<b>Excess Sludge Disintegration by Discharge Plasma Coupled with Thiosulfate</b>

Surplus sludge disposal and treatment are major issues in wastewater treatment plants. Discharge plasma oxidation is an effective approach for sludge dewatering and digestion. In this study, excess sludge disintegration by non-thermal discharge plasma coupled with thiosulfate (TSA) was investigated. After 20 min of the single discharge plasma treatment, the soluble chemical oxygen demand (SCOD) increased to 404.93 mg L−1, and it climbed even more to 549.08 mg L−1 after adding 15 mmol L−1 of TSA. The water content of the filter cake also reduced even more in the presence of TSA. There was an appropriate dosage of TSA available. In the discharge plasma coupled with TSA system, reactive oxygen species (·OH and ·O2-) were generated and had significant involvement in the disintegration of the sludge. The addition of TSA enhanced the production of ·OH. These reactive oxygen species decomposed the floc structures and facilitated the transformation of organic compounds, resulting in a decrease in the average size of the sludge aggregates. The ratio of soluble extracellular polymer substances (S-EPS) was enhanced, while the ratio of the tightly bound fraction was reduced after the treatment. Thus, discharge plasma coupled with TSA promoted microbial cell lysis and facilitated the release of intracellular organic matter and bound water, ultimately enhancing the sludge’s dewaterability.

剩余污泥的处置与处理是污水处理厂面临的主要难题之一。放电等离子体氧化（discharge plasma oxidation）是用于污泥脱水与消解的有效技术手段。本研究针对非热放电等离子体耦合硫代硫酸盐（TSA）破解剩余污泥的效果展开了探究。仅经20分钟放电等离子体单独处理后，可溶性化学需氧量（SCOD）提升至404.93 mg·L⁻¹；当投加15 mmol·L⁻¹的硫代硫酸盐后，SCOD进一步攀升至549.08 mg·L⁻¹。此时滤饼的含水率也出现了更为显著的下降。硫代硫酸盐存在最优投加剂量。在放电等离子体耦合硫代硫酸盐体系中，会生成活性氧物种（·OH与·O2-），且其在污泥破解过程中发挥了关键作用。硫代硫酸盐的添加可促进·OH的生成。上述活性氧物种可破坏污泥絮体结构，推动有机组分的转化，进而降低污泥絮体的平均粒径。经处理后，溶解性胞外聚合物（S-EPS）占比提升，而紧密结合组分占比则有所下降。综上，放电等离子体耦合硫代硫酸盐可促进微生物细胞裂解，推动胞内有机物与结合水的释放，最终改善污泥的脱水性能。