Study On Advanced Treatment Of Coking Wastewater By Pretreatment And MBR Coupling Technique

Coking wastewater mainly comes from the process of coking and coking chemical recycling and refining, which has a large quantity and contains complex pollutant components. With the increasing of ecological requirements becoming more and more stringent and the quantitative management of environmental capacity, which makes the deep disposing of coked waste water and recycling technology research particularly important. Therefore, this study on the advanced processing of coking wastewater by "Pretreatment + MBR" coupling technology.Before the pretreatment, adjust pH or put the C u2+, Fe3+ and Fe2+ into the coking waster water, for the "mutual condensation effect" and ferrous blue method experiment to choose the appropriate "Each coagulant", and then under the synergy of in the Ca(O H)2 and PAM to exploring the most suitable process conditions, last but not least through the response surface method to optimize the test. The results show that when the concentration of H+ or metal ion system in reaches a certain value, then quickly destroys the stability of the colloidal dispersion of the coking wastewater and start cohesion the "mutual-condensation effect". In general, with the increase of metal ions increase the removal rate of pollutants increased. When the dosage of Cu2+, Fe2+ and Fe3+ were 160 mg/L, the decolorization rate were 96.3%, 92.5%, 87.5%, COD removal rate were 49.7%, 50.2%, 45.9%, of the total cyanide removal rate were 63.9% 68.5%, 59.1%. Comprehensive consideration, Fe2+ is most appropriate way to treatment of coking wastewater. Using the Design-Expert optimization program to optimize the test, set the dosing quantity of Fe2+, Ca(OH)2, PAM to minimize, set the removal rate of COD and the total cyanide to maximize, than comes to the best optimize condition of Fe2+ 160.51 mg/L, the Ca(OH)2, 1.8 g/L, PAM 2 mg/L, through the three groups of parallel experiments, the average removal rate of COD and total cyanide compared to the prediction relative errors were 0.06% and 0.05%, which verified the method of Response surface methodology to optimization of experiment is feasible.PVC/PVA membrane has excellent hydrophilicity, the surface of compounding membrane can effective lower the interfacial energy between the compounding membrane and raw water, which has higher water flux and anti-pollution capacity. The SEM results showed that the fracture surface of PVC/PVA compounding membrane are multi-channel finger pore strcture, the aperture of the surface of membrane are between 0.01~0.3?m, which has higher water flux and reject rate. PVC/PVA static contact angle of 65.2°.and the water flux of dry membrane and wet membrane are 9.27L/(m2·h·kPa) and 9.54L/(m2·h·kPa). The decline of dry membrane pure water flux only 2.83%, which shows that the PVC/PVA compounding membrane can be preserved in a dry way. Hydrophilicity PVC/PVA compounding membrane has favorable stability, anti-pollute and water flux recover rate. Using the model of Monod to degradation kinetic characteristics, which results the constant of organic material degradation KS=185.92mgCOD/L, the organic complex maximum degradation rate vmax=0.42d-1, they can provide a reference for MBR advanced processing of coking wastewater design.Hydrophilicity PVC/PVA membrane have a favorable performance in advanced processing of coking wastewater, the condition of membrane pollute can be controlled effectively, the water quality can satisty the limiting level of chart 1 of GB16171-2012, the water can be used by coal washing, coke cooling, flush dregs of blast furnace and so on. The unit processing cost about 1.18yuan/m3 when we take the combination of "Pretreatment+MBR" technology to deep disposing of coked waster water, the economic advantages are very extrude.