The microbial degradation of AAOO based cutting fluid wastewater

Wastewater from cutting fluids, which contain high levels of oils and additives, is difficult to handle. In this article, the biotreatment method of anaerobic (A1) + anaerobic (A2) + aerobic (O1) + aerobic (O2) was used for the cutting fluid wastewater treatment. GC–MS, FTIR, microscopic inspection, and high-throughput sequencing were used to explore the degradation mechanism of the AAOO biosystem. The research results showed that the degradation rates of COD, N3HN, TN, and TP in the cutting fluid wastewater could reach about 90 % after treatment with the AAOO biosystem. The order of hydrocarbon degradation from easiest to hardest was as follows: straight-chain alkanes/cyclic hydrocarbons, branched-chain esters, aromatic compounds, and complex cyclic compounds. Desulfovibrio, Acinetobacter, Extensimonas, and Acidovorax were dominant bacterial genera in the AAOO biological system and played important roles in the degradation of N, P, and COD. There were complex interactive relationships between the microbial community and the environment in the AAOO biosystem, mainly including metabolite exchange, metabolite production, and signal transmission. Adding carbohydrate sources such as glucose and starch may promote microbial growth in the biodegradation system and enhance the treatment efficiency of cutting fluid wastewater.