Enhanced Sludge Blanket Stability Using Two-Stage Dosage of PAC in Drinking Water Treatment Processes

• Main Authors: Kun-Feng Lee, 李坤峰
• Other Authors: Ruey-Shin Juang
• Format: Others
• Language: zh-TW
• Published: 2001
• Online Access: http://ndltd.ncl.edu.tw/handle/63320986394912416015

碩士 === 元智大學 === 化學工程研究所 === 89 === With the development of high technology, the water sources are deteriorated. The most important thing is to improve the efficiency and operation of purification engineering. This research was to investigate the stability and performance of sludge blanket in high-speed flocculation settlers for purification plant of drinking water. In the mean time, a set of experimental equipment of pilot plant was built-up for comparing and analyzing the stability of sludge blanket in the single-stage and two-stage coagulation sedimentation process. It was shown that adopting the two-stage coagulation sedimentation process has increased remarkably the formation time of floc, and the sludge blanket was more stable than single-stage coagulation sedimentation process. When the single-stage coagulation sedimentation process was adopted, due to the variety of raw water quality, the purification plant of drinking water needs to reduce the PAC dosage in rapid mixing basin, and the result has caused the sludge blanket highly eddied, and also increased the heavy loading of rapid filters. On the other hand, the sludge blanket was not eddied easily in spite of the reduction of PAC dosage in rapid mixing basin when two-stage coagulation sedimentation process was adopted. The main reason is, most of non-dissolved organic materials was removed in the first-stage coagulation, and as a result, the floc was not carried over easily in the second-stage coagulation sedimentation process. Another result has shown that, the total residual aluminum in two-stage coagulation sedimentation process was much less than the one in single-stage coagulation sedimentation process. Besides, the existence of humic acid would enhance the sorption of heavy metal Cu(II).