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污水微生物脫氮過(guò)程中N2O產(chǎn)生機(jī)理及影響因素研究進(jìn)展

2016-03-13 21:48:49陳虎王瑩呂永康
化工進(jìn)展 2016年12期
關(guān)鍵詞:異養(yǎng)還原酶溶解氧

陳虎,王瑩,呂永康

(太原理工大學(xué)煤科學(xué)與技術(shù)教育部和山西省重點(diǎn)實(shí)驗(yàn)室,山西 太原 030024)

污水微生物脫氮過(guò)程中N2O產(chǎn)生機(jī)理及影響因素研究進(jìn)展

陳虎,王瑩,呂永康

(太原理工大學(xué)煤科學(xué)與技術(shù)教育部和山西省重點(diǎn)實(shí)驗(yàn)室,山西 太原 030024)

產(chǎn)生于生物脫氮過(guò)程的N2O是一種強(qiáng)效的溫室氣體并會(huì)導(dǎo)致臭氧層破壞。本文綜述了污水脫氮過(guò)程中N2O的產(chǎn)生機(jī)理及影響因素。羥胺氧化和AOB反硝化是硝化過(guò)程產(chǎn)生N2O兩種主要路徑,諸如溶解氧、氨氮和亞硝酸鹽等因素主要通過(guò)影響微生物的活動(dòng)或酶的活性而間接影響硝化過(guò)程中N2O的產(chǎn)生。反硝化過(guò)程是N2O的另一重要產(chǎn)生來(lái)源,其N(xiāo)2O生成量的多少與N2O酶有直接關(guān)系,而溶解氧、有機(jī)碳源和亞硝酸鹽等因素會(huì)影響反硝化過(guò)程中N2O酶的活性。目前新型脫氮工藝也成為N2O的潛在來(lái)源,但其N(xiāo)2O產(chǎn)生機(jī)理還有待深入研究。盡管N2O釋放與周?chē)h(huán)境變化密切相關(guān),但本質(zhì)原因還是由于微生物的作用及酶活性受到影響所致。文章最后指出污水生物脫氮過(guò)程中N2O產(chǎn)量控制與減量化策略是今后研究的主要方向,并給出了幾點(diǎn)建議。

生物脫氮;一氧化二氮;影響因素;污水處理

一氧化二氮(nitrous oxide,N2O)是一種強(qiáng)效且穩(wěn)定的溫室氣體,其溫室效應(yīng)是CO2的298倍、CH4的4~30倍。此外,N2O可與氧原子發(fā)生反應(yīng)生成NO和NO2,進(jìn)而破壞臭氧層形成酸雨。大氣中90%以上的N2O來(lái)源于微生物脫氮過(guò)程,其中污水處理是N2O的一個(gè)重要的潛在來(lái)源:2010年污水處理過(guò)程中釋放的N2O占其排放總量的3.56%,這比20年前增加了近20%[1];DAELMAN等[2]對(duì)新西蘭某城市污水處理廠(chǎng)中 N2O的釋放量進(jìn)行長(zhǎng)達(dá)16個(gè)月的全面監(jiān)控,研究發(fā)現(xiàn)N2O占據(jù)該廠(chǎng)三種溫室氣體排量(CO2、CH4和N2O)的主導(dǎo)地位,并相當(dāng)于78.3%二氧化碳當(dāng)量,遠(yuǎn)遠(yuǎn)高于另外兩種溫室氣體的二氧化碳當(dāng)量。由此可見(jiàn),N2O的產(chǎn)生與排放已經(jīng)不容小覷,它將環(huán)境污染問(wèn)題由水環(huán)境轉(zhuǎn)向大氣環(huán)境,嚴(yán)重違背了生物脫氮的設(shè)計(jì)初衷。因此,深入了解微生物脫氮過(guò)程中N2O的產(chǎn)生機(jī)理和影響因素,可為今后污水處理過(guò)程中一氧化二氮控制與減排提供重要的理論參考。

