反硝化生物滤池的自然挂膜启动研究

研究了反硝化生物滤池的挂膜启动过程,寻求判断启动完成的快速、简便、合理的方法,为反硝化生物滤池的挂膜提供理论依据。控制水力负荷在0.022 m3/(m2·h)即HRT为14 h,水温为25~27℃,反硝化生物滤池运行14 d后对硝态氮的去除率达到99%,第15天平均进水硝态氮浓度由21.86 mg/L减小到8.05 mg/L,出水浓度基本保持不变,仍稳定在0~1 mg/L,反硝化系统生态结构稳定,表明挂膜成功。当有机碳源充足、NO-3-N浓度0.1 mg/L时,反硝化速率与NO-3-N浓度遵循零级反应动力学规律。反硝化生物滤池中的氨氮主要由微生物同化作用去除,去除率约为28.9%。     

滤料粒径对曝气生物滤池硝化性能的影响

为研究滤料粒径对曝气生物滤池(BAF)硝化性能的影响,分别采用粒径为2～3mm和4～5mm的沸石滤料在直径为0.2m的BAF中进行了试验,结果表明,前一种滤料比后一种滤料对氨氮去除率高,20℃时两者的硝化速率常数分别为16.8mg/(L·h)和10.3mg/(L·h),前者比后者高63.1%;同一条件下前一种滤料比后一种滤料硝化强度大39.7%。两种粒径沸石比表面积的比值为1.8,这是引起硝化性能差异的主要原因。在硝化滤池中选择粒径为2～3mm沸石滤料比较适宜,既不影响运行周期,又提高了硝化性能,从而减小了滤池的体积,降低了工程投资。     

DN/CN强化脱氮技术在污水厂提标改造中的应用

以某市城镇污水处理厂NO_3~--N浓度较高的生化出水为研究对象,采用反硝化生物滤池+曝气生物滤池(DN/CN)工艺,研究了碳氮比(C/N值)、进水负荷、温度等对TN去除效果的影响。结果表明,当增加的C/N值为3. 6、水力负荷≤9. 44 m~3/(m~2·h)[NO_3~--N最大负荷为4. 8 kg/(m~3·d)]时,出水TN满足国标要求(≤10 mg/L);去除单位质量TN需3. 7倍COD,碳源不足会导致NO_2~--N积累和碳源单耗升高; 14℃时的TN去除率较19℃时下降了约15%;反硝化过程中pH值增量和TN去除量存在一个对应关系,可用于反硝化滤池处理效果的辅助判断。     

反硝化生物滤池脱氮的中试研究

以某城市污水厂初沉池出水为原水,采用中试规模的移动床生物膜反应器/沉淀池/反硝化生物滤池工艺进行生物脱氮,重点考察了反硝化生物滤池的脱氮效果及C/N值对脱氮效率的影响,探讨了反硝化生物滤池再启动后的恢复情况,并构建了反硝化生物滤池脱氮动力学模型。结果表明,在稳定运行期间反硝化生物滤池对TN的去除率为86.4%~96.5%,当2.5C/N值5时,TN去除率与C/N值无相关性,平均去除率为93.3%,最佳C/N值为3.45。反硝化生物滤池经过3 d维护后再启动,运行12 h后即可恢复到滤池维护前的脱氮水平。在该中试条件下,反硝化遵循零级反应动力学,反应速率为174.4 mg/(L·h)。     

侧向流曝气生物滤池的同步硝化反硝化研究

利用自行研制的侧向流曝气生物滤池处理城市生活污水,考察了同步硝化反硝化现象。试验结果表明,在水力负荷分别为0.43、0.61 m3/(m2.h)以及气水比为10∶1、进水COD负荷为0.395~2.523 kg/(m3.d)、NH3-N负荷为0.082~0.486 kg/(m3.d)、TN负荷为0.047~0.587 kg/(m3.d)的条件下,对氨氮的去除率分别为78.91%和53.33%,对总氮的去除率分别为52.58%和36.85%。对滤池内含氮化合物的空间分布、氧摄取速率以及底物转化速率和微生物数量的监测结果表明,滤池内发生了同步硝化反硝化。     

