含硝基苯、苯胺废水处理的工程实践

采用固定化微生物-曝气生物滤池与铁-炭微电解法联用的工艺方法处理含硝基苯、苯胺的废水.通过培养驯化微生物阶段、半负荷进水阶段、满负荷进水阶段的调试运行,表明:当进水CODCr＜1000 mg/L、硝基苯＜120 mg/L、苯胺＜30 mg/L时,出水可达到CODCr＜300 mg/L、硝基苯＜5 mg/L、苯胺＜5 mg/L的设计要求.铁-炭微电解法在pH值为3～4时,对废水有一定的脱色作用,但pH值升高后脱色效果不明显.     

固定化微生物技术处理硝基苯类废水效果分析

以辽阳市某污水厂的实际处理工艺流程为实验现场,以污水厂的实际运行数据为基础,综合考察了固定化微生物技术对硝基苯类废水的处理效果。结果表明,经过固定化微生物技术处理后,废水中的硝基苯类化合物大多转化,去除率达到90%以上;对COD、BOD_5的平均去除率分别为84%、86%。出水中COD、BOD_5浓度均达到了《辽宁省污水综合排放标准》(DB 21/1627—2008)的要求,硝基苯类化合物浓度则达到了《污水综合排放标准》(GB 8978—1996)的一级排放标准。但是污水处理系统对废水中的氮类污染物仅有较少去除,针对出水中总氮浓度不达标的情况,提出了相应的改善措施。     

难降解制药废水渗坑治理的工艺设计及运行效果

针对天津某制药厂渗坑的废水成分复杂、有毒有害、可生化性差等特点,通过曝气充氧+微生物强化+膜化学反应器(MCR)+连续活性炭吸附再生+景观浮床+投放水生动物等组合措施,对渗坑进行了综合治理和生态修复。运行结果表明,采用微生物强化技术,对苯胺、甲苯、硝基苯和挥发酚的降解率分别达到98.3%、93.2%、98.1%和95.3%。该组合措施可有效去除废水中的有机物、氨氮、总磷等污染物,增加河道中的生物多样性,强化水体的自净能力。渗坑废水处理后水质达到《地表水环境质量标准》(GB 3838—2002)中Ⅴ类标准。     

生物催化滤池处理高氨氮水源水

针对生物滤池处理高氨氮水源水过程中硝酸盐、亚硝酸盐积累的问题,提出一种能够同时去除"三氮"污染物的强化过滤技术——生物催化滤池。该技术将传统生物过滤与催化还原反应相结合,在生物过滤去除氨氮的同时,钯/锡双金属催化滤料可将硝酸盐氮和亚硝酸盐氮还原为氮气。在滤池的滤速为10 m/h时,对氨氮和TOC的去除率分别为82. 12%和71. 94%,主要依靠生物滤层内微生物的降解作用来去除;对硝酸盐氮和亚硝酸盐氮的去除率分别为58. 22%和78. 65%,主要通过催化还原滤料的化学反应来去除;滤池出水浊度<3 NTU。生物催化滤池在生化反应和催化还原的共同作用下能够有效缓冲低温、高氨氮、高硝酸盐氮、高亚硝酸盐氮以及高TOC等特殊条件下短时间连续冲击,具有较强的抗冲击负荷能力,保证产水水质稳定。生物催化滤池可以作为微污染水源水的预处理工艺,保障后续工艺的稳定运行,具有良好的应用前景。     

臭氧/复合滤料生物滤池深度处理饮用水试验研究

利用陶粒/颗粒活性炭组成新型复合滤料,同时结合臭氧氧化作用深度处理饮用水,考察了臭氧/复合滤料生物滤池深度处理饮用水的效果及有关参数对处理效果的影响.试验结果表明,该生物滤池对浊度、UV254、CODMn、 NO2--N的平均去除率分别为69.1%、43.2%、65.4%和75.8%,对NH4+-N的平均去除率可高达91.2%.随着空床接触时间的延长,对各污染物的去除率逐渐增大,综合对各指标的去除情况及经济因素,空床接触时间以15 min左右为宜.对污染物的去除主要集中在滤池上部,去除效果的变化趋势与溶解氧浓度沿滤料层的变化趋势基本一致.该生物滤池对污染物的去除效果与进水污染物浓度有关,经拟合,对CODMn和NH4+-N的去除率与进水CODMn浓度呈对数关系,当CODMn为0-20 mg/L时,随着进水CODMn浓度的增大,对CODMn的去除率逐渐增大,而对NH4+-N的去除率逐渐降低.     

