Matthew E. Verbyla, M.Sc. Candidate
Department of Civil and Environmental Engineering
University of South Florida
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Biography
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Laboratory Assessment of Four Point-of-Use Water Treatment Filters Designed for Households in Developing Countries
Sarah Ness
Civil & Environmental Engineering
University of South Florida
According to the World Health Organization (WHO) and UNICEF’s Joint Monitoring Programme, 884 billion people do not have access to improved sources of drinking water. Household water treatment technologies, termed point-of-use (POU) technologies, have been developed in an effort to solve this problem and improve peoples’ access to clean and safe drinking water.
A laboratory assessment is evaluating the effectiveness of four POU treatment technologies that utilize physical filtration methods. The two clay ceramic filters are further being evaluated in longer term field studies. Three of the systems, Potters for Peace, Filter Pure, and Tulip filters, are ceramic filters that treat water through filtration and also disinfect the water through the use of impregnated or coated silver. The Potters for Peace (PFP) filter is a flower pot-shaped, 8 liter (L) ceramic filter with a silver coating. The Filter Pure (FP) filter is a rounded-bottom lemon-juicer shaped, 7 L ceramic filter with silver fired into the ceramic. The Tulip filter is a submersible candle-type ceramic filter that uses siphon pressure to push water through the filter element, which includes silver impregnated into the ceramic. The fourth filter included in this evaluation is the LifeStraw Family (LS) filter, which utilizes ultrafiltration and water disinfection through chlorination.
In the laboratory, flow rates, turbidity removal, total suspended solids (TSS) removal, coliform removal, and E. coli removal have been measured. All four filter types have been tested using natural pond water. Additionally, the PFP and FP ceramic filters have filtered tap water to simulate rain water, while the Tulip filters and LS filters have filtered a synthetic water that incorporates silica sand to simulate varying levels of natural turbid surface waters. Particle size distribution analysis was also performed on waters associated with the Tulip and LS filters.
Preliminary results are suggesting that none of the POU filters are functioning at the full operational levels reported by their respective manufacturers. The Tulip filters are removing turbidity, TSS, coliforms, and E.coli and are flowing at the expected flow rate of 4-5 L/hour if the filter unit is functioning without a quality control error. However, several of the Tulip filters are appearing to deteriorate in effluent water quality before the expected 7,000 L end-of-life reported by the manufacturer. In contrast, the FP, PFP, and LS filters are removing the predicted coliforms and E.coli, as well as turbidity and TSS. However, none are performing at the expected flow rates. Laboratory results show that both filters are operating around 0.2-0.5 L/hour. In addition, the LS filters are not performing at the expected flow rate of 12-15 L/hour, as claimed by the manufacturer. Continued laboratory results and field measurements of the two clay ceramic filters will be reported in this presentation. This will allow for further analysis to evaluate the efficacy and efficiency of the four POU filters.
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