温度对亚硝酸型硝化/反硝化的影响

以间歇式活性污泥法（SBR）法处理啤酒废水，系统考察了温度变化对亚硝酸型硝化／反硝化的影响。结果表明：温度维持在30℃得到的亚硝酸型硝化的污泥，运行在常温（19．5－23．5℃）50周期，硝化类型转变为硝酸型硝化。而后，逐渐升温，硝化类型逐渐转变为亚硝酸型硝化。当温度达到28－29℃时，硝化类型为稳定的亚硝酸型硝化，硝化反应结束时NO2^--N/NOx^--N平均维持在82．2％－83．5％。28－29℃是本试验条件下亚硝酸型硝化的临界温度。而且不论是亚硝酸型硝化／反硝化还是完全硝化／反硝化，DO、ORP、pH在脱氮过程中的变化规律基本相同，可以作为SBR法脱氮过程的控制参数。     

MBR中同步硝化反硝化及异养硝化现象试验研究

在以限制混合液溶解氧浓度方式运行的MBR反应器中,通过改变进水COD/TKN、混合液DO浓度等工艺参数,研究了对系统中同步硝化反硝化(SND)过程的影响因素.根据试验结果探讨了MBR系统中所实现的SND机理,同时对系统中存在的异养硝化菌进行了分离培养,并对其硝化特性进行了初步研究分析.试验结果表明:影响系统SND的主要因素是进水COD/TKN和反应器中控制的混合液DO浓度,系统中存在一定量的异养硝化菌.     

不同硝态氮组成下反硝化过程控制参数pH变化规律

采用序批式反应器(Sequencing Batch Reactor,SBR)反应器,在(21±1)℃下,以NO3--N和NO2--N为电子受体,在碳源充足的条件下对反硝化过程中的pH变化规律进行了研究。结果表明,反硝化过程中pH曲线上不仅出现了指示反硝化结束的特征点,还出现了表示硝酸盐完全还原为亚硝酸盐的特征点。此外,在起始NOx--N(NO2--N+NO3--N)浓度与pH值相同的条件下,起始NO2--N浓度所占的比例越高,反硝化结束时pH曲线上峰点的值越高,在反硝化过程中产生的总碱度却相等。研究分析发现NO2--N所占比例不同,反硝化过程中产生的碱度类型就不同,这是造成pH增量不同的根本原因。这些研究结果为更好地控制污水处理工艺提供了参考数据。     

短程硝化反硝化技术研究

目前,高效、低耗去除水中氦污染物是国内外广泛关注的环境问题,短程硝化反硝化脱氮技术则是当前的研究热点。本论文针对短程硝化反硝化脱氨的机理和影响因素进行了研究,以深入理解短程硝化反硝化现象,对发展可持续污水生物处理工艺具有重大推动意义。     

污水处理厂生物反硝化工艺

本文主要阐述了生物反硝化工艺原理及控制要点，并列举了计算实例及异常问题的排除方法。     

处理城市污水的反硝化脱氮除磷新工艺研究进展

反硝化脱氮除磷可以实现同步反硝化脱氮和除磷,代表了当前污水处理可持续发展战略的发展趋势。本文对反硝化脱氮除磷的新工艺进行了重点介绍,这些工艺充分发挥了反硝化聚磷菌的优势,可提高处理效率、简化操作、降低处理费用,成为目前脱氮除磷工艺技术研究的热点和重点。     

一体化厌氧氨氧化-反硝化固定微生物反应器协同脱氮研究

采用厌氧氨氧化(ANAMMOX)工艺的厌氧上流式固定化微生物反应器处理含有机物的高浓度含氮废水,考察ANAMMOX与反硝化协同脱氮效果。试验结果显示:在一定范围内,NH4+-N和NO2--N进水负荷不会对ANAMMOX与反硝化协同脱氮造成明显影响,当进水负荷为301～800mg/L时,系统对NH4+-N、NO2--N和TN的去除率分别达到93.3%、98.6%和90.3%的较高水平;当COD浓度为800～850mg/L时,COD对ANAMMOX与反硝化协同脱氮基本不影响,并可实现95.7%的COD去除率。同时,NO3--N浓度、N2产量、pH值和生物相存在的特征性变化,也表明ANAMMOX与反硝化协同作用良好。     

低溶解氧短程硝化及同步脱氮研究

采用SBR反应器,以实际生活污水为研究对象,通过实验研究了在常温条件下通过控制低溶解氧(DO)实现短程硝化的可行性及控制条件.在曝气量由60 L·h-1逐渐降低到28 L·h-1的过程中,实现了由全程硝化到短程硝化的转变,亚硝酸盐积累率达到95%以上,出水硝态氮稳定在2.0mg·L-1以下.在低溶解氧短程硝化过程中,伴随着显著的同步脱氮:曝气量为32 L·h-1条件下实现了平均总氮去除率达54.6%.在实现短程硝化后,再次提高曝气量为40L·h-1时,短程硝化可以稳定保持.实验结果表明,通过控制低溶解氧可以实现常温条件下生活污水的短程硝化,过程中同步脱氮效果明显;系统可以在相对较高的溶解氧浓度下稳定运行.     

