Study On Biological Treatment Of Pulp-Papermaking Wastewater And Anaerobic Digestion Of Excess Sludge By Rumen Microorganisms

The pulp and papermaking industry is one of the most important industries in our country, which brings a lot of economic benefits, while also some environmental problems in the making process. An efficient and appropriate way to post-treat the pulping midcourse wastewater and pulp and paper mill excess sludge is pursued for long time. In this paper the technical feasibility of anaerobic digestion of pulp-papermaking wasterwater and excess sludge by rumen microorganisms was investigated. This study provides theoretical and technical support for future application of rumen microorganisms in the degradation of the contaminant in the pulping midcourse wastewater and pulp and paper mill excess sludge.Hydrolytic acidification-aerobic membrane bioreactor process was performed to investigate the anaerobic degradation performance and efficiency of pulp-papermaking wastewater by rumen microorganisms. Continuous stirred-tank reactor was applied to study the anaerobic degradation characteristics and VFAs production efficiency of pulp-papermaking excess sludge by rumen microorganisms. Batch experiments and continuous experiments were performed. The experiment conditions were T=39±1?, pH= 7. Gas chromatography (GC) was used for the detection of the VFAs and the biogas. The SCOD, MLSS, MLVSS and chromaticity were measured by the National standard method. Microbial population structure, dynamic change process and stability of rumen microorganism were studied by MiSeq sequencing.Hydrolytic acidification-aerobic membrane bioreactor process was performed to treat the pulp-papermaking wastwater. The optimum conditions were MLSS 2500 mg/L, SRT 9 days and HRT 27 hours. Although the SCOD removal rate was not very high, the VFAs was stabilized at about 200 mg/L and the ratio of BOD/COD was increased from 0.34 to 0.45-0.5. The system has been operated for 3 months under the optimum conditions, the average COD removal rate reached 91.9%, the effluent COD?100 mg/L, the removal rate of chromaticity and TSS were 75.6% and 90.4%, respectively. The effluent can satisfy the discharge standard.Continuous stirred-tank reactor was applied to treat the pulp-papermaking excess sludge. The optimum conditions were:input sludge concentration 10% and SRT 20 days. Under these conditions, the average biogas output was 280.2 mL/g-TS, the average volume gas productivity was 1188.4 mL/L·d, the average CH4 and CO2 content in the biogas was 65.1% and 34.2%. These results illustrated that the CH4 production efficiency with rumen microorganism is higher than that with common inoculated sludge.The results indicated that the rumen microorganism could domesticate in vitro and formed new flora structure. The rumen microorganism could degrade the organic contaminants of pulp-papermaking waste water and sludge. The study provides new strains and a new way to the anaerobic biological treatment of pulp-papermaking wastewater and excess sludge.