Study On Novel Processs For Wastewater Treatment Of Waste Paper Pulp And Paper Mill And Scale-up Experiment

As an important basic raw material industry,papermaking industry has the characteristics of sustainable development and occupies an important position in the national economy.Due to the particularity of pulp and paper industry,a large amount of water will be used in the production process.After water recycling and process improvement,a large amount of waste water will also be produced.The main pollution indexes are chemical oxygen demand(COD),biochemical oxygen demand(BOD),p H,total nitrogen,total phosphorus,ammonia nitrogen and suspended solids.In order to avoid serious environmental problems,it is necessary to reuse and discharge waste water to reduce environmental pressure.There are many conventional disposal methods for pulping and papermaking wastewater,which are generally divided into chemical treatment,physicochemical treatment and biochemical treatment.At present,the methods widely used in the deep treatment of papermaking wastewater mainly include: coagulation method,adsorption method,membrane separation technology,advanced oxidation technology such as Fenton,ecological treatment method,biological enzyme method and combination technology,etc.Organic matter in waste water in different water treatment process section using solvent extraction GC-MS analysis test,found that SBR aerobic process,coagulation process and fenton oxidation process can be a large amount of residual organic matter in degradation of papermaking waste water,but as a result of a variety of ways mechanism is different,each process have different kinds of organic matter degradation.There is a synergistic effect between SBR aerobic process and coagulation process.Using the two processes at the same time in the treatment section of waste paper pulping and papermaking wastewater can effectively improve the degradation capacity of organic matter.Fenton has a strong ability of oxidizing and treating organic matter,but the undegraded organic matter can still be detected in the wastewater treated by Fenton.Compared with Fenton oxidation treatment,the new ozonation process developed in this paper can effectively remove organic matters in wastewater and significantly reduce the color of effluent,providing better conditions for in-depth treatment and reuse of wastewater after chemical oxidation.To further reduce the content of environmental pollutants in wastewater,the flocculation effects of various flocculants on impurities in wastewater were studied.PFS prepared from papermaking factory Fenton sludge as flocculant,and the factors of dosage of PFS,volume ratio of PAM to PFS,reaction temperature on COD removal rate of papermaking wastewater efficiency were optimized with response surface method.The results showed that the flocculant process could effectively reduce the pollutant content in papermaking wastewater,the optimum conditions were optimized by response surface method as follows,dosage of PFS was 1.04 m L/L,PAM to PFS volume ratio was 4.99:1,temperature was 31.54?.Under this condition,the COD removal rate of papermaking wastewater was 39.6%,which was consistent with the predicted value by the model equation.The COD removal rate of papermaking wastewater established by response surface method could be effectively predicted.Synergistic effect exists between PFS dosage and PAM/PFS volume ratio parameters,which affects COD removal rate of papermaking wastewater.In order to solve the problem that biochemical effluent from papermaking wastewater can hardly reach the requirement of discharge standard,single factor experiment was studied the advanced treatment effect by ozone oxidation.The results showed that,using nano copper oxide as the catalyst for papermaking wastewater ozonation,when the generation of ozone was 3g/L,dosage of catalyst was 0.25‰,temperature was 30?,reaction time was 30 min,the COD removal rate of papermaking wastewater was 95.7%.Effluent water quality could meet the requirement of GB 3544-2008 Discharge Standard of Water Pollutants for Pulp and Paper Industry.The reuse experiment of Cu O catalyst supported by porous material prepared by the laboratory shows that the catalyst can be reused for 5 times without treatment,and the COD removal rate is basically unaffected.The stability of the ozonation process is high and economically environment-friendly,and suitable for its engineering application to the advanced treatment of papermaking wastewater.In order to further reduce the content of harmful indexes in oxidizing wastewater,a membrane system consisting of inorganic membrane and reverse osmosis membrane(RO)was used to filter oxidizing wastewater.It is found that the membrane filtration system composed of inorganic membrane and RO membrane can effectively reduce the concentration of TDS,COD,chroma,conductivity,sulfate ion and iron ion in the wastewater treated by chemical oxidation.Among them,TDS,chromaticity,sulfate ions and iron ions have significant influence,which can be reduced by more than 95%.The membrane system still has good filtration effect after filtration of chemical oxidation wastewater in different time and times.Compared with inorganic membranes with different pore sizes,TDS,chroma,conductivity,sulfate ions and iron ions in chemical oxidation wastewater were significantly reduced after filtration by RO membranes.