由于低溫嚴(yán)重抑制微生物的數(shù)量和活性，冬季的氨氮廢水處理效率下降嚴(yán)重，達(dá)標(biāo)存在很大的困難。針對(duì)上述問(wèn)題，歸納了在低溫條件下(≤15℃)氨氮廢水去除的可選技術(shù)方法和改進(jìn)工藝，包括生物脫氮改進(jìn)技術(shù)、物化脫氮技術(shù)和高級(jí)氧化脫氮技術(shù)；指出了氨氮的高效經(jīng)濟(jì)處理以及資源化回收利用是今后低溫環(huán)境下氨氮廢水處理的主要發(fā)展方向。

　　Due to the severe inhibition of microbial quantity and activity by low temperatures, the efficiency of ammonia nitrogen wastewater treatment in winter decreases significantly, making it difficult to meet standards. In response to the above issues, optional technical methods and improved processes for the removal of ammonia nitrogen wastewater under low temperature conditions (≤ 15 ℃) have been summarized, including biological denitrification improvement technology, physicochemical denitrification technology, and advanced oxidation denitrification technology; It is pointed out that the efficient and economical treatment of ammonia nitrogen, as well as the resource recycling and utilization, are the main development directions for the treatment of ammonia nitrogen wastewater in low-temperature environments in the future.

　　氨氮是造成水污染的主要污染物之一。傳統(tǒng)的生物脫氮技術(shù)通過(guò)微生物作用對(duì)廢水中的氨氮進(jìn)行去除。然而，在高緯度地區(qū)，氮排放難以達(dá)標(biāo)的情況卻沒(méi)有得到明顯的改善。這是由于溫度作為微生物生長(zhǎng)繁殖的重要因素對(duì)生物處理過(guò)程的效率影響很大。每當(dāng)溫度降低10℃，微生物的酶促反應(yīng)速率降低至原來(lái)的1/2，硝化細(xì)菌和反硝化細(xì)菌的活性受到明顯抑制甚至出現(xiàn)生命活動(dòng)停滯的現(xiàn)象，微生物的生理特性受到巨大影響，且氧化還原電位、溶解氧濃度、污泥體積指數(shù)和胞內(nèi)外聚合物的含量也隨溫度變化而變化，因此，低溫環(huán)境嚴(yán)重抑制了微生物法對(duì)氨氮廢水的處理效果。

　　Ammonia nitrogen is one of the main pollutants causing water pollution. Traditional biological denitrification technology removes ammonia nitrogen from wastewater through microbial action. However, in high latitude regions, there has been no significant improvement in the difficulty of meeting nitrogen emission standards. This is because temperature, as an important factor in microbial growth and reproduction, has a significant impact on the efficiency of biological treatment processes. Whenever the temperature drops by 10 ℃, the enzymatic reaction rate of microorganisms decreases to half of its original rate, and the activity of nitrifying and denitrifying bacteria is significantly inhibited, even leading to the stagnation of life activities. The physiological characteristics of microorganisms are greatly affected, and the redox potential, dissolved oxygen concentration, sludge volume index, and content of intracellular and extracellular polymers also change with temperature. Therefore, the low-temperature environment seriously inhibits the treatment effect of microbial methods on ammonia nitrogen wastewater.

　　近年來(lái)，關(guān)于低溫下脫氮處理技術(shù)的核心主要有以下幾個(gè)方面：①現(xiàn)有脫氮工藝的改進(jìn)和新脫氮工藝的開(kāi)發(fā)。②通過(guò)生物強(qiáng)化的技術(shù)手段培育低溫耐受性的菌株。③研制新型高效的脫氮功能材料。④對(duì)不同脫氮工藝進(jìn)行聯(lián)用，實(shí)現(xiàn)優(yōu)勢(shì)技術(shù)互補(bǔ)。之后再根據(jù)氨氮廢水不同的水質(zhì)特性和處理要求選擇適當(dāng)后續(xù)工藝，使得氨氮得到高效、低耗、合理地消除或利用。根據(jù)氨氮廢水處理的技術(shù)原理不同，本文中將分別從生物脫氮改進(jìn)技術(shù)、物化脫氮技術(shù)和高級(jí)氧化脫氮技術(shù)3方面進(jìn)行介紹。

　　In recent years, the core of low-temperature denitrification treatment technology mainly includes the following aspects: ① Improvement of existing denitrification processes and development of new denitrification processes. ② Cultivate low-temperature tolerant strains through biological reinforcement techniques. ③ Develop new and efficient denitrification functional materials. ④ Combine different denitrification processes to achieve complementary advantages in technology. Afterwards, appropriate follow-up processes will be selected based on the different water quality characteristics and treatment requirements of ammonia nitrogen wastewater, so that ammonia nitrogen can be efficiently, low in consumption, and reasonably eliminated or utilized. Based on the different technical principles of ammonia nitrogen wastewater treatment, this article will introduce three aspects: biological denitrification improvement technology, physicochemical denitrification technology, and advanced oxidation denitrification technology.

