title: Enhanced stable long-term operation of biotrickling filters treating VOCs by low-dose ozonation and its affecting mechanism on biofilm.
abstract: For long-term operation of highly loaded biotrickling filters (BTFs), the prevention of excess biomass accumulation was essential for avoiding BTF failure. In this study, we proposed low-dose ozonation as a biomass control strategy to maintain high removal efficiencies of volatile organic compounds (VOCs) over extended operation of BTFs. To obtain an optimized biomass control strategy, the relative performance of five parallel BTFs receiving different ozone doses was determined, and the affecting mechanism of ozonation on biofilm was elucidated. Experimental results showed that the decline in ozone-free BTF performance began from day 150, which was correlated with excess biomass accumulation, abundant excretion of extracellular polymeric substances (EPS) and a decline in metabolic activity of biofilm over extended operation. Ozone of 5-10 mg m(-3) was effective in preventing excessive growth and uneven distribution of biomass, and eventually maintaining long-term stable operations. Ozone of over 20 mg m(-3) possibly inhibited microorganism growth severely, thereby deteriorating the elimination performance instead. Comparison of the biofilm EPS indicated that the presence of ozone reduce EPS contents to different extents, which was possibly beneficial for mass transfer and metabolic activity. Comparative community analysis showed that ozonation resulted in different microbial communities in the BTFs. Dyella was found to be the most abundant bacterial genera in all BTFs regardless of ozonation, indicating strong resistance to ozonation. Chryseobacterium and Burkholderia members were markedly enriched in the ozone-added biofilm, implying good adaptation to ozone presence. These findings provided an improved understanding of low-dose ozonation in maintaining a stable long-term operation of BTF.
authors: State Key Laboratory of Organic-Inorganic Composites and Research Center of the Ministry of Education for High Gravity Engineering and Technology, Beijing University of Chemical Technology, Beijing 100029, China; School of Biological and Environmental Engineering, Zhejiang University of Technology, No.6 District, Zhaohui, Hangzhou, 310032, China.
authors: Qingwei
authors: Q
authors: Zhou
authors: State Key Laboratory of Organic-Inorganic Composites and Research Center of the Ministry of Education for High Gravity Engineering and Technology, Beijing University of Chemical Technology, Beijing 100029, China. Electronic address: zhangll@mail.buct.edu.cn.
authors: Lili
authors: L
authors: Zhang
authors: School of Biological and Environmental Engineering, Zhejiang University of Technology, No.6 District, Zhaohui, Hangzhou, 310032, China.
authors: Jianmeng
authors: J
authors: Chen
authors: State Key Laboratory of Organic-Inorganic Composites and Research Center of the Ministry of Education for High Gravity Engineering and Technology, Beijing University of Chemical Technology, Beijing 100029, China.
authors: Yong
authors: Y
authors: Luo
authors: State Key Laboratory of Organic-Inorganic Composites and Research Center of the Ministry of Education for High Gravity Engineering and Technology, Beijing University of Chemical Technology, Beijing 100029, China.
authors: Haikui
authors: H
authors: Zou
authors: State Key Laboratory of Organic-Inorganic Composites and Research Center of the Ministry of Education for High Gravity Engineering and Technology, Beijing University of Chemical Technology, Beijing 100029, China.
authors: Baochang
authors: B
authors: Sun
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D018441:Biofilms / Q000187:drug effects* / Q000254:growth & development; D018533:Biomass; D019149:Bioreactors / Q000382:microbiology*; D005374:Filtration / Q000379:methods; D008970:Molecular Weight; D010126:Ozone / Q000737:chemistry / Q000494:pharmacology*; D055549:Volatile Organic Compounds / Q000032:analysis*
chemical_list: D000393:Air Pollutants; D055549:Volatile Organic Compounds; D010126:Ozone
keywords: Biomass accumulation; Biotrickling filter; EPS; Microbial community; Ozone; VOCs