生物强化技术在废水脱氮中的应用

废水脱氮,主要是将污水中过量的营养物质转化为N2和N2O等排放到大气中。从市政和工业污水中脱氮最普遍,有效的方法是生物法,包括传统自养硝化-缺氧反硝化,异养硝化-好氧反硝化,短程硝化和厌氧氨氧化相结合等。目前,氮污染是个很严重的问题。从脱氮方式来说,有传统自养硝化-缺氧反硝化脱氮,异养硝化-好氧反硝化脱氮、厌氧氨氧化脱氮等。本文综述了这几种脱氮方式的生物强化技术的研究进展与实际应用,并对其发展方向进行了展望。     

废水自养生物脱氮技术研究进展

基于短程硝化和厌氧氨氧化的自养脱氮工艺是生物脱氮领域研究的热点,它的发现为低碳氮比废水的处理提供了新的思路。近些年来,人们陆续开发了SHARON、ANAMMOX、CANON、OLAND等自养生物脱氮工艺,进一步推动了高效、低耗脱氮技术的开发和研究。本文从工艺原理、特点等方面,对自养生物脱氮工艺的国内外研究状况进行了总结和对比,并提出了存在的问题及发展方向。     

生产性短程硝化-厌氧氨氧化装置处理制药废水的启动性能

为拓展新型生物脱氮技术的应用领域,研究了生产性短程硝化-厌氧氨氧化装置处理制药废水的启动性能。制药废水氨氮浓度为(430.40±55.43)mg/L时,氨氮去除率达(81.75±9.10)%,实现了短程硝化-厌氧氨氧化工艺对制药废水的生物脱氮。制药废水短程硝化系统的启动时间约为74 d,亚硝氮积累率达(52.11±9.13)%,证明了结合模拟废水和实际废水的"两步法"模式对短程硝化系统启动的适用性。制药废水厌氧氨氧化系统的启动时间约为145 d,最大容积氮去除速率达6.35 kg N/(m3·d),容积效能为传统硝化-反硝化工艺的数十倍,证明了结合菌种自繁和菌种流加的模式对厌氧氨氧化系统启动的适用性。     

限氧自养硝化-反硝化生物脱氮新技术

限氧自养硝化—反硝化是部分硝化与厌氧氨氧化相耦联的生物脱氮反应过程,通过严格控制溶解氧在0．1～0．3mg·L^-1,实现硝化反应控制在亚硝酸阶段,然后以硝化阶段剩余的NH4^+作为电子供体,在厌氧条件下实现反硝化,该反应过程是完全的自养硝化—反硝化过程,具有能耗低、脱氮效率高、反应系统占地面积小等优点,适用于处理COD／NH4^+—N低的废水,是一种非常有应用前景的生物脱氮技术,文中详细介绍了限氧自养硝化—反硝化生物脱氮反应过程的研究进展,讨论了其微生物学机理及应用前景。     

厌氧氨氧化菌特性及其在生物脱氮中的应用

在无分子氧环境中,同时存在NH4^＋和NO2^-时,NH4^＋作为反硝化的无机电子供体,NO2^-作为电子受体,生成氮气,这一过程称为厌氧氨氧化。目前已经发现了3种厌氧氨氧化菌（Brocadia anammoxidans,Kuenenia stuttgartiensis,Scalindua sorokinii）;对厌氧氨氧化菌的细胞色素、营养物质、抑制物、结构特征和生化反应机理的研究表明,厌氧氨氧化菌具有多种代谢能力。基于部分硝化至亚硝酸盐,然后与氨一起厌氧氨氧化,以及厌氧氨氧化菌与好氧氨氧化菌或甲烷菌的协同耦合作用,提出了几种生物脱氮的新工艺（ANAMMOX、SHARON—ANAMMOX、CANON和甲烷化与厌氧氨氧化耦合工艺）。     

