MATao,YANJuanzhi,WANGJunli.Operational Efficiency and Mechanism of Granular Sludge Enhanced by Sludge-based Hydrochar[J].China Water & Wastewater,2026,42(11):89-96.
Operational Efficiency and Mechanism of Granular Sludge Enhanced by Sludge-based Hydrochar
China Water & Wastewater[ISSN:1000-4062/CN:12-1073/TU]
volume:
第42卷
Number:
第11期
Page:
89-96
Column:
Date of publication:
2026-06-01
- Keywords:
- granular sludge; hydrochar; nitrogen and phosphorus removal; functional gene; microbial community
- Abstract:
- To elucidate the enhancement mechanism of sludge-based hydrochar on phosphorus-removing granular sludge, this study prepared hydrochar from waste activated sludge and constructed sequencing batch reactors operated for 100 days with hydrochar addition gradients of 0-2.0 g/L. The effects on sludge characteristics, microbial community, and nitrogen and phosphorus removal performance were systematically investigated. Results showed that the hydrochar possessed a porous structure (specific surface area 68.5 m2/g, total pore volume 0.18 cm3/g) and abundant surface functional groups (e.g., hydroxyl and carboxyl). The optimal effect was observed at 1.0 g/L of hydrochar dosage, which significantly improved sludge compactness and granulation degree, and resulted in the highest richness of functional microbial communities. Proteobacteria (42.6%) and Bacteroidetes (21.5%) were the dominant phyla, with significant enrichment of phosphate-accumulating organisms (Candidatus Accumulibacter, 7.5%) and nitrifying bacteria (Nitrospira, 4.9%). The abundance of the ppk1 gene increased by 2.3 times, and key enzyme activities reached their peak. In this group, the removal efficiencies of total phosphorus, ammonia nitrogen, and COD reached 96.8%, 98.5%, and 94.6%, respectively. However, excessive addition of hydrochar (2.0 g/L) induced hollowing of granules, leading to a decline in functional microbe abundance and treatment performance. Hydrochar optimizes sludge properties and enhances granulation through a synergistic mechanism involving microbial regulation and substance transformation, providing theoretical and technical support for advanced nitrogen and phosphorus removal in wastewater and sludge resource recovery.
Last Update:
2026-06-01