| Coke plant wastewater is a typical, containing high concentration ammoniacal nitrogen, and difficult biodegradational industry wastewater.?Because it contains lots of hard—biodegraded and toxicant substances,it is considered to be one of the most difficult industrial waste water to purify.The traditional method to deal with the coke plant wastewater is a means using by the active dreggy mud, which has less effect on the hard-degraded substance and ammoniacal nitrogen. According to characteristic of the coke plant wastewater, the paper studied the nitrogen removal mechanism and effect in detail by A2/O2 process, during which also added the immobilized preponderant bacilli at the process of O1 and made the study to treat the coke wastewater of the second coke plant which belongs to one of coal gas company in Taiyuan.Experimental results demonstrate: the effluent NH3-N and COD removal rate concentration could achieve 98.21% and 93.65%. While t NH3-N concentration was 203.53~674.93mg/L , COD concentration was 817.4~1874.2mg/L , pH value was 7.0~8.2 , and the average rate of circumfluence was 3.27.By comparation between a variety of methods of immobilized, the decision of this examination used for immobilization of polyvinyl alcohol (PVA) - borate-embedded. The advantage of this method is, PVA have low prices, and the method is easy to operate; the effect of introduction of dium alginate is good, and its protection microorganisms play a role in the and reduce the toxicity of boric acid, and this can improve the relative activity of microorganisms; it is easy to do solid-liquid separation, and be propitious to the next step that help to carry out the tests applied to industrial production of research.The key stage of the process controlling was aerobic reactor (O1), in which put the immobilized predominance bacterium could control the last effluent Ammoniacal—nitrogen. The experimental result showed: the temperature of the effluent wastewater was 25.1~27.8℃, the pH value was 5.9~7.3, alkalinity was 366.67~598.12 mg/L(measured by CaCO3), the NH3-N was 39.38~165.36mg/L(the average was 91.40mg/L), the HRT was 16.76~21.55h(the average was 18.21h),the average removal ratio of NH3-N was 87.04%. Before adding the immobilized predominance bacterium, the average removal ratio of NH3-N was 82.94%. So, adding the immobilized predominance bacterium made the average removal ratio of NH3-N increase 4.1 percent.After the experimentation the whole operating parameters had been got (This parameters was got by the best value when the average reached). Due to the result of this experimentation was adding immobilized predominance bacterium in the aerobic reactor O1 only, others had no changed, only got the statistical parameters of O1. Results as follows: When the reactor temperature is above 26.5℃, pH is 6.8, HRT is 18h, at the time of the highest NH3-N removal efficiency.It will make the chroma of effluent NH3-N reach the primary national standard (NH3-N <15mg/L) about"The standard of sewage comprehensive discharge"(GB8978-1996) to adopt the anaerobic-anoxic-aerobic-aerobic biological reactor(A2/O2), in which put immobilized predominance bacterium to deal with coke plant wastewater when the chroma of effluent of NH3-N increases constantly. This technology is technique feasible and has stable effect.
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