Breeding Of Thermophilic Bacteria In Sludge Bio-Drying

With the rapid development of urbanization and increasing requirement of water quality in recent years,the output of sludge is also accompanied by continuously increases of living sewage and industrial wastewater.Emerging at the right moment,bio-drying technology has very broad prospects for development,because of the characteristics of energy saving and environmental protection.As the core of the technology,thermophilic bacteria's selection is particularly important.It essentially affects the sludge drying process.So thermophiles screening is an effective way to improve the efficiency of biological sludge drying.This paper took Shenyang northern sewage treatment plant sludge as the experimental material.This paper extracted thermophiles from the high temperature test samples and made isolation and purification.Thus the test got eight wild thermophilic bacteria strains(R1?R8).Then the test screened strains R2,R3,R6 and R7 by measuring the moisture content of the sludge after inoculation.After that this test made mutation breeding for screened strains R2,R3,R6 and R7 to get optimal mutant strain.Test found that the mutant strains R2-3,R3-1,R6-2,R7-2 is their optimal mutant strains,respectively as T2,T3,T6,T7.Optimum combination results.showed that mutagenic in the case of proportion of vaccination for breeding strains T2T3T7 2:2:1 combined,biological sludge drying effect is best,for the moisture content down to 49.6%.During mixed culture of mutagenesis breeding strains T2T3T7 combination,it is concluded that the best mixed culture conditions is 55 temperature,C/N at 12/1,pH 7,table speed 170 r/min.Under the optimal culture conditions,growth curve determination found bacteria grow into the plateau at 36h.Therefore in the application,the 36h is considered as the optimal drying time of the flora.Next through putting combination breeding strains of the inoculation 0%,3%,5%and 0%respectively into biodrying bioreactors,the paper researched its influence on urban biodrying process.The study found that putting external bacterium agent into biodrying,the effect was more obvious.In biodrying process,compared with not putting external bacterium agent,putting external bacterium agent into biodrying can rise by 19 temperature of the sludge pile body.The moisture content can reach 43.1%,lower than not putting external bacterium agent by 21%.After putting external bacterium agent,the maximum expansion range of pH of pile body material increased to 7.36?8.40.Which can be more suitable for the growth of microorganisms,and the material content of volatile solid VS can be down to 42.51%,lower by 9%.Comparing different inoculation amount of bacteria agent,it can be found that the inoculation quantity of 5%for biological sludge drying is best,when the change of various index is considered.Finally by PCR technology and using 16s rDNA sequence analysis method,the paper determine the species.The wild thermophilic bacteria strains R2,R3,R6,R7 was Brevibacillus thermoruber,Brevibacillus borstelensis,Brevibacillus sp.S12,and Brevibacillus fulvus respectively.Mutagenesis breeding strain T2,T3,T6,T7 was Bacillus licheniformis,Bacillus spA296,Bacillus spTG4,Brevibacillus levickii,respectively.