废水处理中的非传统脱氮途径

根据实验室小型SBR试验的结果，证实存在其它不同于传统的硝化和反硝化的脱氮途径。结合近几年来在生物脱氮理论方面新的研究进展，指出研究非传统脱氮途径的必要性和重要性，其中很有必要的一项工作是需对硝化、反硝化和脱氮过程作出明确的定义。     

人工湿地脱氮途径及其影响因素分析

简述了人工湿地脱氮模型。各种形态的氮在人工湿地系统中可以通过氨的挥发、植物吸收、介质沉淀吸附以及微生物硝化/反硝化作用等过程被去除。讨论了各脱氮途径对人工湿地脱氮的贡献,在大多数人工湿地的pH条件下,湿地地面氨挥发可以忽略,湿地植物叶片氨挥发量尚不清楚。湿地介质的直接吸附是短期的。植物在湿地脱氮过程中起了重要作用,但一般认为植物直接吸收和存储只占湿地脱氮的一小部分,一般低于30%。微生物的硝化/反硝化作用,是人工湿地脱氮的最主要的形式。讨论了影响人工湿地硝化作用的主要因素:溶解氧,pH和温度。大多数人工湿地的pH适合硝化作用,溶解氧和温度对湿地硝化作用的影响最大。温度不仅影响微生物的硝化作用,而且可以间接地影响植物的生长从而影响人工湿地的脱氮性能。     

垃圾渗滤液生物脱氮新途径

介绍了垃圾渗滤液的传统脱氮技术，对短程硝化反硝化、同步硝化反硝化和厌氧氨氧化的研究作了综述和讨论，并分析了这些新技术的特点以及在垃圾渗滤液脱氮方面的研究和应用前景，指出了厌氧氨氧化是垃圾渗滤液生物脱氮可能的有效方法。     

新型废水生物脱氮的微生物学研究进展

生物脱氮是含氮废水处理公认的最佳处理方式,随着对生物脱氮微生物学原理研究的不断深入,许多新的生物脱氮特殊菌株或菌群及微生物转化机制不断被发现.本文在传统生物脱氮过程机理上,结合最近国内外生物脱氮的新发现,就短程硝化反硝化、同时硝化反硝化、厌氧氨氧化的微生物学原理进行了阐述.图1表2参23     

D0对同步硝化反硝化影响及动力学

研究生物接触氧化法中DO对同步硝化反硝化系统脱氮效率的影响。研究结果表明：在溶解氧(DO)为1．0—3．0mg/L几范围内，随着反应器内溶解氧浓度的降低，总脱氮去除率提高，保持较好脱氮率的最佳DO为2mg/L左右，并分析了其原因；同时探讨了DO为2mg/L时的动力学方程。     

城市黑臭河道底泥内源氮硝化-反硝化作用研究

氮超标是目前许多城市黑臭河道治理过程中急需解决的突出问题。在外源输入有效控制后,底泥内源氮成为水体氮污染的主要来源。硝化与反硝化过程是削减底泥氮负荷和控制内源氮释放的重要途径,从硝化与反硝化耦合作用角度探讨底泥内源氮的行为,对于有效解决黑臭河道氮超标治理难题具有重要的现实意义。对此,文章首先通过理论分析探讨了影响底泥内源氮硝化-反硝化有效耦合的重要因素,认为溶解氧水平和缺氧微环境分布是非常重要的参数,在这矛盾平衡中影响着硝化-反硝化作用的进行。其次评述了黑臭河道底泥内源氮硝化-反硝化作用的研究现状,指出对于污染严重且受人为干扰频繁的城市黑臭河道,曝气扰动是影响底泥内源硝化-反硝化作用的重要因素。为了实现对底泥内源氮的有效控释,往往需要通过选择合理的曝气条件从影响溶解氧水平和缺氧微环境分布两方面来控制硝化-反硝化反应平衡。最后探讨了今后相关研究的发展动态,包括曝气扰动的合理界定、模拟试验装置的有效构建、水动力条件下底泥硝化与反硝化性能的合理评定以及其微生物机制系统分析。     

好氧反硝化菌及其在生物处理与修复中的应用研究进展

好氧反硝化菌因其生长特性与同步异养硝化好氧反硝化功能,为环境生物脱氮提供了崭新的技术思路.综述了已分离获得的好氧反硝化菌类群及其生长特性,重点阐述了好氧反硝化菌生物脱氮性能、影响因素与好氧反硝化机理,探讨了好氧反硝化在环境生物修复领域的应用.已有研究表明,好氧反硝化菌在环境生物脱氮方面具有明显的技术优势,但有关好氧反硝化反应机理、影响因素等仍待解析,以期为好氧反硝化菌固定化、活性持留以及受污染环境水体修复等研究提供理论依据.     

