Enhanced nitrogen and phosphorus removal and microbial analysis of BioDopp process in pilot scale

In order to demonstrate the feasibility of simultaneously upgrading and capacity expanding of existing municipal sewage treatment plants, taking a low C/N domestic sewage in Beijing as the treatment object, a pilot test system was constructed using IFAS combined with micro oxygen A/O technology based on BioDopp process. The removal efficiency of organic matter, nitrogen and phosphorus, and the characteristics of microbial community were investigated, and the economic benefits were calculated as well. The results show that the startup strategy of increasing the load by gradually increasing the treated water volume is feasible in view of the low pollutant concentration of the sewage. After only 8days of startup, the operation became stable and the effluent COD, NH3-N, TN and TP concentration reached 18.9, 0.4, 8.3 and 0.7mg/L respectively. The results of high-throughput sequencing showed that the tested process enhanced the enrichment of functional bacteria, especially denitrifying phosphorus accumulating bacteria, and its total relative abundance reached 7.6%, which was 23.6times of that of the activated sludge inoculated. The HRT of the pilot system is 16.6h, which is only 61.0% of the original process (HRT~27.2h) of the sewage treatment plant. It can be seen that this process has significant advantages in land saving, high biological phosphorus removal efficiency, saving reagent cost, and greatly reducing the energy consumption of aeration and reflux by micro oxygen controlling and air lift reflux. Consequently, BioDopp process can be used for the construction of compact sewage treatment plant, which is an efficient energy-saving and carbon reduction tool for sewage treatment plant. © 2022 Chinese Society for Environmental Sciences. All rights reserved.