Orbal氧化沟生物脱氮的中试研究

采用有效容积为330L的中试Orbal氧化沟模型处理城市污水,研究了Orbal氧化沟的同时硝化反硝化生物脱氮现象。结果表明,Orbal氧化沟具有良好的降解有机物和硝化性能;在不投加外碳源和不设硝化液内回流的条件下,通过控制DO浓度分布,可以实现氧化沟内的同时硝化反硝化,对总氮去除率平均为61%,出水总氮平均为14mg/L。经分析认为,DO浓度分布是氧化沟内同时硝化反硝化的决定因素,进水中的COD/TN是影响总氮去除率的重要因素;通过控制外沟低DO运行,可以稳定实现Orbal氧化沟的低能耗高效脱氮;多沟道串联的反应器布置方式有效防止了低DO运行带来的亚硝酸盐积累和污泥膨胀的发生。     

溶解氧浓度对A~2/O工艺运行的影响

以城市污水厂中最常采用的A2/O工艺为研究对象,开展了处理实际生活污水的研究,系统探讨了DO浓度对该工艺运行的影响。结果表明,当好氧区的DO平均浓度从4.0 mg/L降低至1.0 mg/L时,对COD的去除基本不受影响;而系统的硝化效果逐渐降低,但是低DO浓度引发的SND等作用,使得对TN的去除率反而逐渐升高。单纯从生物脱氮的角度考虑,A2/O工艺可以在DO为1.0～2.0 mg/L之间运行。不过低DO浓度运行对生物除磷效果的影响很大,在DO为1.0 mg/L时,除磷效率逐渐下降,这是由于供氧不足引发了生物除磷性能的恶性循环。另外,低DO浓度运行还引发系统中的污泥发生了微膨胀现象,在污泥微膨胀期间出水SS<5 mg/L。就总体的运行情况而言,不同于A/O等单纯脱氮工艺,A2/O工艺不宜在DO<2.0 mg/L的条件下运行,否则需要引入化学除磷。     

序批式生物膜法的脱氮除磷功效研究

采用序批式生物膜工艺进行了处理广州地区城市污水的脱氮除磷试验研究，结果表明：在碳、氮、磷比例失调（碳量偏低）的情况下，达到了既去除有机物又能脱氮除磷的效果，出水BOD5、COD分别为6．0～9．8、12．7～35．5mg／L，而TN、NH3-N、TP分别在14．8、4．0、0．5mg／L以下；磷的厌氧释放是好氧吸磷和除磷的前提；DO浓度会影响好氧段的磷吸收速率，但不影响磷的去除量；在好氧运行初期发生了同步硝化反硝化，其去除的总氮约为15％。     

好氧颗粒污泥发生丝状菌污泥膨胀的控制措施

在SBR反应器内接种好氧颗粒污泥,经驯化后对人工模拟废水的处理效果良好。考察了培养过程中污泥形态的变化以及发生丝状菌污泥膨胀时反应器对污染物的去除效果,并探讨了丝状菌在污泥颗粒化过程中的作用以及控制丝状菌污泥膨胀的方法。结果表明,丝状菌污泥膨胀对COD的去除率有影响,但对去除NH3-N、TP的效果影响不大。通过增加反应器内的水力剪切力对控制丝状菌污泥膨胀有一定的效果,而减小C/N值,均衡进水中的营养可从根本上解决污泥膨胀问题。成熟的好氧颗粒污泥的MLSS约为3 000 mg/L,沉降性能较好,SVI为77 mL/g;对COD、NH3-N、TP均具有较高的去除率,分别达到94.52%9、5%9、0%左右。     

A/O除磷工艺丝状菌污泥膨胀的研究

丝状菌污泥膨胀是影响活性污泥法高效、稳定运行的重要因素。采用A/O生物除磷工艺中试装置处理实际生活污水,分析了污泥膨胀发生的原因及恢复系统性能的方法。结果显示,长期曝气不均匀是导致丝状菌污泥膨胀的重要原因,通过调控系统运行参数可以有效控制由低DO值或者高负荷引起的丝状菌污泥膨胀。当发生污泥膨胀后,首先降低负荷至0.45 kgCOD/(kgMLSS.d),调节回流比为83%,同时控制好氧池各段的DO分别为1.5、1.0、1.0 mg/L以淘汰丝状菌,在SVI值降至200 mL/g以下后继续降低回流比至53%,同时降低曝气量以形成1.0、0.5、0.5 mg/L的DO浓度梯度。采取上述调控措施后,SVI值由569.8 mL/g降至150 mL/g以下,污泥性状得以恢复;同时出水COD和TP分别在50、0.5 mg/L以下,去除率分别约为85%、95%。     

