Study On Municipal Solid Waste Leachate Treatment With Ozonation-Biological Activated Carbon

This research mainly focused on the advanced treatment of leachate from municipal solid wastes incineration plant by ozonation-biological activated carbon (BAC) process. Semi-batch ozonation test demonstrated that the removal of COD, color and UV254could be divided into a fast reaction stage and a slow reaction stage, in which direct ozone molecular reactions and indirect radical reactions dominated respectively. Ozonation could improve the biodegradability of test water. Color and UV254could be efficiently removed within short reaction time. It was difficult for the direct ozone reaction, which was the only ozonation pathway when pH was adjusted to3.98, to remove the recalcitrant pollutants, It also had been found that under basic condition, the increase of pH could improve the removal efficiency of the pollutants.The laboratory-scale continues-flow ozonation-two stage BAC test revealed that the process was successful in removing COD and color could to meet the discharge standard when ozone dosage was292mgO3/L and BAC hydraulic retention time (HRT) was4.3h, while an ozone dosage of 200mgO3/L or the ozonation-single stage BAC was unsuccessfull.In the end, an scaled-up ozonation-BAC process, in which the BAC unit was9times the volume of that in the lab-scale process was set up to investigate the effectiveness and stableness of the process during the long term operation, trying to provide a framework that enable the application of the process in the industrial treatment plants. The effect of activated carbon catalyzed ozonation-BAC was also investigated during this period. Results demonstrated that the scaled-up process was also successful in removing COD and color to meet the discharge standard under the same operating conditions with the lab-scale process. Most of the pollutants were removed by the economical BAC unit, making the low operation cost possible. The results of GC-MS indicated that the dominant pollutants in the test water were alkanes, aromatic compounds and heterocyclic compounds containing nitrogen, ozonation-BAC was effective in removing the later two kinds of pollutants, but difficult in removing alkanes. It had been found that activated carbon could improve the ozonation efficiency, the effluent COD and color of activated carbon catalyzed ozonation-BAC process could fully meet the standard when the ozone dosage was292mg O3/L and BAC HRT was8.6h.The above results and the stableness of the ozonation-BAC process during the operating period of8months suggested the possibility of the process in the advanced treatment of leachate from municipal solid wastes incineration plant.