Chitosan Acetate Coagulation as a Cloth Filter Aid for Improving Drinking Water Quality

According to the World Health Organization (WHO), 1.8 billion people use fecally contaminated drinking-water sources worldwide. Although there has been increased attention to drinking-water quality and treatment, the WHO still estimates over two million annual deaths are due to diarrheal disease caused by consumption of fecally contaminated water. Cloth is often used in many South Asian communities as a water filtration method. Since the cloth is composed of tightly woven threads, some contaminants are prevented from passing through the filter, making the cloth a potentially effective way to improve water sanitization. Many pathogenic viruses, however, are too small to be sufficiently filtered out. Chitosan is a biodegradable polymer derived from treatment of chitin, found in the exoskeletons of crustaceans. When added to water, chitosan acts as a coagulant to accumulate and agglomerate particles in the water and thereby facilitate the filtration of viruses and other contaminants. Chitosan precipitates the microbes, forming large particles that can then be readily filtered out. The goal of this project is to determine the extent to which the combination of cloth as a filtration device and chitosan as a coagulant will improve water quality. Although there was an increase in microbial reduction resulting from the use of both pre-treatment with 35mg/L of chitosan acetate as a coagulant and 12 layers of a 100% cotton cloth filter compared to the microbial reduction that resulted from filtration alone, it was not enough to meet even the lowest target level of protection (one-star) set by WHO. Filtration in combination with 35 mg/L of chitosan acetate also was not able to remove turbidity to levels below 1 NTU, which is the turbidity standard for US EPA and the guideline value set by the World Health Organization (See raw turbidity and pH levels in Tables 3-8 in appendix). The use of other filtration media such as microporous ceramic filters along with chitosan coagulation is more effective for virus removal from water, based on previous studies.Bachelor of Science in Public Healt