1 硝化過(guò)程中 N2O的產(chǎn)生機(jī)理及影響因素

1.1硝化過(guò)程N(yùn)2O的產(chǎn)生機(jī)理

自養(yǎng)硝化過(guò)程中自養(yǎng)氨氧化細(xì)菌參與的羥胺氧化(hydroxylamine oxidation)以及AOB反硝化反應(yīng)(nitrifier denitrification)是產(chǎn)生N2O的主要路徑。前者是指氨氧化反應(yīng)中間產(chǎn)物羥胺在HAO酶作用下的不完全氧化[3-4],N2O在這一過(guò)程中作為副產(chǎn)物產(chǎn)生:羥胺在HAO酶催化下生成NO[5],然后NO在細(xì)胞色素 c554[6-7]或者一氧化氮還原酶的同源酶NorS[4]的作用下被還原生成N2O。后者是指氨氧化反應(yīng)產(chǎn)物亞硝酸鹽在亞硝酸鹽還原酶(Nir)作用下生成NO,隨后NO被一氧化氮還原酶(Nor)還原生成N2O。

近年來(lái)還發(fā)現(xiàn)一些異養(yǎng)硝化細(xì)菌,它們能夠利用有機(jī)碳源進(jìn)行異養(yǎng)硝化反應(yīng)[8-9]。ANDERSON等[10]研究表明異養(yǎng)硝化菌Alcaligenes faecalis硝化過(guò)程產(chǎn)生的N2O比自養(yǎng)菌Nitrosomonas europaea產(chǎn)生的多。盡管異養(yǎng)硝化的過(guò)程和產(chǎn)物與自養(yǎng)硝化的相同,但酶的性質(zhì)不同,并且異養(yǎng)硝化菌還能夠同時(shí)進(jìn)行好氧反硝化產(chǎn)生N2O。

1.2硝化過(guò)程N(yùn)2O產(chǎn)生的影響因素

生物硝化過(guò)程是一系列的酶促反應(yīng),自養(yǎng)氨氧化細(xì)菌體內(nèi)通常缺少一氧化二氮還原酶基因(Nos)是導(dǎo)致其產(chǎn)生N2O的根本原因[11-12]。各種環(huán)境因子也主要通過(guò)影響微生物的活動(dòng)或各階段酶的活性而間接影響N2O的產(chǎn)生和釋放??偟膩?lái)說(shuō),影響硝化過(guò)程中N2O產(chǎn)生的主要因素有溶解氧、氨氮、亞硝氮等。

1.2.1溶解氧

溶解氧是污水處理廠(chǎng)關(guān)鍵運(yùn)行參數(shù),也是影響硝化過(guò)程N(yùn)2O產(chǎn)生的關(guān)鍵影響因素。研究認(rèn)為在較高溶解氧濃度下N2O主要由羥胺氧化路徑產(chǎn)生[13],而溶解氧濃度較低時(shí)通常會(huì)因?yàn)榇龠M(jìn) AOB反硝化反應(yīng)而積累 N2O[3,14]。傳統(tǒng)生物脫氮工藝中培養(yǎng)條件的瞬時(shí)轉(zhuǎn)換,即由有氧條件直接轉(zhuǎn)換成厭氧條件時(shí),也會(huì)引起N2O產(chǎn)量的瞬時(shí)顯著增加[15]。

1.2.2氨氮

硝化活性污泥有氧處理模擬氨氮廢水時(shí)會(huì)產(chǎn)生大量的N2O,一旦硝化底物氨氮耗盡N2O排放就停滯,并且當(dāng)模擬廢水中氨氮被硝酸鹽和亞硝酸鹽替代后也沒(méi)有N2O的產(chǎn)生[16],這說(shuō)明氨氮對(duì)生物脫氮過(guò)程特別是硝化過(guò)程中 N2O的產(chǎn)生與積累有著重要的作用。在實(shí)際污水處理過(guò)程中,進(jìn)水氨氮負(fù)荷的增加對(duì)好氧段 N2O的釋放有較大影響,且 N2O的釋放速率、累積釋放量和轉(zhuǎn)化率均隨進(jìn)水氨氮負(fù)荷的增加而增大[17]。但是,PIJUAN等[18]研究卻發(fā)現(xiàn)在常規(guī)操作范圍內(nèi)分別改變氨氮和游離氨濃度對(duì)N2O的釋放沒(méi)有影響(N2O釋放因子恒定在4.4%左右),可能是因?yàn)榉磻?yīng)器中菌群適應(yīng)了這些N濃度。