　　1生物脫氮改進(jìn)技術(shù)

　　1. Improvement technology for biological denitrification

　　1.1 低溫生物強(qiáng)化技術(shù)?

　　1.1 Low temperature biological enhancement technology?

　　生物強(qiáng)化技術(shù)是指向生物系統(tǒng)中投加具有特殊功能的微生物以改善原有系統(tǒng)中對(duì)某種難降解污染物去除效果的一類方法。當(dāng)外部環(huán)境溫度較低時(shí)，傳統(tǒng)脫氮過(guò)程（氨化、硝化、反硝化）受到嚴(yán)重抑制，生物強(qiáng)化技術(shù)可以有效地改善低溫環(huán)境下的脫氮效果。

　　Biological enhancement technology refers to a method of adding microorganisms with special functions to biological systems to improve the removal efficiency of certain recalcitrant pollutants in the original system. When the external environmental temperature is low, traditional denitrification processes (ammonification, nitrification, denitrification) are severely inhibited, and biological enhancement technology can effectively improve denitrification efficiency in low-temperature environments.

　　1.1.1??低溫菌群馴養(yǎng)強(qiáng)化氨氮去除技術(shù)生物處理過(guò)程中低溫對(duì)微生物活性和數(shù)量的影響是導(dǎo)致生物處理效果變差的根本因素，因而培育耐低溫的微生物是提高氨氮處理效率的一種常用方法。楊墨等在冬季（10℃）從松花江底泥中篩選分離出脫氮效率最高的低溫硝化菌株M-33，可以在24 h以內(nèi)高效去除90%以上氨氮且反應(yīng)過(guò)程中無(wú)亞硝態(tài)氮積累。Tian等將亞硝酸根完全自養(yǎng)脫氮(CANON)用于污水處理的過(guò)程中，探究了10、20、30℃溫度下的的厭氧氨氧化菌(AAOB)豐度和肼合酶（HZS）表達(dá)水平，發(fā)現(xiàn)10℃時(shí)AAOB活性高于其他體系，顆粒中HZS表達(dá)增加，在基因水平上形成了具有較好短期低溫抗性和恢復(fù)能力的等效體系。

　　1.1.1?? The domestication of low-temperature microbial communities and the enhancement of ammonia nitrogen removal technology are the fundamental factors leading to the deterioration of biological treatment efficiency due to the impact of low temperature on microbial activity and quantity during the biological treatment process. Therefore, cultivating low-temperature tolerant microorganisms is a commonly used method to improve ammonia nitrogen treatment efficiency. Yang Mo et al. screened and isolated the low-temperature nitrification strain M-33 with the highest denitrification efficiency from the sediment of Songhua River in winter (10 ℃). It can efficiently remove over 90% of ammonia nitrogen within 24 hours without accumulating nitrite nitrogen during the reaction process. Tian et al. investigated the abundance of anaerobic ammonia oxidizing bacteria (AAOB) and the expression level of hydrazine synthase (HZS) at temperatures of 10, 20, and 30 ° C during the complete autotrophic denitrification of nitrite (CANON) in wastewater treatment. They found that AAOB activity was higher at 10 ° C than in other systems, and the expression of HZS in particles increased, forming an equivalent system with good short-term low-temperature resistance and recovery ability at the genetic level.

　　此外，研究人員發(fā)現(xiàn)通過(guò)逐步降溫馴化出適宜低溫環(huán)境的微生物，可以達(dá)到較好的氨氮處理效果。Lv等在溫度從35℃降至10℃的過(guò)程中，發(fā)現(xiàn)厭氧氨氧化細(xì)菌和異養(yǎng)細(xì)菌保持較高活性，脫氮效率在90%以上。然而，直接投加耐冷菌存在菌種流失、生存率低等問(wèn)題，采用一定的生物固定化技術(shù)可以有效地緩解上述問(wèn)題。許祥祥等利用聚乙烯醇-海藻酸鈉包埋厭氧氨氧化污泥顆粒處理低溫氨氮廢水，證實(shí)了通過(guò)包埋固定的方式能有效地提高低溫下氨的去除性能。

　　In addition, researchers have found that by gradually cooling down and domesticating microorganisms suitable for low-temperature environments, good ammonia nitrogen treatment effects can be achieved. During the process of reducing the temperature from 35 ℃ to 10 ℃, Lv et al. found that anaerobic ammonia oxidizing bacteria and heterotrophic bacteria maintained high activity, with a denitrification efficiency of over 90%. However, direct addition of cold tolerant bacteria poses problems such as bacterial loss and low survival rate. The use of certain biological immobilization techniques can effectively alleviate these issues. Xu Xiangxiang et al. used polyvinyl alcohol sodium alginate to embed anaerobic ammonium oxidation sludge particles for the treatment of low-temperature ammonia nitrogen wastewater, and confirmed that the embedding fixation method can effectively improve the removal performance of ammonia at low temperatures.