某再生水厂反硝化滤池脱氮性能与生物膜特征解析

反硝化滤池是污水处理厂强化脱氮的重要技术途径之一。研究了进水碳氮比(COD/N)和空床停留时间(EBRT)对某再生水厂后置反硝化滤池反硝化脱氮性能的影响,同时考察了生物膜特征及其活性。在进水COD/N值为4.5、EBRT为28.2 min时,NO_3~--N去除率最高为72.69%,去除负荷为0.42 g N/(m~2·d);在相近EBRT(27.7 min)下,提高进水COD/N值至6.5和7.5,NO_3~--N去除负荷明显提高,分别为0.75和0.73 g N/(m~2·d)。在反硝化滤池底部滤层NO_3~--N的沿程降解符合半阶动力学方程,半阶动力学系数随EBRT的降低和进水COD/N值的提高而增大。反硝化所需COD/N值平均为5.67。中层滤料生物膜的生物量及其厚度最大(分别为8 678.43 mg/m~2和131.25μm)。生物膜密度由下至上逐渐增大,分别为52.58、66.12和104.59mg/cm~3。反硝化活性由下至上略微增大,分别为11.34、11.44和13.47 mg N/(g VSS·h)。生物膜微生物以Beta变形菌为主,相对丰度大于85%;Methylophilaceae科菌群相对丰度最高(42.1%);所检测到的主要菌属包括Georgfuchsia(24.3%)和Sulfuricella(4.6%)。     

沸石曝气生物滤池中亚硝酸盐氮积累的研究

利用沸石曝气生物滤池研究了硝化反应中亚硝酸盐氮的积累现象。试验结果表明:同时增大滤速和进水氨氮浓度可以提高滤池出水中亚硝酸盐氮的浓度。在滤速为1 m/h、气水比为1∶1、水温为13~16℃、进水氨氮负荷为1.5~1.8 kg/(m3.d)的条件下,系统对氨氮的去除能力为0.7~0.9 kg/(m3.d),亚硝酸盐氮占硝化反应产物的90%以上。沸石的离子交换能力对滤池中氨氮浓度具有调节作用,有利于实现亚硝酸盐氮的稳定积累。     

双层填料反硝化深床滤池脱氮的研究

采用同比例反硝化深床中试装置,对比单层填料反硝化深床滤池与双层填料反硝化深床滤池的脱氮能力。结果表明,双层填料反硝化深床滤池对水质的要求更低,脱氮量较单层填料反硝化深床滤池更大;最佳反冲洗周期为1 d,超过设定周期连续运行对TN的去除无明显影响;同时,对于该系统应根据填料层的性质设置不同的反冲洗周期,可有效延长滤池的使用周期。     

蚯蚓生物滤池的硝化性能及其影响因素研究

以厌氧水解池/高负荷生物滤池/蚯蚓生物滤池组合中试工艺为基础,考察了蚯蚓生物滤池的硝化性能及其影响因素.试验结果表明,在滤床温度为16.6～29.5 ℃时,蚯蚓生物滤池具有较好的硝化性能,硝化速率为0.2～0.5 mgNH4 -N/(g·h);当滤床温度＜10℃时硝化速率＜0.1 mgNH4 -N/(g·h),最小值仅为0.045 6 mgNH4 -N/(g·h).蚯蚓密度与硝化菌数量呈线性正相关,说明蚯蚓与硝化菌之间存在协同生长效应.     

二级曝气生物滤池中碳、氮代谢特性的研究

采用以高分子生物载体为填料的二级曝气生物滤池处理生活污水,研究了进水有机负荷和NH3-N负荷对系统处理效果的影响.结果表明,在水温为18-25℃、pH值为5.8-7.4、气水比为3.5:1时,对COD的去除率与进水有机负荷呈正相关,硝化率同有机负荷及NH3-N负荷呈负相关,且主要取决于前者.当有机负荷为2.75-3.90kg/(m3.d)时,对C0D的去除率可高达98%;当有机负荷为0.77-1.48kg/(m3.d)时,硝化率可达93.3-98.1%,对TN的平均去除率达39.4%.降低进水有机负荷可解除高负荷所导致的硝化抑制作用,使硝化的起始点提前,提高峭化率,显示出单独驯化的硝化滤池在去除NH3-N上的优势.硝化菌受反冲洗的影响大于异养菌,反冲洗6h后系统可基本恢复时COD和NH3-N的去除效果.     

