热活化过二硫酸盐改善污泥-餐厨垃圾厌氧消化物脱水性能

为了解热活化过硫酸盐氧化对污泥-餐厨垃圾厌氧消化物脱水性能的影响,以毛细吸水时间(CST)、过二硫酸盐(PDS)分解速率、自由基产生种类、胞外聚合物(EPS)组分含量以及厌氧消化物的微观形貌等观察指标,比较了不同温度条件下(50～80℃)的热活化PDS氧化对脱水性能的影响,并探讨了其作用机理.结果表明,热活化PDS氧化...

Improved dewaterability of anaerobic digestate of sewage sludge and food waste by thermally activated peroxydisulfate oxidation

The influence of thermally activated peroxydisulfate (PDS) oxidation process with different temperature (50~80 ℃) on the dewaterability of the anaerobic digestate of sewage sludge and food waste was investigated in this study. The key parameters affecting the dewatering, such as capillary suction time (CST), PDS decomposition, radical species, the compositions and contents of extracellular polymer substances (EPS) and microstructure of anaerobic digestate, were determined to reveal the potential conditioning mechanism. The results indicated that thermally activated PDS oxidation significantly improved the dewaterability of the sludge-food waste anaerobic digestate, and that the extent of the improvement in the dewaterability increased with the increase in temperature. The optimal conditions for thermally activated PDS treatment were as follows: temperature of 70 ℃, sodium persulfate dosage of 4 mmol·g−1 PDS, and the reaction time of 240 min. After the PDS treatment, the CST of the anaerobic digestate decreased from 1064.9 s to 39.4 s and the final supernatant is clear. It was also found that 76.6% of protein in TB-EPS was degraded and significant signals for ${rm{SO}}_4^ - $· and ·OH were produced during the PDS treatment. Besides, surface morphology of the anaerobic digestate treated by PDS exhibited a porous structure, building a favorable condition for the release of internal water. These results suggest that during thermally activated PDS treatment, the production of radicals resulted in the destruction of the floc structure of anaerobic digestate and the degradation of microbial EPS, which may be responsible for the improvement in the dewaterability of the sludge-food waste anaerobic digestate. The results of this study can provide a fundamental guidance for the application of thermally activated persulfate oxidation technology to improve the dewatering of sewage sludge-food waste anaerobic digestate.