多孔型含贝类硫磺填料的脱氮性能实验研究

硫氧化自养型反硝化中。反硝化菌（Genus Thiobacillus等）将多种硫化物（S2-,So,S2032-,S4062-,S032-）氧化为硫酸盐的同时,硝酸态氮被还原成氮气（ZhangandLampe,1999）。这些自养型微生物把硫当作电子供给体,无需外部碳源（甲醇,乙醇,醋酸盐）,因此价格低廉的硫磺可代替甲醇应用于C／N比较低的废水处理中,其经济性和反硝化效率均较高。特别是做为后续的反硝化工程,代替人工投入有机物,利用价格便宜的硫磺粒子去除水中的氮,处理效率稳定,运行也简便。但是,目前硫磺脱氮工艺在反硝化过程中碱度被破坏,随着pH值下降,反硝化率也随之降低,为了补充减少的碱度,通常投加粒子状的碳酸钙,而长期使用碳酸钙,会引起反应容器堵塞以及反洗时过多的硫磺粒子和石灰石、碳酸钙流失掉的问题,从而导致运行费用的增加。     

乙酸钠与甲醇为外加碳源在反硝化过程中的比较

现有污水厂常存在碳源不足的现象,比反硝化速率较低,反硝化过程得不到彻底进行。本研究利用倒置A2／O系统的活性污泥,以某污水厂初沉池出水与不同量的甲醇及乙酸钠配制为一系列原水,进行反硝化反应效能的研究,以对比甲醇及乙酸钠对反硝化作用的强化效果差异。研究结果表明污水厂初沉池出水碳源中不容或复杂的可溶性有机物占较大比例。以乙酸钠为外加碳源时,可得较高的比反硝化速率。而以甲醇为外加碳源时,反硝化效率较乙酸钠高。通过不同的碳源补偿均能在一定程度上改善脱氮效果。     

Novel two stage bio-oxidation and chlorination process for high strength hazardous coal carbonization effluent

Effluent generated from coal carbonization to coke was characterized with high organic content, phenols, ammonium nitrogen, and cyanides. A full scale effluent treatment plant (ETP) working on the principle of single stage carbon-nitrogen bio-oxidation process (SSCNBP) revealed competition between heterotrophic and autotrophic bacteria in the bio-degradation and nitrification process. The effluent was pretreated in a stripper and further combined with other streams to treat in the SSCNBP. Laboratory studies were carried on process and stripped effluents in a bench scale model of ammonia stripper and a two stage bio-oxidation process. The free ammonia removal efficiency of stripper was in the range 70-89%. Bench scale studies of the two stage bio-oxidation process achieved a carbon-nitrogen reduction at 6 days hydraulic retention time (HRT) operating in an extended aeration mode. This paper addresses the studies on selection of a treatment process for removal of organic matter, phenols, cyanide and ammonia nitrogen. The treatment scheme comprising ammonia stripping (pretreatment) followed by the two stage bio-oxidation and chlorination process met the Indian Standards for discharge into Inland Surface Waters. This treatment process package offers a techno-economically viable treatment scheme to neuter hazardous effluent generated from coal carbonization process.     

Green preparation of nano-zero-valent iron-copper bimetals for nitrate removal: Characterization,reduction reaction pathway,and mechanisms

In this study, green tea was used as a reducing agent to prepare GT-nZVI/Cu nano-zero-valent iron-copper bimetallic materials for nitrate degradation. Through single factor experiments, the process conditions for nitrate removal by GT-nZVI/Cu were optimized. By measuring the contents of nitrate, nitrite, and ammonia nitrogen in the reaction products, the reduction pathway of nitrate-nitrogen in GT-nZVI/Cu was studied. In addition, the removal mechanism of nitrate by GT-nZVI/Cu was also analyzed by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR) and kinetic experiments. The results showed that the size of GT-nZVI/Cu particles is between 50 and 70 nm, and they are irregular spherical shapes. The polyphenol antioxidants in green tea make GT-nZVI/Cu have stronger antioxidant properties, and the denitration products are mostly nitrogen. The addition of copper ions accelerates the reaction time and reaction rate. The maximum removal rate of nitrate by GT-nZVI/Cu within 75 min can be up to 99 %. After three repeated experiments, the removal rate of GT-nZVI/Cu can still reach 70 %. The removal mechanism of GT-nZVI/Cu has enhanced nitrate removal through complexation, redox, and adsorption co-precipitation. This study provides a new route for the green preparation and efficient application of nZVI.     

