Water treatment is the use of physical, biological or chemical methods, the sewage treatment to achieve discharge standards. The so-called standard let sewage pollutants in the standard range, but this does not mean that there is no pollutants, so this water to irrigate vegetables, we must fully understand the quality of the water in the pollution content, is suitable for irrigation requirements, if the use of less than the requirements of the release of water to irrigate vegetables, is not edible.