Study on the Effect of Anaerobic Microbial Flocculant on Cutting Fluid Wastewater

Biological flocculants are currently a research hotspot for the treatment of industrial wastewater. In this study, a microbial flocculant derived from anaerobic flocculant-producing bacteria was prepared and referred to as ABF in the article. Flocculant-producing bacteria were identified for their colony composition through genetic techniques, while ABF was characterized by Fourier transform infrared spectroscopy (FTIR), zeta potential, thermogravimetric analysis (TG), and dynamics stability. One-variable-at-a-time (OVAT) and response-surface-methodology (RAM) analysis were used to analyze the effects of factors such as the initial pH of cutting fluid wastewater, the dosage of microbial flocculant, and the dosage of demulsifier on the flocculation efficiency. Results revealed that the main components of the ABF were high-molecular compounds such as proteins, polysaccharides, and lipids. Its pyrolysis temperature could reach 155 °C, but its chemical properties were unstable and prone to flocculation and aggregation. The optimal experimental conditions for treating cutting fluid wastewater using ABF solution were a pH of 8.41, a flocculant dose of 1.20%, and a demulsifier dose of 1.70%. Under optimal conditions, the flocculation activity of ABF could reach 98.87%, and the chemical oxygen demand (COD) removal rate could reach 44.30%.