Disposal Potency On Small-town Wastewater With Combined Process Of Anaerobic Fermentation And Constructed Wetland

For a small-town wasterwater plant in Chongqing, purification efficiency and the degradation laws along the treatment process way were investigated. The combined process of anaerobic fermentation and constructed wetland(CPAFCW) was employed by the plant. Impact of seasonal variation on sewage decontamination was researched. On the basis of analyzing the operating situations of the combined process some improvements were given. The main conclusions colud be obtainde as followings:For CPAFCW, the pollutant the COD average removal ratios of anaerobic digestion tank, SFW(surface flow constructed wetlands), SSFW(subsurface flow constructed wetland), and the ecological pond were respectively 68.5%, 10.4%, 2.6% and 2.4%. The removal ratios of NH4+-N were respectively 16.6%, 18.4%, 9.7% and 3.7% and those of TP were 9.83%, 13.12%, 7.97% and 4.16%. It was showed that the anaerobic digestion played a major role in organic matter degradation, whereas the constructed wetland played a major role in NH4+-N and TP removal.From disposal efficiency of COD, NH4+-N and TP, the purification potency effect in summer was totally better than that in winter. The degradation ratio of COD was related to concentration of organic pollutant, and small affected by seasonal changes. NH4+-N and TP removal ratios were easily influenced by season change, the concentration of pollutants was also key factor.LAS degradation ratio was closely related with the LAS concentration and seasonal variation in CPAFCW. The removal efficiency of LAS in summer was the best. LAS concentration in effluent exceeded the standard value in winter and spring. The LAS degradation ability of processing units was as follows, SFW> SSFW> Anaerobic fermentation device>ecological pond.Disposal efficiency of wastewater with CPAFCW was vulnerable to seasonal variation and the removal ratios of nitrogen and phosphorus were lower. And thus, the following measures were proposed. The first, an appropriate amount of trace metal nutrients maybe added in anaerobic digestion tank. The second, cold-resistant plants with high removal efficiency of nitrogen and phosphorus were selected. The third, the substrate containg metal ions(Ca, Al, Fe and Mg), which can rich in CEC and organic matter, was employed.