低DO下曝气方式对分段进水脱氮工艺的影响

采用分段进水生物脱氮工艺处理小区生活污水,考察了在低DO条件下,不同曝气方式对硝化率及污泥沉降性能的影响。结果表明,在曝气量为0．27m^3／h、MLSS平均为2700mg／L左右、好氧区的DO为0．26～2．5mg／L的条件下,当进水氨氮为44～55mg／L时,对氨氮的去除率保持在95％以上,对COD的去除率〉90％;当控制好氧区第1、2格室的DO分别为0．5～0．7和1．0～1．2mg／L时,系统的硝化率维持在90％以上,出水中的氨氮〈2mg／L;在恒定曝气量下,向进水中投加有机碳源,当水质改变较快时,容易引起丝状菌污泥膨胀,但通过恒DO曝气控制,可使污泥的沉降性能得到改善。     

低溶解氧下微膨胀污泥对污染物的去除性能

维持SBR反应器好氧段的平均DO为0.30 mg/L,采用好氧/缺氧的运行方式研究了微膨胀污泥在低溶解氧状态下去除污染物的效果.结果表明:在丝状菌污泥微膨胀状态下反应器的除污效果仍较好,出水SS含量很低,对COD、氨氮的去除率分别可达80%、90%以上,同时可以节省曝气量约25%.可见,在低溶解氧状态下采用微膨胀活性污泥处理生活污水是可行的.     

污泥减量工艺:HA-A/A-MCO的好氧脱氮机制分析

针对污泥减量技术存在对氮、磷去除能力低的问题,开发了一种具有强化脱氮除磷功能并可实现污泥减量化的HA-A/A-MCO工艺。在该工艺取得同步脱氮除磷和污泥减量优异效果的条件下,采用其处理校园生活污水,当进水TN平均为47 mg/L时,出水TN为10.9 mg/L,系统的总脱氮率为76.8%,其中好氧脱氮量占总脱氮量的50%,缺氧脱氮量占26%;HA-A/A-MCO系统存在着在好氧条件下具有反硝化能力的菌属,对好氧脱氮有一定贡献,且DO浓度对其反硝化能力没有抑制作用;好氧池中的DO浓度梯度有利于在污泥絮体内形成缺氧环境,从而促进同步硝化反硝化(SND)的发生,但减小污泥絮体尺寸会削弱絮体内部缺氧区域比例、降低SND的脱氮效率。     

Nitrogen removal from wastewater using membrane aerated microbial fuel cell techniques

Nitrogen removal mainly relies on sequential nitrification and denitrification in wastewater treatment. Microbial fuel cells (MFCs) are innovative wastewater treatment techniques for pollution control and energy generation. In this study, bench-scale wastewater treatment systems using membrane-aerated MFC (MAMFC) and diffuser-aerated MFC (DAMFC) techniques were constructed for simultaneous removal of carbonaceous and nitrogenous pollutants and electricity production from wastewater. During 210 days of continuous flow operation, when the dissolved oxygen (DO) in the cathodic compartment was kept at 2 mg/L, both reactors demonstrated high COD removal (>99%) and high ammonia removal (>99%) but low nitrogen removal (<20%). When a lower DO (0.5 mg/L) was maintained after day 121, both the MFC-based reactors still had excellent COD removal (>97%). However, the nitrogen removal of MAMFC (52%) was 2-fold higher than that of DAMFC (24%), indicating an enhanced performance of denitrification after DO reduction in the cathodic compartment of the MAMFC. Meanwhile, terminal restriction fragment length polymorphism (T-RFLP) analysis of ammonia-oxidizing bacteria (AOB) population in the MAMFC indicated the diversity of AOB with equally important Nitrosospira and Nitrosomonas species present in the cathodic biofilm after DO reduction. The average voltage output in the MAMFC was significantly higher than that in DAMFC under both DO conditions. The results suggest that MAMFC systems have the potential for wastewater treatment with improved nitrogen removal and electricity production.     

