【作者】 王凯；

【导师】 王淑莹；

【作者基本信息】 北京工业大学 ， 环境工程， 2013， 博士

【摘要】 2008年，我国颁布了新的垃圾渗滤液排放标准，不仅对原有水质指标的排放浓度作了更加严格的规定，还增加了TN等指标。这给垃圾渗滤液的处理带来了挑战也带来了机遇。为了解决渗滤液处理难尤其是脱氮难的实际问题，本课题以实际垃圾渗滤液为研究对象，对如何实现垃圾渗滤液有机物和氮的同步深度去除进行了大量研究。根据不同的垃圾渗滤液水质特点，本研究提出四套不同的SBR组合工艺，以实现渗滤液有机物和氮素的有效去除。这四套SBR组合工艺包括：单级改进SBR，ASBR-SBR，SBR-ASBR和三级SBR生化系统。对于生物脱氮工艺，无论是传统的硝化反硝化脱氮还是最新的厌氧氨氧化脱氮，短程硝化都是基础。本试验以处理生活污水的全程硝化活性污泥为种泥，通过进水FA浓度抑制作用协同过程控制，好氧SBR可以通过50天的驯化实现稳定的短程硝化，亚硝态氮积累率稳定在98%以上。通过提高SBR的进水氨氮负荷，活性污泥的氨氮去除速率和比氨氮去除速率都会增加。最终，系统的氨氮去除速率和比氨氮去除速率分别达到了2KgN/m3·d和0.02591gN/gVSS·h。对于碳氮比在6:1以上的早期垃圾渗滤液，本试验采用ASBR-SBR的组合处理工艺。ASBR在工艺中主要起到去除有机物、回收部分能源以及调节渗滤液碳氮比的作用。SBR的主要作用是在进一步去除有机物的基础上，实现对渗滤液的深度脱氮。试验所用渗滤液COD为6000±500mg/L，氨氮为1000±100mg/L，ASBR通过快速启动，23天后可以实现对渗滤液有机物的有效去除，COD去除率达到80%以上，能源回收率达到了62.5%。同时，试验研究表明，在处理高氨氮废水时，ASBR的COD去除率和甲烷产率与进水氨氮的浓度成反比。当进水氨氮浓度大于2600mg/L时，ASBR的COD去除率将降至65%以下，甲烷产率低于0.21L/gCOD。COD和产气量减少的原因是由于高浓度将ASBR的发酵类型从乙酸发酵逐渐转变为丙酸发酵，同时抑制了产乙酸菌利用丙酸的能力，而高氨氮对产甲烷菌的抑制作用并不明显。SBR的进水由ASBR的出水和原水按一定比例混合而成，碳氮比控制在4：1左右。为了提高SBR的脱氮效率，在硝化时加入间歇搅拌并在硝化结束后继续搅拌以实现深度脱氮。通过改变操作模式，SBR可以在不添加碳源的条件下实现对渗滤液的深度脱氮，总氮去除率达到95%以上。整个系统出水COD为400～500mg/L，总氮为15～25mg/L，其中有机氮为13～22mg/L，去除率分别达到了90%和95%。由于充分利用了污泥内碳源进行内源反硝化，系统在运行期间污泥浓度基本保持不变。对于碳氮比在4:1-6:1的中期垃圾渗滤液，本试验采用单级SBR，改变了传统的运行模式，分别在曝气前后加入了厌氧和缺氧搅拌段来提高系统的脱氮效率。试验所用渗滤液的COD为3800-6000mg/L，氨氮为1000mg/L左右，经过41天的驯化，不仅污泥沉降性得到了很大的改善，还成功实现了在不添加碳源的条件下对渗滤液进行深度脱氮，出水COD和TN分别小于400mg/L和40mg/L，去除率分别达到了85%和95%以上。由于本工艺主要通过污泥所存储的内碳源（以PHA为主）实现对渗滤液的深度脱氮，在整个试验过程中（160天），SBR的污泥浓度保持基本不变，污泥减量效果明显。工艺的影响因素试验表明，为达到最佳的脱氮效果，曝气前的厌氧搅拌应控制在30min，硝化时的溶解氧应维持在0.5-0.8mg/L。研究结果还表明，对于改进SBR工艺，过曝气不仅会浪费能源，还会消耗活性污泥所存储的内碳源，大大降低系统的脱氮效率。对于碳氮比小于2:1的晚期垃圾渗滤液，本试验采用预曝气SBR+短程硝化SBR+厌氧氨氧化ASBR的组合工艺进行处理以达到深度脱氮的目的。前期试验采用短程硝化SBR+厌氧氨氧化ASBR组合工艺。试验结果表明，当渗滤液中的可生化有机物浓度大于150mg/L时，厌氧氨氧化菌的活性会受到严重的抑制，因此，短程硝化SBR+厌氧氨氧化ASBR组合工艺无法实现对晚期垃圾渗滤液稳定的深度脱氨。为了能够实现对晚期垃圾渗滤液稳定的深度脱氮，试验在原有的两级系统上加上了一级预曝气SBR以解除有机物对厌氧氨氧化菌的不利影响。65天的研究结果表明，三级SBR系统通过预曝气、短程硝化和厌氧氨氧化的联合作用可以实现晚期垃圾渗滤液稳定的深度脱氮，在进水氨氮和COD分别为2000mg/L和2200mg/L的条件下，出水总氮去除率达到了95%以上，充分发挥了自养脱氮的工艺优势。更多还原

【Abstract】 In order to reduce the harm of landfill leachate to environment, Pollution Control onthe Landfill Site of Municipal Solid of PR China was published in the year of2008(GB16889-2008.07.01, carried out in July,2011). In the new Standard, the basic waterqualities were controlled more strictly. Besides, total nitrogen (TN) was also added inthe new discharge standard. This brought to the landfill leachate treatment challengesand opportunities.Because of cost-effective, biological treatment technology is widelyused in the field of wastewater treatment. The biggest advantage is that the methodscould achieve truly organic matter and nitrogen removal by convert wastewaterpollutants into CO2and H2O, or N2. Sequencing Batch Reactor Activated SludgeProcess (SBR) which belongs to biological treatment technology has the advantagesof simple structure of the reactor, the big reaction driving force, flexible operation.Therefore, SBR is often used as a special wastewater treatment.It is well known that the landfill leachate is difficult to treat, especially for theadvanced nitrogen removal. In this study, the real landfill leachate was