HANPei-jun,ZHANGMing,WUYan-hua,et al.Sludge Yield Calculation and Conventional Sludge Treatment Process Design of Sewage Treatment Plant[J].China Water & Wastewater,2024,40(4):71-77.
Sludge Yield Calculation and Conventional Sludge Treatment Process Design of Sewage Treatment Plant
China Water & Wastewater[ISSN:1000-4062/CN:12-1073/TU]
volume:
第40卷
Number:
第4期
Page:
71-77
Column:
Date of publication:
2024-02-17
- Keywords:
- sludge yield; sludge yield coefficient; pretreated sludge; excess sludge; chemical sludge; moisture content
- Abstract:
- Reasonable calculation of sludge yield is the basis of sludge treatment system design. This paper discussed the existing calculation formulas for calculating the yields of pretreated sludge, excess sludge and chemical sludge from the design point of view, and analyzed the determination of important parameters such as coefficient α and effluent SS in the pretreated sludge yield formula, sludge yield coefficient Y and sludge conversion rate f in the excess sludge yield formula, coefficient K of sludge converted by agent and dissolved total phosphorus in influent and effluent in the chemical sludge yield formula. The phosphorus balance method was proposed to check the excess sludge calculation formula, so as to solve the problem of wide range of sludge age θc. It was also proposed that Y should be calculated based on biodegradable COD (BCOD) when θc was greater than 20 days. In addition, it was suggested that the inert residues in the endogenous respiration process of activated sludge should be considered in the revision of the excess sludge calculation formula specified in Standard for Design of Outdoor Wastewater Engineering. It was recommended that the moisture content and hydraulic retention time of gravity concentrated sludge should be 99.2% and 12-16 h to avoid anaerobic phosphorus release. Adding polymeric aluminum chloride (PAC) to the sludge inlet pipe or bottom aeration was employed to reduce the TP in supernatant. Conventional sludge concentration, conditioning and ultra-high plate and frame pressure filtration and dehydration process can reduce the moisture content of the sludge to approximately 55%, and further reducing the moisture content requires additional drying process after dehydration.
Last Update:
2024-02-17