单级自养脱氮反应器效能与微生物群落结构的相关性

于稳定运行但效能有明显差异的2套序批式生物膜反应器单级自养脱氮系统,研究了微生物群落结构的PCR-DGGEr、eal-time PCR等现代分子生物学特点及其运行效能与之的相关性。结果表明:运行效能好的反应器活性污泥及生物膜浓度较高,微生物群落结构差异较大,二者相似性为58.3%,溶解氧在活性污泥及生物膜内的分布特点为各类微生物及其代谢创造了良好环境,系统中好氧氨氧化菌AOB及厌氧氨氧化菌ANAMMOXz在数量上绝对占优,各类细菌的协同代谢使系统总氮去除率达到80%以上。运行效能相对较差的反应器,由于在反应器启动过程中没有将亚硝酸氧化菌NOB完全"洗脱",系统中出现NO3-积累,且系统挂膜不理想,生物膜浓度低,生物膜与活性污泥微生物群落结构相似性为100%,优势功能菌单一,从而造成运行效能较低,总氮去除率仅为20%~30%。维持SBBR自养脱氮系统微生物群落结构的稳定及平衡性,生物膜是关键性因素。     

硅藻土高效生物流化床A/O工艺

硅藻土高效生物流化床A/O(Anoxic/Oxic)工艺是活性污泥法和生物膜法与物化法的结合工艺。在A/O生物反应池内投加硅藻土之类的载体,使之悬浮在混合液中,依靠载体表面附着生长的多菌群生物膜来提高生物反应池内活性污泥的浓度和活性;同时池内载体呈流化状态,载体、污水和空气在反应池内翻滚流动,实现载体与气相、液相、气液相之间的充分混合;载体始终悬浮于液(气)体中并剧烈运动,具有类似液体的自由流动性,强化了物质的扩散过程,提高了生化反应速度和吸附过滤效果,从而达到高效去除污染物、净化污水的目的。     

悬浮填料活性污泥法的脱氮效果及影响因素

投加悬浮填料强化传统活性污泥法的脱氮能力，考察了低温、填料投配比和生物膜量等因素对脱氮效果的影响。中试结果表明，投加悬浮填料和采用前置反硝化的运行方式可使系统的氨氮和总氮去除率得到显著提高。     

MBBR在国内的工程应用与发展前景

典型的MBBR工艺系统包括悬浮载体、拦截筛网、流化系统(曝气、搅拌推流等),整个系统通过优化设计,实现填料的流化与拦截。国内MBBR典型工程应用具有强化脱氮除磷、负荷高、占地省、抗冲击负荷能力强、耐受低温等极端水质、可持续升级、投资省、运行费用低等特点。MBBR采用镶嵌式改造,曝气方式灵活,项目实施周期短,运行管理方便,广泛应用于市政和工业废水处理,应用时不受规模限制。悬浮载体生物膜具有生物选择功能,水力剪切、DO与微生物量及菌落变化密切相关;泥膜复合MBBR工艺,一定程度上克服了传统活性污泥法中脱氮除磷泥龄的矛盾,突破了传统活性污泥法中好氧、非好氧池容比例限制。MBBR改造形成了多条技术路线,根据具体情况选择最合理方式,强化生物脱氮除磷。MBBR的多种池型,包括循环流动池型、微动力混合池型、完全混合池型等,满足绝大多数项目改造需求。MBBR微生物选择性以及工艺镶嵌的特点,让MBBR可作为新技术的载体和工程化平台,具有广阔的应用前景。     

深床过滤与同步生物脱氮的研究

研究了深床过滤工艺对城市污水二级处理出水的处理效果及影响因素.将两个上流式滤柱串联,其中填充以φ3～4 mm的聚苯乙烯发泡粒子,床层高度为2 m.在第一个滤柱底部曝气以集成生物硝化,在第二个滤柱的进水中投加甲醇以集成生物反硝化.研究表明,在水力停留时间为1～2 h时,硝化滤柱的氨氮脱除率达到90%,反硝化滤柱的硝酸盐氮脱除率达到95%以上,最终出水的浊度＜1 NTU,总的脱氮负荷可达1 kg/(m3填料·d).通过试验发现HRT、进水氨氮和外碳源对生物硝化和反硝化有重要影响.过滤介质能很好地吸附微生物而形成生物膜,在扫描电镜下观察到生物膜具有复杂的网状结构及生物相.另外,反冲洗质量对保证系统稳定运行及脱氮除浊效果有重要影响.     

