Chitosan Coagulation Pretreatment to Enhance Ceramic Water Filtration for Household Water Treatment

• Authors: Collin Knox Coleman, University of North Carolina; Eric Mai, University of North Carolina; Megan Miller, University of North Carolina; Shalini Sharma, University of North Carolina; Clark Williamson, University of North Carolina; Hemail Oza, Emory University; Eleanor Holmes, University of North Carolina; Marie Lamer, University of North Carolina; Christopher Ly, University of North Carolina; Jill Stewart, University of North Carolina; Mark D Sobsey, University of North Carolina; Lydia S Abebe,, U.S. Agency for International Development (USAID)
• Journal Title: INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
• Volume: Volume 22, Number 18
• Publisher: MDPI | 2021-09-01
• Type of Work: Article | Final Publisher PDF
• Publisher DOI: http://doi.org/10.3390/ijms22189736
• Subjects: Health Sciences, Public Health; Environmental Sciences
• Keywords: Science & Technology; Life Sciences & Biomedicine; Physical Sciences; Biochemistry & Molecular Biology; Chemistry, Multidisciplinary; Chemistry; chitosan; coagulation; flocculation; ceramic filter; filtration; drinking water; household drinking water treatment; VIRUS REMOVAL; MICROBIOLOGICAL EFFECTIVENESS; MEMBRANE FILTRATION; DRINKING-WATER; POINT; ADSORPTION; MORTALITY; CHILDREN; DISEASE; FILTERS

Abstract

Viruses are major contributors to the annual 1.3 million deaths associated with the global burden of diarrheal disease morbidity and mortality. While household-level water treatment technologies reduce diarrheal illness, the majority of filtration technologies are ineffective in removing viruses due to their small size relative to filter pore size. In order to meet the WHO health-based tolerable risk target of 10−6 Disability Adjusted Life Years per person per year, a drinking water filter must achieve a 5 Log10 virus reduction. Ceramic pot water filters manufactured in developing countries typically achieve less than 1 Log10 virus reductions. In order to overcome the shortfall in virus removal efficiency in household water treatment filtration, we (1) evaluated the capacity of chitosan acetate and chitosan lactate, as a cationic coagulant pretreatment combined with ceramic water filtration to remove lab cultured and sewage derived viruses and bacteria in drinking waters, (2) optimized treatment conditions in waters of varying quality and (3) evaluated long-term con-tinuous treatment over a 10-week experiment in surface waters. For each test condition, bacteria and virus concentrations were enumerated by culture methods for influent, controls, and treated effluent after chitosan pretreatment and ceramic water filtration. A > 5 Log10 reduction was achieved in treated effluent for E.coli, C. perfringens, sewage derived E. coli and total coliforms, MS2 coliphage, Qβ coliphage, ΦX174 coliphage, and sewage derived F+ and somatic coliphages.