Electrochemical treatment of waste activated sludge: Volume reduction mechanism and improvement possibilities

Lu，Sijia1; Li，Xiaoliang1; Zheng，Xing1,4; Tang，Gang2; Liu，Tong1; Ke，Yanchun3; Liu，Bao1; Wu，Hua1

2022-11-01

10.1016/j.seppur.2022.121617

SEPARATION AND PURIFICATION TECHNOLOGY   影响因子和分区

1383-5866

1873-3794

In this study, a PbO plate electrode was synthesized and optimized for the electrochemical treatment application of waste activated sludge from a municipal wastewater treatment. The sludge dewaterability and mass reduction with different electrolysis time and voltage were quantified to evaluate the treatment efficiency. The mechanism of cell breaking was studied by evaluating different electrochemical oxidation pathways. Results showed that the electrochemical treatment at a voltage of 25 V and electrolysis time of 120 min improved the dewaterability of the sludge by 35.9%, and the concentration of mixed liquor suspended solids (MLSS) was reduced by 33.7%. Using Scanning Electron Microscope (SEM) and Cell fluorescence staining experiments, the impact on the integrity of sludge cells was evaluated. Results showed that electrochemical process clearly destroyed the sludge cell structure and lead to the cell death. Further investigation revealed that hydroxyl radicals (·OH) and sulfate radicals (SO·) produced during the electrochemical treatment played a major role in the cell wall-breaking, while chloride ions (Cl) in the electrolyte significantly enhanced the effect due to formation of chloride-related oxidants. The PbO electrode was modified by chemically reduced graphene oxide (RGO) to improve the ·OH production capacity. Results showed that the PbO(0.05 RGO by wt.%) electrode had the highest ·OH production rate (81.7 μmol/(cm·min)). The electrode improved the removal of MLSS and MLVSS by 11.3% and 11.5%, respectively. And the sludge dewatering and cell destruction were enhanced by 7% and 15.1%, respectively. Adding more NaCl was confirmed as an effective method to improve the electrochemical performance of sludge treatment mainly due to the higher content of active Cl species formed.

Cell wall-breaking Electrode modification PbO2 electrode Radicals Sludge dewatering Waste activated sludge

SCI ; EI

英语

其他

National Natural Science Foundation of China[52100104];

Engineering

Engineering, Chemical

WOS:000843375400004

ELSEVIER

20223212544709

Cell death ; Electrochemical electrodes ; Electrolysis ; Electrolytes ; Graphene ; Lead oxide ; Reduction ; Scanning electron microscopy ; Sodium chloride ; Sodium sulfate ; Sulfur compounds ; Wastewater treatment

Industrial Wastes Treatment and Disposal:452.4 ; Biology:461.9 ; Electric Batteries and Fuel Cells:702 ; Nanotechnology:761 ; Electrochemistry:801.4.1 ; Chemical Reactions:802.2 ; Chemical Agents and Basic Industrial Chemicals:803 ; Chemical Products Generally:804 ; Inorganic Compounds:804.2

CHEMISTRY

2-s2.0-85135401386

Scopus

1.State Key Laboratory of Eco-hydraulics in Northwest Arid Region,Xi'an University of Technology,Xi'an,710048,China
2.State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution Control,Southern University of Science and Technology,Shenzhen,518055,China
3.Aerospace Kaitian Environmental Technology Co. Ltd.,Changsha,410100,China
4.National Supervision & Inspection Center of Environmental Protection Equipment Quality (Jiangsu),Yixing,214205,China

Lu，Sijia,Li，Xiaoliang,Zheng，Xing,et al. Electrochemical treatment of waste activated sludge: Volume reduction mechanism and improvement possibilities[J]. SEPARATION AND PURIFICATION TECHNOLOGY,2022,300.

Lu，Sijia.,Li，Xiaoliang.,Zheng，Xing.,Tang，Gang.,Liu，Tong.,...&Wu，Hua.(2022).Electrochemical treatment of waste activated sludge: Volume reduction mechanism and improvement possibilities.SEPARATION AND PURIFICATION TECHNOLOGY,300.

Lu，Sijia,et al."Electrochemical treatment of waste activated sludge: Volume reduction mechanism and improvement possibilities".SEPARATION AND PURIFICATION TECHNOLOGY 300(2022).