Study On The Characteristics And Advanced Treatment Methods Of Papermaking-reconstituted Tobacco Wastewater

Treatment of wastewater from manufacturing process of reconstituted tobacco is the key of the sustainable development of the tobacco industry under the premise of construction of environment-friendly and resource-saving society. Especially the wastewater from reconstituted tobacco by paper-making methods, which has highly concentrated, it can’t meet the emission requirements by traditional physicochemical+biochemical+decoloration treatment. Therefore, it is necessary to research on new technology or advanced methods to treat the wastewater. In this paper, the pollutants in the wastewater from the process of manufacture papermaking-reconstituted tobacco were detailed analyzed. The advanced treatment of wastewater by single coagulation process, single Fenton oxidation process, coagulation-Fenton process and heterogeneous Fenton oxidation were carried out, in order to provide technology and theory support for the practical application.The analysis of tobacco wastewater before biochemical showed that the wastewater is a kind of good biodegradation property, high concentration organic pollutant wastewater with CODCr above10000mg/L, and BOD5above6000mg/L. The analysis of tobacco wastewater before biochemical by non-aqueous titration method also found that the nicotine content in the wastewater is178mg/L. The analysis of tobacco wastewater after biochemical showed that the wastewater constituted of complicated pollutants, including esters, alkanes, amides, ect. The relation of CODCr and UV254was studied and they showed a good linear relationship.The advanced treatment of papermaking-reconstituted tobacco wastewater by single coagulation process, single Fenton oxidation process and coagulation-Fenton process were carried out. The effect of pH and the dosage of chemical reagents on wastewater treatment were mainly investigated. It was found that the Fenton process is better than coagulation process, but the result still could not meet the emission requirements. However, the coagulation-Fenton process had the best treatment efficiency, at the optimal condition the CODCrwas only81mg/L and wastewater chromaticity was only49.2C.U..Using heterogeneous Fenton method to treat the wastewater, Fe-Bent heterogeneous catalysts were prepared by impregnation. The catalyst Fe-Bent was characterized by X-ray diffraction（XRD）,Fourier Transform Infrared Spectrometer（FTIR）, Scanning electron microscopy（SEM），Atomic Force Microscope（AFM），N₂adsorption—desorption,Laser paniclesize analyzer and X-ray fluorescence（XRF）methods．It was found that Fe ion intercalatedinto the layer of Bent．At the conditions of pH=3，205mL/L H₂0₂and1750mg/L Fe-Bentdosage，80.78ï¼…COD_cr removal COUld be achieved with180min UV irradiation．TheBox-Behnken mathematical relational model between COD_cr remove rate and affectingfactors was established，and the technique of photo-assisted treatment wastewater wasoptimized．The results showed that，the optimum conditions were：initial pH value2.7，H₂O₂dosage2.4mL/L，catalyst dosage1830mg/L．At the optimum conditions，the COD_cr removerate was83.19％，validation experiments show that the result was reliable．In addition，themaximum dissolved iron，determined by atomic absorption spectrophotometer（AAS），wasless than1ppm．The kinetics results showed that degradation kinetics of wastewater was wellfitted by a first order equation．A possible catalytic mechanism of Fe-Bent was proposed．Itwas found that under UV irradiation the ferric ion on the surface of Fe-Bent can be convertedinto divalent iron ions，and·OH are produced by the action of divalent iron ions with H₂O₂，while·OH OXidative degradation organic pollutants to small molecule compounds orcompletely mineralized CO₂and H₂O．...