Biofilm Formation and Haloacetic Acids Degradation in Slow Sand Filtertaion Units
Date Issued
2008
Date
2008
Author(s)
Huang, Yong Ting
Abstract
Disinfection with chlorine in water treatments is widely used by water treatment plants because of its convenience and effectiveness. However, formation of disinfection by-products is of concern due to its potential health risk.low-sand filtration (SSF) is one of the most natural processes for water clarification. This study evaluates the biodegradation of haloacetic acids (HAAs) in slow-sand filtration unit. Simulated SSF columns were setup at both laboratory bench scale and pilot scale; and the results were compared with those observed in water treatment plant with SSF units. For both bench and pilot scale columns, water samples were taken from various bed depths of the columns and HAAs were analyzed. Filter sand was also taken to analyze the microbial activities on the sand surface.he results reveal that the microorganism mass on sand surface in the top portion of SSF and operation time have positive correlation, but the microorganism mass in the middle or in the bottom part of the columns are less than those observed in the top portion. MCAA is degradaded in all of the columns tested, but only the columns fed with higher halogen numbers HAAs (DCAA and TCAA) in influent water can effectively eliminate HAAs with high halogens. It may result from the domestication process for the microorganism to eliminate HAAs with higher halogen numbers However, after 16 days of the operation, the simulated SSF columns can eliminate most of the HAAs including TCAA. For water treatment plant with SSF units, the HAAs removal on SSF is affected by the residual chlorine in influent water, and the growth of microorganism is slower on the top portion.
Subjects
slow-sand filtration
HAAs
biodegradation
DAPI
Biofilm
SDGs
Type
thesis
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