膜生物反应器同步硝化反硝化系统的研究

设计结构合理的膜生物反应器,驯化培养硝化污泥,复配反硝化细菌,构建了具有同步硝化反硝化功能且能去除COD的膜生物反应器系统。MLVSS的增高和污泥结构的改善为同步硝化反硝化提供条件。进水氨氮浓度在50mg／L,MLVSS为8g／L时,最佳HRT为4～6h,气量控制在0．5m^3／h左右,TN去除率达80％以上。系统承受负荷变化范围0～0．36kgN／（ma·d）,TN去除率均能保持80％左右,COD去除率稳定在90％。     

不同有机碳源对SBR工艺同步硝化反硝化影响

采用序批式生物反应器(SBR)处理模拟废水,在pH值7.0～8.0、温度30～32℃、DO浓度0.5～1mg/L、MLSS(4000±300)mg/L、NH4+-N35～45mg/L条件下,考察乙酸钠、淀粉和葡萄糖作为碳源对SBR工艺同步硝化反硝化效果的影响。结果表明:投加葡萄糖时,COD去除率达到93.95%,出水硝酸盐浓度为7mg/L;投加淀粉时,COD去除率仅70%,出水硝酸盐浓度为12mg/L;采用乙酸钠作为碳源时,COD去除率为88.34%,出水硝酸盐浓度为4mg/L。COD/NH4+-N为12,分次投加乙酸钠时,氨氮去除率高于95%,总氮去除率高于90%,实现了同步硝化反硝化。在同步硝化反硝化SBR系统中,乙酸钠比淀粉和葡萄糖更适合作为碳源。     

溶解氧对污泥转移SBR工艺除污性能的影响

污泥转移SBR工艺通过并联运行SBR反应器之间以污泥回流方式相互转移,增加反应阶段污泥量而提高系统的除污性能,并减少沉淀阶段污泥量而提高系统的容积利用率。以实际生活污水为处理对象,研究了该新工艺在不同溶解氧水平下对系统除污性能的影响。结果表明,溶解氧对于COD的去除影响不明显,而对TN和TP的去除影响显著。当溶解氧质量浓度控制在1.0～1.5 mg/L时,系统对于COD的去除率为83.8%,出水COD均小于60mg/L;系统对于TN和TP的去除率分别为79.7%和93%,平均出水TN和TP的质量浓度分别为5.9、0.19 mg/L。通过物料衡算发现,系统中TN的去除主要是依靠同步硝化反硝化完成的,占系统TN去除量的55.6%。     

复合式SBR工艺同步硝化反硝化的研究

复合式SBR工艺是在SBR工艺基础上改进,反应器内布置填料而成。试验研究了不同的DO、C／N和MESS对COD、总氮、氨氮和同步硝化反硝化的影响。实验证明：在DO=1mg／L时,系统的同步硝化反硝化效果最好;氨氮和总氮的去除率随着C／N的增而增大,当C／N=15时,同步硝化反硝化效果最好;MLSS越大,总氮的去除率越大,同步硝化反硝化效果越好。在反应器内应保持适当的DO浓度,对于碳源不足的水质,不宜采用同步硝化反硝化,通过控制适宜的MLSS和缩短曝气时间,可能达到降低运行成本的目的。     

低碳氮比污水对同步硝化反硝化脱氮的影响

试验考察了低溶解氧含量连续曝气的序批式反应器内,低C/N污水对氮去除的影响,评价了氮的去除效率。结果表明,m(C)/m(N)为2.95和3.94的条件下,COD的去除并未受到影响,去除率高于95%。最高的TN和NH4+-N的去除率在m(C)/m(N)为2.95时达到,分别为47.4%和54.7%。当m(C)/m(N)降至1.98和1.05时,TN去除率下降为13.66%和16.26%。TN去除率低的原因是反硝化反应受到了C/N的影响,尤其是较低的C/N;并且,不平衡的硝化和反硝化反应导致了低的同步硝化反硝化效率。系统内,最高的同步硝化反硝化效率为94.72%,发生在m(C)/m(N)为3.94时,出水中的NOx--N量很少。     