煤层气采出水达标排放处理技术研究

以鄂东区块采出水为研究对象,在对其水质特征充分分析的基础上,研究提出了“固定化微生物”曝气生物滤池的采出水COD和NH3-N的去除工艺,开展了3个阶段的现场试验进行COD和NH3-N去除效果的验证,同时采用GC-MS分析方法探究采出水中有机物氧化降解情况。试验数据显示：最终出水的COD、NH3-N均低于40,2mg/L排放指标要求,难降解有机物种类和数量大幅减少。其中,COD去除率从70％逐步提升至880％,且随水力停留时间（HRT）增加而不断提升;NH3-N去除率可稳定达到99％以上,远低于标准设定值2mg/L,且对HRT的调整不敏感。研究结果表明,以“固定化微生物-曝气生物滤池＋活性炭吸附”为主体的工艺的处理技术,对鄂东区块采出水中的COD,NH3-N和难降解有机物均具有明显的去除效果,将HRT调整至8h左右时,出水仍可稳定达标,此时的直接运行费用将降至1.40元/m3以下,较化学处理工艺处理费用低70％以上,实现了鄂东区块煤层气采出水的“低成本、 稳定达标排放”处理。     

生物强化滤池在低温低浊水处理中的应用

在低温低浊条件下,通过对生物强化炭砂滤池(BCSFR)与普通炭砂滤池(CSFR)进行对比实验,研究有机物及消毒副产物的去除效果及机制。结果表明,在原水温度4~10°C,浊度为2~6NTU条件下,BCSFR对高锰酸盐指数(PI)、TOC和UV254的平均去除率分别达到48.28%、31.80%和29.32%。此外,可生物同化有机碳(AOC)和可生物降解有机碳(BDOC)的去除率分别为50.83%和51.16%。由于微生物降解与活性炭吸附的协同作用,BCSFR能够比普通CSFR更有效去除有机物,因此有可能成为一种适合处理寒冷地区低温低浊水的安全饮用水保障技术。     

缺氧/好氧生物塘深度处理污水厂尾水的中试

通过设置缺氧区、分区种植水生植物构建微生物与多种水生生物共同作用的缺氧/好氧生物塘,对达到一级A排放标准的污水处理厂尾水进行中试规模的深度处理研究.结果表明,缺氧/好氧生物塘对污水处理厂尾水的处理效果较好,出水DO浓度明显升高,平均值为3.67mg/L;对COD和硝酸盐氮的平均去除率分别可达到58.25％和37.74％,出水浓度可达到地表Ⅲ类水质标准;对总磷的平均去除率为35.66％,出水浓度可达到地表Ⅴ类水质标准.缺氧/好氧生物塘对污染物的去除是微生物降解与生物链摄取共同作用的结果.     

水厂过滤工艺的生物强化技术研究

以水厂沉淀池出水为研究对象,考察了以陶粒滤料进行生物强化过滤的处理效能,并对强化滤池的除污特性与机理进行了探讨.结果表明,陶粒滤池经自然挂膜,运行20 d后对氨氮、有机物和浊度已能达到较高的去除效果.其中氨氮的去除率达90%,对CODMn的去除率达40%,出水浊度可保持在1 NTU以下.污染物的去除是物化反应与生化反应共同作用的结果,且主要集中于陶粒滤池的上部60 cm段.     

生物滤池处理污染河水的中试研究

在新沂河沭阳段的滩地上建设了总处理能力为1 050 m3/d的中试生物滤池,3个滤池分别填充粗(60～80 mm)、中(30～50 mm)、细(10～20 mm)三种粒径的填料,并进行了为期一年多的试验研究.结果表明,采用生物滤池处理新沂河水是可行的,细、中和粗三种粒径的滤池对CODMn和NH4+-N的平均去除率分别为23%、15.5%、9.7%和80.3%、51.2%、33.7%,硝化作用是生物滤池除氮的主要机制,可生化性会影响对CODMn的去除效果.细粒径的滤池对污染物的去除效率最高,对NH4+-N和CODMn的平均去除率分别在80%和20%以上.影响污染物去除效果的主要因素有填料粒径、水力负荷、池长、停留时间、水温等,细粒径的滤池去除污染物的效果受各种因素的影响较小,可保持较高的去除率.为保证除污效果,应使细粒径滤池的池长15 m,中、粗粒径滤池的池长30 m.     

Effects of geochemical constituents on the zero‐valent iron reductive removal of nitrobenzene in groundwater

Nitrobenzene (NB) was chosen as the model contaminant, and batches lab scale experiments were conducted to investigate the effects of geochemical compositions on reductive removal of nitrobenzene by zero‐valent iron (ZVI) in groundwater. Experimental results showed that the kinetics of nitrobenzene reduction by ZVI was a pseudo‐first order with an observed rate constant, k_obs, of 3.67 × 10^?4/s; the calculated half‐life of nitrobenzene was 1.89 × 10³/s. The geochemical constituents of groundwater have significant influences on ZVI reactivity and nitrobenzene reduction. The presence of high concentration of nitrate, carbonate, sulphate and hardness had detrimental effects on reduction of nitrobenzene and formation of aniline; chloride had a slight positive effect on the nitrobenzene reduction and the formation of aniline. Bicarbonate enhanced the ZVI reactivity initially at lower concentration and inhibited the nitrobenzene reduction at high concentration. Therefore, the performance and reactivity of ZVI were found to be strongly affected by the geochemical constituents of groundwater.     

