Adaptability of organic matter and solid content to Fe2+/persulfate and skeleton builder conditioner for waste activated sludge dewatering.

Xiaoran Li, Yafei Shi, Xi Zhou, Lu Wang, Huiqin Zhang, Kewu Pi, Andrea R Gerson, Defu Liu

Environmental science and pollution research international 2022 Feb

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Sludge conditioning is important for improved dewatering, with the sludge characteristics impacting the effect of conditioning. A composite conditioner, Fe2+-activated sodium persulfate (Fe2+/SPS) combined with phosphogypsum (PG), was used to examine its impact on sludges with different organic contents (34.6-43.8%) or different solid contents (2.8-5.9%). Response surface optimization analysis shows that when the best conditioning is achieved, the reduction of the specific resistance to filtration (SRF) is not sensitive to organic matter content, but the dewatering performance of the sludge is greatly affected by the solid content. The oxidation role of Fe2+/SPS and the skeleton builder role of PG together affect the conditioning, oxidation playing a major role in conditioning, especially for greater organic matter content. The organic content (maximum ηSOL value was 0.32) also affects the effectiveness of the skeleton builder more than the solid content (Maximum ηSOL value was 0.25). Changes in PG significantly impacts the optimal molar ratio and dosage of Fe2+/SPS. Sludge with greater solid content requires greater Fe2+/SPS dosage to provide stronger oxidation to destroy flocs, and the maximum Fe2+:SPS molar ratio was 1.14 with solid content of 5.9 wt%. The composite conditioning decreases the content of extracellular polymeric substances and proteins/polysaccharides. This study provides new insight into the relationship between the oxidation role of Fe2+/SPS and the skeleton builder role of PG for sludge conditioning strategies according to the optimal conditions. © 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.

Citation

Xiaoran Li, Yafei Shi, Xi Zhou, Lu Wang, Huiqin Zhang, Kewu Pi, Andrea R Gerson, Defu Liu. Adaptability of organic matter and solid content to Fe2+/persulfate and skeleton builder conditioner for waste activated sludge dewatering. Environmental science and pollution research international. 2022 Feb;29(10):14819-14829