　　1.1.2??共代謝作用強(qiáng)化氨氮去除技術(shù)投加碳源和特定金屬元素以及某類氧化還原介體可以提高低溫下生物脫氮效率，這類共代謝基質(zhì)和營(yíng)養(yǎng)物質(zhì)的投放也是實(shí)現(xiàn)低溫生物強(qiáng)化手段的有效途徑之一。

　　1.1.2?? The co metabolism enhanced ammonia nitrogen removal technology can improve the biological denitrification efficiency at low temperatures by adding carbon sources, specific metal elements, and certain redox mediators. The release of such co metabolism substrates and nutrients is also an effective way to achieve low-temperature biological enhancement.

　　Li等研究發(fā)現(xiàn)低溫條件下（15℃）利用Fe3+會(huì)增強(qiáng)SBR的脫氮效果，當(dāng)Fe（Ⅲ）的投加量為6 mg/L條件下，氨氮、亞硝酸鹽的去除率分別增加到0.42、0.53 kg/(m3·d)。此外，胞外聚合物（EPS）和聚羥基脂肪酸酯（PHA）有利于微生物抵御外界環(huán)境變化，促進(jìn)低溫下生物脫氮有效進(jìn)行。Collins等研究了細(xì)胞外聚合物質(zhì)有關(guān)的適應(yīng)性特性，發(fā)現(xiàn)EPS的凝膠基質(zhì)阻礙了溶質(zhì)擴(kuò)散，從而降低了廢水處理中因低溫導(dǎo)致的滲透壓和干燥損傷。

　　Li et al. found that the use of Fe3+under low temperature conditions (15 ℃) enhances the denitrification efficiency of SBR. When the dosage of Fe (III) is 6 mg/L, the removal rates of ammonia nitrogen and nitrite increase to 0.42 and 0.53 kg/(m3 · d), respectively. In addition, extracellular polymers (EPS) and polyhydroxyalkanoates (PHA) are beneficial for microorganisms to resist external environmental changes and promote effective biological denitrification at low temperatures. Collins and others studied the adaptability related to extracellular polymeric substances, and found that the gel matrix of EPS hindered the diffusion of solutes, thereby reducing the osmotic pressure and drying damage caused by low temperature in wastewater treatment.

　　1.2 脫氮工藝的參數(shù)優(yōu)化及工序創(chuàng)新?

　　1.2 Parameter optimization and process innovation of denitrification process?

　　調(diào)節(jié)工藝參數(shù)是保證低溫下脫氮工藝穩(wěn)步運(yùn)行的首要策略，池體升溫保溫、增加水力停留時(shí)間、碳氮比、延長(zhǎng)曝氣時(shí)間和降低污泥負(fù)荷等是實(shí)現(xiàn)低溫下脫氮工藝穩(wěn)定進(jìn)行的關(guān)鍵因素。Gao等研究了厭氧/好氧/缺氧(AOA)在低溫15℃條件下，在以低碳氮比（3.36）處理真實(shí)城市污水，TIN、NH4+-N去除率分別為（84.3±6.6）%、（97.4±3.3）%。

　　Adjusting process parameters is the primary strategy to ensure the stable operation of denitrification processes at low temperatures. Key factors for achieving stable denitrification processes at low temperatures include temperature and insulation of the tank, increasing hydraulic retention time, carbon nitrogen ratio, extending aeration time, and reducing sludge load. Gao et al. studied the anaerobic/aerobic/anoxic (AOA) treatment of real urban wastewater at a low temperature of 15 ℃ with a low carbon to nitrogen ratio (3.36). The removal rates of TIN and NH4+- N were (84.3 ± 6.6)% and (97.4 ± 3.3)%, respectively.