1.2.3 亞硝酸鹽

CASTRO-BARROS等[19]研究發(fā)現(xiàn)硝化系統(tǒng)中亞硝酸鹽的存在會(huì)導(dǎo)致N2O和NO釋放的增加。PENG等[14]研究發(fā)現(xiàn)N2O的產(chǎn)生速率和釋放因子隨亞硝酸鹽濃度的增大而增大,同時(shí)還發(fā)現(xiàn)亞硝酸鹽濃度越高越容易刺激AOB反硝化而引起N2O積累,推測(cè)是因?yàn)楦邼舛葋喯跛猁}會(huì)促進(jìn)亞硝酸鹽還原酶基因nirK和一氧化氮還原酶基因norB mRNA顯著表達(dá)來(lái)刺激 AOB反硝化反應(yīng)的發(fā)生[20-21],進(jìn)而促進(jìn)N2O的產(chǎn)生。相反,LAW等[22]研究卻認(rèn)為亞硝化系統(tǒng)中極高濃度的亞硝酸鹽會(huì)降低 N2O的產(chǎn)生速率,同時(shí)還發(fā)現(xiàn)這種現(xiàn)象會(huì)隨溶解氧濃度的增大而變得更加明顯。高濃度亞硝酸鹽下導(dǎo)致N2O積累顯著差異的原因可能是由于不同脫氮系統(tǒng)內(nèi)部微生物種類(lèi)的不同。

1.2.4其他因素

廢水生物脫氮過(guò)程中鹽度是一項(xiàng)不容忽視的影響因素,鹽度瞬時(shí)刺激會(huì)增強(qiáng)AOB反硝化路徑產(chǎn)生N2O[23]。此外,無(wú)機(jī)碳源也成為影響自養(yǎng)氨氧化細(xì)菌釋放N2O的重要因素。無(wú)機(jī)碳源不足時(shí)會(huì)降低氨的去除效率和AOB的呼吸速率而導(dǎo)致N2O排放增加[24]。然而無(wú)機(jī)碳源引起的堿度消耗,也會(huì)使N2O產(chǎn)生速率與無(wú)機(jī)碳源濃度在一定范圍內(nèi)呈線(xiàn)性正相關(guān)(R2=0.97)[25]。

2 反硝化過(guò)程中 N2O的產(chǎn)生機(jī)理及影響因素

2.1異養(yǎng)反硝化過(guò)程N(yùn)2O的產(chǎn)生機(jī)理

傳統(tǒng)的反硝化過(guò)程亦是反硝化細(xì)菌硝酸鹽或者亞硝酸鹽的厭氧呼吸過(guò)程。然而,許多異養(yǎng)反硝化菌能夠在有氧條件下利用硝酸鹽或亞硝酸鹽完成反硝化反應(yīng)[26-27],當(dāng)然好氧反硝化亦被認(rèn)為是菌株有氧呼吸的一個(gè)輔助路徑[28]。反硝化需要4種不同的反硝化還原酶來(lái)依次催化完成相應(yīng)反應(yīng)最終生成N2,這4種酶分別是硝酸鹽還原酶(Nar)、亞硝酸鹽還原酶(Nir)、一氧化氮還原酶(Nor)和一氧化二氮還原酶(Nos)。無(wú)論厭氧反硝化還是有氧反硝化,N2O都會(huì)作為反硝化過(guò)程的代謝中間產(chǎn)物生成。

2.2反硝化過(guò)程N(yùn)2O產(chǎn)生的影響因素

顯而易見(jiàn),N2O生成量的多少與一氧化二氮還原酶(Nos)及其活性有直接關(guān)系,諸如溶解氧、有機(jī)碳源和亞硝酸鹽等因素會(huì)通過(guò)影響反硝化過(guò)程中Nos酶的活性而影響N2O生成量的大小[29-30]。

2.2.1溶解氧

眾所周知,氧會(huì)抑制厭氧反硝化過(guò)程相關(guān)反硝化酶的合成與活性。一氧化二氮還原酶是對(duì)氧氣最為敏感的反硝化酶,有微量的氧存在時(shí)就會(huì)抑制它的活性而導(dǎo)致N2O的積累[31]。GONG等[32]研究發(fā)現(xiàn)溶解氧會(huì)強(qiáng)烈影響反硝化過(guò)程N(yùn)2O的釋放,溶解氧濃度≤0.7mg/L時(shí)N2O產(chǎn)量隨著氧濃度的增大而增大。WANG等[33]雖然證明異養(yǎng)反硝化是N2O釋放的主要路徑,但當(dāng)溶解氧濃度為1.0mg/L或者更高時(shí)會(huì)通過(guò)抑制亞硝酸鹽的還原反應(yīng)從而使 N2O的釋放量減少。

