Efficient pollutant removal from deodorization wastewater during sludge composting using MBR-CANON process

Sludge composting is one of the most economical and effective sludge disposal method at present. However, the composting process releases massive odorous gas, and the gas removal process produces a large amount of deodorizing wastewater with low C/N ratio (named as composting wastewater). In this study, completely autotrophic nitrogen removal over nitrite (CANON) process was adopted for treating composting wastewater. After treated, the ammonia decreased to 0-5 mg L-1, and the total nitrogen removal achieved to 0.200 kg m- 3 d-1. Although the introduction of composting wastewater reduced the hydroxylamine oxidoreductase enzyme activity, heme-c, and hzo gene, all of them could be recovered. Microorganisms secreted more extracellular polymeric substances to counteract the cell-damage caused by harmful substances. Chloroflexi, Proteobacteria, and Planctomycetota were detected as the dominant phyla in the system, and the relative abundances of Candidatus_Kuenenia and Nitrosomonas reached 19.8% and 2.8%, respectively. CANON process could be used for treating composting wastewater.

Automated summary

The CANON process was utilized for treating composting wastewater, resulting in decreased ammonia levels and increased total nitrogen removal rate. Microorganisms secreted more extracellular polymeric substances to counteract cell damage caused by harmful substances, maintaining system stability.