复合膜生物反应器的生物学研究

投加载体的膜生物反应器中同时存在附着生长和悬浮生长的微生物，对HSMBR系统的生物相进行分析，发现悬浮生长微生物中的大多数菌属在生物膜中也同样存在，这为微生物在附着相和悬浮相之间的转化提供了物质基础。此外，对反应器内微生物之间的相互关系进行了分析，对微生物的构成进行了探讨。     

SNAD-IFAS工艺对污泥消化液的处理效能

污泥消化液作为污泥厌氧处理过程的副产物,具有低碳高氮的特点,传统生物脱氮技术难以有效处理。为此,利用固定生物膜-活性污泥反应器(IFAS),考察同步硝化、厌氧氨氧化和反硝化(SNAD)工艺对污泥消化液的处理效能。结果表明,在进水NH~+_4-N浓度为400 mg/L、HRT为18 h的最佳运行条件下,SNAD-IFAS系统对NH~+_4-N、TN与COD的最大去除率分别达到92.6%、77.1%和69.4%,TN去除负荷为12.4 mg/(L·h)。菌群特性活性分析结果表明,亚硝化过程主要发生在悬浮污泥中,厌氧氨氧化与反硝化过程主要发生在生物膜上。微生物群落分析表明,HRT的变化会显著影响微生物群落结构。     

新型双污泥脱氮除磷工艺处理生活污水

将活性污泥法与生物膜法相结合，开发出一种新型脱氮除磷处理工艺，成功地解决了传统工艺中硝化细菌与除磷菌之间的泥龄矛盾问题。试验结果表明，该工艺对COD、NH3-N、TP的去除率分别高达85％、95％、90％，同时处理效果稳定，对水质的适应能力也较强。     

单级生物脱氮技术的进展

综述了在一个反应器中同时进行硝化和反硝化的单级生物脱氮技术的进展,对活性污泥、生物膜和固定化细胞等单级生物脱氮工艺进行了评述。     

复合式竹丝填料生物反应器处理化粪池出水

为寻找适合化粪池出水的处理工艺,采用批式试验研究了复合式竹丝填料生物反应器对化粪池出水中COD、SS的去除效果。结果表明:复合式竹丝填料生物反应器能有效去除化粪池出水中的COD和SS,平均去除率分别达到了85.4%和90%以上;复合式竹丝填料生物反应器的微生物数量较多、微生物链较长、微生物种群丰富;复合式竹丝填料生物反应器中的污泥增加量极少。将复合式竹丝填料生物反应器内的活性污泥和竹丝分开组成两个独立的生物反应器并处理化粪池污水,结果发现,竹丝生物膜反应器能在短期(18h)内超过活性污泥反应器的处理效果,且竹丝生物膜反应器的产泥量很低。可见,竹丝填料较为适合处理化粪池出水,是一种价格低廉、污染少、运行管理费用较低的良好填料。     

含腈废水的生物一级处理工艺

采用好氧活性污泥法、悬浮载体膨胀床及厌氧生物反应器分别对含腈废水进行一级处理。实验结果表明,由于含腈废水的CN -毒性和难降解有机物含量高,好氧活性污泥法不适合处理含腈废水。随着活性污泥反应器运行时间的延长,污泥逐渐失去活性,大量微生物死亡。悬浮载体膨胀床处理含腈废水的效果较差,污染物去除率低于15%。厌氧生物反应器适于用作含腈废水的一级处理,污染物去除率可达到35%以上,而且可以改善水质,提高含腈废水的可生化性,有利于后续的生物处理工艺对含腈废水的深度处理。     

Micropollutant removal by attached and suspended growth in a hybrid biofilm-activated sludge process

