Biochar/Clay Composite Particle Immobilized Compound Bacteria: Preparation, Collaborative Degradation Performance and Environmental Tolerance

Immobilized microbial materials can effectively remove pollutants from surface water, and a biochar/clay composite particle (BCCP) material is prepared with immobilized Flavobacterium mizutaii sp. and Aquamicrobium sp. to remove ammonia nitrogen (NH4+–N) and petroleum hydrocarbons (PHCs). The results indicated that the optimal ratios of biochar, Na2SiO3 and NaHCO3 were 15%, 3%, and 3%, and the adsorption process was found to be better described with the pseudo-second-order kinetic equation. The individual immobilization of Flavobacterium mizutaii sp. and Aquamicrobium sp. with sodium alginate–polyvinyl alcohol (PVA + SA) achieved 80% and 90% removal efficiencies for NH4+–N and PHCs at the 10th d. The composite immobilization of two efficient bacteria could degrade 82.48% NH4+–N and 74.62% PHCs. In addition, immobilization relieved the effects of temperature and salinity. This study can provide guidance for the application of immobilized microbial composite materials in natural water environments.