Migration and distribution of sodium ions and organic matters during electro-dewatering of waste activated sludge at different dosages of sodium sulfate
| Autor: | Jiukun Hu, Wenbo Yu, Keke Xiao, Jiakuan Yang, Xu Wu, Yueyuan Gu, Sha Liang, Huali Deng, Jun Xiao, Jiangwei Yu |
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| Rok vydání: | 2017 |
| Předmět: |
Environmental Engineering
Health Toxicology and Mutagenesis Sodium 0208 environmental biotechnology chemistry.chemical_element 02 engineering and technology 010501 environmental sciences Waste Disposal Fluid 01 natural sciences Desalination Electrolysis law.invention chemistry.chemical_compound law Sodium sulfate Environmental Chemistry Humic Substances 0105 earth and related environmental sciences Ions Chromatography Sewage Sulfates Public Health Environmental and Occupational Health Water Electrochemical Techniques General Medicine General Chemistry Pulp and paper industry Pollution Dewatering Cathode 020801 environmental engineering Anode Activated sludge chemistry |
| Zdroj: | Chemosphere. 189:67-75 |
| ISSN: | 0045-6535 |
| Popis: | In this study, the influence of Na2SO4 on electro-dewatering (EDW) of waste activated sludge (WAS) was investigated. The highest water removal efficiency of 42.5% was achieved at the optimum Na2SO4 dosage of 12.5 g kg−1 DS during EDW process at a constant voltage of 20 V. The migration and distribution of water, organic matters and Na+ at different Na2SO4 dosages were investigated through layered experiments. The results indicated the entire EDW process followed the S curve model, and it can be divided into three stages: (1) initial desalination stage: at the initial few min of EDW process, the rate of electroosmosis was extremely slow while electromigration of ions like Na+ was intense, and the electromigration was more obvious with increased Na2SO4 dosage; (2) dewatering stage: the dewatering efficiency increased dramatically via electroosmosis; (3) the dewaterability limit stage: the maximum value of dewatering efficiency has been achieved, while the water removal efficiency and dry solids content remained constant. During the EDW process, the possible electrolysis resulted in a pH gradient in the sludge cake. With the addition of Na2SO4 in the EDW, the pH gradient was intensified, and the migration rate of organic matters moving from cathode to anode increased while compared with the raw WAS. This study provided insights into the mechanism of EDW process at different dosages of Na2SO4. |
| Databáze: | OpenAIRE |
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