　　此外，通過(guò)調(diào)整工藝順序、增加工藝流程和改良運(yùn)行模式的手段等同樣可以增強(qiáng)低溫環(huán)境下的氨氮去除效果。陳杰云等通過(guò)倒置A2/O工藝處理氨氮廢水，在低溫季對(duì)氨氮去除率可達(dá)到88%。吳迪等采用鑲嵌式理念改良A2/O－MBBR工藝，在厭氧區(qū)與好氧區(qū)的基礎(chǔ)上分割出缺氧區(qū)，并在好氧區(qū)中添加SPR-2型懸浮填料，出水水質(zhì)滿足國(guó)家一級(jí)A排放標(biāo)準(zhǔn)，氨氮去除率高達(dá)97.9%。

　　In addition, adjusting the process sequence, increasing the process flow, and improving the operating mode can also enhance the removal efficiency of ammonia nitrogen in low-temperature environments. Chen Jieyun et al. treated ammonia nitrogen wastewater using the inverted A2/O process, and achieved a removal rate of 88% for ammonia nitrogen during the low-temperature season. Wu Di and others adopted the embedded concept to improve the A2/O-MBBR process, dividing the anoxic zone into anaerobic and aerobic zones, and adding SPR-2 suspended packing in the aerobic zone. The effluent quality meets the national first-class A emission standard, and the ammonia nitrogen removal rate is as high as 97.9%.

　　1.3 多級(jí)工藝聯(lián)合?

　　1.3 Multi level process combination?

　　通過(guò)與其他生物處理裝置進(jìn)行工藝聯(lián)合，能有效改善低溫下水體氨氮的去除效果。Zha等開(kāi)發(fā)了一種缺氧過(guò)濾器/多級(jí)水車驅(qū)動(dòng)旋轉(zhuǎn)生物接觸器裝置處理低溫(6~18℃)下低濃度生活污水。在45 d內(nèi)，NH4+-N的平均去除效率達(dá)到（75.5±1.86）%，TN的平均去除效率達(dá)到（44.81±3.67）%。李冬等利用兩級(jí)曝氣+兩級(jí)過(guò)濾的生物凈化工藝低溫下（5.0~7.8℃）去除氨氮高達(dá)99.33%，去除負(fù)荷為29.66 g/(m·h)。Ren等研究了在10℃條件下，鐵負(fù)載生物活性炭濾池(Fe-BACF)去除模擬二次廢水中的氨氮。采用超聲浸漬法負(fù)載鐵活性炭(Fe-AC)作為生物濾池工藝的過(guò)濾材料，在濾料表面形成生物膜后，F(xiàn)e-BACF對(duì)氨氮的平均去除率(97.9%)顯著高于常規(guī)BACF(87.8%)。

　　By combining with other biological treatment devices, the removal efficiency of ammonia nitrogen in water at low temperatures can be effectively improved. Zha et al. developed an anoxic filter/multi-stage waterwheel driven rotating biological contactor device for treating low concentration domestic sewage at low temperatures (6-18 ℃). Within 45 days, the average removal efficiency of NH4+- N reached (75.5 ± 1.86)%, and the average removal efficiency of TN reached (44.81 ± 3.67)%. Li Dong et al. used a biological purification process of two-stage aeration and two-stage filtration to remove up to 99.33% of ammonia nitrogen at low temperatures (5.0~7.8 ℃), with a removal load of 29.66 g/(m · h). Ren et al. studied the removal of ammonia nitrogen from simulated secondary wastewater using iron loaded biochar filter (Fe BACF) at 10 ℃. The ultrasonic impregnation method was used to load iron activated carbon (Fe AC) as the filtration material for the biofilter process. After forming a biofilm on the surface of the filter material, the average removal rate of ammonia nitrogen by Fe BACF (97.9%) was significantly higher than that of conventional BACF (87.8%).

　　2物化脫氮技術(shù)

　　2 Physical and Chemical Denitrification Technologies

　　物化脫氮技術(shù)是通過(guò)物理化學(xué)的手段去除水體中的氨氮和有毒有害的污染物質(zhì)，是一類較為成熟的脫氮處理工藝，低溫下效果比較穩(wěn)定的物化法包括化學(xué)沉淀法、折點(diǎn)氯化法、膜分離法等，缺點(diǎn)是處理費(fèi)用昂貴，不適合處理大規(guī)模的廢水。

　　Physical and chemical denitrification technology is a mature denitrification treatment process that removes ammonia nitrogen and toxic and harmful pollutants from water bodies through physical and chemical means. Physical and chemical methods with stable effects at low temperatures include chemical precipitation, breakpoint chlorination, membrane separation, etc. The disadvantage is that the treatment cost is expensive and not suitable for treating large-scale wastewater.

　　2.1 化學(xué)沉淀法?