A2O工艺削减城市污水毒性的能力评估

依次次改变A^2O系统的水力停留时间、泥龄和混合液回流比，并使用发光菌毒性测试法对系统各反应单元的进、出水毒性进行了测试，从而首次从毒减性削角度对A^2O工艺进行了评估，同时对部分工艺运行参数进行了优化选择。试验结果表明：A^2O工艺对城市污水的毒性（以发光菌抑光率表示）有较好的削减能力；在温度为25℃、污泥回流比为100％的情况下，最佳的工艺运行参数为水力停留时间（HRT）=12．5h、泥龄（SRT）=15d、混合液回流比（r）=100％，此时NH3-N、SS、COD的去除率分别达到90．05％、77．17％、80．02％，毒性削减率也达到82．17％，其中厌氧池、缺氧池、好氧池、二沉池各段毒性削减量分别占毒性总削减量的16．29％、7．58％、52．01％、24．12％。     

Effects of recirculation rate of nitrified liquor and temperature on biological nitrification–denitrification process using a trickling filter

In the modified Ludzack–Ettinger process, high‐energy input is required in a nitrification tank. To address this issue, a new biological nitrification–denitrification system was constructed with a trickling filter for nitrification. The effects of recirculation rate of nitrified liquor and temperature through the treatment of municipal wastewater were evaluated. The highest DN removal efficiency was observed at 6.5 h of hydraulic retention in the denitrification tank and 350% of recirculation rate of nitrified liquid against the influent flow rate. The DN removal efficiencies did not reach theoretical values for all conditions tested because the COD/N ratios in the influent often decreased to less than 5 g‐COD/g‐N and temperatures dropped to less than 15°C in winter. The former inhibited the denitrification process and the latter significantly decreased the bioactivity of nitrifying bacteria. As such, this system is suitable in tropical and subtropical areas with annual minimum temperatures of over 15°C.     

Assessment of energy efficiency in electric storage water heaters

Nowadays there are several ways of supplying hot water for showers in residential buildings. One of them is the use of electric storage water heaters (boilers). This equipment raises the water temperature in a reservoir (tank) using the heat generated by an electric resistance. The behavior of this equipment in Brazil is still a research object and there is not a standard in the country to regulate its efficiency. In this context, an experimental program was conducted aiming to collect power consumption data to evaluate its performance. The boilers underwent an operation cycle to simulate a usage condition aiming to collect parameters for calculating the efficiency. This 1-day cycle was composed of the following phases: hot water withdrawal, reheating and standby heat loss. The methods allowed the identification of different parameters concerning the boilers work, such as: standby heat loss in 24 h, hot water withdrawal rate, reheating time and energy efficiency. The average energy efficiency obtained was of 75%. The lowest efficiency was of 62% for boiler 2 and the highest was of 85% for boiler 9.     

Effect of low ORP in anoxic sludge zone on excess sludge production in oxic-settling-anoxic activated sludge process

This paper studied the effect of oxidation-reduction potential (ORP) in the anoxic sludge zone on the excess sludge production in the oxic-settling-anoxic process (OSA process), a modified activated sludge process. Two pilot-scale activated sludge systems were employed in this study: (1) an OSA process that was modified from a conventional activated sludge process by inserting a sludge holding tank or namely the "anoxic" tank in the sludge return line; and (2) a conventional process used as the reference system. Each was composed of a membrane bioreactor to serve the aeration tank and solid/liquid separator. Both systems were operated with synthetic wastewater for 9 months. During the operation, the OSA system was operated with different ORP levels (+100 to -250 mV) in its anoxic tank. It has been confirmed that the OSA system produced much less excess sludge than the reference system. A lower ORP level than +100 mV in the anoxic tank is in favor of the excess sludge reduction. When the ORP level decreased from +100 to -250 mV the sludge reduction efficiency was increased from 23% to 58%. It has also been found that the OSA system performed better than the reference system with respect to the chemical oxygen demand removal efficiency and sludge settleability. The OSA process may present a potential low-cost solution to the excess sludge problem in an activated sludge process because addition of a sludge holding tank is only needed.     