Removal of organic micropollutants in a hybrid biofilm-activated sludge process was investigated through batch experiments, modeling, and full-scale measurements. Batch experiments with carriers and activated sludge from the same full-scale reactor were performed to assess the micropollutant removal rates of the carrier biofilm under oxic conditions and the sludge under oxic and anoxic conditions. Clear differences in the micropollutant removal kinetics of the attached and suspended growth were demonstrated, often with considerably higher removal rates for the biofilm compared to the sludge. For several micropollutants, the removal rates were also affected by the redox conditions, i.e. oxic and anoxic. Removal rates obtained from the batch experiments were used to model the micropollutant removal in the full-scale process. The results from the model and plant measurements showed that the removal efficiency of the process can be predicted with acceptable accuracy (±25%) for most of the modeled micropollutants. Furthermore, the model estimations indicate that the attached growth in hybrid biofilm-activated sludge processes can contribute significantly to the removal of individual compounds, such as diclofenac.     

Suspended biofilm carrier and activated sludge removal of acidic pharmaceuticals

Removal of seven active pharmaceutical substances (ibuprofen, ketoprofen, naproxen, diclofenac, clofibric acid, mefenamic acid, and gemfibrozil) was assessed by batch experiments, with suspended biofilm carriers and activated sludge from several full-scale wastewater treatment plants. A distinct difference between nitrifying activated sludge and suspended biofilm carrier removal of several pharmaceuticals was demonstrated. Biofilm carriers from full-scale nitrifying wastewater treatment plants, demonstrated considerably higher removal rates per unit biomass (i.e. suspended solids for the sludges and attached solids for the carriers) of diclofenac, ketoprofen, gemfibrozil, clofibric acid and mefenamic acid compared to the sludges. Among the target pharmaceuticals, only ibuprofen and naproxen showed similar removal rates per unit biomass for the sludges and biofilm carriers. In contrast to the pharmaceutical removal, the nitrification capacity per unit biomass was lower for the carriers than the sludges, which suggests that neither the nitrite nor the ammonia oxidizing bacteria are primarily responsible for the observed differences in pharmaceutical removal. The low ability of ammonia oxidizing bacteria to degrade or transform the target pharmaceuticals was further demonstrated by the limited pharmaceutical removal in an experiment with continuous nitritation and biofilm carriers from a partial nitritation/anammox sludge liquor treatment process.     

浙江某工业废水处理厂升级改造运行效果解析

浙江某工业废水处理厂升级改造,采用AAO—MBBR复合生物膜工艺,在未新增建设用地和扩建池容的基础上,日处理量由3×10⁴m³/d提高至6×10⁴m³/d。改造后实际运行出水COD、TP、NH₃-N和TN浓度分别为(37.7±6.61)、(0.09±0.03)、(0.25±0.14)和(5.87±1.54)mg/L,出水水质稳定达到一级A标准。实际监测表明,在好氧MBBR区存在TN去除现象,约占TN总去除量的10.36%。系统内的优势硝化菌属为硝化螺旋菌属Nitrospira,其在悬浮载体生物膜和活性污泥中的相对丰度分别为8.98%和0.92%,悬浮载体的投加使硝化细菌得到有效富集;反硝化菌在生物膜中的占比为7.94%,为悬浮载体同步硝化反硝化(SND)效果的发生提供了微观保证,提高了TN去除率。     

驯化污泥固定化快速启动BAC反应器的研究

采用驯化污泥以动态挂膜和静态膜固定的方法进行了生物活性炭(BAC)反应器的快速挂膜和启动研究。将驯化污泥配制成500 mg/L的污泥菌液,控制挂膜污泥量为2~4 g/L、挂膜液循环流量为400~560 mL/min并以下向流循环方式运行,在1~2 d内就能实现BAC的稳定挂膜。启动后应用其处理某垃圾焚烧厂渗滤液处理站的生化处理出水,对COD的去除率70%,显著优于SBR法的处理效果。     