Study of the aromatic by-products formed from ozonation of anilines in aqueous solution

Aqueous solutions of aniline and p-chloroaniline were treated with ozone in order to study the reaction and oxidation by-products. Aniline solutions were ozonated at low and high pH, so as to compare both molecular and hydroxyl free radical mechanisms, respectively. The main identified aromatic by-products were nitrobenzene and azobenzene when the experiment was carried out at acid pH. Formation of nitrobenzene, azobenzene, azoxybenzene and 2-pyridine-carboxylic was observed when the ozonation was carried out at basic pH. p-Chloroaniline was treated with ozone only at high pH and the identified by-products were in accordance with those obtained in the ozonation of aniline: p-chloronitrobenzene, 4,4'-dichloroazobenzene and 4-chloro-2-pyridine-carboxylic acid. All the aromatic by-products found were less toxic than the raw materials. The pseudo-first-order constants in aniline concentration were calculated, whilst kinetic in p-chloroaniline concentration could not be adjusted to a first-order reaction.     

Biocenosis of BAC(F)s used for groundwater treatment

The studies on the biocenosis of biologically active carbon filters (BAC(F)) used in treatment of Miocene water revealed the presence of protozoa of the group of flagellates and ciliates (Glaucoma sp., Opercularia sp.), saprophytic bacteria, phase I and II nitrifying bacteria, Fe(II) and Mn(II) oxidizing bacteria of the family Siderocapsaceae, Leptothrix ochracea and Pedomicrobium sp., as well as microscopic fungi. The stratification of biofilter colonisation by these microorganisms was found to be similar to that occurring in biofilters applied in sewage treatment. A hypothetical model of microbiological transformations in BAC(F)s, brought about by various physiological groups of microorganisms, is presented. It is shown that ozone pre-treatment of water dosed to the biofilter reduces the number of saprophytic bacteria and moulds in its upper layer, as well as Fe(II) oxidizing bacteria of the family Siderocapsaceae across the full section of the biofilter; it does not, however, influence the abundance of nitrifying phase I and II autotrophic bacteria and Mn(II) oxidizing bacteria of the family Siderocapsaceae. The abundance of microorganisms in the biofilter outflow is increased in comparison with that in untreated water; they do not, however, create a health hazard for human beings.     

Effect of sulfate on anaerobic reduction of nitrobenzene with acetate or propionate as an electron donor

Sulfate is frequently found in wastewaters that contain nitrobenzene. To reveal the effect of sulfate on the reductive transformation of nitrobenzene to aniline - with acetate or propionate as potential electron donors in anaerobic systems - an acetate series (R1-R5) and a propionate series (R6-R10) were set up. Each of these was comprised of five laboratory-scale sequence batch reactors. The two series were amended with the same amount of nitrobenzene and electron donor electron equivalents, whereas with increasing sulfate concentrations. Results indicated that the presence of sulfate could depress nitrobenzene reduction. Such depression is linked to the inhibition of nitroreductase activity and/or the shift of electron flow. In the acetate series, although sulfate did not strongly compete with nitrobenzene for electron donors, noncompetitive inhibition of specific nitrobenzene reduction rates by sulfate was observed, with an inhibition constant of 0.40 mM. Propionate, which can produce intermediate H₂ as preferred reducing equivalent, is a more effective primary electron donor for nitrobenzene reduction as compared to acetate. In the propionate series, sulfate was found to be a preferential electron acceptor as compared to nitrobenzene, resulting in a quick depletion of propionate and then a likely termination of H₂-releasing under higher sulfate concentrations (R9 and R10). In such a situation, nitrobenzene reduction slowed down, occurring two-stage zero-order kinetics.     

