title: Performance improvement of raw water pretreatment process with pre-inoculation biofilm: feasibility and limiting factors.
abstract: The initial formation of biofilm and the removal performance of pollutants in biological pretreatment process for polluted raw water were limited due to the oligotrophic niche in raw water. In this study, the feasibility of using pre-inoculation biofilm formed under nutrients enhanced condition for polluted raw water treatment was analyzed in nine batch reactors. Results showed that the pollutants removal performance of biofilm was improved under nutrients enhanced conditions. Ammonia oxidation rate (AOR) was exponentially increased with the increasing in NH4+-N levels, and organic matter removal rate (ORR) was positively related to the initial total organic carbon (TOC) concentration. The biofilm formation and microbial diversity were further improved via adding more substrates, seeding river sediment and feeding effluent from a mature biofilm reactor. However, the biofilm formed under higher substrate conditions had higher half-saturation constant values (KS) to both NH4+-N and TOC, which decreased AOR and ORR values when it was used to treat polluted raw water. The reduction percentage of AOR and ORR showed logarithmic growth modes with the increase in KSvalues. Fortunately, improvement of nutrients flux via accelerating influent replacement could enhance the start-up performance effectively and decrease the operation risk introduced by the changes in substrate affinity.
authors.affiliation: Department of Environmental Engineering, Zhejiang University, No. 866 Yuhangtang Road, Hangzhou, 310058, People's Republic of China. ygfscu@126.com.|Department of Environmental Engineering, Zhejiang Ocean University, No.1 Haida South Road, Zhoushan, 316022, People's Republic of China. ygfscu@126.com.
authors.forename: Guang-Feng
authors.initials: GF
authors.lastname: Yang
authors.affiliation: Department of Environmental Engineering, Zhejiang University, No. 866 Yuhangtang Road, Hangzhou, 310058, People's Republic of China.|Department of Environmental Engineering, Zhejiang Ocean University, No.1 Haida South Road, Zhoushan, 316022, People's Republic of China.
authors.forename: Li-Juan
authors.initials: LJ
authors.lastname: Feng
authors.affiliation: Department of Environmental Engineering, Zhejiang University, No. 866 Yuhangtang Road, Hangzhou, 310058, People's Republic of China.
authors.forename: Cai-Rong
authors.initials: CR
authors.lastname: Guo
authors.affiliation: Department of Environmental Engineering, Zhejiang University, No. 866 Yuhangtang Road, Hangzhou, 310058, People's Republic of China.
authors.forename: Tian
authors.initials: T
authors.lastname: Xia
authors.affiliation: Department of Environmental Engineering, Zhejiang University, No. 866 Yuhangtang Road, Hangzhou, 310058, People's Republic of China.|Zhejiang Province Key Laboratory for Water Pollution Control and Environmental Safety, Hangzhou, 310058, People's Republic of China.
authors.forename: Xiang-Yang
authors.initials: XY
authors.lastname: Xu
authors.affiliation: Department of Environmental Engineering, Zhejiang University, No. 866 Yuhangtang Road, Hangzhou, 310058, People's Republic of China. felix79cn@hotmail.com.|Zhejiang Province Key Laboratory for Water Pollution Control and Environmental Safety, Hangzhou, 310058, People's Republic of China. felix79cn@hotmail.com.
authors.forename: Liang
authors.initials: L
authors.lastname: Zhu
mesh_terms: D001673:Biodegradation, Environmental; D018441:Biofilms / Q000254:growth & development; D019149:Bioreactors; D005240:Feasibility Studies; D018570:Risk Assessment; D045483:Rivers / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*; D018508:Water Purification / Q000379:methods*
chemical_list: D014874:Water Pollutants, Chemical
keywords: Nutrients addition; Polluted raw water; Pre-inoculation biofilm; Pretreatment process; Substrate affinity