Decentralized wastewater containing elevated salinity is an emerging threat to the local environment and sanitation in remote coastal communities.Regarding the cost and treatment efficiencies,we propose a passive aeration ditch(PAD)using non-woven polyester fabric as a feasible bubbleless aerator and biofilm carrier for wastewater treatment.Consideration has been first given to PAD's efficacy in treating saline decentralized wastewater,and then to the impact of chemical oxygen demand-to-nitrogen(C/N)ratio and salinity on biofilm formation.A multispecies model incorporating the salinity effect has been developed to depict the system performance and predict the microbial community.Results showed that the PAD system had great capacity for pollutants removal.The biofilm thickness increased at a higher C/N ratio because of the boost of aerobic heterotrophs and denitrifying bacteria,which consequently improved the COD and total nitrogen removal.However,this led to the deterioration of ammonia removal.Moreover,while a higher salinity benefited the biofilm growth,the contaminant removal efficiencies decreased because the salinity inhibited the activity of aerobic heterotrophs and reduced the abundance of nitrifying bacteria inside the biofilm.Based on the model simulation,feed water with salinity below 2％and C/N ratio in a range of 1 to 3 forms a biofilm that can reach relatively high organic matter and ammonia removal.These findings not only show the feasibility of PAD in treatment of saline decentralized wastewater,but also offer a systematic strategy to predict and optimize the process performance.

Jibin Li;Jinxing Ma;Li Sun;Xin Liu;Huaiyu Liao;Di He

Key Laboratory for City Cluster Environmental Safety and Green Development of the Ministry of Education,Institute of Environmental and Ecological Engineering,Guangdong University of Technology,Guangzhou 510006,China;Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou),Guangzhou 511458,China;School of Environmental Science and Engineering,Southern University of Science and Technology,Shenzhen 518055,China

环境科学与工程前沿

[1]Jibin Li;Jinxing Ma;Li Sun;Xin Liu;Huaiyu Liao;Di He-.Mechanistic insight into the biofilm formation and process performance of a passive aeration ditch(PAD)for decentralized wastewater treatment)[J].环境科学与工程前沿,2022(07):33-44

bubbleless,aerator,heterotrophs,nitrifying

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