According to the kinetic analysis of nitrification anddenitrification, there is a point at which nitrification rate is equal to denitrification rate of 4.7mg/(Lh) when DO is about0.14mg/L, The ralated kinetics parameters are kN =0.37mg/L for nitrification and kD=0.48mg/L for denitrification.

3. In dynamic experiments, maximum specific nitrification rate (SAUR) of 4.55 NH3-N/gMLVSS ' h and maximum specific denitrification rate (SNUR) of 19.68 NO3-N/gMLVSS ' h ,which have been compared with SAUR and SNUR values by nitrogen balance calculation, were obtained, and maximum specific oxygen uptake rate (SOUR) of 75.7mgO2/gMLVSS h was observed.

Under the conditions of ammonia concentration ≤500 mg/L,99% NH~+_4-N conversion rate could be achieved and biomass in the reactor changed little. The specific nitrification rate increased from 0.2 kg/(kg·d) to 0.52 kg/(kg·d).

The removal rate of NH_3 is more than 92% and the nitrification rate of immobilized beads is more than 0. 63g N/kg immobilized beads(wet)·d,which is much higher than other deodorization techniques such as soil or biofilm treatment.

The total decay rate constant, KT, and nitrification rate constant, KN of ammonia nitrogen, and temperature coefficient,θ were obtained through simulation experiment and field sample determination.

The total decay rate constant kT, nitrification rate constant, kNof ammonia nitrogen and temperature coefficient θ we rse obtained through simulation experiments and field sample determinationn.

(2) The research results of domestic wastewater show that when HRT is 24h and temperature is between 20 to 24 degrees centigrade, the COD removal efficiency is about 90%, nitrification rate and TN removal efficiency reach 85% and 70%. The effluent concentration of NOa-N and NO2-N are about 15mg/L and Img/L respectively.

Under the condition of medium loading of BOD 1.0kg/(m3·d) and TN 0.19kg/(m3·d) respectively, the nitrification rate after reactor-comparting was enhanced 33%.

Furthermore,the biofilm nitrifying reactor with carbon fiber as carrier operates steadily during the operating period (nitrification rate approaches to 100%).

When the partitional reactor operating at high TN loading of 0.26kg/(m3·d), its nitrification rate declined due to decrease of nitrifying bacterium activity; while operating at low loading of 0.08kg/(m3·d), the too low NH4+-N concentration of rear-area limited the exertion of nitrification ability; therefore, the comparting reactor should be operated under medium loading.

Stable and high COD removal efficiency reached to 90%～95% and the specific nitrification rate at 30℃ was 0.3? kg(NH_4-N)/(kg(MLSS)·d). Ammonia, nitrate and nitrite in the effluent were reduced to detection level.

The experiment results show that when alkalinity is in excess and there is no organic load, the nitrification rate can be determined either by the ammonium concentration or by the oxygen concentration.

We have found that the oxygen concentration imposes a great influence on the nitrification rate when oxygen becomes a rate limiting factor. When the oxygen concentration is about 4.5mg/l, the nitrification rate can reach at 240gNOx N/m 3·d.

当氧的浓度为硝化反应限速因素时 ,氧的浓度对硝化反应速率有很大影响 ,当氧的浓度达到 4 .5 mg/ l时 ,硝化反应速率可达到 2 4 0 g NOx- N/ m3· d

As compared to SBR,COD degradation rate and nitrification rate in TSSBR were increased obviously. COD removal efficiency was increased from 84% to 93% as compared to SBR,but denitrification rate of two processes was almost same.

TSSBR avoided the inhibition of the high organic loading to nitrification and nitrification rate was two times of that in SBR under the high influent COD.

At normal operation, the nitrification rate obtained from the system was in the range of 0.14-0.87 gNH3-N/m2d and the denitrification rate was 0.04 gNO3-N/m2d.

The effect of monolerpenes on nitrification rate and growth of Nitrosomonas europaea was examined in whole-cell pure culture experiments using the five most abundant monoterpenes in coastal redwood needles.

The results indicated that aqueous extracts and residues of roots and shoots of all test cultivars significantly reduced the nitrification rate in soil.

Although simulated nitrification showed a stronger relationship with measured streamflow NO3- flux than did N mineralization, nitrification rate depended upon availability of soil ammonium supplied from N mineralization.

Nitrification rate and percent nitrification were highest at Sites 3 and 4.

The properties of fertilizer appeared under the interaction behaviors between nitrogen fertilizer applied in soil and components of soil such as adsorption by soil, leaching and volatilization from soil as well as nitrification and denitrification of nitrogen fertilizer are regarded as its agrochemical properties.Although ammonium bicarbonate is easy to decompose and volatilize and inconvenient to store, transport and apply, laboratory simulating experiments have showed that ammonium bicarbonate is more easily...

The properties of fertilizer appeared under the interaction behaviors between nitrogen fertilizer applied in soil and components of soil such as adsorption by soil, leaching and volatilization from soil as well as nitrification and denitrification of nitrogen fertilizer are regarded as its agrochemical properties.Although ammonium bicarbonate is easy to decompose and volatilize and inconvenient to store, transport and apply, laboratory simulating experiments have showed that ammonium bicarbonate is more easily adsorbed by soil, less leached from soil, as compared with ammonium sulphate and urea; and its volatilization sharply decreases after incorporating with soil; only the rate of nitrification is similar to that of ammonium sulphate and urea. There fore, if the method of deep application is adopted, its effect on crops in fields can also be similar to that of ammonium sulphate or urea.The volatilization process of ammonium bicarbonate, ammonium sulphate and urea can be simulated by power regression equation Y=Ax~b, and the correlation between the initial volatilization amount (mgN/h) and regression constant A is significant. Their nitrification process on different soils can be simulated by exponential equation Y=Ae~(bx), their initial nitrification rate (%) and regression constants A and B are approximate on the same soil but very different on different soils, which indicates that nitrification rate of nitrogen fertilizer after it being applied in soil depends mainly on the soil properties.

Nitrogenous pollutants transformation and temperature effect on the process in Tuojiang River were studied. The total decay rate constant, KT, and nitrification rate constant, KN of ammonia nitrogen, and temperature coefficient,θ were obtained through simulation experiment and field sample determination. A mathematical model with modified parameter estimation procedure for nitrogenous pollutants assimulation capacity was developed and used to calculate loading capacity of Tuojiang River for nitrogenous...

Nitrogenous pollutants transformation and temperature effect on the process in Tuojiang River were studied. The total decay rate constant, KT, and nitrification rate constant, KN of ammonia nitrogen, and temperature coefficient,θ were obtained through simulation experiment and field sample determination. A mathematical model with modified parameter estimation procedure for nitrogenous pollutants assimulation capacity was developed and used to calculate loading capacity of Tuojiang River for nitrogenous pollutants

Nitrogenous pollants transformation and principal effect on the process inTuojiang River were studied .The total decay rate constant kT, nitrification rate constant, kNof ammonia nitrogen and temperature coefficient θ we rse obtained through simulation experiments and field sample determinationn. A mathematical model with modified parameter estimation procedure for citrogenous pollutants assimulation capacity was set up and can be used to alculate loading capacity of Tuojiang River for nitrogenous pollutants....

Nitrogenous pollants transformation and principal effect on the process inTuojiang River were studied .The total decay rate constant kT, nitrification rate constant, kNof ammonia nitrogen and temperature coefficient θ we rse obtained through simulation experiments and field sample determinationn. A mathematical model with modified parameter estimation procedure for citrogenous pollutants assimulation capacity was set up and can be used to alculate loading capacity of Tuojiang River for nitrogenous pollutants.