Enhanced Simultaneous Nitrogen and Phosphorus Removal in A Denitrifying Biological Filter Using Waterworks Sludge Ceramsite Coupled with Iron-Carbon.

Xiaoying Zheng,Zhi Xu,Mengmeng Yang,Wei Chen,Yuan Zhang,Xiaoyao Shao,Mengqi Jin,Hang Xu,Weihong Wang

doi:10.3390/ijerph16152646

Abstract

In this study, waterworks sludge ceramsite (WSC) was combined with 3% iron-carbon matrix in a denitrifying biological filter (ICWSC-DNBF) to enhance the simultaneous removal of carbon, nitrogen and phosphorus in secondary effluent of wastewater treatment plant (SE-WTP). The chemical oxygen demand (COD) and nitrogen removal, as well as phosphorus removal and the adsorbed forms of phosphorus were measured and the removal mechanism of these pollutants by the ICWSC-DNBF system for treating SE-WTP were investigated. The results showed that the ICWSC-DNBF achieved good removals of COD, NH4+-N, NO3−-N, total N and total P; effluent concentrations were 17.23 mg/L, 3.72 mg/L, 14.32 mg/L, 17.38 mg/L and 0.82 mg/L, respectively. WSC enhanced the P removal due to its high specific surface area and the high number of adsorption sites. Fe-P and Al-P were the main forms of P adsorbed by WSC, accounting for 78.53% of the total adsorbed P. WSC coupled with Fe and C improved the biodegradability of SE-WTP and promoted the removal of organic matter. The removal of N was attributed to the abundant denitrifying microorganisms in the system and the electrochemical effect produced by the internal electrolysis of Fe and C.

Highlights

Serious water resource problems, such as shortage of freshwater, deteriorated water quality, threats to public health by water pollution and other environmental issues, have attracted global attention
waterworks sludge ceramsite (WSC) coupled with Fe and C improved the biodegradability of Secondary effluent from wastewater treatment plant (SE-WTP) and promoted the removal of organic matter
The removal of N was attributed to the abundant denitrifying microorganisms in the system and the electrochemical effect produced by the internal electrolysis of Fe and C

Summary

Introduction

Serious water resource problems, such as shortage of freshwater, deteriorated water quality, threats to public health by water pollution and other environmental issues, have attracted global attention. The requirements for water resources protection and water pollution control have become increasingly stringent, and water reuse has become more important in many places. Secondary effluent from wastewater treatment plant (SE-WTP), as an unconventional water resource, has attracted increasing attention. Limited by sewage treatment technology, SE-WTP contains high concentrations of nitrogen (N), phosphorus (P) and other pollutants. SE-WTP typically exhibits a low carbon-to-nitrogen ratio, is produced in large volumes, and delivers a high pollution load. SE-WTP has insufficient organic matter content to meet the requirements of further treatment by traditional biological denitrification. Further N and P removal is necessary to improve the reuse potential

Objectives

Results

Conclusion