Chitosan Coagulation to Improve Microbial and Turbidity Removal by Ceramic Water Filtration for Household Drinking Water Treatment

Lydia S. Abebe, Xinyu Chen and Mark D. Sobsey
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Lydia S. Abebe: Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, Campus Box 7431, Chapel Hill, NC 27599-7431, USA
Xinyu Chen: Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, Campus Box 7431, Chapel Hill, NC 27599-7431, USA
Mark D. Sobsey: Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, Campus Box 7431, Chapel Hill, NC 27599-7431, USA

IJERPH, 2016, vol. 13, issue 3, 1-11

Abstract: The use of porous ceramic filters is promoted globally for household water treatment, but these filters are ineffective in removing viruses from water. In order to increase virus removal, we combine a promising natural coagulant, chitosan, as a pretreatment for ceramic water filters (CWFs) and evaluate the performance of this dual barrier water treatment system. Chitosan is a non-toxic and biodegradable organic polymer derived by simple chemical treatments from chitin, a major source of which is the leftover shells of crustacean seafoods, such as shrimp, prawns, crabs, and lobsters. To determine the effectiveness of chitosan, model test water was contaminated with Escherichia coli K011 and coliphage MS2 as a model enteric bacterium and virus, respectively. Kaolinite clay was used to model turbidity. Coagulation effectiveness of three types of modified chitosans was determine at various doses ranging from 5 to 30 mg/L, followed by flocculation and sedimentation. The pre-treated supernatant water was then decanted into the CWF for further treatment by filtration. There were appreciable microbial removals by chitosan HCl, acetate, and lactate pretreatment followed by CWF treatment, with mean reductions (95% CI) between 4.7 (±1.56) and 7.5 (±0.02) log 10 for Escherichia coli , and between 2.8 (±0.10) and 4.5 (±1.04) log 10 for MS2. Turbidity reduction with chitosan treatment and filtration consistently resulted in turbidities < 1 NTU, which meet turbidity standards of the US EPA and guidance by the World Health Organization (WHO). According to WHO health-based microbial removal targets for household water treatment technology, chitosan coagulation achieved health protective targets for both viruses and bacteria. Therefore, the results of this study support the use of chitosan to improve household drinking water filtration processes by increasing virus and bacteria reductions.

Keywords: water treatment; coagulation-flocculation; chitosan; viruses; bacteria (search for similar items in EconPapers)
JEL-codes: I I1 I3 Q Q5 (search for similar items in EconPapers)
Date: 2016
References: View complete reference list from CitEc
Citations: View citations in EconPapers (2)

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