低温下碳源对同步硝化反硝化的影响

为了提高生物脱氮效率,采用序批式生物反应器(SBR)处理模拟废水。在pH=7.0—8.5、温度10—15℃、溶解氧(DO)为3—5 mg/L、污泥浓度(MLSS)为(3 500±200)mg/L、ρ(NH4+-N)为50—70 mg/L条件下,分别考察蔗糖、醋酸钠和乙醇作为碳源对SBR工艺同步硝化反硝化(SND)脱氮效果和胞外聚合物(EPS)的影响。结果表明,蔗糖作为碳源时,当进水COD为370 mg/L时,COD去除率达到86%,SND率为88.3%,ρ(EPS)为659 mg/L;当醋酸钠作为碳源时,COD去除率达83.9%,SND率为68.8%,ρ(EPS)为742 mg/L;当乙醇作为碳源时,COD去除率仅为72.8%,SND率为58%,ρ(EPS)为736 mg/L。与醋酸钠和乙醇相比,蔗糖更适合作为低温下SBR工艺同步硝化反硝化的碳源。     

同步硝化反硝化膜生物反应器脱除钨冶炼废水中氨氮的影响因素研究

考察了同步硝化反硝化膜生物反应器(SNdNMBR)过程脱除钨冶炼废水中氨氮的影响因素。试验结果表明,当ρ(DO)=1 mg/L、HRT=8 h、m(C)/m(N)=1.5～2.0时,系统SNdN较高,处理效果最佳;污泥停留时间(SRT)为30～40 d时,污泥活性比在0.75左右,污泥活性较好,MLSS的质量浓度维持在5.5 g/L左右,系统对NH4+-N、TN的去除效果分别达到70%和57%左右。     

温度和碳源对短程反硝化除磷效果的影响

以处理生活污水为目标,开展了温度、碳源浓度及碳源种类对A2SBR反应器中短程反硝化除磷脱氮效果影响研究。实验结果表明:反应系统最佳温度为24℃,碳源浓度为200 mg/L反硝化除磷效果最佳,TP和NO_2~--N的去除率分别达到93.22%和91.36%,与丙酸钠和葡萄糖相比,乙酸钠作为碳源系统反应效果更明显,释磷速率和COD降解速率为3.38 mg PO_4~(3-)-P/(g MLSS·h)和29.66 mg COD/(g MLSS·h)。     

移动床生物膜反应器中同步硝化反硝化的实现及动力学分析

以低COD/N人工模拟废水为基质,研究移动床生物膜反应器(MBBR)内同步硝化反硝化(SND)过程。进水COD和NH4+-N的质量浓度分别为200 mg/L和40 mg/L,以K1型填料为载体(填充率为40%),DO控制在3~4mg/L,20 d后有稳定的生物膜形成。生物膜完全成熟后,每个填料上平均生物膜量为33.5 mg,出水COD和NH4+-N去除率平均分别达86.68%和97.25%,NO2--N基本无累积,NO3--N的质量浓度均保持在5 mg/L以下,TN去除率在后期最高达90.6%,计算得到SND率达91.66%,结果证实在单一反应器内实现了良好的同步硝化反硝化过程。动力学模拟得出同步硝化反硝化过程中的NO3--N饱和常数为5.83 mg/L,大于单级反硝化过程中的硝酸盐氮饱和常数。     

同时硝化反硝化处理渗滤液和粪水混合液研究

研究了采用序批式反应器同时硝化反硝化处理垃圾渗滤液与市政粪水混合液的可行性。实验过程中COD、BOD5、TN和NH4 -N的平均去除率分别达到93.76%、98.28%、84.74%和99.21%,相应的污泥平均去除负荷为238.99g/(kgMLSS·d)、76.70g/(kgMLSS·d)、39.43g/(kgMLSS·d)和36.13g/(kgMLSS·d)。反应器内存在高效同时硝化反硝化反应,硝化率和反硝化率分别达到99%和84%,电子计量学研究表明,反应器内存在比全程反硝化消耗碳源更少的脱氮反应形式。结果表明,粪水的混入可有效提高垃圾渗滤液的可生化性,渗滤液和粪水混合液同时硝化反硝化处理效果良好,但反应器出水COD浓度仍略高,仍需进一步的深度处理。     

碳源利用方式对好氧颗粒污泥同步硝化反硝化的影响

研究了好氧颗粒污泥利用外源碳源和胞内储存物质对同步硝化反硝化(SND)的影响.当序批式反应器(SBR)运行方式不同时好氧颗粒污泥对进水碳源的利用方式不同.在一定m(COD):m(N)下,以外源基质为碳源的缺氧反硝化速率为胞内储存物质的4.5～5.5倍;当m(COD):m(N)相同时,利用胞内储存物质的SND效率明显高于外源基质.外源碳源的大量存在使得硝化反应相对滞后,好氧中后期尽管硝态氮充足,但反硝化所需的碳源往往不足:而胞内储存物质的慢速降解特性使得硝化与反硝化过程能够同步进行,从而实现了较高效率的同步硝化反硝化.     

