程雪婷， 楊殿海

(同濟(jì)大學(xué)環(huán)境科學(xué)與工程學(xué)院，上海 200092)

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膜生物反應(yīng)器處理抗生素廢水研究進(jìn)展

程雪婷， 楊殿海*

(同濟(jì)大學(xué)環(huán)境科學(xué)與工程學(xué)院，上海 200092)

綜述了膜生物反應(yīng)器(MBR)對(duì)抗生素的去除效果，剖析了去除抗生素的生物降解和吸附途徑，討論了溫度、pH、污泥濃度、污泥齡、水力停留時(shí)間、氧化還原電位等因素對(duì)MBR中抗生素去除效果的影響，介紹了膜生物反應(yīng)器組合工藝對(duì)抗生素的強(qiáng)化去除效果，旨在為MBR去除抗生素的工藝設(shè)計(jì)與運(yùn)行條件的優(yōu)化提供參考。

膜生物反應(yīng)器；抗生素；去除效果；去除途徑；影響因素

近年來，抗生素被廣泛應(yīng)用于人類疾病治療、畜禽養(yǎng)殖和農(nóng)業(yè)生產(chǎn)中，其大量使用所引發(fā)的人類健康和環(huán)境安全問題備受社會(huì)關(guān)注。由于傳統(tǒng)活性污泥法無法有效去除生活污水[1-3]、畜禽養(yǎng)殖污水[4-5]及制藥廢水[6]中的抗生素，從而使得大量抗生素經(jīng)由城市污水廠排放到河流水沙[7-9]、土壤[10-11]、地下水[12]等天然環(huán)境中。我國每年抗生素使用量達(dá)16.20萬t，經(jīng)污水處理廠處理后排放到天然環(huán)境中的抗生素仍然高達(dá)5.38萬t[13]。可見，城市污水處理廠排水已成為天然環(huán)境中抗生素的重要來源，城市污水廠升級(jí)改造問題亟需解決。膜生物反應(yīng)器(MBR)是將膜的高效分離與生物降解作用相結(jié)合的一種高效污水處理工藝，與傳統(tǒng)的活性污泥系統(tǒng)相比，其具有污泥濃度高、固液分離能力強(qiáng)、污泥齡長(zhǎng)、菌群多樣性高等特點(diǎn)，因此越來越多的學(xué)者將MBR應(yīng)用于含抗生素廢水處理的研究中。筆者綜述了MBR對(duì)抗生素的去除效果，剖析了MBR中去除抗生素的生物降解和吸附途徑，討論了溫度、pH、污泥濃度、污泥齡、水力停留時(shí)間和氧化還原電位等因素對(duì)MBR中抗生素去除效果的影響，介紹了MBR組合工藝對(duì)抗生素的強(qiáng)化去除效果，旨在為MBR去除抗生素的工藝設(shè)計(jì)與運(yùn)行條件的優(yōu)化提供參考。

1　MBR對(duì)抗生素的去除效果

目前，絕大多數(shù)城市污水廠采用的是活性污泥法工藝。由于抗生素的理化性質(zhì)各異及生物降解性的不同，因而不同種類的抗生素在傳統(tǒng)城市污水處理廠的進(jìn)水、出水中的濃度存在較大差異?？股卦趥鹘y(tǒng)城市污水廠進(jìn)水和出水中的濃度水平在ng/L～μg/L，但在污泥中卻可以達(dá)到mg/g的濃度水平。這表明傳統(tǒng)的活性污泥法對(duì)抗生素的去除效果有限，從而導(dǎo)致大量的抗生素隨著傳統(tǒng)城市污水廠出水進(jìn)入到天然環(huán)境中。主要類型抗生素在城市污水廠傳統(tǒng)活性污泥法工藝進(jìn)水、出水和污泥中的存在濃度見表1。