　　2.1 Chemical precipitation method?

　　磷酸銨鎂法（鳥糞石）是現(xiàn)階段較為成熟的技術(shù)，是通過(guò)向氨氮廢水中加入鎂離子和磷酸根離子來(lái)生成MgNH4PO4?6H2O沉淀物質(zhì)，后者可用作復(fù)合肥料實(shí)現(xiàn)氨氮的二次利用。為尋找高效低廉的化學(xué)藥劑進(jìn)一步改善磷酸銨鎂法的處理效果，Siciliano等提出了一種基于磷酸銨鎂化學(xué)沉淀的工藝并使用海水鹽鹵和骨粉用作鎂和磷的低成本試劑有效地回收，該工藝可以去除90%以上的氨氮，并生成含有鳥糞石晶體的有潛在價(jià)值的沉淀物。此外，化學(xué)沉淀法也可與吸附法聯(lián)用。Ren等研究結(jié)果表明，改性Fe-AC可有效去除低濃度低溫廢水中的氨氮，F(xiàn)e-AC對(duì)氨氮的吸附量比AC高54.4%。

　　The magnesium ammonium phosphate method (bird guano stone) is a relatively mature technology at present, which generates MgNH4PO4 by adding magnesium ions and phosphate ions to ammonia nitrogen wastewater? 6H2O precipitation material can be used as a compound fertilizer to achieve secondary utilization of ammonia nitrogen. In order to find efficient and low-cost chemical agents to further improve the treatment effect of the magnesium ammonium phosphate method, Siciliano et al. proposed a process based on magnesium ammonium phosphate chemical precipitation and used seawater brine and bone powder as low-cost reagents for the effective recovery of magnesium and phosphorus. This process can remove more than 90% of ammonia nitrogen and generate potentially valuable precipitates containing bird guano crystals. In addition, chemical precipitation method can also be combined with adsorption method. The research results of Ren et al. showed that modified Fe AC can effectively remove ammonia nitrogen from low concentration and low-temperature wastewater, and the adsorption capacity of Fe AC for ammonia nitrogen is 54.4% higher than that of AC.

　　2.2 折點(diǎn)氯化法?

　　2.2 Conversion point chlorination method?

　　折點(diǎn)氯化法是向氨氮廢液中通入氯氣或加入次氯酸鈉將廢水中的氨氮轉(zhuǎn)化為氮?dú)獾囊环N方法。水中的氨氮濃度會(huì)隨著氯氣的增加而降低，氨氮濃度為零的點(diǎn)被稱為折點(diǎn)，反應(yīng)機(jī)理為：NH4++1.5HOCl→0.5N2+1.5H2O+2.5H++1.5Cl-折點(diǎn)氯化法相較于其他的物化技術(shù)最大優(yōu)勢(shì)在于根據(jù)處理液的實(shí)際情況（pH、溫度、氨氮濃度），通過(guò)控制加氯量實(shí)現(xiàn)完全脫氮并同時(shí)達(dá)到消毒目的。然而，折點(diǎn)氯化法會(huì)引起二次污染。處理過(guò)程中，可以通過(guò)折點(diǎn)氯化和其他工藝組合來(lái)實(shí)現(xiàn)優(yōu)勢(shì)互補(bǔ)。黃萬(wàn)撫等通過(guò)磷酸銨鎂沉淀法（MAP）和折點(diǎn)氯化法聯(lián)合工藝對(duì)氨氮廢水進(jìn)行有效處理。結(jié)果表明，pH為9.5、N/Cl2的摩爾比為1/1.6時(shí)，氨氮處理效果為98.8%。

　　The breakpoint chlorination method is a method of converting ammonia nitrogen in wastewater into nitrogen gas by introducing chlorine gas or adding sodium hypochlorite into the wastewater. The concentration of ammonia nitrogen in water will decrease with the increase of chlorine gas. The point where the ammonia nitrogen concentration is zero is called the inflection point. The reaction mechanism is: NH4++1.5HOCl → 0.5N2+1.5H2O+2.5H++1.5Cl - inflection point chlorination. Compared with other physicochemical technologies, the biggest advantage of the chlorination method is to achieve complete denitrification and disinfection by controlling the amount of chlorine added according to the actual situation of the treatment solution (pH, temperature, ammonia nitrogen concentration). However, the breakpoint chlorination method can cause secondary pollution. During the processing, complementary advantages can be achieved through the combination of point chlorination and other processes. Huang Wanfu et al. effectively treated ammonia nitrogen wastewater through a combined process of magnesium ammonium phosphate precipitation (MAP) and breakpoint chlorination. The results showed that when the pH was 9.5 and the molar ratio of N/Cl2 was 1/1.6, the ammonia nitrogen treatment effect was 98.8%.

　　2.3 膜分離法?