新型一体化生物反应器的同步脱氮除磷影响因素研究

为了提高对污水的处理效能,设计了一种新型一体化生物反应器并采用其处理生活污水,研究了DO和HRT对同步脱氮除磷效果的影响,并探讨了其实现机理。试验结果表明：在进水COD为290～510mg／L、MLSS为2500mg／L、污泥龄为15d以及好氧区和缺氧区的溶解氧分别为2mg／L和0．2mg／L时,系统的脱氮除磷效果较好,对TN、TP的去除率分别可达80％和90％,DO过高或过低都会影响同步脱氮除磷的效果。控制DO为最优值,并保持其他操作条件相同,当HRT为12h时对总氮和总磷的去除率均在80％以上,随着HRT的延长,同步脱氮除磷效果反而下降。该一体化反应器集厌氧、缺氧和好氧区为一体,在一定的运行条件下能够实现同步脱氮除磷,是处理生活污水的有效方法。     

复合生物反应器的同步硝化反硝化研究

以实际生活污水为处理对象,利用有效容积为12 L的间歇式复合生物反应器（填料填充率：30%,运行方式：瞬间进水—曝气660 min—沉淀40 min—排水20 min）,研究了DO、COD/TN值、MLSS对同步硝化反硝化的影响。结果表明：当溶解氧浓度从4 mg/L降到0.5 mg/L时,对总氮的去除率从48.9%升至74.2%;当污泥浓度从1 000 mg/L提高至6 000 mg/L时,对总氮的去除率从63.4%升至81.6%;当COD/TN值从3升至15.6时,对总氮的去除率从59%提高至82.5%,但当COD/TN值〉8后,对总氮的去除率提高得并不明显。整个试验过程中SVI〈105mL/g,污泥的沉降性能良好。复合生物反应器易于实现稳定的同步硝化反硝化,并可通过控制DO、MLSS等参数来有效提高对总氮的去除率。     

低溶氧下低C/N值生活污水的同步硝化反硝化

采用改良的Orbal氧化沟中试系统处理低C／N值生活污水，考察了溶解氧浓度对同步硝化反硝化（SND）的影响。结果表明，当外沟溶解氧浓度为0．3mg／L时，约有29．97mg／L的总氮在氧化沟的外沟通过SND去除，外沟对COD的实际去除量为9．03mg／L，外沟的SND主要是利用微生物内贮有机碳源或生物吸附碳源进行的。控制氧化沟的外、中、内沟溶解氧浓度分别为0．3、0．5和2．0mg／L时，系统的SND率和总氮去除率最高。在优化的溶解氧条件下，系统对总氮的平均去除率和平均SND率分别为66．0％和42．6％，分别比优化前提高了13．8％和24．3％。     

Steady-state model-based evaluation of sulfate reduction, autotrophic denitrification and nitrification integrated (SANI) process

Recently we developed a process for wastewater treatment in places where part of the fresh water usage is replaced by seawater usage. The treatment of this saline sewage consists of sulfate reduction, autotrophic denitrification and nitrification integrated (SANI) process. The process consists of an up-flow anaerobic sludge bed (UASB) for sulfate reduction, an anoxic filter for autotrophic denitrification using dissolved sulfide produced in the UASB and an aerobic filter for nitrification. The system was operated for 500 days with 97% COD removal and 74% total nitrogen removal without withdrawal of sludge. To verify these results and to understand this novel process, a steady-state model was developed from the COD, nitrogen and sulfur mass and charge balances based on the stoichiometries of the sulfate reduction, the autotrophic denitrification and the autotrophic nitrification. The model predictions agreed well with measured data on COD, nitrate and sulfate removal, sulfide production, effluent TSS, and mass balances of COD, sulfur and nitrogen in the three reactors. The model explains why withdrawal of sludge from the SANI system is not needed through comparisons of the predictions and measurements of effluent TSS and phosphorus concentrations.     

