Study On The Screening Of Indigenous Bacteria And The Enhancement Of Exogenous Bacteria In Pollutants From Long-term Deposition Of Oil Sludge

The pollution of long-term deposition of oil sludge is universal.Its pollutants are characterized by complex composition,poor water solubility,poor bioavailability and high concentration.These characteristics of oil sludge are not conducive to the growth of microorganisms,and are highly toxic to microorganisms,so the treatment is more difficult.The combination of exogenous bacteria and indigenous bacteria can not only improve the antimicrobial ability of the entire system of microorganisms,but also enrich the species and number of microorganisms in the oil sludge,resulting in their combination having the effect of strengthening the treatment of sludge.Therefore,it is of practical value to study indigenous bacteria,exogenous bacteria and their mutual interactions for the actual remediation of old oil sludge pollution.In this paper,based on the determination of the number of viable bacteria in the degradation system?measured by the rapid fluorescence detection method?and the degradation efficiency?measured by the gravimetric method?,with the pollutants in the long-term deposition of oil sludge as the tested pollutants.The optimal conditions of the5 indigenous strains and the exogenous FF bacteria were optimized respectively,the optimal compounding ratio of 6 strains was determined,and the application conditions were optimized.The following results was obtained:?1?A fast and simple fluorescence detection method for the total number of viable bacteria was established to determine the optimal staining conditions for microbial live cells:resuspended cell cells Tris-HCl solution pH=8,OD_600nm value in the range of0.01?0.30,the range of dye concentration and dyeing time is 1-20?mol/L and 20-30 min respectively,staining can be fixed in the range of room temperature to 37?.the number of viable cells can be measured in the range of 10⁵?10⁹ CFU/mL;the standard curve of viable cell count of 6 strains was established?R²>0.99?;the method has good repeatability,stability and accuracy,and the relative standard deviation is RSD<5%.?2?Using 2 g/L of pollutants in long-term deposition of oil sludge as carbon source,5 strains of excellent indigenous bacteria?including T1 bacteria,T3 bacteria,T5 bacteria,NY bacteria and NYGB bacteria?and exogenous FF bacteria were screened out;all 6strains could be contaminated with hydrocarbons as the growth carbon source,amang which T1 bacteria,T3 bacteria,T5 bacteria and FF bacteria grew fast.The optimal conditions for single application of 6 strains are:initial inorganic salt pH=8,temperature 31.5?.?3?Co-metabolic carbon sources such as lactic acid,oxalic acid,and succinic acid can significantly promote the growth and degradation efficiency of strain T5 on sludge pollutants.The synergistic effect of succinic acid on degradation was most obvious,and there are many living cells;it can also promote the growth and degradation of strain FF Efficiency,When 0.7 g/L succinic acid coexisting for 4 days,the degradation rate increased by 13%and the number of viable bacteria is increased by more than 2 times;Rha can improve the degradation efficiency of T5 bacteria and FF bacteria by about 10%,and the number of viable bacteria is also significantly increased.?4?Under the optimal ratio of five indigenous bacteria and exogenous FF bacteria to treat the pollutants in the tested sludge,when the pollutants were added 1 g/L,inoculated with 15%,and succinic acid was used as a co-metabolic carbon source,the degradation rate increased by 6%in 3 days and the number of viable bacteria measured by fluorescence method increased significantly,reaching 1.69×10¹⁰ CFU/mL.