A novel strategy for improving volatile fatty acid purity, phosphorus removal efficiency, and fermented sludge dewaterability during waste activated sludge fermentation. (1st January 2021)

• Record Type: Journal Article
• Authors: Chen, Yun; Ruhyadi, Roby; Huang, Jinjin; Yan, Wang; Wang, Guoxiang; Shen, Nan; Hanggoro, Wido
• Is Part Of: Waste management. Volume 119(2021)
• Page Start: 195
• Page End: 201
• Publication Date: 2021-01-01
• Subjects: Sludge fermentation -- Volatile fatty acid -- Nutrients removal -- Fermented sludge dewaterability; Hazardous wastes -- Periodicals; Refuse and refuse disposal -- Periodicals; 363.728
• DOI: 10.1016/j.wasman.2020.09.044
• Languages: English
• ISSNs: 0956-053X

Abstract

Graphical abstract: Highlights: Effects of different pH control treatments on WAS fermentation were studied. The purity of VFAs were enhanced by initial pH 10 fermentation (RIA). P removal efficiency and fermented sludge dewaterability was also improved in RIA. VFAs via RIA was a better way to applied as carbon resource into the WWTP. Abstract: Volatile fatty acids (VFAs) from waste activated sludge (WAS) via alkaline fermentation have been shown to provide an effective alternative carbon source for biological nutrient removal in wastewater treatment plants (WWTPs) that promotes the subsequent release of phosphorus (P) and refractory dissolved organic matter. The dewatering ability of fermented sludge is known to decrease during alkaline fermentation. Here, a novel strategy of initiating fermentation at a pH of 10 was developed to improve VFA purity, P removal efficiency, and fermented sludge dewaterability during WAS fermentation. Although VFAs concentration was lower (1.69 ± 0.09 g COD/L) when the pH was only initially adjusted to pH 10 (RIA ) relative to when the pH was maintained at 10 on a daily basis (RDC ), the purity of VFAs in the fermented liquid was improved (58.48%). Furthermore, the release of total phosphorous (TP) in RIA was 5.90 times lower than that in RDC (139.37 mg/L). The normalized capillary suction time and specific resistance to filtration in RIA decreased to 42.23% and 40.70%, respectively, suggesting that the dewaterability of fermented sludge also improved. The amount of alkali needed was 17.44 kg for each ton of total solid (TS) in RIA, which was 5.49 times lower than that in RDC . Thus, approximately 45.44 USD was saved in operational costs for each ton of TS processed in RIA . These results indicated that VFAs production via initial pH 10 fermentation was a robust and cost-efficient way for providing carbon resources in WWTPs.