Fenton 氧化调理改善剩余污泥脱水性能及作用机制

Chemical conditioning is an effective means to improve sludge concentration and dewatering performance, and achieve deep sludge dewatering. The new iron-based advanced oxidation conditioning method has attracted much attention due to its advantages in redox potential, flocculation effect, and sludge dewatering performance. Taking excess sludge as the treatment object, from the perspectives of conditioning effect, filtrate quality, and chemical cost, three sludge conditioning processes including the combination of K₂FeO₄ and FeCl₃, Fenton oxidation, and Fe²⁺ activated peroxodisulfate were systematically compared, and the optimal conditioning method and conditioning conditions were clarified. By studying the changes in sludge properties before and after conditioning, the mechanism of conditioning action was elucidated. The results showed that after Fenton oxidation conditioning, the moisture content of dehydrated sludge could be reduced to about 45%, the TP concentration in the filtrate was less than 2.5 mg·L⁻¹, and the chemical cost was only 43 yuan·t of sludge⁻¹. The optimal operating conditions for this conditioning method were: The dosages of Fe²⁺ and H₂O₂ were both 0.8 mmol·gTSS⁻¹, with a pH of 6.5 for the original mud and room temperature conditioning. Fenton conditioning mainly utilized the generated ·OH oxidation to degrade sludge flocs and extracellular polymers, reducing the water holding capacity of sludge flocs. At the same time, the generated Fe²⁺/Fe³⁺ was used to weaken the polarity between sludge flocs, promoting the contact between flocs to squeeze out the water enclosed by the flocs. This study provides a theoretical basis for the application of Fenton oxidation in improving the dewatering performance of residual sludge.