Design And Engineering For Treatment Of Livestock Wastewater By Integrated Technique Of Solid-liquid Separator, UASB, A~2/O,Coagulation Of Disinfection

Since the reform and opening up, with the adjustment of agricultural structure,industrial policy support and the construction of "food basket project", the rapid development of livestock and poultry breeding industry in China, the degree of intensive,large-scale, and the proportion of the scale of its output in agriculture is increasing. With the rapid development of the industry, the pressure on the environment of livestock and poultry breeding has also increased sharply, and the water pollution problem caused by the intensive farms or the breeding areas of livestock and poultry caused by livestock and poultry breeding farms has also increased. Livestock wastewater is a typical "three high" characteristics, namely organic matter, ammonia nitrogen and suspended solids(SS) high concentration of organic wastewater with high concentration and pollution load is very high. The treatment mode of livestock and poultry breeding wastewater can be divided into the field treatment mode, natural treatment mode and industrial processing mode.Because of the good biodegradability of wastewater, Anaerobic + aerobic biochemical treatment technology. However, there are still problems in domestic livestock wastewater treatment, such as the low efficiency of wastewater treatment, the effect of instability, the high operating costs and other issues.In this paper, on the basis of in-depth analysis of livestock wastewater at home and abroad research status and engineering practice experience, in view of the high load of organic wastewater, suspended solids and high concentration of ammonia nitrogen characteristics, integrated a set of good treatment effect, stable operation, affordable,reliable technology industry combined art-- "solid-liquid separator- pre-acidification-UASB A~2/O- coagulation sedimentation- disinfection process. Based on the technological transformation project of a pig farm wastewater treatment station in Huizhou, Guangdong Province, the design calculation and equipment selection of the main structures of the wastewater treatment are carried out on the basis of the combinedprocess. Through engineering practice, to ensure that the waste water can reach the standard discharge and the system stable operation, and get the following main conclusions:(1) swine wastewater load of livestock wastewater is a typical "three high" characteristics, the "solid-liquid separator- pre acidification UASB A~2 / O- coagulation precipitation- disinfection," the joint processing technology can solve the problem needs to be solved urgently in the treatment with theoretical feasibility.(2) regulating acidification tank in order to make the sewage with suitable residence time and ascending velocity, the reaction is in control in the acidification phase and design points is the pool of water evenly, and upward flow, constant reaction time;UASB reactor to meet the methanogenic bacteria growth and reproduction, granular sludge in the sludge bed generation of anaerobic biochemical reaction and solid phase,liquid phase and gas phase, full separation, the design should be to reaction volume load,structure of the reactor, a three-phase separator selection, pool velocity increased as the key points of the design. The A~2 / O process design should take full account of the C / N ratio and carbon source, dissolved oxygen concentration(redox potentials), SRT and sludge reflux ratio(R) and mixed liquor reflux ratio(RN) and other process parameters.(3) combined with the engineering practice of treating the wastewater of livestock and poultry breeding, the removal efficiency of COD, BOD5, NH3-N, TP and SS was evaluated.(4) installation and commissioning of the project, the operation of the unit is stable after the operation. After the local environmental protection administrative departments of the organization of the project environmental protection facilities acceptance, the results show that the use of combined process, the main pollutant removal rate of pig wastewater are more than 97%, which, BOD5, SS, COD, TP removal rate of more than99%. Control "livestock and poultry industry pollutant discharge standard"(Guangdong DB44/613-2009) water pollutant discharge limits, wastewater discharge standards.(5) in the treatment of the wastewater from the engineering treatment unit, thepharmaceutical cost, the electric charge and the labor expenses are 0.99 yuan /t water,0.78 yuan /t water and 0.80 yuan /t water. After the project anaerobic biological treatment of biogas produced by the recovery of electricity, equivalent to the direct economic benefit of 1.2 yuan per ton of water /t water, therefore, the comprehensive operation of this project is 1.45 yuan /t water.(6) the wastewater treatment project of livestock and poultry breeding based on the combined process, not only the wastewater discharge standard, the main pollutant reduction: 230.20t/a is 3398.24t/a, COD is 1079.09t/a, BOD5 is SS, NH3-N is 19.98t/a,TP is 35.56t/a, which has been greatly reduced. After the discharge of waste water can reach the standard discharge, the annual reduction of sewage charges to 7998172 yuan,but also to achieve considerable indirect economic benefits. Thus, the combined treatment process has a remarkable comprehensive benefit.(7) the successful application of the combined process in the treatment of livestock and poultry wastewater can also provide reference for the engineering practice of similar wastewater treatment.