A review of the eco-revolution of organic carbon capture in wastewater treatment: limitations and coupled processes

The organic carbon in wastewater is a potential resource. Using sludge as a carrier for organic carbon in hydrolysis acidification and anaerobic digestion maximizes utilizing organic carbon resources and reduces sludge. Organic carbon capture systems must be established to enrich the sludge with additional organic carbon. This review systematically expounds on the mechanism and processes of organic carbon capture. However, the organic carbon capture process still needs several challenges, as evidenced by the low carbon capture efficiency, the loss of organic carbon due to mineralization, and the reduction in overall system operational efficiency due to the degradation of sludge settling performance. A method to improve carbon capture efficiency and stabilize sludge settling performance through enhanced extracellular polymeric substances secretion is clarified. A carbon capture coupled partial nitrification-anammox and denitrification phosphorus removal-endogenous partial denitrification process is proposed for nutrient removal in a carbon capture system for the first time. In this way, the demand for organic carbon in the nutrient removal process is reduced, and energy consumption for aeration is saved.