The response of structure and nitrogen removal function of the biofilm on submerged macrophytes to high ammonium in constructed wetlands  

作　　者：Xue Jiang Mengmeng Wang Shunqing Yang Di He Fei Fang Liuyan Yang 

机构地区：[1]State Key Laboratory of Pollution Control and Resource Reuse,School of the Environment,Nanjing University,Nanjing 210023,China [2]School of Resources and Environment,Anqing Normal University,Anqing 246133,China

出　　处：《Journal of Environmental Sciences》2024年第8期129-141,共13页环境科学学报（英文版）

基　　金：supported by the National Special Program of Water Environment(No.2017ZX07204002);the National Natural Science Foundation of China(No.41871082)。

摘　　要：The ammonium exceedance discharge from sewage treatment plants has a great risk to the stable operation of subsequent constructed wetlands(CWs).The effects of high ammonium shocks on submerged macrophytes and epiphytic biofilms on the leaves of submerged macrophytes in CWs were rarely mentioned in previous studies.In this paper,the 16S rRNA sequencing method was used to investigate the variation of the microbial communities in biofilms on the leaves of Vallisneria natans plants while the growth characteristics of V.natans plants were measured at different initial ammonium concentrations.The results demonstrated that the total chlorophyll and soluble sugar synthesis of V.natans plants decreased by 51.45%and 57.16%,respectively,and malondialdehyde content increased threefold after8 days if the initial NH_(4)^(+)-N concentration was more than 5 mg/L.Algal density,bacterial quantity,dissolved oxygen,and pH increased with high ammonium shocks.The average removal efficiencies of total nitrogen and NH_(4)^(+)-N reached 73.26%and 83.94%,respectively.The heat map and relative abundance analysis represented that the relative abundances of phyla Proteobacteria,Cyanobacteria,and Bacteroidetes increased.The numbers of autotrophic nitrifiers and heterotrophic nitrification aerobic denitrification(HNAD)bacteria expanded in biofilms.In particular,HNAD bacteria of Flavobacterium,Hydrogenophaga,Acidovorax,Acinetobacter,Pseudomonas,Aeromonas,and Azospira had higher abundances than autotrophic nitrifiers because there were organic matters secreted from declining leaves of V.natans plants.The analysis of the nitrogen metabolic pathway showed aerobic denitrification was the main nitrogen removal pathway.Thus,the nitrification and denitrification bacterial communities increased in epiphytic biofilms on submerged macrophytes in constructed wetlands while submerged macrophytes declined under ammonium shock loading.

关 键 词：Ammonium shock loading BIOFILM Autotrophic nitrifiers Heterotrophic nitrification aerobic denitrification bacteria Submerged macrophyte 

分 类 号：X703[环境科学与工程—环境工程] X173