Size effect of polyethylene terephthalate microplastics on Anammox granular sludge
HONG Xian-tao1,2, ZHOU Xin1,2
1. College of Environmental Science and Engineering, Taiyuan University of Technology, Jinzhong 030600, China; 2. Shanxi Municipal Engineering Graduate Education Innovation Center, Jinzhong 030600, China
Abstract：To investigate the size-dependent effect of microplastics (MPs) on nitrogen removal performance of activated sludge, the effect of polyethylene terephthalate (PET) on anaerobic ammonia-oxidizing granular sludge (AnGS) at different particle sizes (75~500μm) was explored using the methods of water quality determination, activity test, physicochemical characterization and microbial community analysis in this study. Results showed that the nitrogen removal efficiency of Anammox was lower than that of the control group when 75 and 150μm PET-MPs were dosed, while the 300 and 500μm groups showed superiority over the control group. Anaerobic ammonia oxidation activity (SAA) tests showed similar results. Extracellular polymeric substances (EPS) analysis revealed that the smaller the particle size of PET-MPs, the higher the EPS secretion and PN/PS, and the more incomplete the AnGS structure. The inhibition of Anammox by PET at small particle size was mainly associated with the granular sludge's lower Zeta potential and smaller specific surface area. In contrast, large-size PET-MPs reduced the chance of contact with MPs and provided more active sites, facilitating Anammox substrates' delivery efficiency. High-throughput sequencing results showed that the particle size of PET-MPs determined the diversity and abundance of microbial community, especially the relative abundance of Candidatus Kuenenia.
[1] Thompson R C, Olsen Y, Mitchell R P, et al. Lost at Sea: Where is all the plastic?[J]. Science, 2004,304(5672):838-838. [2] Blair R M, Waldron S, Gauchotte-Lindsay C. Average daily flow of microplastics through a tertiary wastewater treatment plant over a ten-month period[J]. Water Research, 2019,163:114909. [3] Jiang J, Wang X, Ren H, et al. Investigation and fate of microplastics in wastewater and sludge filter cake from a wastewater treatment plant in China[J]. Science of the Total Environment, 2020,746:141378. [4] Ma B, Wang S, Cao S, et al. Biological nitrogen removal from sewage via anammox: Recent advances[J]. Bioresource Technology, 2016,200:981-990. [5] Sun X, Chen B, Li Q, et al. Toxicities of polystyrene nano- and microplastics toward marine bacterium Halomonas alkaliphila[J]. Science of the Total Environment, 2018,642:1378-1385. [6] Zhou C, Wu J, Ma W, et al. Responses of nitrogen removal under microplastics versus nanoplastics stress in SBR: Toxicity, microbial community and functional genes[J]. Journal of Hazardous Materials, 2022,432:128715. [7] 李金璞,张雯雯,杨新萍.活性污泥污水处理系统中胞外多聚物的作用及提取方法[J]. 生态学杂志, 2018,37(9):2825-2833. Li J P, Zhang W W, Yang X P. The roles and extraction methods of extracellular polymeric substances in activated sludge wastewater treatment system[J]. Chinese Journal of Ecology, 2018,37(9):2825- 2833. [8] Martin L M A, Gan N, Wang E, et al. Materials, surfaces, and interfacial phenomena in nanoplastics toxicology research[J]. Environmental Pollution, 2022,292:118442. [9] Bos R. Physico-chemistry of initial microbial adhesive interactions-its mechanisms and methods for study[J]. FEMS Microbiology Reviews, 1999,23(2):179-229. [10] Lee J, Jeong S, Long C, et al. Size dependent impacts of a model microplastic on nitrification induced by interaction with nitrifying bacteria[J]. Journal of Hazardous Materials, 2022,424:127363. [11] Qian J, He X, Wang P, et al. Effects of polystyrene nanoplastics on extracellular polymeric substance composition of activated sludge: The role of surface functional groups[J]. Environmental Pollution, 2021,279:116904. [12] 王天慧.微塑料对土壤中菲的水土界面行为及微生物群落的影响[D]. 马鞍山:安徽工业大学, 2022. Wang T H. Effects of microplastics on soil and water interface behavior and soil microbial community in the Philippines[D]. Maanxhan: Anhui University of Technology, 2022. [13] Wang C, Wei W, Zhang Y T, et al. Different sizes of polystyrene microplastics induced distinct microbial responses of anaerobic granular sludge[J]. Water Research, 2022,220:118607. [14] Costa M C M S, Carvalho L, Leal C D, et al. Impact of inocula and operating conditions on the microbial community structure of two anammox reactors[J]. Environmental Technology, 2014,35(14): 1811-1822. [15] Cui Y, Gao J, Zhang D, et al. Responses of performance, antibiotic resistance genes and bacterial communities of partial nitrification system to polyamide microplastics[J]. Bioresource Technology, 2021, 341:125767. [16] Lin X, Su C, Deng X, et al. Influence of polyether sulfone microplastics and bisphenol A on anaerobic granular sludge: Performance evaluation and microbial community characterization[J]. Ecotoxicology and Environmental Safety, 2020,205:111318. [17] Ahmad H A, Guo B, Zhuang X, et al. A twilight for the complete nitrogen removal via synergistic partial-denitrification, anammox, and DNRA process[J]. npj Clean Water, 2021,4(1):31. [18] Zhang C, Tayyab M, Abubakar A Y, et al. Bacteria with different assemblages in the soil profile drive the diverse nutrient cycles in the sugarcane straw retention ecosystem[J]. Diversity, 2019,11(10):194. [19] Liu C, Dong Y, Hou L, et al. Acidobacteria community responses to nitrogen dose and form in Chinese fir plantations in southern China[J]. Current Microbiology, 2017,74(3):396-403.
