Pilot Study On Short-Cut Nitrification And Denitrification Nitrogen Removal With Synthetic Ammoni Wastewater

Synthetic ammonia industry of our country is not only the basic inorganic chemicalindustry, but also one of key polluting industries. The main pollutants is ammonianitrogen, which can not only cause the eutrophication of water, but also affect thesustainable development of entire nitrogen fertilizer industry. Anoxic/aerobic （A/O）process is a kind of biological treatment of wastewater for synthetic ammonia industry,which is a widespread adoption. But this process is difficult to remove nitrogeneffectively, and the effluent can not reach the high emission standard problem. Inorder to meet the more stringent synthetic ammonia industrial water pollutantdischarge standards, the realization of A/O short-cut biological nitrogen removalprocess has important significance.Although many factors lead to nitrite accumulation, the main factor is variable indifferent wastewater and process. A pilot-scale study on shortcut biological nitrogenwith synthetic amminia industrial wastewater was researched in an aerobic-anoxicsystem. The industrial wastewater contained a high NH₄⁺-N concentration with80～110mg/L. The results showed that a stably short-cut nitrification and denitrificationwas achived after a period of90d operation. The accumulation nitrite was keepingabove80%. The mechanism analysis showed the main reason for getting the stablyshort-cut nitrification and denitrificationthe in the pilot system was attributed to thecollaboration of low dissolved oxygen （DO）, high free ammonia （FA） and appropriatehydraulic retention time （HRT）.In addition, The removal efficiency of COD、NH₄⁺-Nand TN was95%,99%and80%, respectively.Active sludge was from a pilot-scale synthetic ammonia industrial wastewatertreatment plant with an anoxic-oxic （A/O） technology.The results showed that short-cut denitrification could reduce14.1%carbon source consumption and55.7%denitrification time respectively, comparing with complete denitrification. Themaximum specific denitrification rate was0.509g/（g.d） with an initial NO_<sup>2--Nconcentration of36.82mg/L and pH7.5. In the industrial practice, it must be avoidedpH higher than9.0in anoxic zone for industrial treatment. Replication-selective denitrifying bacteria showed a strong adaptability to methanol and ethanol, butmaladaptation to other small molecular and easily biodegradable organics, such asglucose and acetic acid.The test also developed with the short-cut denitrification process with multipleparameters control system.According to the water quality changes, the system cancomplete real-time adjustment of quantity of key influence factor such as aeration, pH,carbon source addition and so on. It can realize denitrification process conditionsoptimization, and provides theoretical basis for practical application.