好氧异养硝化菌Acinetobacter sp.YY-5的分离鉴定及脱氮机理

通过异养硝化培养基获得一株高效脱氮细菌,并通过形态学特征、生理生化反应及16S rDNA同源性比较对筛得菌株进行了鉴定;分别以NO3--N和NO2--N为唯一氮源,通过对脱氮过程中各种含氮代谢物的定量及对脱氮相关基因氨单加氧酶基因(amoA)、羟胺氧化酶基因(hao)、周质硝酸盐还原酶亚基基因(napA)的扩增及测序比较,对该菌株的生理途径及脱氮机理进行了研究.结果表明,高效脱氮细菌YY-5不能发生好氧反硝化,但能在3 d内将氨氮由95.23 mg/L降解至1.29 mg/L,降解率达妻98.6%,同时未发现亚硝酸盐氮、硝酸盐氮积累;对该菌主要代谢气体产物进行检测,发现CO2和N2明显增多,无N2O生成;经鉴定,初步判定该菌为不动杆菌属,命名为Acinetobacter sp.YY-5;从该菌基因组中均能扩增出amoA、hao、napA等基因,其中napA与hao基因与已报道的napA与hao基因进行Blaster较,发现具有较大差别.图6表3参15     

农田土壤硝化-反硝化作用与N2O的排放

在北京潮土上研究了冬小麦夏玉米轮作体系下土壤硝化反硝化作用以及N2O排放情况.结果表明,小麦生育期土壤温度及含水量较低,无论是反硝化损失氮量还是土壤的N2O生成排放量均不高.土壤的N2O生成排放量与反硝化氮量相当或低于反硝化氮量.玉米生育期土壤温度升高以及孔隙含水量有较大的改善,反硝化损失氮量、N2O生成排放量有明显上升.通常情况下土壤反硝化损失氮量与N2O排放氮量基本处于同一水平.在玉米十叶期追肥后的较短时间内,N2O总排放量明显高于反硝化损失氮量,说明至少在这一阶段中,硝化作用在北方旱地土壤N2O的排放中发挥了主要作用.在评价北方旱地农田土壤氮素硝化反硝化损失中,硝化作用的氮素损失是不可忽视的重要方面.     

农田土壤硝化-反硝化作用与N_2O的排放

在北京潮土上研究了冬小麦夏玉米轮作体系下土壤硝化反硝化作用以及N2O排放情况。结果表明,小麦生育期土壤温度及含水量较低,无论是反硝化损失氮量还是土壤的N2O生成排放量均不高。土壤的N2O生成排放量与反硝化氮量相当或低于反硝化氮量。玉米生育期土壤温度升高以及孔隙含水量有较大的改善,反硝化损失氮量、N2O生成排放量有明显上升。通常情况下土壤反硝化损失氮量与N2O排放氮量基本处于同一水平。在玉米十叶期追肥后的较短时间内,N2O总排放量明显高于反硝化损失氮量,说明至少在这一阶段中,硝化作用在北方旱地土壤N2O的排放中发挥了主要作用。在评价北方旱地农田土壤氮素硝化反硝化损失中,硝化作用的氮素损失是不可忽视的重要方面。     

Nitrification and denitrification in biological activated carbon filter for treating high ammonia source water

Since the ammonia in the effluent of the traditional water purification process could not meet the supply demand, the advanced treatment of a high concentration of NH₄ ⁺-N micro-polluted source water by biological activated carbon filter (BACF) was tested. The filter was operated in the downflow manner and the results showed that the removing rate of NH₄ ⁺-N was related to the influent concentration of NH₄ ⁺-N. Its removing rate could be higher than 95% when influent concentration was under 1.0 mg/L. It could also decrease with the increasing influent concentration when the NH₄ ⁺-N concentration was in the range from 1.5 to 4.9 mg/L and the dissolved oxygen (DO) in the influent was under 10 mg/L, and the minimum removing rate could be 30%. The key factor of restricting nitrification in BACF was the influent DO. When the influent NH₄ ⁺-N concentration was high, the DO in water was almost depleted entirely by the nitrifying and hetetrophic bacteria in the depth of 0.4 m filter and the filter layer was divided into aerobic and anoxic zones. The nitrification and degradation of organic matters existed in the aerobic zone, while the denitrification occurred in the anoxic zone. Due to the limited carbon source, the denitrification could not be carried out properly, which led to the accumulation of the denitrification intermediates such as NO₂ ^?. In addition to the denitrification bacteria, the nitrification and the heterotrophic bacteria existed in the anoxic zone.     

