Synchronized carbon capture and nitrogen removal from municipal wastewater in a novel HRAS-SNPDA system: Carbon and nitrogen metabolism pathways

The adsorption-biodegradation (AB) process exhibits dual characteristics of carbon capture and wastewater treatment, significantly enhancing the economic benefits of wastewater treatment plants. The proposed anaerobic ammonia oxidation (anammox) procedure offers a promising approach for further optimization. In this study, a novel system, synchronous nitrification, partial denitrification coupled with anammox (SNPDA), was developed to achieve advanced treatment of municipal wastewater and high-rate activated sludge (HRAS) effluent. The research identified the optimal feeding ratio and demonstrated stable operation under real wastewater conditions. Notably, the HRAS + SNPDA system achieved a remarkable total nitrogen (TN) removal efficiency of 94.9 %, yielding an effluent TN concentration as low as 2.4 mg/L. This performance underscored the system's proficiency in nitrogen removal. Moreover, the pivotal roles of microbial quorum sensing and multi-channel nitrite supply were elucidated in fostering the enrichment of anammox bacteria within the biofilm, reaching a significant abundance of 10.58 %. This microbial enrichment not only bolsters the anammox process but also contributes to the overall system's robustness and efficiency. This innovative technology marks a significant step forward in achieving simultaneous carbon capture and nutrient removal from real municipal wastewater, thereby providing a robust scientific foundation for the practical deployment of the AB process in real-world applications. Our findings underscore the potential of the SNPDA system as a transformative solution for sustainable wastewater management and resource recovery.