The ammonia nitrogen (NH3 and NH4+)is an important pollutant that causes water eutrophication and environmental pollution. In recent years, due to the continuous development of nitrogen fertilizer industry, environmental pollution has became more and more serious. According to statistics, the waste water discharged from fertilizer enterprises accounts for about 43 percent of the total waste water in chemical industry. The pollution extent of nitrogen fertilizer plant greatly exceeds enterprises from other industries .
The ammonia nitrogen waste water from the fertilizer plant mainly includes desulfurization waste water, regenerated waste water from desalination system, sewage from cooling tower, process water from the plant and effluent from boilers. Its main characteristics are large flow, high concentration of ammonia nitrogen, low COD and low organics. The FGD wastewater is the main source in the ammonia production system. The desulphurization waste water has many impurities and poor water quality, and its main pollutants are alkalines, salts, SS and COD. If directly discharge it, will not only pollute the drainage pipes, but also pollute the surface water.
Normally enterprises adopt mechanical filtration processes to treat ammonia nitrogen wastewater, such as: plate filter presses. It has the characteristics of simple structure, stable operation, reliable performance, high solid capture and clear filtrate. So it's one of necessary for final sludge dewatering. After treatment, the sewage can be reused in different stages (cooling water etc).