好氧反硝化菌株在適宜的溶解氧濃度下反硝化終產(chǎn)物為 N2而不積累 N2O,如好氧反硝化菌株P(guān)seudomonas stutzeri PCN-1[26]在溶解氧濃度低于8.28mg/L(50% O2)時(shí)幾乎沒(méi)有N2O積累,但是當(dāng)溶解氧濃度增大到18.39mg/L(100%純氧)硝酸鹽反硝化出現(xiàn)一定程度的滯后,并且N2O最大累積量為22.58mg N/L,占反硝化硝酸鹽氮含量的25.90%,這一過(guò)程中大量 N2O積累的原因是高濃度的氧一方面會(huì)抑制N2O還原酶的活性[34],另一方面會(huì)引起氧呼吸速率加快而產(chǎn)生活性自由基,從而導(dǎo)致菌體DNA、RNA及蛋白質(zhì)氧化損傷[35]。因此,與傳統(tǒng)反硝化一樣,好氧反硝化過(guò)程中N2O的積累與釋放與溶解氧濃度密切相關(guān),都需要控制在適宜范圍內(nèi)。

2.2.2碳源

有機(jī)碳源對(duì)于異養(yǎng)反硝化過(guò)程是至關(guān)重要的。SONG等[36]研究發(fā)現(xiàn)投加乙酸鈉為碳源系統(tǒng)中N2O的產(chǎn)生速率(1.6±0.6μg N–N2O/min)低于投加甲醇的系統(tǒng)中 N2O的產(chǎn)生速率(3.0±0.7μg N-N2O/min),這主要是由于碳源不同導(dǎo)致微生物群落結(jié)構(gòu)不同,使得乙酸鈉系統(tǒng)中的菌群比甲醇系統(tǒng)中的菌群有著更高的N2O還原速率。HU等[37]利用厭氧/好氧生物脫氮系統(tǒng)分別研究葡萄糖、乙酸鈉和可溶性淀粉對(duì)N2O釋放的影響,研究發(fā)現(xiàn)乙酸鈉是最適合生物營(yíng)養(yǎng)物質(zhì)去除的碳源,但同時(shí)會(huì)導(dǎo)致N2O大量釋放,主要原因是相比其他兩種碳源,乙酸鈉作為碳源時(shí)反硝化微生物的種類(lèi)較少。因此,不同的碳源會(huì)通過(guò)影響微生物的種類(lèi)而影響反硝化過(guò)程中N2O的積累與釋放。另外,有機(jī)碳源的可利用性也是反硝化過(guò)程中影響 N2O釋放的重要因素,碳源的可利用性還常常反映在化學(xué)需氧量(COD)上,于是 COD/N成為影響N2O釋放的重要因素之一。一般而言,低COD/N比會(huì)造成N2O的大量釋放[38]。但近年來(lái)也存在許多不同的結(jié)論,如李鵬章等[39]研究認(rèn)為在電子競(jìng)爭(zhēng)環(huán)境下,N2O積累的關(guān)鍵因素不是COD/N,而是取決于電子在Nos酶上分布的多少。

2.2.3亞硝酸鹽

亞硝酸鹽是引起反硝化過(guò)程中 N2O的積累與釋放的關(guān)鍵因素。委燕等[40]研究發(fā)現(xiàn)高亞硝酸鹽濃度是導(dǎo)致反硝化過(guò)程N(yùn)2O產(chǎn)生與積累的原因,一方面來(lái)自于游離亞硝酸(FNA)對(duì)N2O還原酶活性的抑制,另一方面來(lái)自于N2O還原酶與亞硝酸鹽還原酶對(duì)電子的競(jìng)爭(zhēng)。WANG等[41]研究發(fā)現(xiàn)長(zhǎng)期生存于亞硝酸環(huán)境中的微生物群體會(huì)提高它們對(duì)亞硝酸鹽的適應(yīng)性,進(jìn)而會(huì)減少反硝化過(guò)程中的N2O的積累與釋放,這為反硝化過(guò)程中N2O減排提供了一個(gè)很好的借鑒方法。

