Utilizable Treatment Of Effluent From High Yield Pulping Of Poplar By Aspergillus Niger

The requirements for practicable technology of effluent treatment from high yield pulping (HYP) had become emerging needs with the application and development of HYP technology in China. The loads of COD and BOD of HYP effluent are higher than it of mechanical pulping, but lower than it of chemical pulping, and the effluent contains some toxic organic compounds. Almost all of the effluent treatment technologies are not suitable for HYP effluent treatment because most of the inefficiency cause by the moderate load of pollution. In the other hand, the moderate load provides a chance for biological pre-treatment. The idea of cleaner production is making the best of every thing in all processes. Biological pre-treatment process is for the purpose of cleaner production. Biological pre-treatment can reduce the pollution load and produce biomass at the same time which may have some values in use in the future.Firstly, the relevance between the conditions of pulping and the pollution loads was studied in the article. The effects of dosage of NaOH, H2O2, Na2SiO3, and operator conditions such as temperature, time at maximum temperature on pollution load were studied in this article. The results showed that dosage of NaOH and H2O2, maximum temperature had remarkable effect on the pollutant load. The COD of the effluent in this article was between the10000and20000mg/L in convention conditions.Secondly, the conditions of biological pre-treatment were optimized by testing of Removal of COD and yield of biomass. The optimized pretreatment conditions were as follows:Aspergillus niger S13is the selected species, volume of germ is3%, medium pH6, culture for44-52h at150rpm,30℃. The removal of was48.77%and the yield of biomass was much than6g/L. The IR analysis showed that some pollutants has disappeared after the SI3pretreatment. UV-scan showed that the removal of acid-soluble lignin was up to60%and the removal of color reached28.57%after biological treatment.Finally, the separation of sludge from bio-pretreated effluent was studied. And flocculation sedimentation and centrifugal separation were put into application for the separation. The results showed that the flocculation separation was more effective than centrifugal separation. The removal of COD was as much as two times it of centrifugal separation at the dosage of PAC and APMP were50ppm and5ppm for flocculation separation. Further studies on biomass sludge shows that content of protein was8.91%, the total amino acid was9.1558%in the sludge. Eight kinds of essential amino acids were47.16%occupy of total amino acid in the biomass sludge.The biological treatment for APMP effluent was proved practicability from this work with Aspergillus niger S13.