　　2.3 Membrane separation method?

　　膜分離法是在壓力作用下通過(guò)膜對(duì)溶液中某種成分選擇性分離的一種方法，可分為電滲析、反滲透、微濾、納濾、超濾等。對(duì)于氨氮廢液的水質(zhì)和水量變化具有較強(qiáng)的抗變性，不受溫度和pH波動(dòng)的影響。但會(huì)出現(xiàn)膜堵塞和膜污染現(xiàn)象，對(duì)于低濃度氨氮廢水處理效果較好，但是在處理高濃度有機(jī)廢水時(shí)需要進(jìn)行反復(fù)清洗，產(chǎn)生的清洗液對(duì)環(huán)境會(huì)造成二次污染，因此，需要與其他工藝聯(lián)用才能達(dá)到較好的處理效果。邢金良等結(jié)合陽(yáng)離子交換膜-超濾(CEM-UF)組合膜與硝化/反硝化過(guò)程處理氨氮廢水。當(dāng)進(jìn)水總氮（TN）為60 mg/L，COD/TN為2.65時(shí)，氨氮去除率為98.7%。

　　Membrane separation is a method of selectively separating a certain component in a solution through a membrane under pressure, which can be divided into electrodialysis, reverse osmosis, microfiltration, nanofiltration, ultrafiltration, etc. It has strong resistance to changes in water quality and quantity of ammonia nitrogen waste liquid, and is not affected by temperature and pH fluctuations. However, membrane blockage and fouling may occur, and the treatment effect is good for low concentration ammonia nitrogen wastewater. However, repeated cleaning is required when treating high concentration organic wastewater, and the resulting cleaning solution will cause secondary pollution to the environment. Therefore, it needs to be combined with other processes to achieve better treatment effects. Xing Jinliang et al. combined cation exchange membrane ultrafiltration (CEM-UF) composite membrane with nitrification/denitrification process to treat ammonia nitrogen wastewater. When the total nitrogen (TN) in the influent is 60 mg/L and the COD/TN ratio is 2.65, the removal rate of ammonia nitrogen is 98.7%.

　　3高級(jí)氧化脫氮技術(shù)

　　3 Advanced Oxidation Denitrification Technologies

　　高級(jí)氧化脫氮技術(shù)主要是利用反應(yīng)產(chǎn)生的強(qiáng)氧化物質(zhì)（羥基自由基等）與氨氮充分反應(yīng)，最終使氨氮從水體中脫除的目的。

　　Advanced oxidation denitrification technology mainly utilizes the strong oxidizing substances (such as hydroxyl radicals) generated by the reaction to fully react with ammonia nitrogen, ultimately achieving the goal of removing ammonia nitrogen from the water.

　　3.1 臭氧氧化技術(shù)?

　　3.1 Ozone oxidation technology?

　　臭氧氧化法是利用O3和分解產(chǎn)生的自由基作為強(qiáng)氧化劑對(duì)污染物進(jìn)行降解的一類方法。研究表明，低溫環(huán)境下對(duì)pH進(jìn)行適當(dāng)調(diào)控，可以對(duì)氨氮廢水實(shí)現(xiàn)較好的脫氮效果。Liu等研究了低溫下（10℃）通過(guò)MgO催化臭氧氧化反應(yīng)去除水中的氨，發(fā)現(xiàn)較低的pH有利于選擇性生成氣態(tài)產(chǎn)物（N2或N2O）。在pH為9時(shí)，氨的去除效率顯著提高，在0~10℃的溫度范圍內(nèi)實(shí)現(xiàn)了較高的氨去除率（77.53%~80.17%）。由于O3較高的處理成本，臭氧氧化技術(shù)往往需要和其他工藝聯(lián)用。劉春等通過(guò)微氣泡臭氧催化氧化-生化耦合工藝對(duì)工業(yè)廢水進(jìn)行處理，發(fā)現(xiàn)微氣泡臭氧催化氧化能有效降解廢水中的氨氮，出水氨氮平均濃度為5.1 mg/L，且臭氧利用率接近100%。

　　Ozone oxidation is a type of method that uses O3 and the free radicals generated by decomposition as strong oxidants to degrade pollutants. Research has shown that adjusting pH appropriately in low-temperature environments can achieve good denitrification effects on ammonia nitrogen wastewater. Liu et al. studied the removal of ammonia from water by MgO catalyzed ozone oxidation reaction at low temperature (10 ℃) and found that lower pH is conducive to the selective generation of gaseous products (N2 or N2O). At pH 9, the removal efficiency of ammonia was significantly improved, achieving a high ammonia removal rate (77.53%~80.17%) within the temperature range of 0~10 ℃. Due to the high processing cost of O3, ozone oxidation technology often needs to be combined with other processes. Liu Chun et al. treated industrial wastewater using a microbubble ozone catalytic oxidation biochemical coupling process and found that microbubble ozone catalytic oxidation can effectively degrade ammonia nitrogen in wastewater. The average concentration of ammonia nitrogen in the effluent was 5.1 mg/L, and the ozone utilization rate was close to 100%.

