Study On Treating Wastewater Containing First Controlled Contaminant By Oxidation-Coagulation

With the development of the petrochemical industry, light industry, textile industry, and foodstuff industry, more and more high concentration organic wastewater has been discharged by pesticide, dye, medication, spice, additive industry and so on, which is very harmful to the environment. Most of the organic wastewater contains many unbiodegradable contaminations such as phenol, nitrobenzene, and aniline. There are many treatment methods to treat these wastewaters, such as physical methods, chemical methods, physical-chemical methods, biochemical methods, fire methods and so on. These methods both have merits and demerits. Based on the related information home and abroad, this dissertation summarizes the harm of phenol, nitrobenzene, and aniline wastewater to the environment and the recent application of treatment technology; produces polyelectrolyte coagulant by polyacrylonitrile; studies the oxidation-coagulate way to treat three organic wastewaters through a great deal of experiments combining the theory of oxidation. Major research work and conclusions are summarized as follows:(1) The study on producing polyelectrolyte coagulant by reaction of polyacrylonitrile's alkaline hydrolyze is developed. When the proportion of materials(polyacrylonitrile:NaOH: H_<sub>2O) is 1:2.4:0.4 at the temperature of 80—90℃, the most production can be get after 30min which can depress the chaotic degree and accelerate sedimentation speed of wastewater when associating with polymeric aluminum chloride. Compared with the polyacrylamide of market, this production is more choiceness and more cheap.(2) The study on treatment of the phenol wastewater by oxidation-coagulate method is performed. Based on the theory of Fenton and coagulate, the oxidation- coagulate way to remove the phenol of wastewater is suggested. The more reasonable reagent proportion and reaction condition is get as follows: when the W_phenol: Fe²⁺ is 1, adjusting the pH value of waste water to 3⁴, adding Fe²⁺ solution and H₂O₂ solution( the Fe²⁺/H₂O₂ is 1), reacting 30min, then adjusting the pH value to 8⁹ to make the oxidation reaction pause, adding polymeric aluminum chloride and hydrolyze production (the proportion is 5:1) to coagulate, at last adjusting the pH value to 10, filtrating, the removing ratio of COD of wastewater is 77.2%. The capability of biodegradable is multiplified two times. At thesame time, using sodium hypochlorite as a substitute for H2O2, the result of treatment is inferior.(3) The study on treatment of the nitrobenzene wastewater by oxidation-coagulate method is performed. Based on the theory of Fenton and coagulate, the oxidation-coagulate way to remove the nitrobenzene of wastewater is suggested. The more reasonable reagent proportion and reaction condition is get as follows: when the W nitrobenzene: Fe2+ is 1.5, adjusting the pH value of waste water to 3-4, adding Fe2+solution and H2O2 solution( the Fe2+/H2O2 is 1), reacting 30min, then adjusting the pH value to 8⁹ to make the oxidation reaction pause, adding polymeric aluminum chloride and hydrolyze production (the proportion is 5:3) to coagulate, at last adjusting the pH value to 9, filtrating, the removing ratio of COD of wastewater is 86.1%. The capability of biodegradable is increased one times. At the same time, using sodium hypochlorite as a substitute for H2O2, the result of treatment is inferior.(4) The study on treatment of the aniline wastewater by oxidation-coagulate method is performed. Based on the theory of Fenton and coagulate, the oxidation- coagulate way to remove the aniline of wastewater is suggested. The more reasonable reagent proportion and reaction condition is get as follows: when the W aniline: Fe2+ is 2, adjusting the pH value of waste water to 3-4, adding Fe2+solution and H2O2 solution( the Fe2+/H2C>2 is 2), reacting 30min, then adjusting the pH value to 8-9 to make the oxidation reaction pause, adding polymeric aluminum chloride and hydrolyze production (the proportion is 5:3) to coagulate, at last adjusting the pH value to 9, filtrating, the removing ratio of COD of wastewater is 77.2%. The capability of biodegradable is increased two times. At the same time, using sodium hypochlorite as a substitute for H2O2, the result of treatment is inferior.