Xi'an water purification equipment design principles (1) Water is the source of water to contain different impurities into line with the requirements of the water, due to the diversity of surface water, as well as different objects and water quality requirements, should take a different approach and technology systems, on urban water supply is concerned, no matter what kind of technology, the treated water must meet drinking water standards prescribed by the state. For surface water as a water plant water should also be consistent with the standard of drinking water sources. Choice of surface water (ie, rivers, reservoirs, lakes, etc.) as the sources of surface water to meet the three criteria above water. Generally rivers, lakes, reservoirs perennial turbidity 500mg / l or less, some of the water, ammonia, nitrogen, CODmn, iron, manganese, algae and other content over the water standards. This micro-polluted water after conventional water treatment process, general can meet drinking water source standards. Perennial water quality remained stable, the standard indicators. (2) take full account of the scope of land, equipment requirements, low noise, the area near the treatment plant no odor, treatment facilities must be sealed measures to minimize the impact on the surrounding environment; (3) beautiful shape, in coordination with the surrounding environment; (4) water treatment system is simple, easy maintenance management, project cycle is short, long life; (5) the processing system can automatically run, low recurring operational and maintenance costs, with a total investment of the province; (6) should have a larger water treatment facilities adaptability, emergency, to meet water quality, changes in water, and to consider the status of the various incidents of emergency measures.