The Effects of Aluminium- and Ferric-Based Chemical Phosphorus Removal on Activated Sludge Digestibility and Dewaterability

Processes

AugustineOsamor Ifelebuegu¹  Peter Ojo¹ 

[1] School of Energy, Construction and Environment, Coventry University, Coventry CV1 5FB, UK;

关键词: activated sludge;    anaerobic digestion;    biogas;    metal salts;    surplus activated sludge;    capillary suction time;   

DOI  :  10.3390/pr7040228

来源: DOAJ

【 摘 要 】

The uses of Al³⁺ and Fe³⁺ salts in chemical phosphorus removal (CPR) in activated sludge plants have increased considerably in recent years and their full impacts on downstream processes such as dewaterability and digestibility are not fully understood. In this research, the effects of CPR on sludge digestibility and dewaterability were investigated in laboratory-scale experiments using sludge samples from a full-scale wastewater treatment plant. The results of the digestibility tests showed a 21% and 36% reduction in the biogas volume generated during anaerobic digestion of surplus activated sludge at 0.1 g/L doses of Al³⁺ and Fe³⁺ salts, respectively. This demonstrates that Al³⁺ dosing for CPR has less of a reduction effect compared with Fe³⁺ salts on biogas generation during anaerobic digestion of sludge. The dewaterability tests showed that primary sludge dewaterability was improved by up to 25% by Fe³⁺ and 16% by Al³⁺, while that of surplus activated sludge was reduced by 64% and 73%, respectively, at a metal salt dose of 50 mg/L. Consequently, a pre-precipitation process during CPR where phosphorus is removed in the primary tank would, therefore, enhance sludge dewaterability.

【 授权许可】

Unknown