Abstract:Against the low C/N ration in dispersed piggery wastewater after the treatment of anaerobic and constructed wetland, using low-cost rice straw as solid carbon source and biofilm carrier to study the performance in start-up stage, the effect of hydraulic loading and pollutants removal profile along the height of the reactor were investigated. The results showed that the NO3--N was removed mainly in the top layer of the reactor, which filled with rice straw. The removal rate of NO3--N was over 95% and the denitrification rate was 0.052mg/(g·h), the effluent without obvious accumulation of NO2--N, simultaneously. In addition, the COD and NH4+-N of effluent was higher than the influent at the early stage owing to the rice straw itself leaching organic and nitrogen substance (mainly is NH4+-N), but the concentration was still much less than the emission limits of discharge standard of pollutants for livestock and poultry breeding (GB18596-2001). COD reduced to about 40mg/L gradually after forty days. COD and NO3--N can be further removed by the brick slag fill layers in the bottom reactor.