Study On The Character Of Leachate Wastewater Effluent After Biological Treatment With Biological Activated Carbon Technology

In recent years, power generation by incinerating municipal solid wastes (MSW) is one of the ways in disposing wastes in metropolis, which shows a great advantage in pollutant minimization, resource ruse and detoxification of MSW and so on. However, this way in disposing MSW leads to the secondary pollution problem including leachate from MSW dumpsite, the character of which is different from that from landfill in high organic contents, toxicity and biodegradability. What is worse, there still remains much refractory contaminant in the leachate after the biochemical treatment resulting in failing to meet the discharge standard. This paper is a tentative study on the character of Leachate wastewater effluent after biological treatment with biological activated carbon technology. The main focuses are onâ‘ the ozone oxidation procedure in biological activated carbon pool;â‘¡the procedure of selecting, cultivating and immobilizing the engineering bacteria in biological activated carbon pool;â‘¢the biological activated carbon technology which is suitable to be applied to treat the Leachate wastewater effluent after a comparative experiment study on three biological activated carbon technology (natural bio-film of BAC1, fixation of engineering bacteria of BAC2, and fixation of engineering bacteria of o3-BAC3).Ozonization is not to change the amount of the organics, but to change its character and improve its biochemical degradation. The removal rate of UV₂₅₄ and the chroma is 29.03% and 48% respectively when ozone is used with the amount of 10mg/L. The UV₂₅₄/TOC is 0.0264 in the original water, and it changes to be 0.015 with the reducing rate of 48.31%. According to the standard that the water with UV₂₅₄/TOC , smaller than 0.02 is qualified to be dagradated. It shows that Ozonization helps to improve the biodegradability of the water. It is plausible to input the amount of ozone of 2mg/L with the time of 10min.The author makes use of the biotechnology to select three high effective engineering bacteria from activated sludge in biochemical treatment system aeration pool in Tong Xiong power generation plant of MSW incineration. These three high effective engineering bacteria are identified as sea bacillus, eegje bacteria and acinetobacter after 16SrDNA identification with different forms but high capacity in degrading organics in secondary leachate .Three high effective engineering bacteria goes through the process of microbial species expanding culture, and on the other hand, artificial immobilized biochemical activated carbon is created by physical circle absorption method.During the stable procedure, the author tries the flow rate of 15mL/min, 25mL/min, 35mL/min and 45mL/min to see the influence of flow rate on the method of BAC's degradation of organics. The monitoring data in experiment concludes that the flow rate, 25mL/min is the best choice for present study, allowing for the factors of efficiency and economy. When input amount of water is 25mL/min, the thickness of carbon layer is bigger than 70cm and the removal rate of UV₂₅₄ is lower than10% in the three processes. The TOC with the method of O3-BAC is 15% lower than that with the method of BAC1 and 10% lower than that with the method of BAC2. When the input TOC is 110mg/L, and the input flow rate is 15～25mL/min, the output TOC amounts to 60mg/L in a stable way. Taking TOC index into consideration, the measurement of O3-BAC in disposing leachate lives up to the secondary discharge standard (COD<300mg/L,that is, TOC<60 mg/L) in Standard of Controlling MSW Incineration Pollution (GB18485-2001). The biomass and biological activity decrease along the direction of water flow. With a consistent treatment and monitor, the author finds that BAC works by intermittent gas and water combined reverse washing, and the water consumption intensity is 2³ L/(s.m2), gas consumption intensity is 6 L/(s.m2), interval time is 1min, and the time of reverse washing is 20min. BAC needs one day for recovery after reverse washing.