氧化亚氮形成的微生物学分子机制研究进展

1　氧化亚氮 (Ｎ2 Ｏ)的形成Ｎ2 Ｏ是继ＣＯ2 、ＣＨ4之后的第三大温室气体 ,它能破坏大气中的臭氧层 .在过去的 2 0～ 30年间 ,Ｎ2 Ｏ以每年 0 .2 %～ 0 .3%的速率增长 ,并且有进一步增长的趋势[1 ] .地球上人类和其他生物的活动是Ｎ2 Ｏ产生的主要来源 ,而微生物是其中最重要的生物源 .微生物产生Ｎ2 Ｏ的机理主要是通过硝化作用和反硝化作用过程进行的 ,如图 1所示 .反硝化过程中Ｎ2 Ｏ的形成 :硝化过程中Ｎ2 Ｏ的形成 :图 1　Ｎ2 Ｏ的形成Ｆｉｇ.1　ＦｏｒｍａｔｉｏｎｏｆＮ2 Ｏ　　催化反硝化过程的酶有 4种 :硝酸还原酶 (Ｎａｒ)、亚…     

Factors affecting simultaneous nitrification and denitrification in an SBBR treating domestic wastewater

An aerobic sequencing batch biofilm reactor (SBBR) packed with Bauer rings was used to treat real domestic wastewater for simultaneous nitrification and denitrification. The SBBR is advantageous for creating an anoxic condition, and the biofilm can absorb and store carbon for good nitrification and denitrification. An average concentration of oxygen ranging from 0.8 to 4.0 mg/L was proved very efficient for nitrification and denitrification. Volumetric loads of TN dropped dramatically and effluent TN concentration increased quickly when the concentration of average dissolved oxygen was more than 4.0 mg/L. The efficiency of simultaneous nitrification and denitrification (SND) increased with increasing thickness of the biofilm. The influent concentration hardly affected the TN removal efficiency, but the effluent TN increased with increasing influent concentration. It is suggested that a subsequence for denitrification be added or influent amount be decreased to meet effluent quality requirements. At optimum operating parameters, the TN removal efficiency of 74%–82% could be achieved.     

Identification of iron and sulfate release processes during riverbank filtration using chemical mass balance modeling

Environmental Geochemistry and Health - Various hydrogeochemical processes can modify the quality of river water during riverbank filtration (RBF). Identifying the subsurface processes responsible...     

A road-map for energy-neutral wastewater treatment plants of the future based on compact technologies (including MBBR)

In the paper concepts for wastewater treatment of the future are discussed by the use of a) one flow diagram based on established, compact, proven technologies (i.e. nitrification/denitrification for N-removal in the mainstream) and b) one flow diagram based on emerging, compact technologies (i.e. de-ammonification in the main stream).The latter (b) will give an energy-neutral wastewater treatment plant, while this cannot be guaranteed for the first one (a). The example flow diagrams show plant concepts that a) minimize energy consumption by using compact biological and physical/chemical processes combined in an optimal way, for instance by using moving bed biofilm reactor (MBBR) processes for biodegradation and high-rate particle separation processes, and de-ammonification processes for N-removal and b)maximize energy (biogas) production through digestion by using wastewater treatment processes that minimize biodegradation of the sludge (prior to digestion) and pretreatment of the sludge prior to digestion by thermal hydrolysis. The treatment plant of the future should produce a water quality (for instance bathing water quality) that is sufficient for reuse of some kind (toilet flushing, urban use, irrigation etc.). The paper outlines compact water reclamation processes based on ozonation in combination with coagulation as pretreatment before ceramic membrane filtration. In the paper concepts for domestic wastewater treatment plants of the future are discussed by the use of a) one flow diagram based on established, compact, proven technologies (i.e. nitrification/denitrification for N-removal in the mainstream) and b) one flow diagram based on emerging, compact technologies (i.e. de-ammonification in the main stream).The latter (b) will give an energy-neutral wastewater treatment plant, while this cannot be guaranteed for the first one (a). The example flow diagrams show plant concepts that a) minimize energy consumption by using compact biological and physical/chemical processes combined in an optimal way, for instance by using moving bed biofilm reactor (MBBR) processes for biodegradation and high-rate particle separation processes, and de-ammonification processes for N-removal and b)maximize energy (biogas) production through digestion by using wastewater treatment processes that minimize biodegradation of the sludge (prior to digestion) and pretreatment of the sludge prior to digestion by thermal hydrolysis. The treatment plant of the future should produce a water quality (for instance bathing water quality) that is sufficient for reuse of some kind (toilet flushing, urban use, irrigation etc.). The paper outlines compact water reclamation processes based on ozonation in combination with coagulation as pretreatment before ceramic membrane filtration.     

