Construction Of Microbial Inoculum And Its Effects On Oil And Grease Wastewater Treatment

The pollution in rivers and lakes in China are resulted partially from oil and grease(O&G) originated from industry, slaughterhouse and domestic sewage, especially from restaurants. The fact that the degradation of protein and oil in O&G wastewater mainly depends on microorganisms designated that it is possible and important to isolate and screen out oil-degrading microorganisms and to setup an effective microbial community. Recently, the knowledge on setup of microbial community in optimization is scarce and just reaches to an extent that the screened bacteria were simply mixed and the degradation rate was tested. Thus, the underlying mechanisms between microorganisms interaction still remain unclear and further research is urgently required. On the basis of present methods of optimization, fractional factorial design was adopted to optimize microbe combination to get consortium YB, and then the degradability of O&G wastewater by YB was tested to confirm the rationality of optimization and provided the guidance for the further research on the application of O&G degradation consortium. The results are run as follows:1. Fourteen strains of bacteria were isolated from wastewater and activated sludge by crossed separation experiments, transparent rings screening experiment, lipase producing test, and the O&G wastewater degradation experiments.2. Six strains were separated from the eighteen strains by Plackett-Burman design experiments, O&G degradation experiments by single strain, a two-level fractional factorial design of experiments. The O&G removal efficiency of the selected six strains named as "consortium YB" on synthetic O&G wastewater treatment was 70.34%, which was much higher than the stain mixture before optimization (41.56%). It suggests that the optimization method be feasible and provide the theoretical basis for O&G degradation consortium. After identification, consortium YB contained Burkholderia sp, Bacillus sp, Yarrowia sp, Penicillium sp and Micrococcus sp.3. The CODcr removal efficiency of YB on real O&G wastewater was much higher (84.27%) than commercial mixed inoculums A (77.40%), both of which were much higher than the self-purification of real O&G wastewater. It is indicated that consortium YB has the value of practical application.