LIU Lai-sheng, ZHOU Huai-dong, LIU Ling-hua, WU Lei-xiang

Department of Water Environment, IWHR, Beijing 100038, China

Abstract: In order to investigate the microbial mechanism in bio-slow sand filter, the filter material was sampled at different depth of the filter bed. Scanning Electron Microscopy (SEM) analysis results show that the surface layer is rich in biological membranes of microorganisms, including bacteria, algae, protozoa and various microbial secretions. These microbes form a virtuous food chain. In this paper, the filter material was sampled at different depth of the filter bed. Three indices of the total number of bacteria, SS, POC were analyzed. The results show that microorganism mainly concentrates in the surface of the filter within 2cm in thickness, and the filter bed is 90cm height which can guarantee the water quality. These will provide reference data for bio-slow sand filter design and operation. In this paper, the covered bio-slow sand filter was tested. The results show that taking appropriate measures to keep out light can effectively reduce the algae growth, increase the operation cycle, and will not reduce the treatment effect. This will help us guide the bio-slow sand filter of Fujian, Sichuan, Hubei provinces in China.

Key words: bio-slow sand filtration, particulate organic carbon, microorganism, mechanism

Published in: Journal of China Institute of Water Resources and Hydropower Research (Vol. 11 No. 2, 2013)