Study Of New Technology On Biological Denitrification For Post-Treatment Of Anaerobically Digested Effluent Of Piggery Wastewater

Anaerobically digested effluent of piggery Wastewater had the characteristic of high ammonia, low C/N, which is hard to biodegrade. Sequencing Batch Reactor was used to treat anaerobically digested effluent by means of adding some swine waste to increase the biodegradability in order to accelerate denitrification?complement alkalinity, and maintain pH to guarantee the stable performance of degradation for ammonia. Then in order to find the effecting factors of via nitration, such divisors as addition amount of swine waste, inflation quantity, running cycle and concentration of free ammonia were chosen to make experiments. Finally under the optimisation condition the new technology on biological denitrification via nitrate was established to solve the puzzle for treatment of anaerobically digested effluent with high ammonia and low carbon.The results showed that after increasing the biodegradability, pH was between 7.5 and 8.0 and removal rate for COD and NH3-N achieved a significant improvement in system performance. Under the condition of adding 30% swine waste, inflation quantity of 180L/h and 3 running cycle per day, the removal rate for COD attained about 100% and the accumulation of nitrate was high. The rate of nitrification via nitrate is above 90%, which did good to realise shortcut nitrification.The chief factors effecting nitrification via nitrate included pH and diffluent oxygen (DO). If pH was between 7.5 and 8.0, the effect of ammonia oxidation was well and the accumulation of nitrate was high. If DO under 1.0 mg/L, the main processof nitrification was via nitrate and the rate of nitrification via nitrate was high. Adjusting addition amount of swine waste and diffluent oxygen could be regarded as path to realise shortcut nitrification.The results of denitrification experiments showed that C/N had apparent influence on the process of denitrification. The more C/N was high, the more the rate was fast. If the amount of TN was certain, when the rate of NO2-N was high and the concentration of NO3-N was low the rate of denitrification was higher.