氨吹脱—混凝处理奶牛养殖废水厌氧出水的试验研究

发布时间：2018-01-01 03:05

本文关键词：氨吹脱—混凝处理奶牛养殖废水厌氧出水的试验研究　出处：《安徽工业大学》2015年硕士论文　论文类型：学位论文

【摘要】：奶牛场废水氨氮、有机物浓度高,经过厌氧处理后,虽然大部分有机物得以去除,但氨氮浓度不降反升,碳氮比失调,给后续好氧处理带来困难,处理效果差,往往难以达标排放,探索高效、适用的厌氧出水后续处理工艺具有重大的现实意义。本文针对奶牛场废水厌氧出水的后续处理问题,以马鞍山蒙牛现代牧场废水处理中的UASB出水为研究对象,进行氨吹脱和混凝试验处理,试验过程中,采用单因素试验、响应曲面试验,分析了运行参数对氨吹脱和混凝工艺对奶牛养殖场厌氧出水的处理的影响,以及各工艺参数之间的交互作用,确定了氨吹脱和混凝的最佳工艺条件,分别得出了以氨氮、CODCr以及SS去除率为响应值的二次多项式回归模型,为该组合工艺处理奶牛养殖废水提供理论依据和基础数据,主要研究结论如下:(1)试验首先对UASB厌氧出水进行氨吹脱处理单因素试验,随着吹脱时间的增加,氨氮去除率逐渐增加,5h以后变化均趋于平缓,且吹脱时间5-6h之间不存在显著差异(P0.05),试验确定较佳的吹脱时间范围为5-6h;氨氮去除率随着pH值的增大逐渐升高,pH值大于11以后变化趋势减缓,且pH值为11与12之间不存在显著差异(P0.05),试验确定氨吹脱的较佳pH值范围为11-12;氨氮去除率随气液比的增大而增大,当气液比为1000-3000时,氨氮去除率较显著增加(P0.01),而当气液比大于3000时,氨氮去除率变化趋于平缓,试验确定的较佳气液比范围为3000-4000;氨氮去除率随着温度的升高而逐渐增加,温度为10℃-30℃时,氨氮去除率变化较显著(P0.01),温度继续升高,氨氮去除率变化不大,试验确定适宜的吹脱水温为30℃。(2)氨吹脱响应曲面试验采用Box-Behnken设计,建立了以氨氮去除率为响应值的二次多项式回归模型方程。对氨吹脱工艺参数的交互作用分析得出:pH值和吹脱时间以及吹脱时间和温度的交互作用不显著,pH值和温度的交互作用显著。对氨吹脱工艺进行了优化,得出优化参数:pH值为11.5,吹脱时间为5.3h,温度为32.5℃。其对应的响应值所能取到的最大值为92.8%。(3)对氨吹脱出水进行混凝单因素试验,确定PFS为较优的试验用絮凝剂。随着PFS投加量的逐渐增加,CODCr和SS去除率呈现先升高后降低的趋势,具有显著差异(P0.05);随着搅拌速率的增大,CODCr和SS去除率呈先增大后减小的趋势,且有显著差异(P0.05);随着搅拌时间的增加,CODCr和SS去除率呈现先升高后逐渐降低的趋势,差异显著(P0.05),当搅拌时间为4、5min时,其对应的SS去除率相差不大;沉淀时间在5-20min,随着沉降时间的延长,CODCr和SS去除率迅速增大,有显著差异(P0.05),20min以后增幅明显变小,无显著差异(P0.05)。试验确定的PFS投加量、搅拌速率、搅拌时间、沉降时间分别为2.85g·L-1、180r·min-1、4-5min、20-25min。(4)采用Box-Behnken设计对混凝工艺进行了响应曲面试验,分别以CODCr去除率和SS去除率为响应值,建立了二次多项式回归模型。并评价了混凝参数对响应值的交互作用:对CODCr去除率,PFS投加量、搅拌速率、搅拌时间、沉降时间两两交互作用不显著;对SS去除率,搅拌速率和沉降时间的交互作用显著,其它参数之间的两两交互作用均不显著。优化试验得出混凝的优化参数:PFS投加量为2.75g·L-1,搅拌速率为180r·min-1,搅拌时间为4.4min,沉降时间为22.8min。此优化参数下,CODCr去除率可达79.8%,SS去除率可达73.6%。(5)奶牛养殖废水UASB出水经吹脱和混凝处理后,出水CODCr、BOD5、SS、氨氮浓度达到《畜禽养殖业污染物排放标准》(GB18596-2001)。对组合工艺进行经济可行性分析,吹脱和混凝水处理成本约为5.6元·(m3)-1。
[Abstract]:Dairy wastewater, high concentration of organic compounds, by anaerobic treatment, although removal can be most organic compounds, but the ammonia concentration did not fall but rise, carbon and nitrogen ratio, bring difficulties to the subsequent aerobic treatment, the treatment effect is poor, often difficult to discharge, to explore efficient, has great realistic significance for subsequent treatment of anaerobic effluent suitable for the process. The dairy processing wastewater anaerobic effluent, Ma'anshan Mengniu modern ranch in wastewater treatment UASB water as the research object, ammonia stripping and coagulation test, during the test, the single factor experiment, response surface test, analysis of the operation parameters on ammonia stripping and the coagulation process of dairy farm anaerobic effluent treatment effect, and interaction between various process parameters, to determine the optimum conditions of ammonia removal and coagulation, were obtained by ammonia nitrogen, CODCr And the SS removal rate as the response value of two order polynomial regression model, and provide a theoretical basis and basic data for the combined process for treatment of dairy wastewater, the main conclusions are as follows: (1) the first test of UASB anaerobic effluent ammonia stripping process of single factor test, with the increase of the time of blowing off, ammonia nitrogen removal rate increased gradually after the change, 5h tended to be stable, and there is no significant difference between the blow off time of 5-6h (P0.05), the test to determine the better stripping time range is 5-6h; the removal rate of ammonia nitrogen increased gradually with the increase of pH value, pH value is greater than 11 after the trend slowed down, for 11 and 12 and there is no significant difference between the value of pH (P0.05), the ammonia stripping test to determine the optimal