A critical review on the effect of different carbon sources on EBPR: Revaluation of performance and applications

Abstract

Enhanced biological phosphorus removal (EBPR), as one of the most sustainable and economical technologies for efficient P removal from wastewater, is widely applied in full-scale wastewater treatment plants (WWTPs). The types of carbon sources exert key effects on the performance of EBPR, resulting in different microbial communities. Polyphosphate accumulating organisms (PAO) contribute to P removal. However, the dominance of glycogen accumulating organisms (GAO) under certain carbon source can outcompete PAO, leading to reduced stability of EBPR and even system failure. A key aspect in the choice of carbon source is the potential to alter PAO/GAO ratio and thus the EBPR performance. The advanced investigations show more versatile metabolic pathways of various putative PAO (e.g. Tetrasphaera, Dechloromonas, Thiothrix) with different carbon source strategies, which could be beneficial for the full-scale WWTPs to increase the resistance to unstable environment. This review carefully re-evaluates the application of different carbon sources (sole, multiple or complex carbon sources) in the field of EBPR in recent years, with special emphasis on the fermentation products from wastewater and waste solids as an additional carbon source by different strategies. The application of waste fermentation as additional carbon source not only shows successful system performance, but also avoids the need for commercial carbon source input and alleviates the waste disposal problem, which could be a promising development trend in view of the insufficient COD of raw wastewater as well as the environmental pressure problem.