Study On The Selection Of Highly Efficient Degradation Bacteria And Immobilization Process For The Treatment Of Containing DNT Wastewater

In this work, the selection of degradation strains for DNT and aniline and its immobilization processes were investigated, which was later combined with the three-phase biological fluidized bed and the absorption immobilization reactor for the treatment of actual wastewater, and the degradation kinetics were investigated.The high efficient bacteria was domesticated and screened from six different strains, which was able to utilize DNT and aniline under aerobic condition. Under the concentration of DNT 80 mg/L and aniline 1400 mg/L, the removal rate of DNT, aniline and COD were 81% ,99% and 94%, respectively. Under the optimal conditions, the degradation kinetics of high-efficiency bacterium was well fit with Andrews kinetic model with R= 0.9952.The results of adsorption immobilization experiments indicated that compared to the free bacteria, the immobilization bacteria had a higher tolerance for salinity and DNT. When the carrier dasage was 4 mg/L, inocula 8 mg/L and NaCl 1%, DNT 50 mg/L, aniline 300 mg/L, the removel rate of DNT and aniline reached 56% and 100% after 24h degradation, and for the free bacteria it was 14% and 52.7%.By comparing the mechanical properties and bioactivities of immobilized particles by different immobilization methods, the PVA-SA-H3BO3 method may be a promising technique. Then the optimum parameters were determined by orthogonal experiments which were bacteria inocula 5%, CaCl23%, crosslinking time 4 h and hardening time 2 h. Under the conditions of liguid-solid ratio 4:1 and NaCl 1%, the removel rate of 50 mg/L DNT and 300 mg/L aniline were 58% and 100%.The combination of the three-phase biological fluidized bed and the absorption immobilization reactor were carried out for the treatment of actual wastewater containing DNT. Under the optimum conditions of glucose dosage both 100 mg/L, HRT 20 h and 12 h, aeration rate 20 L/h and 30 L/h respectively. The average COD, DNT and aniline of the effluent were 254 mg/L-263 mg/L, 2.0 mg/L-3.6 mg/L and 0.5 mg/L-0.7 mg/L, respectively. Under the optimal conditions, the degradation kinetics of the two-grade reactors were both well fit with Lawrence-Mc Cartys kinetic model with R 0.9775 and 0.9901. By UV and GC-MS analysis, the water qualities of the inffluent and effluent were determined.