Journal of Zhejiang University SCIENCE
(ISSN 1009-3095, Monthly)
2005 Vol. 6B No. 5 p.427-432
Biomass and microbial activity in a biofilter during backwashing
BAI Yu†1,2, ZHANG Jie2, LI Yi-fan2, GAO Yu-nan2, LI Yong3
(1Beijing Drainage Group Limited Company, Beijing 100061, China)
(2School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin 150090, China)
(3School of Environmental Engineering, Nanyang Technological University, 639798, Singapore)
†E-mail: Baiyu75322@163.com
Received Aug. 13, 2004; revision accepted Nov. 10, 2004
Abstract: Biomass and microbial activity in backwashing processes of a biofilter for tertiary treatment were investigated. The microbial groups revealed new distribution along the biofilter depth after low flow rate backwashing for a short time. Then the start-up process was accelerated by backwashing. The biomass profile and microbial activity profile both varying with depth before and after backwashing, can be mathematically described by quadratic equations. Using the profiles, the difference of oxygen demand can be calculated to determine the airflow rate during backwashing. Combined with the difference between biofilters and rapid gravity filters, analysis of biomass and microbial activity can determine more accurately the required airflow rate during backwashing.
Key words: Biofilter, Backwashing, Biomass, Microbial activity, Oxygen demand
doi:10.1631/jzus.2005.B0427 CLC number: Q93