The artificial soil rapid infiltration is one of the best way for wastewater removal, but it still has some limits: one aspect is that water quality of output is close or excel the secondary level discharge standard of secondary biological treatment plant, but it is still needing to meet with higher level, especially removal efficiency to TN (30%~40%) is not good enough; Another aspect is that nutrient in output water is leanness for plant's irrigation.Our study has two task: one is test that output water f...