　　3.2 電化學(xué)氧化技術(shù)?

　　3.2 Electrochemical oxidation technology?

　　電化學(xué)氧化法有直接氧化和間接氧化2種方法。前者是利用電極直接接觸的方式與氨氮進(jìn)行電子轉(zhuǎn)移，后者是通過(guò)電極產(chǎn)生的強(qiáng)氧化物與氨氮發(fā)生反應(yīng)，最終達(dá)到氨氮去除的目的。由于實(shí)際生活中氨氮廢水的復(fù)雜性，單獨(dú)的電化學(xué)氧化技術(shù)無(wú)法達(dá)到預(yù)期要求，Zhou等研究了兩階段電化學(xué)過(guò)程（鳥糞石電化學(xué)沉淀和氨電氧化）用于處理水解污泥的上清液。在最佳條件下，堿性水解污泥的上清液氨氮去除率為79.3%。

　　There are two methods of electrochemical oxidation: direct oxidation and indirect oxidation. The former uses direct electrode contact to transfer electrons with ammonia nitrogen, while the latter reacts with ammonia nitrogen through the strong oxide generated by the electrode, ultimately achieving the goal of ammonia nitrogen removal. Due to the complexity of ammonia nitrogen wastewater in practical life, single electrochemical oxidation technology cannot meet the expected requirements. Zhou et al. studied a two-stage electrochemical process (bird guano stone electrochemical precipitation and ammonia electro oxidation) for treating the supernatant of hydrolyzed sludge. Under optimal conditions, the removal rate of ammonia nitrogen in the supernatant of alkaline hydrolyzed sludge is 79.3%.

　　此外，低溫電化學(xué)反應(yīng)過(guò)程中存在界面焦耳熱（IJH）效應(yīng)，即陽(yáng)極施加電流會(huì)將熱量散發(fā)到周圍的環(huán)境中，從而導(dǎo)致界面溫度遠(yuǎn)高于本體溶液的界面溫度。Pei等對(duì)電化學(xué)氧化過(guò)程中界面焦耳熱效應(yīng)進(jìn)行了表征。實(shí)驗(yàn)結(jié)果表明，在電流密度為10 mA/cm2的情況下電解120 min后，界面溫度從25℃升高到70.2℃。利用界面焦耳效應(yīng)，在水溫低至8.5±1℃、電流密度增加到20 mA/cm2的情況下，界面溫度急劇增加到38.7℃，在此溫度下苯酚、對(duì)氯苯酚和2,4-二氯苯氧基乙酸的氧化速率分別為0.158、0.084、0.070 min-1，與室溫（23.5±1℃）下所得值幾乎相等。

　　In addition, there is an interface Joule heating (IJH) effect in the low-temperature electrochemical reaction process, which means that applying current to the anode will dissipate heat to the surrounding environment, resulting in an interface temperature much higher than that of the bulk solution. Pei et al. characterized the Joule heating effect at the interface during electrochemical oxidation process. The experimental results showed that after 120 minutes of electrolysis at a current density of 10 mA/cm2, the interface temperature increased from 25 ℃ to 70.2 ℃. By utilizing the Joule effect at the interface, the interface temperature rapidly increases to 38.7 ℃ at a water temperature as low as 8.5 ± 1 ℃ and a current density of 20 mA/cm2. At this temperature, the oxidation rates of phenol, p-chlorophenol, and 2,4-dichlorophenoxyacetic acid are 0.158, 0.084, and 0.070 min-1, respectively, which are almost equal to the values obtained at room temperature (23.5 ± 1 ℃).

　　3.3 光催化氧化技術(shù)?

　　3.3 Photocatalytic oxidation technology?

　　光催化氧化法是以半導(dǎo)體作為光催化劑，在光照下產(chǎn)生有效電子和空穴，利用光生空穴和后續(xù)產(chǎn)生的羥基自由基，對(duì)氨氮進(jìn)行氧化。He等研究了Cu/ZnO/rGO在可見(jiàn)光下對(duì)NH4+-N的光催化降解效能。發(fā)現(xiàn)在氙燈照射2 h，NH4+-N去除率高達(dá)83.1%。此外，使用Cu/ZnO/rGO處理實(shí)際生活污水，總氮的去除效率達(dá)到80.7%。

　　The photocatalytic oxidation method uses semiconductors as photocatalysts to generate effective electrons and holes under illumination, and utilizes the photo generated holes and subsequently generated hydroxyl radicals to oxidize ammonia nitrogen. He et al. investigated the photocatalytic degradation efficiency of Cu/ZnO/rGO towards NH4+- N under visible light. It was found that after 2 hours of xenon lamp irradiation, the removal rate of NH4+- N was as high as 83.1%. In addition, the use of Cu/ZnO/rGO to treat actual domestic sewage achieved a total nitrogen removal efficiency of 80.7%.

