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Treatment of Arsenic Contaminated Drinking WaterEPA Grant Number: U915800
Title: Treatment of Arsenic Contaminated Drinking Water
Investigators: Sanchez, Cassia M.
Institution: New Mexico State University - Main Campus
EPA Project Officer: Broadway, Virginia
Project Period: December 1, 2000 through December 1, 2001
Project Amount: $45,636
RFA: Minority Academic Institutions (MAI) Fellowships for Graduate Environmental Study (2000) RFA Text | Recipients Lists
Research Category: Academic Fellowships , Engineering and Environmental Chemistry
The objective of this project is to test the efficiency of akaganeite, an iron oxide, as an ion adsorption media in removing arsenic (As) in drinking water sources.
First, the absorbent material, akaganeite, an iron oxide precipitate, is prepared by incubation of a ferric chloride solution. The efficiency of the precipitation process is tested using colorimetric techniques. A batch study then is conducted, using the akaganeite precipitate in suspension, and given a known concentration of As in solution. The batch studies are conducted in a controlled environment and the samples are analyzed by a graduate student in the chemistry department using an atomic adsorption spectrophotometer. Unfortunately, the akaganeite is fragile and cannot withstand the hydraulic forces in a typical filtration environment. A rigid and porous media is required to fix the material, so it can then be used in filtration devices. Different types of crystalline structure media, such as zeolites or pumice, are being considered. A bench-scale column evaluation will be performed to determine the efficiency of As removal and the amount of iron leaching from the column media.
In the 1996 amendments to the Safe Drinking Water Act (SDWA), Congress directed the U.S. Environmental Protection Agency (EPA) to issue a proposed rulemaking by January 1, 2000, and take final action on an arsenic rule a year later. This is a very critical time to revise the process to more fully consider both health benefits and costs of imposing new limits. The maximum contaminant level (MCL) for As was 0.050 milligrams per liter, and the EPA is considering lowering the limit to 10 micrograms per liter. An estimated 50 percent of the communities in New Mexico would be in violation if the SDWA standard for As is set below 50 micrograms per liter. This problem extends beyond New Mexico into the surrounding states of Utah, Colorado, and other southwest areas. The smaller communities would not be able to handle the fines imposed for not meeting the regulations set by the Act, so an economical solution must be developed. This research is expected to result in the development of an economical approach for removing As from drinking water sources to levels at or below the proposed 10 micrograms per liter level.