| Because of the pollution of surface water and sewage of small towns, sewage treatment ecological engineering technology of constructed rapid infiltration system (CRI) is in the rapid infiltration system (RI) based on the establishment of a new sewage ecological treatment technology, is becoming the focus of domestic research and application. Due to its process without adding medicament, also do not need the mechanical aeration and high energy consumption equipment, greatly reducing treatment facilities investment and operation cost, is the high efficiency and low energy consumption ecological wastewater treatment technology, and it’s very suitable for rural and small town sewage treatment. The removal rate of COD and ammonia nitrogen is better, but the removal rate of TN is less than 30%.In this study, the optimal operating conditions for the treatment of domestic sewage (pH, COD, CRI, ammonia nitrogen, hydraulic load and wet dry ratio) were studied in the short cut nitrification section after successful start-up of the domestic wastewater. Optimum operating conditions for the short cut denitrification section (pH, C/N ratio). Finally in shortcut nitrification and denitrification using Monod equation microbial proliferation in the column to the CRI simulation is discussed in the paper, the dynamic equation by using the mathematical derivation, and the corresponding kinetic parameters was determined through the analysis of the test data.CRI simulation column microbial biofilm start appropriate to start the sewage, by gradually increase the hydraulic load to system microbial biofilm formation, biofilm during six CRI simulation column should adopt the same water inlet, to exclude water quality fluctuation on the system of hanging membrane effect.CRI system in the best operating conditions of shortcut nitrification stage for the influent pH is 7.9, COD concentration control in about 200 mg/L, ammonia influent concentration in 60-80mg/L, the hydraulic loading maintained in 0.5-1.Om/d, wet/ dry ratio is 1:3. At this point the system effluent COD, ammonia nitrogen concentration lower, the system of nitrite accumulation phenomenon is obvious.CRI system in shortcut denitrification stage optimum pH value range between 7.0～8.0, when pH deviated from this range, denitrification rate decreased gradually, the influent C/N value between the 4:1-6:1, filter speed control within a proper range, the denitrification rate can reach more than 75%.Finally in nitrification stage using Monod equation microbial proliferation in the column to the CRI simulation are discussed, shortcut nitrification kinetics equation by using the mathematical derivation, verified and kinetic parameters of the low concentration and can better meet, high concentrations of error large, to derive the kinetic equation for in room temperature of 25℃,concentration in the degradation of ammonia nitrogen in 19.82～80.26mg/L. Also in shortcut denitrification stage get denitrification kinetics equation, short cut denitrification rate is only as a function of temperature and pH value. |
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