溶解氧对单级自养脱氮系统功能菌数量的影响

摘要：【目的】研究溶解氧（Dissolved oxygen, DO）对单级自养脱氮系统功能菌数量的影响,为系统运行操控提出理论指导。【方法】从不同DO水平下的单级自养脱氮反应器中,分别提取活性污泥及生物膜样品基因组DNA,通过特异引物扩增系统内亚硝化菌（Ammonia oxidizing bacteria, AOB）、硝化菌（Nitrite oxidizing bacteria, NOB）及厌氧氨氧化菌（Anaerobic ammonia oxidizing bacteria, ANAMMOX）基因序列,PCR产物经回收克隆测序后,证实扩增产物为AOB、NOB及ANAMMOX 16S rDNA 保守序列,以含该序列的重组质粒作为定量PCR标准品。用荧光定量PCR技术对单级自养脱氮系统中各类功能菌进行定量分析。【结果】高DO有利于亚硝化菌AOB及硝化菌NOB生存,同时,活性污泥中AOB、NOB数量多于生物膜。DO对厌氧氨氧化菌ANAMMOX数量影响明显,高DO浓度将对ANAMMOX数量产生直接抑制,低DO浓度水平时,由于系统内缺乏厌氧氨氧化反应的电子受体NO3-或NO2-,也将间接影响ANAMMOX数量。【结论】本试验研究条件下,DO为(曝气)2.0/(停曝) 0.4 mg/L时系统运行效能最佳,ANAMMOX数量最多,AOB、NOB及ANAMMOX在此时构成一个协同代谢的稳定状态。     

流加菌种对厌氧氨氧化工艺的影响

厌氧氨氧化工艺具有很高的容积氮去除速率,现已成功应用于污泥压滤液等含氨废水的脱氮处理,容积氮去除速率高达9.5 kg/(m3·d)。但由于厌氧氨氧化菌为自养型细菌,生长缓慢,对环境条件敏感,致使厌氧氨氧化工艺启动时间过长,运行容易失稳,并且不适合处理有机含氨废水和毒性含氨废水,极大地限制了该工艺的进一步推广应用。为了克服厌氧氨氧化工艺实际应用中存在的问题,结合发酵工业中常用的菌种流加技术,提出了一种新型的菌种流加式厌氧氨氧化工艺,研究了该新型工艺在厌氧氨氧化工艺的启动过程、稳定运行以及处理有机含氨废水和毒性含氨废水等方面的应用情况。结果表明,通过向反应器内补加优质厌氧氨氧化菌种,可提高厌氧氨氧化菌数量及其在菌群中的比例,强化厌氧氨氧化功能。据此研发的菌种流加式厌氧氨氧化工艺不仅可以实现快速启动,而且可以稳定运行,并突破了有机物和毒物所致的运行障碍,拓展了厌氧氨氧化工艺的应用范围。     

新型脱氮微生物与水体脱氮新工艺研究进展

氨氮是河流等淡水资源有机污染的主要污染指标之一。生物脱氮具有低成本、高效、无二次污染和易操作等优点,极具发展前景。重点概述了水体净化系统中新型脱氮微生物的种类及研究进展,介绍了厌氧氨氧化、短程硝化-反硝化和分段进水生物脱氮等高效节能新工艺的工艺原理。     

厌氧氨氧化与反硝化耦合反应研究进展

厌氧氨氧化是氮循环中一个重要的反应,对处理含高氨氮废水具有重大的潜在实际应用价值.高浓度有机碳源对厌氧氨氧化反应具有明显的抑制作用.如何在有机碳源存在的条件下实现厌氧氨氧化与反硝化的耦合,是实现厌氧氨氧化工程应用面临的巨大挑战.本文综述了有关厌氧氨氧化与反硝化耦合反应机理、反应功能性微生物种群、耦合工艺启动、过程调控及环境影响因素等的最新研究进展,并对厌氧氨氧化与反硝化耦合反应研究前景及其在废水处理中的应用进行了展望.     