Impact of total organic carbon and chlorine to ammonia ratio on nitrification in a bench-scale drinking water distribution system

Nitrification occurs in chloraminated drinking water systems and is affected by water quality parameters. The aim of this study was to investigate the impact of total organic carbon and chlorine to ammonia ratio on nitrification potential in a simulated drinking water distribution system as during chloramination. The occurrence of nitrification and activity of nitrifying bacteria was primarily monitored using four rotating annular bioreactors (RAB) with different chlorine to ammonia ratios and total organic carbon (TOC) levels. The results indicated that nitrification occurred despite at a low influent concentration of ammonia, and a high concentration of nitrite nitrogen was detected in the effluent. The study illustrated that reactors 1(R1) and 3 (R3), with higher TOC levels, produced more nitrite nitrogen, which was consistent with the ammonia-oxidizing bacteria (AOB) counts, and was linked to a relatively more rapid decay of chloramines in comparison to their counterparts (R2 and R4). The AOB and HPC counts were correlated during the biofilm formation with the establishment of nitrification. Biofilm AOB abundance was also higher in the high TOC reactors compared with the low TOC reactors. The chlorine to ammonia ratio did not have a significant impact on the occurrence of nitrification. Bulk water with a high TOC level supported the occurrence of nitrification, and AOB development occurred at all examined chlorine to ammonia dose ratios (3:1 or 5:1).     

Partikelentfernung in der Trinkwasseraufbereitung: Problematiken und Lösungsansätze

The drinking water treatment plant (WTP) in Irsch-Treves is one of the WTPs operated by the Public Utility Company of Treves (SWT) responsible for supplying the city of Treves with drinking water. This treatment plant has been responsible for the treatment of raw, soft water from the oligotrophic reservoir Riveris since 1958. The main functions of the WTP are the removal of particulate matter, manganese, iron, aluminium and organic material, especially humic substances. The removal of particulate matter such as bacteria, other microorganisms and plankton is very important to ensure a microbiologically and hygienically stable drinking water. Insufficient removal of particulate manganese may lead to manganese scaling in the supply system and, in extreme conditions, may lead to a brown-coloured drinking water. The so called Multi-Barrier-System is being used in the entire water treatment process. Under this system, great importance is given to the monitoring of the catchment area, the inflows, and the reservoirs. After a preliminary and subsequent sedimentation and biological treatment in the preliminary and in the main reservoirs respectively, the raw water is finally treated through flocculation filtration over the rapid multi-layer sand filters in the WTP Irsch. With this approach, only a rigid application of the above mentioned steps and the application of the latest recognized technology to maintain the supply system can best guarantee a constant supply of clean drinking water. Online particle count in raw water and in drinking water is one of the main quality control measures applied in the WTP Irsch. The conventional flocculation filtration is not always able to fulfil the increasing quality demands for drinking water, especially during adverse raw water quality conditions. This is the reason why more and more membrane filtration units are currently being installed in completely new plants, as substitutes in conventional plants, or for upgrade purposes. The SWT is currently planning an enlargement and upgrade of the WTP Irsch, integrating ultrafiltration, which was successfully tested in a pilot study. The upgrade of the elimination of particulate matter is one of the most important targets, after the enlargement and upgrade of the plant.     

What have we known so far about microplastics in drinking water treatment? A timely review

• 23 available research articles on MPs in drinking water treatment are reviewed. • The effects of treatment conditions and MP properties on MP removal are discussed. • DWTPs with more steps generally are more effective in removing MPs. • Smaller MPs (e.g.,<10 μm) are more challenging in drinking water treatment. Microplastics (MPs) have been widely detected in drinking water sources and tap water, raising the concern of the effectiveness of drinking water treatment plants (DWTPs) in protecting the public from exposure to MPs through drinking water. We collected and analyzed the available research articles up to August 2021 on MPs in drinking water treatment (DWT), including laboratory- and full-scale studies. This article summarizes the major MP compositions (materials, sizes, shapes, and concentrations) in drinking water sources, and critically reviews the removal efficiency and impacts of MPs in various drinking water treatment processes. The discussed drinking water treatment processes include coagulation-flocculation (CF), membrane filtration, sand filtration, and granular activated carbon (GAC) filtration. Current DWT processes that are purposed for particle removal are generally effective in reducing MPs in water. Various influential factors to MP removal are discussed, such as coagulant type and dose, MP material, shape and size, and water quality. It is anticipated that better MP removal can be achieved by optimizing the treatment conditions. Moreover, the article framed the major challenges and future research directions on MPs and nanoplastics (NPs) in DWT.