pH value range is 11-12; the removal rate of ammonia nitrogen with the gas-liquid ratio increases when the gas-liquid ratio was 1000-3000, the removal rate of ammonia nitrogen was significantly increased (P0.01), and when the gas-liquid ratio is greater than 3000, The removal rate of ammonia nitrogen changes slowly, test the optimum gas-liquid ratio is in the range of 3000-4000; the removal rate of ammonia nitrogen increased gradually with increasing temperature, the temperature of 10 DEG -30 DEG C, the ammonia removal rate changes significantly (P0.01), the temperature continues to rise, the removal rate of ammonia nitrogen stripping test to determine the changes a little, the water temperature is 30 C is suitable. (2) ammonia stripping using Box-Behnken design response surface test, established on the ammonia nitrogen removal rate as the response value of the two polynomial regression equation. The interaction of ammonia removal process parameters obtained: pH value and stripping time and blow off the interaction of time and temperature is not significant. The interaction of temperature and pH value significantly. The ammonia stripping process was optimized, the optimized parameters are: pH value is 11.5, the stripping time is 5.3h, the temperature of 32.5 DEG. The corresponding response value of the maximum can reach to 92.8%. (3) of ammonia stripping The single factor test of mixed coagulation, PFS was determined to test the better with flocculant. With increasing dosage of PFS, CODCr and SS removal rate increased firstly and then decreased, with significant difference (P0.05); with the increase of stirring rate, CODCr and SS removal rate of the first increased and then decreased. The trend, and there is significant difference (P0.05); with the increase of stirring time, CODCr and SS removal rate increased firstly and then decreased gradually, significant difference (P0.05), when the stirring time was 4,5min, the removal rate of SS had little difference; precipitation in 5-20min, with prolonging the settling time. CODCr and SS removal rate increased rapidly, there was significant difference (P0.05), 20min increase significantly smaller, no significant difference (P0.05). Experimental determination of PFS dosage, stirring rate, stirring time and settling time were 2.85g, L-1180r, min-1,4-5min, 20-25min. (4) by Box-B The ehnken design of the response surface test of coagulation process, respectively, with CODCr removal rate and SS removal rate as the response value, established two polynomial regression model. And to evaluate the coagulation parameters on interaction response values: the removal rates of CODCr, PFS dosage, stirring rate, stirring time, settlement 22 there was no significant interaction; the removal rate of SS, the interaction of stirring rate and settling time was 22, the interaction between other parameters were not significant. The optimized parameters of the optimized coagulation test: PFS dosage was 2.75g - L-1, 180r - min-1 stirring rate, stirring time is 4.4min. The settlement time is 22.8min. the optimization parameters, the removal rate of CODCr was 79.8%, SS removal rate of 73.6%. (5) of cattle farm wastewater by air stripping and UASB effluent after coagulation treatment, the effluent CODCr, BOD5, SS, ammonia nitrogen concentration reached the "discharge standard of pollutants (> GB18596-2001). Economic feasibility analysis of combined process, the cost of stripping and coagulating water treatment is about 5.6 yuan (M3) -1..

【学位授予单位】：安徽工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X713

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