2.2.4其他因素

污水生物氮磷去除過(guò)程中通常會(huì)出現(xiàn)糖原積累微生物(GAO)和聚磷微生物(PAO)大量富集生長(zhǎng),它們可在厭氧時(shí)采用一種特殊機(jī)制來(lái)存儲(chǔ)有機(jī)碳源作為內(nèi)源物質(zhì),如聚羥基丁酸酯(polyhydroxybutyrate,PHB)。當(dāng)廢水中 COD/N低時(shí),微生物可以利用它們自身存儲(chǔ)的碳源物質(zhì)來(lái)進(jìn)行反硝化,這是N2O釋放的又一潛在來(lái)源[42-43]。此外,氨氮也會(huì)引起反硝化過(guò)程中 N2O釋放的增加[44]。

3 簡(jiǎn)述新型脫氮工藝中 N2O的產(chǎn)生機(jī)理及影響因素

目前普遍認(rèn)為 N2O主要產(chǎn)生于生物硝化過(guò)程和反硝化過(guò)程。但是,隨著人們對(duì)脫氮微生物認(rèn)識(shí)的深入,陸續(xù)出現(xiàn)諸如同步硝化反硝化、短程硝化反硝化等新的污水生物脫氮工藝,它們?cè)谶\(yùn)行過(guò)程中也存在產(chǎn)生N2O的風(fēng)險(xiǎn)。

3.1同步硝化反硝化

好氧反硝化菌和異養(yǎng)硝化菌的發(fā)現(xiàn),打破了傳統(tǒng)脫氮的觀(guān)點(diǎn),它們能夠同時(shí)進(jìn)行硝化反硝化反應(yīng),這為同步硝化反硝化(SND)的實(shí)現(xiàn)提供了重要的菌種資源。SND是同一操作條件下能夠在同一反應(yīng)器中完成硝化和反硝化脫氮反應(yīng)。當(dāng)操作條件不當(dāng)時(shí)會(huì)刺激同步硝化反硝化工藝中N2O的產(chǎn)生,如溶解氧受限時(shí)同步硝化反硝化過(guò)程會(huì)產(chǎn)生N2O,且遠(yuǎn)高于傳統(tǒng)生物脫氮過(guò)程N(yùn)2O的生成量[45]。

3.2短程硝化反硝化

短程硝化反硝化工藝是將硝化反應(yīng)控制在亞硝酸鹽階段,直接進(jìn)行反硝化反應(yīng)。研究發(fā)現(xiàn)短程硝化反硝化過(guò)程會(huì)產(chǎn)生N2O[46],并且N2O主要產(chǎn)生于短程硝化過(guò)程中[47]。一般而言,亞硝酸鹽的積累是短程硝化反硝化過(guò)程產(chǎn)生較多 N2O 的主要原因[48-49]。此外,短程硝化反硝化過(guò)程中,N2O的積累與釋放還受到進(jìn)水氨氮濃度、溶解氧、COD/N、pH等因素的影響[50-51]。

3.3厭氧氨氧化

厭氧氨氧化菌是污水處理過(guò)程中不容忽視的一類(lèi)菌群,其厭氧氨氧化反應(yīng)是在缺氧條件下將NO2–和NH4+同時(shí)轉(zhuǎn)化為N2的過(guò)程,其中,以NO2–為電子受體、NH4+為電子供體。盡管厭氧氨氧化工藝中會(huì)產(chǎn)生N2O[52],但研究認(rèn)為厭氧氨氧化顆粒內(nèi)部的異養(yǎng)反硝化菌的反硝化作用可能是厭氧氨氧化反應(yīng)器中N2O的真正來(lái)源[53]。也有研究認(rèn)為厭氧氨氧化反應(yīng)中N2O來(lái)自其中間產(chǎn)物NO的去毒作用[54]。有意思的是,厭氧氨氧化反應(yīng)還被認(rèn)為是N2O減排反應(yīng)[55],因?yàn)樗梢詫钡苯愚D(zhuǎn)化成氮?dú)舛环e累 N2O。因此,目前對(duì)于厭氧氨氧化過(guò)程能否產(chǎn)生N2O存在較大爭(zhēng)議,還需要深入研究。

4 結(jié) 語(yǔ)

