【作者】 马焕春；

【导师】 陈玉成；

【作者基本信息】 西南大学 ， 农业环境保护， 2013， 博士

【摘要】 随着我国的畜禽养殖业逐步走向规模化、集约化,大中型沼气工程也随之得到迅猛发展,畜禽养殖场沼气工程在利用废物产生清洁能源的同时形成了大量的成分复杂,浓度高的沼液,这已成为大中型沼气工程发展的制约因素。目前对于沼液处理尽管可以采用还田处理或者是资源化利用的方式,但是这两种消纳方式受到多种条件的制约,尤其受到我国地少人多等实际条件的限制,因此工艺性工程化处理畜禽养殖场沼气工程所产生的大量沼液仍是必然的选择。鉴于沼液高氮磷、低C/N比的特点,考虑通过物化的预处理方法,改变其溶液的理化性质,去除或降解难降解的有机物,强化后续的生化处理,使排放废水能够达到《畜禽养殖行业污染物排放标准》(GB18586-2001)规定的要求。开展沼液处理工艺研究,考察铁炭微电解、电解物化处理单元的可行性,考察SBBR及电极-SBBR工艺生化处理单元的可行性,研究“三级微电解-电解”物化处理沼液组合工艺的可行性及处理效能,进行微电解-电极-SBBR组合工艺的处理效能试验研究。1、铁炭微电解试验铁炭微电解试验选择曝气量、初始pH值、铁炭体积比(Fe/C)和水力停留时间(HRT)作为试验影响因素,经单因素试验结果推荐反应条件分别为：15.0mL/min-L沼液(曝气量)、4-5(初始pH值)、1：1(Fe/C),2.5h(HRT),其COD、NH4+-N、TN、TP的去除率分别为37.22%～44.74%、18.47%～30.42%、20.32%～40.75%、66.01%～87.56%。正交试验表明,各因素对COD去除率的影响程度大小为HRT>曝气量>pH值>Fe/C,对NH4+-N去除率的影响程度大小为Fe/C>HRT>pH值>曝气量,对TP去除率的影响程度大小为曝气量>HRT>pH值>Fe/C。通过综合平衡分析后,铁炭微电解的推荐工作条件是曝气量为15.0L/min-L,初始pH值为4,Fe/C为2：1,HRT为2.5h。微电解的多级串联试验表明,3级反应的去除效果最为合理。通过平行试验证明了微电解处理效果的稳定性。填料的扫描电镜发现,用水冲洗过的反应后的填料可以恢复其活性；沉淀物的XRD图谱分析,证实了磷是以FeP04的形式去除的。2、电解试验电解试验选择极电压、反应时间、初始pH值、极板间距作为试验的影响因素,试验结果表明,在10V(极电压)、3.0h(反应时间)、5.0(pH值)和20mm(极板间距)的条件下,其去除效果最好,COD、NH4+-N和TP的去除率分别为：30.77%～59.00%、6.34%～10.66%和22.91%～44.04%,在此推荐反应条件下,通过变换极板的电极、三维电极、曝气和增加极板数等方式来改变反应的条件,试验结果表明,曝气对于COD、NH4+-N的影响最大,而增加极板数对TP的影响最大,因此最终选择增加曝气作为反应改变的条件。3、SBBR及电极-SBBR试验历时6周完成了对SBBR及电极-SBBR反应器活性污泥的挂膜驯化,结束时,软性填料上形成了1.2～1.5mm生物膜,镜检发现系统中累枝虫、轮虫等原生动物为优势微生物,且形成了较为密实的菌胶团。SBBR及电极-SBBR的比较试验结果表明,经过电极强化的SBBR工艺,对污染物的去除能力有大幅度的提高。最终依据试验结果,推荐7.0h作为反应的运行周期,其运行工况为：进水→厌氧(1.0h)→曝气(4.0、通电)→缺氧/厌氧(2.0h、通电)→出水→闲置。按照确定的运行工况,选择极电压、DO质量浓度、填料密度作为运行的影响因素,试验结果表明,在15V、4～5mg/L和30%的反应条件下,其COD、氨氮和TP的去除率分别为61.57%～69.81%、84.38%～90.69%和54.80～65.26%。在推荐的工艺条件下,运行电极-SBBR工艺稳定运行的30d内,COD和NH4+-N的去除效果较好,其去除率分别维持在70%和80%以上,出水较为稳定,基本都能够达到《畜禽养殖行业污染物排放标准》规定的要求,并且都有一定的抗冲击负荷的能力：对TP的处理效果也较为稳定,但去除效果不理想,平均出水浓度为8.86mg/L,超过了8.00mg/L的限值要求,因此还需进行强化处理。4、工艺组合试验在微电解、电解处理工艺的基础上,进一步开展了“微电解-电解”物化处理组合工艺的试验研究。该工艺对COD、BOD5、氨氮、TP和SS都有明显的去除效果,BOD5/COD由进水的0.19提高到0.53～0.57,显著的提高了出水的可生化性,出水TP(3.95～7.17mg/L)能够达到GB18586-2001的标准要求,其余与标准之间还存在较大差距。微电解与电解的对比试验表明,按照各自推荐的反应条件,在相同的时间内,微电解的处理效果优于电解,尤其是NH4+-N、TP和SS的去除效果差异性较大,因此选择铁炭微电解作为沼液的预处理方法。在此基础上,进行了“三级微电解-电极-SBBR"工艺的组合的试验研究,在COD、氨氮、TP和SS的进水浓度分别为4400.00～6660.00、804.43～1675.95、89.87～175.41和5724～11462mg/L,进水pH值4.3～5.1的情况下,经过运行可知,前8天,各指标的出水浓度分别为231.00～396.00、56.55～79.39、5.82～7.84和89.20～177.30mg/L之间,达到了GB18586-2001规定的400.00、80.00、8.00和200.00mg/L的指标要求。因此将8d作为一个运行周期,用自来水通过反冲洗的方式去除吸附在铁炭填料表面的物质,使铁炭填料活化,然后再继续进行处理。本文在单工艺基础上,构建“微电解-电极SBBR"耦合新工艺处理沼液废水,处理效果较好,出水水质能够达到《畜禽养殖行业污染物排放标准》(GB18586-2001)规定的要求,且稳定性较好。更多还原

【Abstract】 Along with our country’s livestock and poultry industry to scale, intensive direction, large and medium-sized biogas project has been rapid development, livestock biogas engineering would has produced large quantity of organic wastewater with complex components and high concentration at the same time generating clean energy in the utilization of waste--biogas slurry, which has become the restricting factors of the development of large and medium-sized biogas project. At present, the biogas slurry disposal methods although cover cropland application or resource utilization, but they are restricted by many conditions, especially by the actual conditions of China’s crowded restrictions, so the process of industrialization is the inevitable choice processing large amounts of biogas slurry produced by livestock biogas engineering.In view of the fact that biogas slurry consists of the high nitrogen and phosphorus, low C/N ratio, so consider to