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。     

A/A/MBBR工艺处理混合污水的脱氮除磷中试研究

采用A/A/MBBR工艺处理由粪便液和生活污水组成的混合污水,试验条件:填料投配比为20%,好氧池1和好氧池2中的填料体积比为1:3,好氧池的水力停留时间为5 h,混合液回流比为120%,污泥回流比为60%,泥龄为6 d,好氧池的溶解氧为3.0 mg/L,温度为16～20℃.系统稳定运行一个月的结果表明:脱氮除磷效果及对有机物的去除效果均稳定而良好,出水氨氮、总氮、总磷和COD平均浓度分别为0.3、12.9、0.35和36.22 mg/L,均达到了国家一级A排放标准.     

剩余污泥回流至初沉池对A/O污水处理系统的影响

基于静态模拟试验结果，进行了将A／O处理工艺中二沉池剩余污泥按比例回流至初沉池的生产性试验，运行结果显示，这一措施能明显提高初沉池的沉淀效率，且当剩余污泥的回流比例为40％～60％时，初沉池对SS、COD等去除效果最佳，同时可提高A／O池进水的可生化性及处理能力，并降低浓缩池出泥含水率。该工艺运行稳定，可有效降低污水处理厂的总体运行成本。     

水解酸化/悬浮滤料BAF一体化装置处理生活污水

水解酸化/悬浮滤料曝气生物滤池,是将水解酸化与曝气生物滤池结合为一体的新型污水处理工艺。在滤速为37.7 m/d、水力停留时间为3.98 h、进水pH平均值为7.69、平均水温为18.1℃的条件下,考察了该工艺对城镇污水的处理效果。试验结果表明,当BOD5容积负荷为2.14 kg/(m3.d)、NH3-N容积负荷为0.38 kg/(m3.d)、反冲洗周期为3 d、反冲洗强度为39.3m3/(m2.h)时,该工艺具有良好的除碳脱氮性能,对COD、BOD5、NH3-N、SS、TN、TP的平均去除率分别可达90.1%、96.0%、90.1%、92.8%、38.4%、75.5%。此外,该工艺还具有结构简单、占地面积小、运行稳定、出水水质好、管理简便的特点,适合于居住小区等小水量的生活污水处理工程。     

Real-time control of an immobilized-cell reactor for wastewater treatment using ORP.

The performance of an immobilized-cell reactor for simultaneous carbon nitrogen removal in synthetic wastewater with an intermittent aeration (IA) process under real-time control of oxygen supply was investigated. The oxidation-reduction potential (ORP) was monitored during operation. The ORP-time profile showed distinctive turning points. which directly correlated with the changes in the system chemistry and biological activity. The reactor was conducted by cyclic fixed-time aeration nonaeration operation at the beginning, followed by real-time control technology using ORP setpoint. A moving window along the slope of the ORP curve was employed to search for the nitrate breakpoint of the aeration cycle. Once the breakpoint was found, the reactor was aerated for a fixed period. The treatment process could effectively avoid the anoxic fermentation state under the real-time control. The cycle time was reduced around 30%. The duration of aeration period was found to be optimum at 3 h under the consideration of the removal efficiencies of COD and total nitrogen. The real-time control system not only exhibited a better nitrogen removal efficiency than the fixed-time control operation, but it also showed a stable effluent quality during the change of HRT from 3 to 8 h. Good operation stability was demonstrated even when a very high disturbance of the influent loading occurred.     

厌氧/跌水充氧接触氧化/人工湿地处理农村污水

为了使太湖地区农村污水处理达到占地面积小、除磷脱氮效率高、管理简单、运行和建设费用低的目标，采用厌氧／跌水充氧接触氧化／人工湿地组合工艺进行了工程规模的试验研究。结果表明，在厌氧池水力停留时间为2d、5级跌水充氧接触氧化池总水力停留时间为2h、并采用50cm／d的高水力负荷人工湿地的条件下，该组合工艺对COD和TN的平均去除率分别为81％和83％，对TP的平均去除率在进水TP〉1．5mg／L时达82％，在进水TP〈1．5mg／L时为72％。