Total nitrogen removal in a hybrid, membrane-aerated activated sludge process

The hybrid (suspended and attached growth) membrane biofilm process (HMBP) is a novel method to achieve total nitrogen removal from wastewater. Air-filled hollow-fiber membranes are incorporated into an activated sludge tank, and a nitrifying biofilm develops on the membranes, producing nitrite and nitrate. By suppressing bulk aeration, the bulk liquid becomes anoxic, and the nitrate/nitrite can be reduced with influent BOD. The key feature that distinguishes the HMBP from other membrane-aerated processes is that it is hybrid; heterotrophic bacteria are kept mainly in suspension by maintaining low bulk liquid BOD concentrations. We investigated the HMBP's performance under a variety of BOD and ammonium loadings, and determined the dominant mechanisms of nitrogen removal. Suspended solids increased with the BOD loadings, maintaining low bulk liquid BOD concentrations. As a result, nitrification rates were insensitive to the BOD loadings, remaining at 1gNm(-2)day(-1) for BOD loadings ranging from 4 to 17gBODm(-2)day(-1). Nitrification rates decreased during short-term spikes in bulk liquid BOD concentrations. Shortcut nitrogen removal was confirmed using microsensor measurements, showing that nitrite was the dominant form of oxidized nitrogen produced by the biofilm. Fluorescence in situ hybridization (FISH) showed that ammonia oxidizing bacteria (AOB) were dominant throughout the biofilm, while nitrite oxidizing bacteria (NOB) were only present in the deeper regions of the biofilm, where the oxygen concentration was above 2mg/L. Denitrification occurred mainly in the suspended phase, instead of in the biofilm, decreasing the potential for biofouling. When influent BOD concentrations were sufficiently high, full denitrification occurred, with total nitrogen (TN) removal approaching 100%. These results suggest that the process is well-suited for achieving concurrent BOD and TN removal in activated sludge.     

The influence of sludge age on heavy metal removal in the activated sludge process

In a laboratory simulation of the activated sludge process ten heavy metals were added continuously to the system which was allowed to equilibrate at six sludge ages between 3 and 18d. Cobalt, manganese and molybdenum removals were poor and were unaffected by changes in the sludge age. The highest removal efficiencies for the other metals occurred at the 15d sludge age. Chromium (trivalent) and cadmium had the highest removal efficiencies, typically greater than 50%. The behaviour of the majority of the metals which were removed to a significant extent was related to one of the parameters influenced by sludge age, i.e. mixed liquor suspended solids, effluent suspended solids or effluent chemical oxygen demand. The metals which were poorly removed showed little affinity for the activated sludge, while most metals exhibited maximum specific uptake by the mixed liquor at a sludge age of 9–12d. However, the affinity of silver for the mixed liquor continued to increase as the sludge age increased to 18d. An affinity series, based on an arbitrary measure of the specific accumulation of metals by the mixed liquor, indicated that chromium, cadmium and silver were most readily adsorbed by the activated sludge.     

Aerobic moving bed biofilm reactor treating thermomechanical pulping whitewater under thermophilic conditions

The continuously operated laboratory scale Kaldnes moving bed biofilm reactor (MBBR) was used for thermophilic (55 degrees C) aerobic treatment of TMP whitewater. In the MBBR, the biomass is grown on carrier elements that move along with the water in the reactor. Inoculation with mesophilic activated sludge gave 60-65% SCOD removal from the first day onwards. During the 107 days of experiment, the 60-65% SCOD removals were achieved at organic loading rates of 2.5-3.5 kg SCODm(-3) d(-1), the highest loading rates applied during the run and HRT of 13-22h. Carbohydrates, which contributed to 50-60% of the influent SCOD. were removed by 90-95%, while less than 15% of the lignin-like material (30-35% of SCODin) was removed. The sludge yield was 0.23g VSSg SCOD(-1)removed. The results show that the aerobic biofilm process can be successfully operated under thermophilic conditions.     

淹没式复合型MBR处理城市生活污水的效能研究

为了缓解缺水压力，在传统膜生物反应器（CMBR）的基础上开发出了一种新型城市污水处理回用工艺——淹没式复合型膜生物反应器（SHMBR），并考察了对城市生活污水的处理效果。试验结果表明，SHMBR可以在CMBR的基础上进一步提高生物量，并明显改善了对有机物和NH4^＋-N的去除效果。试验中对TN、TP的去除效果没有提高，原因可能是生物膜的厚度不够，没有在生物膜内部形成厌氧微环境。另外，SHMBR的除磷效果没有增强还可能与生物膜的SRT较长以及聚磷菌主要生活在活性污泥中有关。