序批式移动床生物膜反应器脱氮除磷影响因素及特性

考察了曝气量、进水C/N比（COD/TN）及进水氮、磷浓度对序批式移动床生物膜反应器（SBMBBR）脱氮除磷效果的影响,分析了该复合生物系统的污染物去除特性。实验结果表明,反应器脱氮主要是基于好氧段发生的同时硝化反硝化（SND）作用实现的,而除磷是基于常规生物除磷和反硝化除磷过程而完成;在保持载体良好流化状态的前提下,反应器硝化效果和TP去除受曝气量变化影响不大,反硝化效果随曝气量的减小而改善;采用厌氧/好氧序批式运行方式,能够使进水中的有机物被反硝化聚磷菌优先利用,实现一碳两用,节省了脱氮对外部碳源的需要,在进水C/N为2.8～4.0时能获得良好的硝化、反硝化和TP去除效果;随着进水氮、磷浓度的提高,反应器除磷效果相对稳定,脱氮效果变差,最大氮、磷去除负荷分别达到0.17 kg TN·m^-3·d^-1和0.06 kg TP·m^-3·d^-1。     

碳氮比与氨氮负荷对序批式活性污泥法同步硝化反硝化的影响

为了提高生物脱氮的效率,研究采用序批式活性污泥法(SBR工艺)考察碳氮质量比w(C/N)与氨氮负荷对同步硝化反硝化的影响。结果表明:当w(C/N)为5.6,氨氮负荷为0.024 g/(g.d),碳源快速消耗,SBR工艺较难实现同步硝化反硝化,同步硝化反硝化率只能够达到0.76%。当w(C/N)为10.5,氨氮负荷为0.024 g/(g.d)时,SBR系统能够实现同步硝化反硝化,同步硝化反硝化率达到97.6%,NH4+-N和COD去除率均接近100%;当w(C/N)为16.3,氨氮负荷为0.024 g/(g.d)时,同步硝化反硝化率为94.5%,增加外加碳源的成本。同步硝化反硝化可以取代二段独立的硝化和反硝化过程,节省运行费用。     

复合SBR系统中同步硝化反硝化现象及其脱氮效果

研究了复合SBR系统对有机物和氮的去除过程及其效果。结果表明:在有氧条件下,存在着反硝化现象,即同步硝化反硝化作用。在试验条件下,当溶解氧为3～5mg/L时,总氮去除率可达80%,同时CODCr的去除率达95%。     

Effects of operational parameters on aeration on/off time in an intermittent aeration membrane bioreactor

This study was performed to evaluate the operational parameters on aeration on/off time in an intermittent aeration membrane bioreactor for wastewater treatment. The membrane bioreactor has 5.5 L of effective working volume including a microfiber membrane. The influent wastewater contained 133mg/L of BOD, 195 mg/L COD, 98 mg/L SS, 30 mg/L total nitrogen, and 3.8 mg/L total phosphorous. Operational conditions related to aeration on/off time were 8.8 h HRT, 10 LMH flux, 10 L/min air flow, and 6300 mg/L MLSS. For 2 h/cycle, aeration on/off time was operated for 12 cycles in three variations: 60/60 min, 50/70 min (I), and 40/80 min. Suction on/off time was 10/2 min, 8/2 min, and 8/2 min, respectively, but also 50/70 min (II) when aeration on/off time was operated at 8300 mg/L MLSS. The BOD removal efficiency rate of this process was higher than 97% regardless of the aeration on/off time distribution. To get higher than 82% total nitrogen removal efficiency rate, aeration off time in the reactor needs to be more than 70 min. The specific denitrification rate was 2.68 mgNO₃-N/gMv/h at 40/80 min on/off aeration times, which was 2.6 times more than at 60/60 min, and 1.4 times more than at 50/70 min (I) for 6300 mg/L MLSS. The specific nitrification rate was 1.96 mgNH₄-N/gMv/h at on/off aeration times of 50/70 min, 1.4 times less than at 40/80 min, but was ineffective for nitrification. Microbial activity was affected only a little by variation in aeration on/off time, though oxygen demand was reduced by aeration off time and allowed microbial concentration to increased. EPS (extracellular polymeric substance) per unit of microorganisms increased with aeration off time.     

