The Modified Conditions Of Bacillus Subtilis Immobilized Carrier And The Treatment Of Simulated Sewage

The carrier of immobilized microorganism can adsorb microorganisms, andcarrier can increase effective selectivity, adsorption of ammonia nitrogenand organic in the sewage. The infrared ring, the white zeolite and the naturalzeolite were modified in this study. The optimal modified solution and modifiedconcentration were researched. The sewage was treated with the operation ofcontinuous reactor, pH, dissolved oxygen(DO), chemical oxygen demand(COD)and ammonia nitrogen(NH3-N) in effluent were analyzed.For basic properties of Bacillus subtilis, the most suitable conditions tocultivate were that temperature was35℃and pH was7.5.Logarithmic phase ofBacillus subtilis was between9-15h. The infrared ring, white zeolite and naturalzeolite were modified by the different concentrations of NaCl, HCl, H2SO4,HNO3and NaOH solution, respectively. The Bacillus subtilis was immobilizedon the carrier. By modifying the natural zeolite in0.6mol/L of NaCl solution, theresearch obtained the maximum microbial adsorption, and the dry weight ofBacillus subtilis adsorped to carrier was0.160g, by modifying the white zeolitein concentrated HCl solution, the research obtained the maximum microbialadsorption dry weight was0.152g, by modifying the infrared ring in0.5mol/L ofNaCl solution, the research obtained the maximum microbial adsorption dryweight was0.133g. The adsorption dry weight of the natural zeolite modifiedreached the maximum value0.1602g when keeping the natural zeolite modifyingin the0.6mol/L NaCl solution for2h and bacteria adsorption time24h.The maximum treatment effect was obtained when taking the naturalzeolite immobilized with Bacillus subtilis into simulated sewage at35℃and pH7.5. With continuous operation of the reactor, pH stabled in the range of7~8, DO stabled in the range of4.5~5.5mg/L. The influent COD was750mg/L, Theremoval rate of the COD reached60%in8~10d, the effluent COD can bereduced to100mg/L in10~20d. The influent NH3-N was30mg/L, the removalrate of the NH3-N reached60%in8~10d, the effluent NH3-N can be reduced to5mg/L in10~20d.