Study On Biodegradation Using Biofilm Technology Of EM

Effective Microorganisms (EM) are one kind of new bacterial reagent which consists of more than 80 microorganism species belonging to 10 different genera, mainly including photosynthetic bacterium, yeast, lactic acid bacterium and actinomyceto. At present, the technology of EM has already been applied to various fields, such as agriculture, aquaculture and environmental protection etc., and achieved great economic and social profits.The main research contents in this thesis mainly include the cultivating of EM and the application of biofilm technology in wastewater treatment. From this research, the following conclusions have been obtained:(1) Dominant bacterial species, photosynthetic bacterium, yeast, lactic acid bacterium and actinomyceto and mixed bacteria, could be obtained by cultivating EM stock solution in corresponding selective mediums after around 5 days' cultivation. When mixed medium was used, the growth rate and bacterium concentration were relatively high, and the biophase was relatively abundant.(2) The OD value of suspended bacterial liquid in EM medium has linear relation with the number of microorganism cells, so OD value can represent he efficiency of EM cultivation quite well.(3) When cultivated with fillings and mixed medium, EM could attach to the fillings and form biological films. Temperature has significant effects on immobilization rate of EM. When the temperature was more than 30 ℃and aeration rate was sufficient, biological films came into being around 10 days after cultivation using Attapulgite clay, montmorillonite, flexible material, combined material and soft material as the fillings. When the temperature was lower than 10 ℃, this process was completed one month after cultivation. The biomass from the biofilm was tested and the bacterial species and morphology were persistent with those of EM, which proving the success of immobilization of EM.(4) In sequence batch reactor (SBR), the removal rate of CODCr was 80%-90% when Attapulgite clay and montmorillonite were used as the fillings; in SBR with flexible material, combined material and soft material as the fillings, more than 70% of CODCr was removed.(5) In the experiment about the degradation of sewage using contact oxidation method, the removal rates of CODcr were kept around 70% when the temperature was lower than 10 ℃ using flexible material, combined material and soft material as the fillings.