used to explorehow to realize the advanced removal of nitrogen and organics in the landfill leachate.According to the different characteristics of different landfill leachate, four differentcombined processes were applied in this study. In the four combined processes, theoperation mode of SBR was modified to remove nitrogen and organics effectively.The four combined processes include single-stage modified SBR process, ASBR/SBRcombined process, SBR/ASBR combined process and three-stage SBR process.As biological treatments, the traditional nitrification/denitrification and the latestanaerobic ammonium oxidation (ANAMMOX) process are both based on thenitritation. The sludge treating domestic sewage through nitrification taken from apilot-scale SBR was used as the inoculums for the SBR. Via the inhibition of freeammonia (FA) combined with real-time control, stable nitritation was realized in SBRafter50days acclimatization. The NO2-N/NOx-N was maintained at above98%.During the period of acclimatization, the ammonia removal rate and specialammonia removal rate increased gradually by increasing the influent ammonialoading rate of SBR. The ammonia removal rate and special ammonia removal ratefinally reached at2KgN/m32d and0.02591gN/gVSS2h, respectively.For the landfill leachate with C/N ratio of6:1, a novel system coupling anaerobicsequencing batch reactor (ASBR) and SBR was proposed, in order to remove organicsand realize advanced nitrogen removal. ASBR in this system was used to produce methane maximumly through anaerobic fermentation and to adjust the C/N ratio ofleachate for SBR. The SBR operated under anaerobic/aerobic mode was to achieveideal performance of advanced nitrogen removal through endogenous denitritationand simultaneous nitritation and denitritation (SND) without external carbon sourcesadded. The leachate with COD of6000mg/L and NH4+-N of1000mg/L was used inthe experiment. After quick start-up of23days, the final COD removal efficiency ofASBR kept at above80%and the recycle efficiency of energy was62.5%. Besides,the experiment showed that COD removal efficiency and methane production ratiowere inversely proportional to the influent ammonia concentration when treating thewastewater of high ammonia. When the influent ammonia was above2600mg/L,COD removal efficiency and methane production ratio were below65%and0.21L/gCOD. The reason why NH4+-N would suppress anaerobic digestion appeared to bethat high NH4+-N concentration would change the fermentation type of acid formationbacterias from acetic into propionic, and reduce the abilities of propionic acidutilization for methanogens. Opposite to that, NH4+-N concentration didn’t have asignificant influenc on acetic acid utilization for methanogens.The influent of SBRwas the mixture of effluent of ASBR and raw landfill leachate with a certain volumeratio, which made the influent C/N maintained at4:1. In order to enhance the nitrogenremoval efficiency, the operation mode of SBR was modified. The modified SBR wasoperated at alternate anoxic/aerobic mode during nitritation and operated at