Research Of Advanced Treatment And Recycling Technology Of Coal Chemical Wastewater

The coal-based energy situation in our country determines the important position of coal chemical industry in the future for a long time.The overuse and pollution of water resources brought by coal chemical industry has become one of the most serious environmental problems.The advanced treatment and recycling technology of coal chemical wastewater were studied in the thesis.The overall situation is grasped by the analysis of the source and quality of wastewater in the park,which is divided into four categories:high tar,ammonia nitrogen or volatile phenol content wastewater;Saline wastewater;Methanol production wastewater and the others.The first one is fed into A/O/O biochemical system after pretreatment.Through the analysis of the biochemical system,the quality of the wastewater to be advanced treated is fully grasped.Base on high content of phenolic and cyanide organic substances,deep chroma,high content of CODcr and ammonia nitrogen in the biochemical effluent,a capacity of 0.6 t/h of double-membrane advanced treatment technology with ultrafiltration and nanofiltration as the core was developed.The turbidity,CODcr,ammonia nitrogen,total hardness,conductivity,water temperature change,system operating pressure,operating pressure and membrane pressure drop of nanofiltration system,flux change of ultrafiltration membrane in the process of advanced treatment were studied.The operating pressure of ultrafiltration is 0.07 MPa,the operating pressure of nanofiltration is 0.7 MPa and the pressure difference is below 0.1 MPa,and it should be cleaned regularly depending on the situation.The application of this technology were investigated.The effluent water quality of advanced treatment meets the requirements of industrial circulating cooling water quality,and partial recycling is realized.The characteristics of the membrane filtration concentrate were analyzed,and the optimal technological conditions of the ozone oxidation and Fenton oxidation treating the concentrate were determined experimentally.Ozone oxidation method:p H=9,ozone dosage is 40.8 mg/min,reaction time is 50 min.COD removal rate is about 50%,chroma removal rate is above 95%,and ammonia nitrogen was not removed.Fenton oxidation method:H₂O₂:COD（mass ratio）is 2:1,p H=4,reaction time is 50min,H₂O₂:Fe²⁺（mole ratio）is 6:1,stirring speed is 80rpm/min,reaction time is 50min.The COD removal rate is70%,ammonia nitrogen removal rate is 80%,and chroma removal rate is more than 74%.Comparing the two methods,Fenton oxidation method is selected.Figure 28;Table 13;Reference 55...