The Experimental Study Of Photochemical Oxidation To Degrade The Refinery's Alkali Wastewater

Large quantities of organic waste water with complex composition produced by the refining industry, especially the one containing alkaline, is very difficult to be treated. With normal alkaline content of 5% to 10%, pH value above 11 and high density of phenol, sulphide, mercaptan and naphthenic acid, the waste water makes a foul smell and contaminates the surrounding environment severely. In addition, as its COD value often exceeds 5000mg/L, it will affect the successive biochemical system and the normal operation of the treatment system as well as the final water quality. For this, many national refineries is striving to solve this tough problem.In this work, photochemical oxidation technology is introduced to degrade the refinery's waste buck, and explore the possibility of this technology for the degradation of high density organic waste water.This work is mainly concerned with the design of reactors for industrial use, the experiments of O3/UV,AIR/UV,AIR-O3/UV,TiO2/UV/H2O2 processes, and the comparison between treatment results of waste water using different processes.In this work, all contamination indexes of waste water, such as COD, Oil, Ar-OH,S,NH and BOD, were determined. Treatment results of different treating methods, such as UV/O3,UV/AIR,UV/TiO2/H2O2 were compared. The effects of density, measuring method and reaction time of UV,O3,H2O,TiO2 on the treatment results were investigated. The waste water biochemical ability was improved by the UV/O3 method. The use of photochemical oxidation method to degrade the refinery's waste buck was studied to determine optimum conditions for pretreatment.The following conclusions can be made that (1) the method of Air-03/UV is the best process combination for waste buck pretreatment; (2) the density and contact time of O3 are factors determining for the degradation results. Under the condition of O3's density of 0.1A, first blow air into the reactor for half an hour, then remove the S " and put into 1.5HO3/UV, The average degradation rate of COD, Oil, Ar-OH and S2" which was respectively to 43.4%,46.3%,74.5% and 96.7%, meets the requirements of pretreatment respectively; (3) By using UV/O3 method, the average BOD/COD value increased to 0.45 after treatment, and the waste water's biochemical ability had been improved; (4)This work provides technical reference for the development of new technology for the refining industrial waste water treatment.Based on these studies, A Pseudo-first-order kineties model for COD removal by UV/O3 was proposed and proved.The experimental results show that the technology can meet all treatment requirements. It has the following advantages:reaction can be made under normal temperature and normal pressure, the contaminant can be degraded quickly and completely without foul and colour, and the process can be controlled easily. Comparing with other technology, as there is no sludge ensued from the reaction process, so sludge treatment is not necessary, it costs economically and saves space. This technology is the best choice for such waste water treatment process. Now it has been applyed as a topic to Science and Plan Projects, and planned further small-scaled industrial work.