Application of PTA2O Process in Swine Wastewater Treatment and Its Anammox Phenomenon Analysis

PTA²O process is an improved process on the basis of traditional A²O process, which integrates aeration, sludge reflux and sludge sedimentation in one structure, occupies small area and saves investment. The capacity of a swine wastewater treatment project was 1 500 m³/d under the originally AO process. Swine wastewater has the characteristics of high COD and highª²strength ammonium, so the transformation project adopts hydrolysis acidification and PTA²O process. The effluent after transformation is required to meet the Discharge Standard of Pollutants for Livestock and Poultry Breeding (GB 18596-2001). Anammox occurred spontaneously after about 100 days¡¯ operation of the project. Afterwards, fullª²scale Anammox was carried out for 5 months. The power consumption of the biological tank was reduced by 74.1£¥ from 143 kW to 37 kW; alkali and carbon source were basically stopped addition. The treatment cost excluding labor decreased from 9.49 yuan/m³ to 1.38 yuan/m³; the removal rate of COD was about 80%; the removal rate of total nitrogen was maintained at the level of 90%. Anaerobic ammonia oxidation process operated for more than a year, with no collapse, stable operating, effluent up to standard, energy saving remarkable. This case showed that the aeration, sedimentation, sludge reflux and hydraulic circulation that PTA²O process adopted could easily produce spontaneous anaerobic ammonium oxidation under suitable water quality conditions, and had strong sustainability.