change physicochemical properties of solution by the physical and chemical pretreatment method, remove or degradate refractory organic compounds, strengthen the subsequent biochemical treatment, so that discharge wastewater could achieve requirements of pollutant discharge standard in Discharge standard of pollutants for livestock and poultry breeding (GB18596-2001). Developing research treatment technology of biogas slurry, Their feasibilities of treatment biogas slurry were researched, including processing unit of micro-electrolysis with iron-carbon and electrolysis, biochemical treatment unit of SBBR and electrode-SBBR.The feasibility and efficiency of "three micro-electrolysis and electrolysis" and "micro-electrolysis-electrode-SBBR" were studied.1. micro-electrolysis experiments with iron-carbonAeration, initial pH value, iron-carbon volume ratio and the hydraulic retention time (HRT) were selected as the effective factors of micro-electrolysis experiments with iron-carbon, Through the single factor experiment to determine the reaction conditions recommended were as follows:aeration rate of15.0L/min·L, initial pH value of4, iron-carbon volume ration of1:1, HRT of2.5h., the removal of its COD, ammonia nitrogen,TN and TP respectively was37.22%-44.74%,18.47%～30.42%,20.32%～40.75%,66.01%～87.56%,. The orthogonal experiments showed that each factor on the order of COD removal rate was as follow:HRT> aeration> initial pH value> Fe/C, on the removal rate of ammonia nitrogen was as follow:Fe/C> HRT> initial pH value> aeration, on the removal rate of TP affects the degree of aeration> HRT> initial pH value> Fe/C. Through comprehensive analysis, the commendatory working conditions of micro-electrolysis with iron-carbon were as follows:aeration rate of15.0L/min·L, initial pH value of4, iron-carbon volume ration of2:1, HRT of2.5h. Tests showed that the multilevel series micro-electrolysis, the removal effect of3order reaction was the most reasonable. The parallel tests showed the stability of micro-electrolysis treatment effect.The SEM analysis showed that iron and carbon filler washed by water could restore its activity; The analysis of the XRD profiles of sediment showed that phosphorus was removed in the form of FePO4.2. electrolysis experimentsThe voltage, reaction time, initial pH value and electrode plate interval were selected as the influential factors of electrolysis experiments, the results showed that there were the best removal effect in the voltage of10V, reaction time of3.Oh, initial pH value of5and electrode plate interval of20mm conditions, COD, ammonia nitrogen and TP removal rates respectively were:30.77%～59.00%,6.34%～10.66%, and22.91%～44.04%. In the reaction conditions recommended, to change the electrode plates, transform three-dimensional electrode, aeration and increase the number of electrode plates, the results showed that aeration was the maximum effect of COD and ammonia nitrogen, and the effect of TP, increasing plate number to the maximum. So the aeration was selected as reaction to change conditions.3. the SBBR and the electrode-SBBR experimentLasted6weeks, the attaching biofilm and acclimation of activated sludg were completed on SBBR and electrode-SBBR reactor. The biofilm about1.2～1.5mm was formatted on the surface of soft filler at the end of the attaching biofilm, the microscopic examination showed that the system protozoa was the dominant microorganisms,such as