厌氧氨氧化技术应用于主流城市污水处理的研究进展

长期以来,基于硝化和反硝化过程的传统生物脱氮工艺被广泛应用于废水中氮素污染物的去除,但其能耗物耗高,不能适应节能减排的时代发展要求。近年来新兴的厌氧氨氧化(Anammox)工艺,因具有低能耗、低剩余污泥量、无需外加碳源等优点而备受关注,在废水脱氮领域具有非常广阔的应用前景。综述了Anammox生物脱氮技术应用于城市污水处理的最新研究进展,探讨了主流污水处理应用Anammox所面临的挑战,并提出今后的研究重点。     

Novel microbial nitrogen removal processes

The present-day wastewater treatment practices can be significantly improved through the introduction of new microbial treatment technologies. Recently, several new processes for nitrogen removal have been developed. These new nitrogen removal technologies provide practicable options for treating nitrogen-laden wastewaters. The new processes are based on partial nitrification of ammonium to nitrite combined with anaerobic ammonium oxidation. These processes include the single reactor system for high ammonia removal over nitrite (SHARON) process, which involves part conversion of ammonium to nitrite; the anaerobic ammonium oxidation (ANAMMOX) process, which involves anaerobic ammonium oxidation; and the completely autographic nitrogen removal over nitrite (CANON) process, which involves nitrogen removal within one reactor under oxygen-limited conditions. These new processes target the removal of nitrogen from wastewaters containing significant quantities of ammonium.     

Sensitivity analysis of a biofilm model describing a one-stage completely autotrophic nitrogen removal (CANON) process.

A mathematical model for nitrification and anaerobic ammonium oxidation (ANAMMOX) processes in a single biofilm reactor (CANON) was developed. This model describes completely autotrophic conversion of ammonium to dinitrogen gas. Aerobic ammonium and nitrite oxidation were modeled together with ANAMMOX. The sensitivity of kinetic constants and biofilm and process parameters to the process performance was evaluated, and the total effluent concentrations were, in general, found to be insensitive to affinity constants. Increasing the amount of biomass by either increasing biofilm thickness and density or decreasing porosity had no significant influence on the total effluent concentrations, provided that a minimum total biomass was present in the reactor. The ANAMMOX process always occurred in the depth of the biofilm provided that the oxygen concentration was limiting. The optimal dissolved oxygen concentration level at which the maximum nitrogen removal occurred is related to a certain ammonium surface load on the biofilm. An ammonium surface load of 2 g N/m2. d, associated with a dissolved oxygen concentration level of 1.3 g O2/m3 in the bulk liquid and with a minimum biofilm depth of 1 mm seems a proper design condition for the one-stage ammonium removal process. Under this condition, the ammonium removal efficiency is 94% (82% for the total nitrogen removal efficiency) (30 degrees C). Better ammonium removal could be achieved with an increase in the dissolved oxygen concentration level, but this would strongly limit the ANAMMOX process and decrease total nitrogen removal. It can be concluded that a one-stage process is probably not optimal if a good nitrogen effluent is required. A two-stage process like the combined SHARON and ANAMMOX process would be advised for complete nitrogen removal.     

An investigation of a process for partial nitrification and autotrophic denitrification combined desulfurization in a single biofilm reactor

In this study, a vertical submerged biofilm reactor was applied to investigate autotrophic partial nitrification/denitrification and simultaneous sulfide removal by using synthetic wastewater. The appropriate influent ratios of ammonia and sulfide needed to achieve partial autotrophic nitrification and denitrification were evaluated with influent ammonium nitrogen ranging from 54.6 to 129.8 mg L^?1 and sulfide concentrations ranging from 52.7 to 412.4 mg S L^?1. The results demonstrated that the working parameter was more stable when the sulfur/nitrogen ratio was set at 3:2, which yielded the maximum sulfur conversion. Batch experiments with different phosphate concentrations proved that a suitable phosphate buffer solution to control pH values could improve synchronous desulfurization denitrification process performance.     

Engineering application of anaerobic ammonium oxidation process in wastewater treatment

Anaerobic ammonium oxidation (Anammox), a promising biological nitrogen removal process, has been verified as an efficient, sustainable and cost-effective alternative to conventional nitrification and denitrification processes. To date, more than 110 full-scale anammox plants have been installed and are in operation, treating industrial NH₄ ⁺-rich wastewater worldwide, and anammox-based technologies are flourishing. This review the current state of the art for engineering applications of the anammox process, including various anammox-based technologies, reactor selection and attempts to apply it at different wastewater plants. Process control and implementation for stable performance are discussed as well as some remaining issues concerning engineering application are exposed, including the start-up period, process disturbances, greenhouse gas emissions and especially mainstream anammox applications. Finally, further development of the anammox engineering application is proposed in this review.     