幾大類抗生素在傳統(tǒng)活性污泥法工藝(CAS)與MBR中的去除效果如表2所示?；前奉愒诔鞘形鬯畯S出水和污泥中的濃度較低(表1)，表明CAS對(duì)磺胺類有一定去除效果，然而其去除效果不夠穩(wěn)定，由表2可以看出，其去除率范圍為-138.0%～96.0%。CAS對(duì)大環(huán)內(nèi)酯類的去除效果一般，大部分低于50.0%。與CAS相比，MBR可將磺胺類和大環(huán)內(nèi)酯類抗生素的去除率提升至50.0%～90.0%，顯示出其明顯的去除優(yōu)勢(shì)。喹諾酮類和四環(huán)素類在CAS中的去除率可達(dá)70.0%以上，其在污泥中較高的濃度表明這2類抗生素很有可能是通過排泥而去除的；這2類抗生素經(jīng)MBR去除其去除率可以提升至90.0%以上，比CAS去除率高約20.0%。在整體去除率方面，MBR對(duì)各類抗生素的去除效果較佳，雖然各研究結(jié)果有所差異，但基本可達(dá)80.0%～90.0%的去除效果。

由于不同的研究中MBR所在的環(huán)境條件及運(yùn)行條件不同，因此得出的去除率范圍有較大差異。即使是同一種抗生素，在不同研究中其去除效果也不盡相同，這是因?yàn)槠淙コ适艿蕉喾N因素的影響。以磺胺甲惡唑?yàn)槔窃诟黝惌h(huán)境中被檢出頻率最高的1種抗生素，因此研究者對(duì)磺胺甲惡唑的研究最多[46]。MBR對(duì)磺胺甲惡唑的去除效果見表3。由表3可以看出，污泥齡、水力停留時(shí)間、污泥濃度等因素均會(huì)影響MBR對(duì)磺胺甲惡唑的去除效果。此外，MBR中抗生素去除率出現(xiàn)較大差異的原因還有以下幾種：進(jìn)水濃度差異較大，這與進(jìn)水來源中居民抗生素使用量及是否含有制藥廢水密切相關(guān)；水質(zhì)具有波動(dòng)性，取樣不能完全反映整個(gè)過程的去除情況[15]，采樣方式不同也會(huì)導(dǎo)致數(shù)據(jù)差異較大；吸附于進(jìn)水中顆粒物上的抗生素在整個(gè)處理過程中脫附[47]，或著進(jìn)水中一些代謝或中間產(chǎn)物轉(zhuǎn)化造成出水抗生素濃度升高[48]。此外，也有磺胺甲惡唑去除率為負(fù)值的報(bào)道[20]，其原因可能是污水中存在的N4-乙?；前芳讗哼蛑匦罗D(zhuǎn)化為母體導(dǎo)致出水濃度增高。

表1　抗生素在城市污水廠進(jìn)水、出水和污泥中的存在濃度

表2　CAS與MBR對(duì)抗生素的去除效果比較

表3　 MBR對(duì)磺胺甲惡唑的去除效果

2　抗生素去除途徑

2.1生物降解抗生素的生物降解過程與抗生素自身性質(zhì)、污泥特性、運(yùn)行條件等因素有關(guān)[49]，這些條件通過影響微生物的生長(zhǎng)、抗生素的代謝途徑來影響細(xì)胞生物降解過程。抗生素的物化性質(zhì)顯著制約其自身去除效果，抗生素內(nèi)部多樣的分子結(jié)構(gòu)也使得抗生素的生化性差異巨大。酯類、腈類、芳族醇結(jié)構(gòu)可以提高其生化性，而芳香胺類、鹵基、硝基和偶氮基、長(zhǎng)支鏈以及復(fù)雜芳環(huán)等基團(tuán)可降低其生化性[50-52]。例如，大環(huán)內(nèi)酯類抗生素一般具有帶有支鏈和糖類的環(huán)，而磺胺類具有2個(gè)被—SO2NH—結(jié)構(gòu)聯(lián)結(jié)的小環(huán)，這使得磺胺類極性和親水性更強(qiáng)，從而決定了磺胺類抗生素比大環(huán)內(nèi)酯類抗生素更易通過生物降解作用去除[24]?？股氐拇x途徑也會(huì)影響到生物降解過程。毒性較小、在環(huán)境中濃度存在較高的抗生素可以作為碳源被微生物通過直接代謝途徑降解，毒性大、濃度低的抗生素則需通過微生物的共代謝作用得以去除[53]。共代謝是指微生物在主要底物存在條件下，對(duì)非生長(zhǎng)底物進(jìn)行降解的代謝方式[54]。微生物可以通過共代謝作用將抗生素轉(zhuǎn)變成能夠易生物降解的中間產(chǎn)物參與到主要代謝途徑中去。某些種類的微生物如自養(yǎng)氨氧化菌被認(rèn)為具有共代謝多種抗生素的能力[55]，其在硝化條件下會(huì)生成氨單加氧酶[56]，這種酶能夠羥基化抗生素從而達(dá)到降解抗生素的目的?？股厣锝到馔緩饺鐖D1所示。

