title: Mechanisms of nitrite addition for simultaneous sludge fermentation/nitrite removal (SFNR).
abstract: Simultaneous sludge fermentation and nitrite removal (SFNR) was investigated as a novel sludge/wastewater treatment process with high nitrogen concentrations. The results showed that introducing nitrite improved the primary sludge (PS) fermentation system by improving the chemical oxygen demand (COD) yields and the volatile suspend solid (VSS) reduction. At a nitrite dosage of 0.2 g g SS(-1), the COD production was 1.02 g g VSS(-1) and the VSS reduction was 63.4% within 7-day fermentation, while the COD production was only 0.17 g g VSS(-1) and the VSS reduction was only 4.9% in the blank test. Nitrite contained in wastewater was removed through denitrification process in the SFNR system. The solubility of carbohydrate and protein was substantially enhanced, and their contents reached the peak once nitrite was consumed. In addition, the nutrient release and methane generation were inhibited in the SFNR system, which alleviated the environmental pollution. Unlike traditional fermentation systems, neither alkaline condition nor high free nitrite acid (FNA) concentration affected the PS fermentation in the SFNR system. Molecular weight distribution (MWD) and Live/Dead cell analysis indicated that the sludge disruption by nitrite and the consumption of soluble organic substances in sludge might play important roles in SFNR.
authors.affiliation: Key Laboratory of Beijing for Water Quality Science and Water Environment Recovery Engineering, Engineering Research Center of Beijing, Beijing University of Technology, Beijing 100124, China.
authors.forename: Chengcheng
authors.initials: C
authors.lastname: Wu
authors.affiliation: Key Laboratory of Beijing for Water Quality Science and Water Environment Recovery Engineering, Engineering Research Center of Beijing, Beijing University of Technology, Beijing 100124, China. Electronic address: pyz@bjut.edu.cn.
authors.forename: Yongzhen
authors.initials: Y
authors.lastname: Peng
authors.affiliation: Key Laboratory of Beijing for Water Quality Science and Water Environment Recovery Engineering, Engineering Research Center of Beijing, Beijing University of Technology, Beijing 100124, China.
authors.forename: Shuying
authors.initials: S
authors.lastname: Wang
authors.affiliation: Key Laboratory of Beijing for Water Quality Science and Water Environment Recovery Engineering, Engineering Research Center of Beijing, Beijing University of Technology, Beijing 100124, China; Department of Civil and Environmental Engineering, University of Connecticut, Storrs, CT 06269, USA.
authors.forename: Baikun
authors.initials: B
authors.lastname: Li
authors.affiliation: Beijing Drainage Group Co. Ltd (BDG), Beijing 100124, China.
authors.forename: Liang
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Beijing for Water Quality Science and Water Environment Recovery Engineering, Engineering Research Center of Beijing, Beijing University of Technology, Beijing 100124, China.
authors.forename: Shenbin
authors.initials: S
authors.lastname: Cao
authors.affiliation: Key Laboratory of Beijing for Water Quality Science and Water Environment Recovery Engineering, Engineering Research Center of Beijing, Beijing University of Technology, Beijing 100124, China.
authors.forename: Rui
authors.initials: R
authors.lastname: Du
mesh_terms: D001419:Bacteria / Q000378:metabolism; D057919:Biological Oxygen Demand Analysis; D019149:Bioreactors; D058440:Denitrification; D005285:Fermentation; D006863:Hydrogen-Ion Concentration; D008697:Methane / Q000378:metabolism; D009573:Nitrites / Q000378:metabolism*; D012722:Sewage / Q000737:chemistry / Q000382:microbiology*; D014865:Waste Disposal, Fluid / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000378:metabolism*
chemical_list: D009573:Nitrites; D012722:Sewage; D014874:Water Pollutants, Chemical; D008697:Methane
keywords: Chemical oxygen demand (COD); Fermentation; Primary sludge (PS); denitrification; nitrite