Feasibility of nitrification/denitrification in a sequencing batch biofilm reactor with liquid circulation applied to post-treatment

An investigation was performed on the biological removal of ammonium nitrogen from synthetic wastewater by the simultaneous nitrification/denitrification (SND) process, using a sequencing batch biofilm reactor (SBBR). System behavior was analyzed as to the effects of sludge type used as inoculum (autotrophic/heterotrophic), wastewater feed strategy (batch/fed-batch) and aeration strategy (continuous/intermittent). The presence of an autotrophic aerobic sludge showed to be essential for nitrification startup, despite publications stating the existence of heterotrophic organisms capable of nitrifying organic and inorganic nitrogen compounds at low dissolved oxygen concentrations. As to feed strategy, batch operation (synthetic wastewater containing 100 mg COD/L and 50 mg N-NH(4)(+)/L) followed by fed-batch (synthetic wastewater with 100 mg COD/L) during a whole cycle seemed to be the most adequate, mainly during the denitrification phase. Regarding aeration strategy, an intermittent mode, with dissolved oxygen concentration of 2.0mg/L in the aeration phase, showed the best results. Under these optimal conditions, 97% of influent ammonium nitrogen (80% of total nitrogen) was removed at a rate of 86.5 mg N-NH(4)(+)/Ld. In the treated effluent only 0.2 mg N-NO(2)(-)/L,4.6 mg N-NO(3)(-)/L and 1.0 mg N-NH(4)(+)/L remained, demonstrating the potential viability of this process in post-treatment of wastewaters containing ammonium nitrogen.     

Treatment of effluents polluted by nitrogen with new biological technologies based on autotrophic nitrification-denitrification processes

In recent years, various technologies have been developed for the removal of nitrogen from wastewater that is rich in nitrogen but poor in organic carbon, such as the effluents from anaerobic digesters and from certain industries. These technologies have resulted in several patents. The core of these technologies is some of the processes and patents described in this paper: Aerobic denitrification, Sharon, Anammox, OLAND, CANON, NOx process, DEMON. More specifically, one of the first innovative options described for removing nitrogen include partial nitrification under aerobic conditions (partial Sharon process) followed by autotrophic anaerobic oxidation (Anammox process). The partial Sharon-Anammox process can be performed under alternating oxic and anoxic conditions in the same bioreactor or in two steps in two separate bioreactors. This overview focuses on the technical and biological aspects of these new types of treatment system, and compares them to other technologies. Given the fact that nitrification is a sensitive process, special attention is paid to conditions such as temperature, dissolved oxygen, hydraulic retention time, free ammonia, nitrous acid concentration, and pH. A discussion of the pros and cons of such treatment systems is also included since autotrophic nitrogen removal has advantages as well as drawbacks. The paper concludes with a discussion of future research that could improve these systems by enhancing performance and reducing costs.     

The development of simultaneous partial nitrification, ANAMMOX and denitrification (SNAD) process in a single reactor for nitrogen removal

The simultaneous partial nitrification, ANAMMOX and denitrification (SNAD) process was validated to potentially remove ammonium and COD from wastewater in a single, oxygen-limited, non-woven rotating biological contactor (NRBC) reactor. An ammonium conversion efficiency of 79%, TN removal efficiency of 70% and COD removal efficiency of 94% were obtained with the nitrogen and COD loading rate of 0.69 kgN/m(3)d and 0.34 kg/m(3)d, respectively. Scanning electron microscopy (SEM) observation and fluorescence in situ hybridizations (FISH) analysis revealed the existence of the dominant groups of bacteria. As a result, the aerobic ammonia-oxidizing bacteria (AOB), with a spot of aerobic heterotrophic bacteria were mainly distributed in the aerobic outer part of the biofilm. However, ANAMMOX bacteria with denitrifying bacteria were present and active in the anaerobic inner part of the SNAD biofilm. These bacteria were found to exist in a dynamic equilibrium to achieve simultaneous nitrogen and COD removal in NRBC system.