Application of response surface methodology for simultaneous carbon and nitrogen (SND) removal from dairy wastewater in batch systems

The application of batch systems to the direct treatment of dairy wastewater was investigated. Batch experiments were conducted to study the organics removal and simultaneous nitrification and denitrification (SND) process. The experiment was conducted by varying four independent parameters (mixed liquor suspended solids, chemical oxygen demand [COD]/N ratio, aeration time and cycling time), using a central composite design under response surface methodology. The process responses of five dependent parameters (COD, Total kjehldahl nitrogen (TKN), NO₃ ^?, effluent NO₃ ^? and effluent total nitrogen) were studied, and in each case, the percentage removal in batch runs was determined with each process displayed in contour plots. Finally, after optimizing the process conditions, the best treatment of dairy wastewater under optimized conditions was established and the responses were shown. This study shows that microbial granules cultivated under the alternating aerobic/anaerobic conditions in batch systems could efficiently remove organic carbon and convert all the ammonium to nitrogen gas.     

UBAF/化学除磷处理宾馆污水并回用

济南南郊宾馆的排水量及杂用水量均较大,为此采用水解—上向流曝气生物滤池(UBAF)—纤维过滤器(加药除磷)工艺处理宾馆污水,通过将UBAF的滤层分成缺氧区和好氧区,使UBAF具有了碳化、硝化与反硝化的功能,其对氨氮的去除率>85%,对COD的去除率在80%左右,在回流比为50%的条件下对总氮的去除率约30%。UBAF出水投加硫酸铝后进行纤维过滤除磷,在投量为20mg/mgTP的条件下可确保出水TP<1mg/L。     

亚硝酸盐对聚磷菌厌氧代谢的影响

以2种强化生物除磷(EBPR)系统中的活性污泥为研究对象,考察亚硝酸盐对聚磷菌厌氧代谢的影响,结果表明：不同EBPR系统中的聚磷菌对于亚硝酸盐的耐受能力不同。人工配水富集聚磷菌的活性污泥,当亚硝态氮浓度超过10 mg/L时,聚磷菌吸收VFA受到抑制, PHA的合成减少,磷酸盐的释放增加;处理生活污水的SBR短程脱氮除磷活性污泥,亚硝酸盐的浓度高达30 mg/L时,未对聚磷菌的厌氧代谢造成抑制,但引起异养反硝化菌与聚磷菌竞争VFA,导致PHA合成量和释磷量的减少。富集聚磷菌的活性污泥投加亚硝酸盐后P/VFA     

SBR短程同步硝化反硝化耦合除磷的研究

在序批式活性污泥反应器(SBR)中,以模拟城市污水为处理对象,考察了在稳定运行期间的典型周期里COD、TP、TN、DO、pH以及ORP的变化规律。试验表明,在SBR反应器中实现短程同步硝化反硝化耦合除磷是完全可行的,在温度为20～25℃、pH值为7.12～7.43的条件下,系统对COD的去除率达到95.6%,对TP和TN的去除率分别为88.8%和87%,实现了短程同步硝化反硝化与反硝化除磷的统一。     

味精废水好氧同步硝化反硝化的试验研究

采用SBR处理味精废水,考察了味精废水的可生化性、好氧条件下的同步硝化反硝化以及不同C/N下有机负荷和氨氮负荷的变化.结果表明,对COD的去除率为91.6%～97.2%,对BOD5的去除率>95%,味精废水的BOD5/COD为0.5,说明其可生化性较好,可为反硝化过程提供充足的碳源;试验中存在明显的同步硝化反硝化现象,对氨氮和总氮的去除率分别达到99%、96%;随着进水C/N的降低,有机负荷降低,氨氮负荷升高.     

Performance of an aerobic/anaerobic hybrid bioreactor under the nitrogen deficient and low F/M conditions

A bioreactor system without a biomass-liquid separation unit is evaluated for its chemical oxygen demand (COD) removal and biomass retention capabilities under the nitrogen deficient and low F/M conditions that are known to produce bulking biomass. A fully oxygenated stream recycled from an external oxygenator delivers the oxygen to an upflow bioreactor in which a biomass zone is formed and maintained in the absence of gas effervescence. COD is removed with up to 90% efficiency by means of aerobic and anaerobic bacterial activities occurring in the biomass zone. The biomass is bulking which is brought about by the extensive filamentous growth caused by the nitrogen deficient and low F/M conditions adopted. However, the biomass zone is undisturbed at superficial upflow velocities as high as 0.66 cm/min, because it has a porous, mat-like matrix that is augmented by the entanglement of filamentous bacteria with the cell clusters. A low-VSS effluent (i.e.,< 10 mg/L) is produced directly from the bioreactor.