| Wastewater with high concentration organic pollutants poses a serious threat to the environment. Due to the inefficiency and high cost of current treatment technology, a large amount of wastewater with high concentrations of organic matters is pooly treated and discharged directly into the environment in China these years. Hence it is crucial to develop a technology that requires low investment cost, simple operation, and is farily adaptable under different operation conditions for treatment of wastewater with high concentration of organic matters. Such techonology is urgently needed for treating and recycling wastewater from piggery corne and food processing with high concentration of organic matters.Black film anaerobic digesters, activated sludge process and post processing technique were applied in the combined process. Piggery wastewater and chestnut starch wastewater were selected as two contrast typical high concentration organic wastewater in this research to study the removal efficiency of pollutants in all processing units and the control direction under the test conditions. This trial obtained the following conclusions through the engineering experiments:(1) Both of the two studies on the research got a satisfactory result through the combined process. NH4+-N, NO3--N, TP, TN and COD in final effluent of the original combined process of piggery wastewater were 42.64, 65.18, 4.31, 230.83 and 220.05 mg/L respectively; the adding UF membrane one were 28.69, 122.42, 2.80, 244.19 and 212.53 mg/L respectively; the modified one were 64.63, 62.96, 1.87, 212.80 and 238.53 mg/L respectively. While the chestnut starch wastewater experiment final effluent monitoring indexes were declined to 0.44, 2.69, 4.24, 49.54 and 68.27 mg/L respectively. Thus, the final effluent of monitoring indexes in two types of high concentration organic wastewater met the requirements of Livestock and Poultry emission standards(DB44613-2009) and Integrated wastewater discharge standard(GB8978-1996) respectively.(2) Black film anaerobic digesters to piggery wastewater and chestnut starch wastewater had a low removal efficiency of NH4+-N, which only attained by-43.77% and-3.84% respectively. The former TN removal efficiency was worse than the later, while other pollutants removal efficiencies were better than the former. The average removal rate of NO3--N, TP, TN and COD of the former were 70.02%, 50.77%, 45.92% and 93.58% respectively, while the latter were 54.39%, 41.56%, 64.28% and 55.28% respectively.(3) Piggery wastewater bio-processing unit had a poor bio-removal of nitrogen, excess capacity of nitrification, and obvious insufficient de-nitrification efficiency. While the bio-removal efficiency of nitrogen pollutants in bio-processing unit of chestnut starch wastewater treatment were better than the former. The removal rate of NH4+-N, NO3--N and TN in the former bio-processing unit achieved by 80.38%,-551.74%, 21.90% respectively, while the latter achieved by 96.81%, 61.47%, 61.93% respectively. Therefore, the former test should strengthen the nitrogen removal of de-nitrification stage.(4) Treated by different post treatment technique, pollutants were removed obviously and the effluent is stable. Chemical strengthening methods were adapted to further remove TP and COD in the effluent of bio-processing unit of chestnut starch wastewater treatment. The final effluent concentration of TP and COD declined to 4.24 mg/L and 68.27 mg/L respectively, and got removal rate of 70.93% and 76.46% respectively. While chemical strengthening and UF membrane separation methods, and constructed wetland processing section were used as the post treatment of piggery wastewater, which were to further remove NH4+-N,TP and COD in bio-processing unit. After the processing procedures, final effluent concentration of the above pollutants descended to 42.50, 4.08 and 223.11 mg/L respectively, and reached to a removal rate of 43.71%, 93.42% and 52.35% respectively.(5)Pollutants removal efficiencies were varied in different seasons and weather conditions. The piggery wastewater combined process removed NH4+-N and COD performed as summer>autumn>winter, while the chestnut starch wastewater treatment removal efficiency had no significant correlation with the temperature. The former removal of TP pollutants performed as winter>autumn>summer, while the latter had extremely significant positively correlation with temperature.(6)Under the conditions of the research, extremely significant negative correlation between MLSS and the removal efficiency of NH4+-N and COD, and no significant correlation with NO3--N,TN,TP in the bio-processing unit of piggery wastewater treatment. Improving the MLSS in the bio-processing unit of chestnut starch wastewater treatment had little effect on the removal of COD and TN, and when it rised to 1900 mg/L, the removal efficiency of NH4+-N, NO3--N and TN, and the bio-removal of nitrogen reached optimun. |
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