在污水處理中,N2O主要產(chǎn)生于微生物的硝化反硝化過(guò)程,但新型脫氮工藝中N2O產(chǎn)生也不容小覷,還有待深入研究。微生物脫氮過(guò)程中N2O產(chǎn)生機(jī)理雖然與實(shí)際操作所處的周?chē)h(huán)境有著密切的關(guān)系,但其本質(zhì)原因則是系統(tǒng)中多種微生物的相互作用以及自身酶活性所受影響所致。

因?yàn)镹2O具有超強(qiáng)的溫室效應(yīng),所以污水生物脫氮過(guò)程中 N2O產(chǎn)量控制與減量化策略將成為未來(lái)研究的重點(diǎn)和熱點(diǎn)。對(duì)此提出以下兩點(diǎn)建議。

(1)生物脫氮過(guò)程中微生物種群影響并決定了N2O的產(chǎn)生。雖然近年來(lái)對(duì)N2O的產(chǎn)生機(jī)理研究較多,但是仍然存在著許多不足,畢竟自然界還有許多未知的菌種。因此需要深入研究微生物種群結(jié)構(gòu)及其關(guān)鍵酶活性,這對(duì)于充實(shí)N2O的產(chǎn)生機(jī)理和控制N2O產(chǎn)生量是非常必要的。與此同時(shí),研究者還需要篩選脫氮效果好、N2O產(chǎn)量小、對(duì)環(huán)境有較強(qiáng)適應(yīng)能力和競(jìng)爭(zhēng)力的優(yōu)勢(shì)菌,淘汰劣勢(shì)菌種,實(shí)現(xiàn)種群優(yōu)化。

(2)同步硝化反硝化、短程硝化反硝化等新工藝過(guò)程在脫氮效率上較傳統(tǒng)工藝具有一定的優(yōu)勢(shì),但其在運(yùn)行過(guò)程中潛在 N2O的釋放量也遠(yuǎn)遠(yuǎn)高于傳統(tǒng)的生物脫氮過(guò)程。因此,針對(duì)污水性質(zhì)選擇合理的處理工藝、準(zhǔn)確控制并優(yōu)化工藝運(yùn)行參數(shù)以及合理調(diào)控微生物種群結(jié)構(gòu)等手段均是污水生物脫氮過(guò)程中N2O減量化的策略。

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Progress on mechanisms and influence factors of N2O production in microbial nitrogen removal process from wastewater

CHEN Hu,WANG Ying,Lü Yongkang
(Key Laboratory of Coal Science and Technology,Ministry of Education and Shanxi Province,Taiyuan University of Technology,Taiyuan 030024,Shanxi,China)

Nitrous oxide(N2O)emitted during biological nitrogen removal process is a potent greenhouse gas and can result in the destruction of the ozone layer. This paper summarizes the mechanisms and influencing factors of N2O production during wastewater biological nitrogen removal process. Hydroxylamine oxidation and nitrifier denitrification are two main pathways to produce N2O for nitrification,and factors such as dissolved oxygen,ammonium nitrogen and nitrite mainly affect microbial activity or enzyme activity that influences indirectly N2O emission from nitrification process. Denitrification process is another important source for the production of N2O,and the quantity of N2O emission has a direct connection with nitrous oxide reductase,whose activities can be affected by factors such as dissolved oxygen,organic carbon,and nitrite. New biological nitrogen removal technologies have become potential sources of N2O,but further research on mechanisms of N2O production is needed. Although N2O emission is closely related to the changes of surrounding environment,the main cause for N2O emission is the effect of microbial actions and enzyme activities. The future research on the wastewater biological nitrogen removal process should focus on the control and reduction strategy of N2O,and shows some suggestions.

biological nitrogen removal;nitrous oxide;influence factors;wastewater treatment

X 703.1

A

1000–6613(2016)12–4020–06

10.16085/j.issn.1000-6613.2016.12.040

2016-05-16;修改稿日期:2016-08-25。

國(guó)家重點(diǎn)研發(fā)計(jì)劃(2016YFB0600502)及山西省國(guó)際合作計(jì)劃(201603D421040)項(xiàng)目。

陳虎(1987-),男,博士研究生,主要研究方向是大氣污染物及污水治理。聯(lián)系人:呂永康,教授,長(zhǎng)期從事煤化工、環(huán)境工程與技術(shù)領(lǐng)域的科學(xué)研究工作。E-mail yongkanglv@163.com。

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