[Efficiency and Microecology of a Soil Infiltration System with High Hydraulic Loading for the Treatment of Swine Wastewater].

The swine wastewater after treated with an anaerobic reactor was used to investigate the removal efficiency of COD, ammonia nitrogen, and total nitrogen in an ecological high hydraulic loading soil infiltration system. Meanwhile, the microbial community structure and the contents of the catalase, urease, and nitrate reductase were analyzed. The results showed that with the hydraulic load of 11 cm·d and the influent COD concentration of 700 mg·L, the removal rate of COD was 78.8%, 63.0%, and 92.6%for the first land infiltration column, the secondary land infiltration column, and the total system, respectively. When the hydraulic load increased to 22 cm·d; the total removal rate of COD was also above 90.0%. The system was more significant for ammonia nitrogen removal. The removal rate of ammonia nitrogen reached approximately 99%. The contents of catalase were 1.899, 0.990, and 0.323 mL·g at the upper, middle, and bottom sections of the system, respectively. The organic matter in the swine wastewater was removed at the upper and middle of the system. On the secondary soil infiltration system, the content of nitrate reductase was 3.453, 3.831, and 1.971 mL·g, respectively. Denitrification mainly occurred in the upper and middle of the secondary soil infiltration system. Gram Negative and Gram Positive bacteria were given priority in the soil infiltration system. Especially, arbuscular mycorrhizal fungi and Actinomycetes dominated the secondary soil infiltration system. The system provides a guarantee for the removal of the refractory organic compounds from the swine wastewater.