Reduction of nitrobenzene and formation of corrosion coatings in zerovalent iron systems

Batch tests were conducted to investigate reduction of nitrobenzene in a zerovalent iron system (Fe0) under various conditions. The results indicated that a limited amount of nitrobenzene (ArNO2) could be reduced to aniline by Fe0, but formation of a lepidocrocite (gamma-FeOOH) coating could significantly slow down the reaction. However, augmenting Fe0 with substoichiometric FeCl2 could dramatically accelerate the reaction. Surface-adsorbed Fe(II), not pH nor Cl-, was found to be responsible for rejuvenating the system. O2 and nitrobenzene could be concomitantly reduced by Fe0 in the presence of Fe2+. In the Fe0 system, both nitrobenzene and O2 favored formation of lepidocrocite; in the presence of aq. Fe(II), a stratified corrosion coating could develop, with magnetite (Fe3O4) as the inner layer and lepidocrocite as the outer layer. Fe2+ was not the main reductant for the reactions, but might accelerate the autoreduction of lepidocrocite to magnetite by the underlying Fe0. Our understanding on the role of Fe(II) in conjunction with a stratified, evolving corrosion coating may be useful for establishing an iron aquatic corrosion model.     

Microbial degradation of quinoline by immobilized cells of Burkholderia pickettii

A quinoline-biodegrading microorganism was isolated from activated sludge of coke-oven wastewater treatment plant using quinoline as sole carbon and nitrogen source. It is a gram negative, rod-shaped and aerobic strain, which was identified as Burkholderia pickettii. The biodegradation of quinoline was carried out with this isolated strain. Analysis by high performance liquid chromatography and gas chromatography/mass spectrum (GC/MS) revealed that 2-hydroxyquinoline (2-OH-Q) was the first intermediate in the course of quinoline biodegradation. A novel immobilization carrier, that is, polyvinyl alcohol (PVA)-gauze hybrid carrier, was developed. The isolated strain was immobilized by two different immobilizing techniques and used for the quinolinerdegradation. It was found that biodegradation rate of quinoline by the microorganisms immobilized on PVA-gauze hybrid carrier was faster than that by the microorganisms immobilized in PVA gel beads. Kinetics of quinoline biodegradation by cells of Burkholderia pickettii immobilized on PVA-gauze hybrid carrier was investigated. The results demonstrate that quinoline degradation could be described by zero-order reaction rate equation when the initial quinoline concentration was in the range of 50-500 mg l(-1).     

Biological treatment of H(2)S using pellet activated carbon as a carrier of microorganisms in a biofilter

Biological treatment is an emerging technology for treating off-gases from wastewater treatment plants. The most commonly reported odourous compound in off-gases is hydrogen sulfide (H(2)S), which has a very low odor threshold. This study aims to evaluate the feasibility of using a biological activated carbon as a novel packing material, to achieve a performance-enhanced biofiltration processes in treating H(2)S through an optimum balance and combination of the adsorption capacity with the biodegradation of H(2)S by the bacteria immobilized on the material. The biofilm was mostly developed through culturing the bacteria in the presence of carbon pellets in mineral media. Scanning electron microscopy (SEM) was used to identify the biofilm development on carbon surface. Two identical laboratory scale biofilters, one was operated with biological activated carbon (BAC) and another with virgin carbon without bacteria immobilization. Various concentrations of H(2)S (up to 125 ppmv) were used to determine the optimum column performance. A rapid startup (a few days) was observed for H(2)S removal in the biofilter. At a volumetric loading of 1600 m(3)m(-3)h(-1) (at 87 ppmv H(2)S inlet concentration), elimination capacity of the BAC (181 gH(2)Sm(-3)h(-1)) at removal efficiency (RE) of 94% was achieved. If the inlet concentration was kept at below 30 ppmv, high H(2)S removal (over 99%) was achieved at a gas retention time (GRT) as low as 2s, a value, which is shorter than most previously reported for biofilter operations. The bacteria population in the acidic biofilter demonstrated capacity for removal of H(2)S in a broad pH range (pH 1-7). There are experimental evidences showing that the spent BAC could be re-used as packing material in a biofilter based on BAC. Overall, the results indicated that an unprecedented performance could be achieved by using BAC as the supporting media for H(2)S biofiltration.     

EGSB的后续处理工艺选择

考察了与厌氧污泥膨胀床（EGSB）串联的厌氧生物滤池、好氧生物滤池和活性污泥法等3种工艺的除污性能。结果表明，厌氧生物滤池出水COD浓度较高，好氧生物滤池出水水质不够稳定，而采用活性污泥法作为EGSB的后续工艺，则出水水质良好且运行稳定。     

生物滤塔处理含三甲胺气体的研究

研究了分别填充堆肥和污泥的生物滤塔对含三甲胺气体的处理能力.结果表明,两种生物滤塔均能有效处理含三甲胺的气体,对三甲胺的去除率几乎达到了100%,三甲胺被生物降解并生成氨.堆肥生物滤塔各段填料中的硝态氮含量随时间的延长呈显著提高的趋势,但pH值出现下降,说明其中发生了氨的硝化作用.而在污泥生物滤塔中,随着氨的积累则各填料层的pH值迅速升高,并且没有观察到亚硝态氮以及硝态氮含量的增加,因此其不具备进一步降解氨的能力.