Western Kentucky University
Limestone-Based Material for Arsenic Removal from Drinking Water
Institution
Western Kentucky University
Faculty Advisor/ Mentor
Sreedevi Dawadi; Cathleen Webb
Abstract
Arsenic in surface water and ground water is of great concern because of potential toxic effects in drinking water supplies. The EPA recommended that the drinking water standard for arsenic, currently set at 50 parts per billion (ppb), be lowered to 10 ppb by the year 2006. Current remediation technologies are quite expensive and are designed for large water treatment facilities. Many rural water supplies will be out of compliance when the new lower standards are put into effect. This will place increased socioeconomic pressure on rural America, primarily because of the lack of inexpensive pointof-source treatment technology. Arsenic is readily soluble and transports easily through ground water. Observations of arsenic contamination from mining areas in the Black Hills of South Dakota indicate arsenic is retained by native limestone. Batch tests conducted as a function of time show that over 70% of the arsenic was removed within 2 hours. Analyses clearly indicate that limestone reduced arsenic concentrations from > 100 ppb to less than 5 ppb. The arsenic removal efficiency of a novel, small scale device with a continuous, fresh exposure of limestone was tested. Arsenic test strips were evaluated for ease of use and for quality analysis and quality control studies. Water samples with various concentrations were tested before and after the batch experiments in order to evaluate the accuracy of the test strips. These inexpensive tests strips can detect arsenic levels on the spot from 1 ppb to 100 ppb.
Limestone-Based Material for Arsenic Removal from Drinking Water
Arsenic in surface water and ground water is of great concern because of potential toxic effects in drinking water supplies. The EPA recommended that the drinking water standard for arsenic, currently set at 50 parts per billion (ppb), be lowered to 10 ppb by the year 2006. Current remediation technologies are quite expensive and are designed for large water treatment facilities. Many rural water supplies will be out of compliance when the new lower standards are put into effect. This will place increased socioeconomic pressure on rural America, primarily because of the lack of inexpensive pointof-source treatment technology. Arsenic is readily soluble and transports easily through ground water. Observations of arsenic contamination from mining areas in the Black Hills of South Dakota indicate arsenic is retained by native limestone. Batch tests conducted as a function of time show that over 70% of the arsenic was removed within 2 hours. Analyses clearly indicate that limestone reduced arsenic concentrations from > 100 ppb to less than 5 ppb. The arsenic removal efficiency of a novel, small scale device with a continuous, fresh exposure of limestone was tested. Arsenic test strips were evaluated for ease of use and for quality analysis and quality control studies. Water samples with various concentrations were tested before and after the batch experiments in order to evaluate the accuracy of the test strips. These inexpensive tests strips can detect arsenic levels on the spot from 1 ppb to 100 ppb.