The Research Of Treatment Technology On Wastewater From Synthetic Ammonia Gas-making Process

A great deal of gas—making wastewater is produced in compounding ammonia process, which contains a great variety of pollutants and complicated components, particularly high concentrated SS and poisnous CN^-, accompanying with high temperature , which is hard to be treated. There are many methods to treat the wastewater. Usually people adopt "precipitation + bio—tower + impulse—clearer". The method is mature.but it has many problems such as hung—membrane difficult, tower jamed, CN^- removal rate low etc. In this thesis , the gas—making wastewater was treated in Jinshi Chemical Fertilizer Limited Company of Shijiazhuang. I studied the treated process start-up and run, the factors which affect result. The experimental results showed:1. Using precipitation removes the SS of wastewater, and with the help of grad, when influent SS was 98-157mg/L , SS removal rate was up to 70.9-86.5%, average 76.6%.2. The bio—tower adopted armoured concrete frame, whith using regular—half —soft filling. According to BOD₅: N : P = 100 : 5 : 1 proportion , putting Dextrose, Urea and KH2PO4 into the wastewater, It ensured biological alimentation, so as to select biological which can removal CN^-. In the first phase, bio—tower was covered with biological, just the wastewater contained O₂ 3-5mg/L, the load was controled between 40-60% of the usual. When influent CN^- was 9.092-15.40 mg/L, the removal rate was increase from 74.8% to 87.5%; In the second, the amount of wastewater was improved, up to 1100m³/h. The removal rate was 82.2-94.3%. In the third, The average removal rate was 89.4%.3. The impulse—clarify—equipment was fit with inclined pipeline, so as to clear the wastewater more. SS was decrease from 98-157 mg/L to 84.6 mg/L. CN was removed relying on biological coming from bio—tower.The CN^- contain went down from 1.358-2.210 mg/L to 0.358-0.827 mg/L. The recharge wastewater reached the country level.4. There were many elements that effect CN^- removal rate, when the temperature was between 25-35°C, pH 6.5-8.0, SS below 150mg/ L, CN^- below 20 mg/L, the removal rate was the highest. It was sure the wastewater correspond the standard steadily for a long period.5. The total investment of the project was 8,120,000Yuan. The charge of...