Treated Chlorine Bleaching Effluents With Fludized Bed Bioreactor

Firstly introduced the serious situation of the environment in nowadays of the world, analysed the environmental pressure that the paper making industry was facing, it's very clear that the treatment of the pulp chlorine bleaching effluents were very improtant and necessary. Secondly, the histories and current situations of fluidization techniques applied in environment engineering field are reviewed, the special feature and advantage of the fluidized bed bioreactor were also carried out. Depended on other people's experience and ideas of the writer, a inner-loop fluidized bed bioreactor was developed. The fluidized bed bioreator's hydrodynamics, microoganism domesticating character, biofilm degradating organic kinetics and flocculation subsequent treatment process in secondary sedimentation basin were studied.Treated pulp chlorine bleaching effluents with fluidized bed —flocculation process. The percentage of the effluence is 70%, TOC1 is 52mg/L, chromaticity color is 1487 C.U. Add nutritious substance to increase the COD load to 1250mg/L, BOD load is 400mg/L, then pump the effluents into the fluidized bed bioreactor. HRT of the bioreactor is 6h, gas flow rate is 0.75m~3/h, treated in normal temperature, charcoal phase holdup is 6%, with perfect biofilm on it. Treated the effluents outlet from the fluidized bed bioreactor with flocculation in the secondary settling tank. Flocculating agent and coagulant aid are PAC and PAM, their dosage were 200mg/L and 5mg/L. The treatment results were: COD is 125mg/L, removal rate is 89.7%; BOD is 30mg/L, removal rate is 92.5%, chromaticity color is 135 C.U, removal rate is 91%, TOC1 lower than 1 mg/L, remaval rate got 98.4%; TSS is 85mg/L, VSS is 65mg/L, met the national regulation set. Operation total cost account is 0.822 yuan/m~3. Compare to other treatment methods, it shows that the fluidized bed bioreactor treatment process have the features of good treatment results and moderately cost, It could be quite stable when there were shock loading happen. The system could be recovered quickly even though there is an accident stop.