RO-coagulation Treatment Of Paper-making Reconstituted Tobacco Leaves And Preparation And Application Of Iron-containing Activated Carbon

Generally,the manufacture of papermaking-reconstituted tobacco slice includes several processes as follows:extraction of tobacco materials and concentration,pulping,papermaking,dip-coating and drying etc.To produce 1 ton papermaking-reconstituted tobacco slice will produce 30?60 tons wastewater.The high concentrated organic wastewater from papermaking-reconstituted tobacco slice is refractory because of its large quantity of emission,complicated ingredients,high color and COD,critical fluctuant concentration.Hence,it is make sense to study the coagulation treatment for the reverse osmosis?RO?concentrate of papermaking-reconstituted tobacco slice wastewater.In this dissertation,iron/active carbon?PF-AC?was prepared and in which the iron component worked as oxidant and flocculant;the active carbon component worked as adsorbent,catalyzer and skeleton in floc growth process.And the RO concentrate coagulation treatment was studied by using polymeric ferric sulfate?PFS?,potassium ferrate?PF?,cationic polyacrylamide?CPAM?,active carbon?AC?and iron/active carbon?PF-AC?as coagulant or flocculant.The best pH value and dosage of PFS and CPAM were found by single factor experiment.A central composite design and response surface methodology were carried out to evaluate the effects and interactions of three factor,i.e.,PFS dosage,CPAM dosage,pH and to optimize the coagulation process.In addition,the functions of PF,AC and PF-AC in RO concentrate treatment were also studied.PF-AC was chosen to purify the RO concentrate after the PFS-CPAM coagulation treatment.The dosage range and dosing sequence of PFS,PF-AC and CPAM were studied by jar tests,and the results showed that if the RO concentrate(color = 975,COD = 404.96 mg·L^-1,pH = 7.56,conductivity = 6.21 mS·cm^-1)were coagulated by PFS(3000?3500 mg·L^-1),PF-AC(1500?2500 mg·L^-1)and CPAM(1000?L·L^-1),the treated effluent color,COD,pH and conductivity will be 16?29,30.83?47.78 mg·L^-1,6.91?7.15 and 6.77?6.86 mS·cm^-1 respectively,which can reach the first level A standard requirement of Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant?GB 18918-2002?.