Pilot-scale integration of micron-sized powder carriers and a hydrocyclone separator enhances nutrient removal in wastewater treatment
Hong Wang, Boran Wu, Hongbo Han, Qun Gu, Xiaohu Dai
Abstract
Activity, abundance, and synergy of functional microorganisms are pivotal for wastewater treatment. Here, we developed a micron-medium biofilm composite sludge system, integrating powder carriers and a hydrocyclone separator to enhance functional bacterial enrichment and micro-granule formation. Powder carriers acted as bridges between zoogloea, facilitating coexistence of micro-granules (~115.8 μm) and suspended flocs, thereby improving microbial synergy. The pilot-scale system doubled treatment capacity without expansion or downtime, achieving effluent total nitrogen <5 mg L−1 and total phosphorus <0.3 mg L−1 at a hydraulic retention time of 4.85 h. Micro-granules enhanced sludge settleability, mass transfer, and endogenous carbon metabolism, including polyhydroxyalkanoate and glycogen synthesis, which provided essential electron donors for nutrient removal. Denitrifying and phosphorus-accumulating bacteria were enriched in micro-granules (4.46%), whereas nitrifying bacteria (1.25%) were concentrated in flocs. Differentiated spatial distribution balanced the sludge age conflict among functional bacteria. This work provided an efficient and low-carbon strategy for municipal wastewater treatment. Hong Wang and colleagues developed a wastewater treatment process using powder carriers and a hydrocyclone to enhance enrichment of functional bacteria and granulation. This offers an efficient, low-carbon solution for municipal wastewater treatment.