注：a.直接代謝； b.共代謝。 Note：a.Direct metabolism;b.Co-metabolism.圖1　抗生素生物降解途徑[53] Fig.1　Biodegradation ways of antibiotics[53]

目前公認(rèn)的生物降解模型主要為假一級(jí)模型，其用來解釋抗生素生物降解行為。學(xué)者通過質(zhì)量平衡算式計(jì)算Kbiol(降解速率常數(shù))值作為抗生素生物降解性能的指標(biāo)。生物降解模型：

2.2污泥吸附吸附在絮體、懸浮物以及污泥中的抗生素會(huì)隨著沉淀作用以及排泥去除，這也是MBR去除抗生素的重要途徑。吸附作用主要從2個(gè)方面來進(jìn)行：①分子脂肪鏈和芳香基團(tuán)與微生物親脂細(xì)胞膜間的疏水作用；②組分的帶正電基團(tuán)與污泥負(fù)電表面的靜電作用[57]?？股氐挠H疏水性是影響污泥吸附的重要指標(biāo)。Rogers[58]提出用辛醇-水分配系數(shù)(Kow)值判斷抗生素親疏水性，由于未考慮到抗生素的pKa以及pH對(duì)抗生素的影響，lgKow在評(píng)價(jià)親疏水性上存在一定缺陷。通常學(xué)者利用表觀分配系數(shù)Kd來對(duì)抗生素吸附作用進(jìn)行評(píng)估[59]，其計(jì)算公式為：

(2)

式中，Cs為平衡條件下水相濃度(μg/L)；Cw為泥相濃度(μg/g)。

Li等[57]認(rèn)為，對(duì)于Kd<500 L/kg (lgKd< 2.7) 的抗生素，其吸附作用影響很小。對(duì)于Kd較大的抗生素，其通過吸附作用去除的比重很大。喹諾酮類抗生素如環(huán)丙沙星和諾氟沙星(Kd>15 000 L/kg)難以生物降解，其去除效果與Kd間有明顯的正相關(guān)關(guān)系，且需通過與污泥絮體的靜電作用來去除，而非疏水作用[2,60]。與活性污泥法相比，MBR中惰性物質(zhì)含量較高，污泥粒徑小且表面積大，有利于吸附[61]。但由于MBR排泥量較少，因此通過吸附去除的抗生素總量不一定高[62-63]。MBR中抗生素的吸附和生物降解途徑已經(jīng)得到絕大多數(shù)學(xué)者的公認(rèn)，且MBR中抗生素的吸附過程較為迅速，而抗生素的生物降解是其去除過程的限速步驟。Dorival-García等[42]在研究中考查喹諾酮類抗生素的降解行為，發(fā)現(xiàn)吸附在60 min內(nèi)快速完成，抗生素濃度從24 h后隨著污泥生物降解而緩慢下降。Fernandez-Fontaina等[24]也發(fā)現(xiàn)，吸附過程結(jié)束后MBR水相和泥相中的抗生素濃度以相近的速度降低，表明水相和泥相中抗生素存在相似的生物降解行為。

總之，一方面MBR中較小尺寸絮體的存在增大了吸附接觸面積，提高了吸附效果，另一方面復(fù)雜的微生物菌群有利于生物降解[63]。MBR反應(yīng)器突出的泥水分離效果歸結(jié)于膜組件的間接截留作用，它可以使得出水中基本不含污泥，保證了出水中不會(huì)有污泥攜帶抗生素排放到環(huán)境中[64]。此外，對(duì)于那些疏水性強(qiáng)且含有吸電子基團(tuán)的抗生素，雖然其在水相中去除率高，但其會(huì)積累在污泥中并隨之進(jìn)入環(huán)境，因此污泥的安全處置問題亦需要學(xué)者更多的關(guān)注。

