Research on the Removal of Organic Matter from Rice Washing Wastewater by the Combination of Bacteria and Algae

Abstract:

The decomposition and removal of solid particles from rice washing wastewater by Aspergillus oryzae, Bacillus subtilis, Bacillus amyloliquefaciens and Saccharomyces cerevisiae were investigated, along with evaluating the feasibility of using treated wastewater for microalgal cultivation. The data showed that Aspergillus oryzae exhibited the best solid removal efficiency, which was (89.320±0.052)%, and Bacillus amyloliquefaciens demonstrated the best solid degradation efficiency, with an increase in soluble nitrogen concentration by (327.52±0.08)% and phosphorus concentration by (505.42±0.42)%. Rice washing wastewater treated with different microbial strains was used to culture Chlorella vulgaris. After 5 ?d of culture with wastewater treated by Bacillus amyloliquefaciens, the cell concentration reached 1.2×10⁸ cells/mL. Under similar culture conditions, the microbial biomass of this group reached 1.4 times that of the BG-11 culture medium. With microalgae, the Bacillus amyloliquefaciens group exhibited removal rates of 84.450% for TN, 95.079% for TP, 85.710% for NH₄⁺-N, and 90.413% for COD in rice washing wastewater. The results showed that the treated rice washing wastewater could be used as a source of nitrogen and phosphorus for the cultivation of microalgae, enabling high-value utilization of rice washing wastewater through combined bacterial and algal treatment