anoxicmode after the anoxic/aerobic period. Under the modified mode, advanced nitrogenremoval could be realized without external carbon sources addition, and the TNremoval efficiency reached above95%. In the whole system, the effluent COD was400～500mg/L with the removal efficiency of90%. The effluent TN was15～25mg/L, including total organic nitrogen (TON)13～22mg/L, and TN removalefficiency could reache above95%. More significantly, low sludge was producedresulting from long-term endogenous metabolism, which simplified the wasted sludgedisposal.For the landfill leachate with C/N ratio of4:1-6:1, a single-stage SBR wasapplied in this experiment. The single-stage SBR was also modified by introducingthe anaerobic period and the anoxic period before and after nitritation, respectively, inorder to enhance the nitrogen removal efficiency. The excess sludge taken from apilot-scale SBR treating sanitary sewage was used as the80%inoculums for themodified SBR. The other20%inoculums came from a lab-scale SBR which hadrealized nitritation with the mature leachate. The SVI of the inoculums was290mg/L, which indicated the sludge bulking was serious. The COD and NH4+-N of the landfillleachate used in this experiment were3800-6000mg/L and1000-1500mg/L,respectively. After acclimation of41days, the effluent COD was below400mg/L withremoval efficiency of85%and the effluent TN was below40mg/L with removalefficiency of95%, which suggested the advanced nitrogen removal from landfillleachate was realized without external carbon source addition. Besides, the sludgesettleability was improved. Since the stored carbon source (mainly PHA) of sludgewas used to remove nitrogen, the MLSS kept stable. The tests of the influencingfactors showed that in order to reach the best performance of nitrogen removal, theanaerobic mode before nitritation should last30minutes and DO during nitritationshould be maintained at0.5-0.8mg/L.For the mature landfill leachate with C/N ratio of2:1or below2:1, a two-stagesystem consisting of SBR and ASBR was used in this experiment. Nitritation andANAMMOX were implemented in SBR and ASBR, respectively. However, the testsshowed that the activity of anammox could be inhibited seriously when thebiodegradable organics of the landfill leachate was above150mg/L. That resulted inthat the advanced nitrogen removal from the mature landfill leachate couldn’t berealized in two-stage system. So a three-stage system coupling two SBRs and ASBRwas applied. In this system, one SBR was used to remove organics in order to relievethe inhibition to anammox. ANAMMOX and Nitritation were conducted in ASBR andthe other SBR, respectively. The results of65days experiment showed that advancednitrogen removal from the mature landfill leachate could be realized in the three-stagesystem under the combination of organics removal, nitritation and ANAMMOX.When the influent ammonia and COD were2000mg/L and2200mg/L, respectively,the TN removal efficiency could reach above95%. It suggested that the combinedsystem made full use of the advantage of the autotrophic nitrogen removal.更多还原