Epistylis, rotifers, and a more dense zoogloea has formated. SBBR and the electrode-SBBR comparison test results showed that SBBR process after enhancing by electrode, could greatly improve the pollutant removal ability. Finally according to the test results,7.Oh was recommended as the running period of reaction, and its operating conditions were:adding wate→anaerobic processing (1.0h)→aeration (4.0h, electricity)→anoxic or anaerobic processing (2.0h,electricity)→effluent dewatering→idle.According to the operation condition detemined, voltage, concentration of DO and packing density were selected as the most factor of influencing the operation, the test results showed that it is better in the15V,4～5mg/L and30%conditions, the removal of COD, ammonia and TP was61.57%-69.81%,84.38%-90.69%and54.80%-65.26%respectively. Under the commendatory conditions, the electrode-SBBR stabilized run within30days, COD and ammonia have been better removal effect, the removal rate was maintained at above70%and80%, the effluent were stable, could reach discharge standard requirements of 《Discharge standard of pollutants for livestock and poultry breeding》, electrode-SBBR could stand up to a certain of impact load-The treatment effect on TP was also relatively stable, but the effect was not ideal, the average effluent concentration of8.86mg/L exceeded the limit requirements of8mg/L, so it was the need for strengthening treatment.4. process combinationBased on micro-electrolysis and electrolysis tests, and the physicochemical treatment combination technology" micro-electrolysis and electrolysis" were further researched. The process has obvious effect on COD, BOD5, ammonia, TP and SS removal. BOD5/COD increased from0.19of influent to0.53-0.57of effluent, the biodegradability of the effluent was significantly improved. The TP of effluent (3.95-7.17mg/L) could reach the standard requirements of GB18586-2001,then the rest could not reach standard requirements. The micro-electrolysis and electrolysis test showed that at the same time, the micro-electrolysis treatment effect was better than that of electrolysis according to their respective optimum reaction conditions, especially the effect on ammonia, TP and SS, the disparity of removal rate were very big, therrfore, the micro-electrolysis experiments with iron-carbon was seleted as a method of pretreatment of biogas slurry.On this basis, the combined process of "three micro-electrolysis-electrode-SBBR" were studied. The influent concentration of COD, ammonia, TP and SS was4400.00-6660.00,804.43～1675.95,89.87～175.41,5724～11462mg/L respectively, and pH value from4.3to5.1, after running,the results showed that the effluent concentration of each index was231.00～396.00,56.55～79.39,5.82-7.84and89.20～177.30mg/L respectively, pH value of4.3～5.1, reached the requirements specified in GB18586-2001400,8,8and200mg/L at the first eight days.Therrfore, eight days would be run as a cycle, the material absorbed on the iron-carbon filler surface was removed by backwashing way with tap water, and then continued processing.Based on the single process,a new system of micro-electrolysis-electrode-sequencing batch biofilm reactor(SBBR) technique was constructed for treating biogas slurry,its treatment effect was good,and the effluent could achieve requirements of pollutant discharge standard in Discharge standard of pollutants for livestock and poultry breeding (GB18596-2001),then has better stability.更多还原