The Characteristics of Haloacetic Acids Degradation with Slow Sand Filtration
Date Issued
2006
Date
2006
Author(s)
Lai, Shih-Peng
DOI
zh-TW
Abstract
Chlorination is commonly used in water treatment processes to prevent the water from microbial contamination. However, many studies show that chlorination resulted in disinfection by-products（DBPs）, and some of DBPs could cause adverse health effects. In general, trihalomethanes（THMs）are the major group of DBPs and haloacetic acids（HAAs）are the second. Concerns regarding the health effects of HAAs led the USEPA to promulgate the Stage 1 D/DBP rule that regulate the HAA5 at a MCL at 60μg/L.
Slow sand filtration（SSF） is one of the oldest water treatment processes that still been operated in small communities. Because of the long operation period, biofilm can be developed on the surface of the sand. For that reason, SSF has both physical-chemical and biological removal mechanisms for both particulate and organic removal. However, there are few studies focusing on organic matter removal in the SSF, especially for DBPs removal.
The objectives of this study were to investigate the roles of physical-chemical and biological removal mechanisms for HAA removal through column study, batch study and field study, by using different experimental conditions to evaluate HAA removal in the SSF.
The results indicate that biological process was the major mechanism for HAA removal, and biodegradation rates of HAA decreased as the number of halogen atoms increased. However, single filtration could not remove HAA efficiently. The batch sand studies revealed that microbial associated with filter sand could degrade monochloroacetic acid and dichloroacetic acid within 1 day. Furthermore, active carbon adsorption can efficiently remove HAA and no HAA breakthrough was observed after 6 weeks of operation.
Subjects
慢濾池
含鹵乙酸
降解
slow sand filtration
haloacetic acids
degradation
Type
thesis
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