| The denitrification technology of high nitrogen organic wastewater, currently, is a difficult problem. So it is necessary to put forward a feasible process that is useful for nitrogen removal and advanced treatment of high concentration nitrogen wastewater.Nylon-6 production wastewater has the characteristic of high concentration nitrogen and good biodegradability, the main contaminations of which are CODCr and caprolactam, as well as few oligomers and oil solution. In this paper, optimal operating parameters were achieved, nitrogen transformation and removal theory in the system were also discussed. In addition, the characteristics of the biofilm and organic substances degradation were analyzed in this paper. Furthermore, biofilm growth dynamic models were established.The experimental results showed that circumfluence ratio, HRT, organic loading and DO were all the important affecting factors on the system performance. When the system is HRT=12.0 h, hydraulic loading for 1135.33 mg/L, nitrification liquid reflux ratio for 3, pH value maintained at 5.5 to 6.5, volume loading for 2.94 kg/(m3·d), dissolved oxygen controlled in 3.0～3.5 (1# oxidation ponds),1.8～2.3 mg/L (2# oxidation ponds), the condition is the optimal operating conditions for hydrolysis acidification-sbr-contact oxidation-two paragraphs biological contact oxidation ponds processing polyamide wastewater.The results showed that DO and hydraulic loadings were the important affecting factors in the advanced treatment. When gas ratio of water is 2:1, the average removal rate of CODCr, NH3-N and TN reach maximum, respectively, are 48.30%,84.24% and 42.18%.Improving gas water has obvious inhibition in biological aerated filters synchronous denitrifying denitrification. When the hydraulic loading for 0.4 m3/(m2·h), CODCr, NH3-N and TN the average removal rate reaches maximum, respectively 48.53%,84.81% and 42.55%. High hydraulic loading, go against CODCr, NH3-N and TN removal. Moreover, different characteristics of each substance removal in UBAF were presented. COD removal mainly occurred after the influent port 60cm in UBAF, NH3-N and TN removal mainly occurred in UBAF 20-80cm range.Using the return sludge, the surplus sludge backflow to the anaerobic segment of the A/O1/O2 technology can effectively achieve the of the surplus sludge digestion. Comprehensive consideration of the discharge standards and the stable operation of the system, the selection of A section volume kg CODCr/m3 load in 254d around as the system runs normally load. In addition, hydraulic retention time of system accumulated inert materials the excretion of influence. The wastewater A section hydraulic retention time for 7.55 h or so, can satisfy the requirements and standards of wastewater sludge system implementation of effective reduction. Meanwhile, return sludge to A of quantity-reducing, sludge (cell) in N, P the release effective compensation polyamide fiber production wastewater C/N/P disorders faults can be greatly reduced to system add N, P nutrient expenses.The infrared spectrograms showed that CO-NHR, amide I, CH3-R, CH2-R, C-CO-C, C-NO2 and HCO3- were included in seven wastewater samples.The relationship between biofilm growth and substances concentrations was reflected in the biofilm growth dynamics model, and the varying trend of substances concentrations along with UBAF height was also reflected in the substances removal dynamic model.
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