU) treatment options may be acceptable treatmentalternatives. POE and POU systems offer ease of installation, simplify operation and maintenance,and generally have lower capital costs (Fox, 1989). These systems may also reduce engineering, legaland other fees typically associated with centralized treatment options. Use of POE and POU systemsdoes not reduce the need for a well-maintained water distribution system. In fact, increasedmonitoring may be necessary to ensure that the treatment units are operating properly.Home water treatment can consist of either whole-house or single faucet treatment. Wholehouse,or POE treatment is necessary when exposure to the contaminant by modes other thanconsumption is a concern. POU treatment is preferred when treated water is needed only for drinkingand cooking purposes. POU treatment usually involves single-tap treatment.Section 1412(b)(4)(E) of the 1996 Safe Drinking Water Act (SDWA) Amendments requiresthe EPA to issue a list of technologies that achieve compliance with MCLs established under the act.This list must contain technologies for each NPDWR and for each of the small public water systemscategories listed below:# Population of more than 50, but less than 500;# Population of 500 or more, but less than 3,300; and# Population of 3,300 or more, but less than 10,000.The SDWA identifies POE and POU treatment units as potentially affordable technologies, butstipulates that POE and POU treatment systems “shall be owned, controlled and maintained by thepublic water system, or by a person under contract with the public water system to ensure properoperation and compliance with the maximum contaminant level or treatment technique and equippedwith mechanical warnings to ensure that customers are automatically notified of operationalproblems.”Research has shown that POE and POU devices can be an effective means of removing arsenicfrom potable water (Fox and Sorg, 1987; Fox, 1989). Influent arsenic concentration and other source5-1