Performance evaluation of a modified anaerobic/anoxic/oxic (A/O) process treating low strength wastewater

A full scale modified A²/O process which combined pre-anoxic selector and the staging strategy treating low strength wastewater was investigated. In South China, domestic wastewater is always low in strength due to the high level of groundwater and setting of septic tank at the beginning of wastewater collection system. The results suggested that inadequate denitrification could result in deterioration of phosphorus removal. In addition, influent phosphorus concentration had effect on phosphorus removal. The pre-anoxic selector in modified A²/O process changed the distribution of nitrogen denitrified in different tanks. Characteristics of 3-stage aeration tanks were also studied. The simplified design of rectangular aeration tank could also perform as plug flow as conventional channel aeration tank. In 3-stage aeration tanks, mixed liquid suspended solid (MLSS) increased from one tank to another, while specific oxygen uptake rate (SOUR) of sludge, chemical oxygen demand (COD) and total phosphorus (TP) removal rate decreased, however ammonia nitrogen (NH₃-N) and nitrate nitrogen (NO₃-N) reaction rate remained constant. Furthermore, high MLSS concentration was not suitable for treating low strength wastewater. Waste sludge discharge could improve removal efficiency of COD, NH₃-N, and TP. Without waste sludge discharge, nitrite accumulated in settler.     

耦合生物阴极SND的MLMB -MFC的构建与运行

为有效提高脱氮效率、降低微生物燃料电池运行成本，设计了一种新型多通道折流板无膜微生物燃料电池（MLMB -MFC）。该系统耦合生物阴极同步硝化反硝化（SND），实现产电的同时脱氮除碳。分别考察了系统的启动和运行情况，研究了不同阴极溶解氧（DO）和不同进水碳氮比（C/N）对MLMB-MFC的产电性能和SND效果的影响。经5 d启动运行后，平均功率密度达42.65 mW·m^-3，稳定运行后的最大功率密度（P_M）为94.22 mW·m^-3，有机物去除率为96.6%。阴极DO浓度为4.90~5.23 mg·L^-1、阳极基质C/N比为4时，总氮（TN）的去除率为27.9%，SND率为48.7%，表明该系统的生物阴极能较好地耦合硝化反应、异养反硝化反应和自养反硝化反应于一体，从而达到脱氮目的。     

复合生物反应器亚硝酸型同步硝化反硝化脱氮

Sequence hybrid biological reactor （SHBR） was proposed, and some key control parameters were investigated for nitrogen removal from wastewater by simultaneous nitrification and denitrification （SND） via nitrite. SND via nitrite was achieved in SHBR by controlling demand oxygen （DO） concentration. There was a programmed decrease of the DO from 2.50 mg·L^-1 to 0.30 mg·L^-1, and the average nitrite accumulation rate （NAR） was increased from 16.5% to 95.5% in 3 weeks. Subsequently, further increase in DO concentration to 1.50 mg·L^-1 did not destroy the partial nitrification to nitrite. The results showed that limited air flow rate to cause oxygen deficiency in the reactor would eventually induce only nitrification to nitrite and not further to nitrate. Nitrogen removal efficiency was increased with the increase in NAR, that is, NAR was increased from 60% to 90%, and total nitrogen removal efficiency was increased from 68% to 85%. The SHBR could tolerate high organic loading rate （OLR）, COD and ammonia-nitrogen removal efficiency were greater than 92% and 93.5%, respectively,, and it even operated under low DO concentration （0.5 mg·L^-1） and maintained high OLR （4.0 kg COD·m^-3·d^-1）. The presence of biofilm positively affected the activated sludge settling capability, and sludge volume index （SVI） of activated sludge in SHBR never hit more than 90 ml·L^-1 throughout the experiments.     

长/短HRT联合低/高曝气实现短程硝化反硝化脱氮除磷

为了实现从同步硝化反硝化除磷向短程硝化反硝化除磷颗粒的转变，以颗粒污泥为接种污泥，采用低C/N比的人工配水，通过长/短HRT下的低/高曝气强度交替策略驯化短程硝化反硝化除磷系统。本策略能够维持更高的游离亚硝酸（FNA）浓度和持续时间，在抑制好氧聚磷菌的同时富集反硝化聚磷菌（denitrifying phosphate accumulating organisms, DPAOs）；此外，利用氨氧化菌与亚硝酸盐氧化菌（nitrite oxidizing bacteria, NOB）的亲氧能力差异产生亚氮积累，为DPAOs提供电子受体，最终实现短程硝化反硝化除磷。结果表明，第60天时采用低/高曝气策略的颗粒污泥中\mathrm{N}{\mathrm{O}}_{\mathrm{2}}^{-}型DPAOs占比达45%，NOB 活性下降至3.28mgN/(gMLVSS·h)。在处理低碳源污水时，低/高曝气强度模式相较于恒定曝气强度模式展现出了更强的适应性和稳定性。稳定期出水COD浓度在50mg/L以下，出水总氮（TN）和总磷（TP）浓度分别低于15mg/L和0.5mg/L，TN去除率达94.54%，TP平均去除率为96.90%。