A2N反硝化除磷脱氮系统处理生活污水研究

研究了生活污水COD／TN比值变化对A2N反硝化除磷脱氮新工艺去除氮、磷的影响情况。同时利用间歇试验着重探讨了DNPAOs污泥在不同硝态氮浓度、不同电子受体时的摄磷和放磷状况。A2N连续流工艺长期的运行结果表明：双泥系统的建立(生物膜硝化池独立于除磷污泥)可以降低碳源的好氧消耗,较大程度地减少聚磷菌和反硝化菌之间对碳源的竞争,同时保证了生长速率较小的硝化菌可以在稳定状态中生长,利于增强系统脱氮除磷的稳定性。     

Kinetics of nitrogen removal in high rate anammox upflow filter

The process kinetics for laboratory-scale anammox (anaerobic ammonium oxidation) upflow filter using synthetic wastewater as feed were investigated. The experimental unit consisted of a 2.0 L reactor filled with three-dimensional plastic media. The filter was tested for different influent substrate concentrations and hydraulic retention time (HRT). The substrate loading removal rate was compared with prediction of Stover–Kincannon, second-order and the first-order substrate removal models. Upon approaching pseudo-steady-state condition, substrate ammonium or nitrite concentrations were increased from 280 to 462 mg N/L, while HRT was stepwise decreased from 14.4 to 2 h, with a concomitant increase in nitrogen loading rate (NLR) from 0.93 to 7.34 g/L day. Based on calculations, Stover–Kincannon model and second-order “Grau” model were found to be the appropriate models to describe the upflow filter. According to Stover–Kincannon model, the maximum total substrate removal rate constant (U_max) and saturation value constant (K_B) were suggested as 12.4 and 12.0 g N/L day, respectively. As Stover–Kincannon model and second-order model gave high correlation coefficients (97.9% and 98.6%, respectively), these models may be used in predicting the behavior or design of the anammox filter.     

Influence of hydraulic loading and air flowrate on urban wastewater nitrogen removal with a submerged fixed-film reactor

Nutrient disposal to sensitive areas, particularly nitrogen and phosphorus from wastewater treatment plants, provokes eutrophication reducing water quality. Fixed film technology is widely used for the removal of organic matter and nitrogen by the biological process of nitrification-denitrification. This paper studies a nitrification and post-denitrification lab-scale plant with a downflow aerobic submerged filter for removal of organic matter and nitrification, followed by an anoxic upflow biofilter for denitrification. Recycled construction material (clay shists) was employed as support material and methanol was used as carbon source. After 2 weeks of acclimation in which nitrification reached steady-state conditions, different hydraulic loadings (0.35-1.59 m(3)/m(2)h) and air flowrates (7.78-43.5 m(3)/m(2)h) were applied for 1 year. The highest hydraulic loading which complied with the EU regulation on nitrogen disposal was 0.71 m(3)/m(2)h (1.6 h). Hydraulic retention time (HRT), which corresponded to a nitrogen removal of 0.64 kg N/m(3) per day operating at an air flowrate of 25.6 m(3)/m(2)h. Concerning to organic matter removal efficiency, the aerobic reactor accepted a maximum chemical oxygen demand (COD) volumetric loading of 16.0 kg COD/m(3) per day with a 75% COD removal efficiency. For all the tests carried out, suspended solids (SS) concentration in the outlet water was less than 35 mg/l.     

Estimation of optimum experimental parameters in chlorination of UO2 with Cl2 gas and carbon for UCl4

For the preparation of uranium tetrachloride, the chlorination of UO₂ was carried out and an appropriate reaction system was confirmed. The effects of reaction temperature, time, injection ratio of N₂ gas and appropriate amount of carbon using a reductant on the conversion ratio and volatilization were evaluated. The optimum reaction time and temperature in chlorination of UO₂ for the preparation of UCl₄ were 2 h and 500–700°C, respectively. Also 50% of N₂ gas in chlorine gas proved to be the appropriate injection ratio.     