　　為了提高氨氮氧化過(guò)程中N2產(chǎn)物的選擇性，多項(xiàng)研究以Pt或Ru等作為助催化劑。例如，Dozzi等發(fā)現(xiàn)Pt（0.8%）與Ru（0.1%）作為助催化劑沉積在TiO2上可將70%的NH3催化氧化成N2。然而，貴金屬的使用大大提高了光催化過(guò)程的成本。部分研究工作者將光催化技術(shù)與反硝化菌相結(jié)合，利用細(xì)菌的反硝化作用來(lái)完成NO2-、NO3-向N2的轉(zhuǎn)變。

　　In order to improve the selectivity of N2 products in the process of ammonia nitrogen oxidation, multiple studies have used Pt or Ru as co catalysts. For example, Dozzi et al. found that Pt (0.8%) and Ru (0.1%) as co catalysts deposited on TiO2 can catalyze the oxidation of 70% of NH3 to N2. However, the use of precious metals greatly increases the cost of the photocatalytic process. Some researchers have combined photocatalytic technology with denitrifying bacteria to utilize their denitrification process to complete the conversion of NO2- and NO3- to N2.

　　4低溫氨氮廢水處理技術(shù)對(duì)比

　　Comparison of Low Temperature Ammonia Nitrogen Wastewater Treatment Technologies

　　由于處理技術(shù)之間存在較大差異，可根據(jù)氨氮廢水的各類水質(zhì)參數(shù)并結(jié)合實(shí)際情況選擇較為合適的處理方法。

　　Due to significant differences in treatment technologies, a more suitable treatment method can be selected based on various water quality parameters of ammonia nitrogen wastewater and combined with actual conditions.

　　5結(jié)論與展望

　　5 Conclusion and Prospect

　　針對(duì)低溫條件下生物活性降低、脫氮微生物酶促反應(yīng)受到抑制等問(wèn)題，可通過(guò)生物強(qiáng)化技術(shù)馴養(yǎng)出耐低溫微生物，優(yōu)化生物脫氮工藝以及多工藝聯(lián)用等手段對(duì)氨氮廢水進(jìn)行綜合性生物處理。在物化脫氮技術(shù)中面對(duì)不同水質(zhì)特征的氨氮廢水，可調(diào)控影響污染物去除效率的因素，采取聯(lián)合工藝、實(shí)現(xiàn)技術(shù)優(yōu)勢(shì)互補(bǔ)，以徹底去除水體中的氨氮，最終達(dá)到提高出水水質(zhì)的目的。而高級(jí)氧化技術(shù)作為現(xiàn)階段新型的水處理工藝，目前由于發(fā)展不太成熟、處理成本昂貴、反應(yīng)條件苛刻等特點(diǎn)限制了在實(shí)際中的大規(guī)模應(yīng)用。

　　To address the issues of decreased biological activity and inhibited enzymatic reactions of denitrifying microorganisms under low temperature conditions, low-temperature tolerant microorganisms can be trained through biological enhancement technology, and comprehensive biological treatment of ammonia nitrogen wastewater can be achieved by optimizing biological denitrification processes and combining multiple processes. In the physical and chemical denitrification technology, when facing ammonia nitrogen wastewater with different water quality characteristics, factors affecting pollutant removal efficiency can be regulated. Joint processes can be adopted to achieve complementary technological advantages, in order to completely remove ammonia nitrogen from the water body and ultimately improve the effluent quality. However, advanced oxidation technology, as a new type of water treatment process at present, is limited in its large-scale application due to its immature development, expensive treatment costs, and harsh reaction conditions.

　　結(jié)合國(guó)內(nèi)外對(duì)低溫下氨氮廢水處理研究及其發(fā)展態(tài)勢(shì)來(lái)看，筆者認(rèn)為氨氮的高效經(jīng)濟(jì)處理以及資源化回收利用將成為低溫環(huán)境下氨氮廢水處理的主要發(fā)展方向。

　　Based on the research and development trend of low-temperature ammonia nitrogen wastewater treatment at home and abroad, the author believes that efficient and economical treatment of ammonia nitrogen and resource recycling will become the main development direction of low-temperature ammonia nitrogen wastewater treatment.

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