Enhanced biological phosphorus removal in low-temperature sewage with iron-carbon SBR system

Wei Li,Mingjie Gao,He Wang,Yunhe Hou,Yiming Chen,Yuqi Wang,Yunan Gao

doi:10.1080/09593330.2022.2049889

Abstract

ABSTRACT This study proposed an AO-SBR (Anaerobic Aerobic Sequencing Batch Reactor) combined with iron-carbon micro-electrolysis (ICME) particles system for sewage treatment at low temperature and explored the dephosphorisation mechanism and microbial community structure. The experimental results illustrated that ICME particles contributed to phosphorus removal, metabolic mechanism of poly-phosphorus accumulating organism (PAO) and microbial community structure in the AO-SBR system. The optimal treatment effect was achieved under the conditions of pH 7, DO 3.0 mg/L and particle dosage of 2.6 g Fe-C/g MLSS, and the removal rates of COD, TP, NH4 +-N and TN reached 80.56%, 91.46%, 69.42% and 57.57%. The proportion of phosphorus accumulating organisms (PAOs) increased from 4.54% in the SBR system to 10.89% in the ICME-SBR system at 10°C. Additionally, the metabolic rate of PAOs was promoted, and the activities of DHA and ETS both reached the maximum value of 13.34 and 102.88 μg·mg−1VSS·h−1. These results suggest that the ICME particles could improve the performance of activated sludge under low-temperature conditions. This technology provides a new way for upgrading the performance of sewage treatment in the cold area.

Highlights

This study proposed an AO-SBR combined with iron-carbon micro-electrolysis (ICME) particles system for sewage treatment at low temperature and explored the dephosphorization mechanism and microbial community structure
ICME particles were granular with an average particle size of 0.8 cm, under the joint action of binder and pore-forming agent, a distinct porous structure was formed, which can provide a place for microorganisms to attach
The XRD results showed the main substances in ICME particles include Fe and C, which were the components of the electrode

Summary

Introduction

Nitrogen and phosphorus are important nutrient sources, the high concentration of nitrogen and phosphorus in sewage will lead to water eutrophication, which will have a great impact on people's lives and seriously affect industrial and agricultural production. The sedimentation performance of activated sludge become worse, the adsorption capacity of activated sludge decrease, and the community structure and quality reduce According to this problem, most wastewater treatment plants usually adopt the chemical agent, reducing the pollution load, increasing the return flow of sludge and the residence time of sewage to ensure the effluent standard of sewage at low temperature. Most wastewater treatment plants usually adopt the chemical agent, reducing the pollution load, increasing the return flow of sludge and the residence time of sewage to ensure the effluent standard of sewage at low temperature These measures couldn't meet the requirements of sewage treatment, and would increase the project investment and operation cost it is necessary to explore a more effective method to improve the poor performances of the traditional process at low temperature

Methods

Results

Conclusion