Tertiary treatment of textile wastewater with combined media biological aerated filter (CMBAF) at different hydraulic loadings and dissolved oxygen concentrations

An up-flow biological aerated filter packed with two layers media was employed for tertiary treatment of textile wastewater secondary effluent. Under steady state conditions, good performance of the reactor was achieved and the average COD, NH(4)(+)-N and total nitrogen (TN) in the effluent were 31, 2 and 8mg/L, respectively. For a fixed dissolved oxygen (DO) concentration, an increase of hydraulic loading resulted in a decrease in substrate removal. With the increase of hydraulic loadings from 0.13 to 0.78m(3)/(m(2)h), the removal efficiencies of COD, NH(4)(+)-N and TN all decreased, which dropped from 52 to 38%, from 90 to 68% and from 45 to 33%, respectively. In addition, the results also confirmed that the increase of COD and NH(4)(+)-N removal efficiencies resulted from the increase of DO concentrations, but this variation trend was not observed for TN removal. With the increase of DO concentrations from 2.4 to 6.1mg/L, the removal efficiencies of COD and NH(4)(+)-N were 39-53% and 64-88%, whenas TN removal efficiencies increased from 39 to 42% and then dropped to 35%.     

Studies of a membrane aerated bioreactor for wastewater treatment

This study was undertaken specifically to collect engineering and process performance information on the behaviour of a membrane supported bio-film in a well-characterised bioreactor. A novel membrane aerated bioreactor has been tested in the laboratory on synthetic sewage, and also piloted for the treatment of primary effluent at a local municipal wastewater treatment plant. The reactor's design employs gas-permeable, hollow-fibre membranes that are submerged in the wastewater. Air is blown through the inside of the fibres. Aeration costs for such a reactor are likely to be lower than conventional systems because gas compression is not required. Thick bio-films grow on the outside of the fibres and effectively treat the wastewater. The bio-films grown in this manner are capable of biological oxygen demand (BOD) removal, nitrification, denitrification, and simultaneous sludge digestion. The character of the bio-film is very different from conventional bio-films grown on inert surfaces, since in this case the bio-film receives its oxygen and the wastewater components from different directions. In pilot studies, a reactor having a hydraulic residence time of 6.5 h and equipped with no sedimentation tank achieved 70–75% BOD and nitrogen removal, and produced an effluent containing less than 30 mg/l total suspended solids.     

Evaluation of potential integration of entrapped mixed microbial cell and membrane bioreactor processes for biological wastewater treatment/reuse

The challenge of biological wastewater treatment process is the design and operation of effective retention of mixed microbial cells within the reactor. Entrapped mixed microbial cell (EMMC) technology is designed to entrap the mixed microbial cells in polymeric carriers; membrane bioreactor (MBR) process utilizes membrane sheets/fibers to effectively retain the biomass in the reactor. These two biotechnologies are considered potential alternatives for conventional biological treatment/reuse because of their capability of retaining high concentration of biomass in the reactor, or in other words increasing the solid retention time (SRT). The simultaneous removal of organics and nitrogen were investigated using a modified EMMC system design. The modified EMMC system demonstrated higher organic and nitrogen removal performance due to high SRT. Compared to single-stage MBR process operated at similar conditions, the modified EMMC system was able to achieve slightly lower organic removal, comparable nitrification, and higher total nitrogen removal. One limitation in applying an EMMC only treatment process regime for potential reuse of treated wastewater is that such an operation requires the removal of pathogens and large particles if disinfection and solid/liquid separation were not followed. The major challenge of MBR process to overcome is membrane fouling, and the high energy consumption associated with fouling control. The intrinsic features of EMMC process including high SRT, low, and stabilized effluent suspended biomass concentration may significantly reduce the chance and extent of membrane fouling; while the membrane filtration can further polish the effluent quality from EMMC process. Therefore, integrating MBR and EMMC is strongly recommended because it may be a ??break-through?? for solving the membrane fouling problem and in improving effluent quality for potential reuse.     

氮压机节能降噪新方法

针对氮气供大于求的矛盾,采取减小氮压机设定最大电流以降低其运行负荷和对低压氮压机实施节能双式控制的措施,减少氮气放空量,降低放空噪声,延长低压氮压机的卸载运行时间,取得了节能降噪的效果。简介氮气供应系统流程和控制,详细分析优化措施、节能双式控制模式以及相关参数的设定值。