3　影響因素

3.1溫度溫度的改變能夠?qū)е驴股匚锘再|(zhì)、微生物活性、增殖速率等受到影響，進(jìn)而導(dǎo)致出水水質(zhì)及系統(tǒng)穩(wěn)定運(yùn)行受到影響[65]。

過高或過低的溫度條件會(huì)降低抗生素的去除效果。低溫條件下微生物的活性減弱會(huì)影響微生物對(duì)抗生素的生物降解過程，導(dǎo)致抗生素去除效率降低[66]。高溫條件下，污泥會(huì)分解釋放出污染物造成出水濃度的增加[65]，物質(zhì)的去除率同樣會(huì)變低。溫度的改變也會(huì)帶來混合液特性的變化。Hai等[65]觀察到污泥濃度會(huì)隨著溫度的升高而變低，胞外聚合物特性表現(xiàn)穩(wěn)定，而溶解性微生物代謝產(chǎn)物中蛋白質(zhì)的含量在低于20 ℃和高于45 ℃時(shí)明顯增加?；旌弦禾匦耘cMBR中污泥絮體結(jié)構(gòu)、沉降性能以及膜污染有著非常密切的關(guān)系，因此溫度對(duì)混合液特性的改變會(huì)影響MBR的穩(wěn)定運(yùn)行。溫度還會(huì)影響吸附作用，從而影響抗生素的去除效果。一般來說，溫度的改變對(duì)帶有強(qiáng)吸電子功能團(tuán)、親水性強(qiáng)的組分影響更大[65]。對(duì)于大多數(shù)物質(zhì)來說，吸附等溫線隨著溫度升高而降低[67]，因此溫度的升高會(huì)造成吸附能力的降低。對(duì)于喹諾酮類抗生素來說，其通過污泥吸附去除的效果會(huì)隨著溫度的升高而明顯降低，但由于溫度升高有利于生物降解，因此整體的去除率隨溫度升高依然呈現(xiàn)增大的趨勢(shì)[42]。

3.2pHpH能夠顯著影響抗生素的去除，在不同的pH條件下，抗生素可能為中性、陰性或兩性的，隨之其物化性質(zhì)及生化性質(zhì)也會(huì)相應(yīng)發(fā)生改變[68]。

對(duì)于能夠發(fā)生電離的組分，其在pH較低的條件下以疏水形式存在，而在pH較高的條件下其會(huì)帶上負(fù)電不利于吸附于污泥上。對(duì)于不可電離組分，pH的影響很小?；前芳讗哼蛟趐H=5時(shí)主要以中性形式存在，疏水性強(qiáng)，有利于其吸附作用，去除效率最高[69]。Tadkaew等[69]還發(fā)現(xiàn)可電離組分受pH的影響非常大，且辛醇水分配系數(shù)的改變與去除率的變化非常一致。Watkinson 等[34]研究發(fā)現(xiàn)，當(dāng)pH<7時(shí)，紅霉素能夠脫去一個(gè)水分子生成脫水紅霉素，從而使其無法被檢測(cè)到。pH條件不僅影響吸附作用，而且還影響微生物活性和菌群結(jié)構(gòu)[70]。

3.3污泥濃度與CAS相比，較高的污泥濃度是MBR反應(yīng)器的一大特點(diǎn)。體系中的污泥濃度升高意味著有更多的微生物可以參與到抗生素的去除中，這不僅可以使總體的生物降解能力得到增強(qiáng)，而且可以使得抗生素在污泥上的吸附總量得到增加，從而減小出水中抗生素濃度[42]。

污泥濃度高也意味著有較低的食微比(F/M)，體系中可產(chǎn)生更多復(fù)雜的微生物菌群，這些微生物需要代謝難降解組分以維持其生長(zhǎng)，因此整體上可以提高其降解抗生素的能力。MBR系統(tǒng)能夠減少微生物的流失，因此也有利于難降解組分的降解。高濃度的污泥濃度還可使MBR擁有更高的抗沖擊負(fù)荷的能力[71]。

Sahar等[72]觀察污泥濃度積累過程(3.8～10.4 g/L)中抗生素的去除率變化，發(fā)現(xiàn)磺胺甲惡唑去除效果隨污泥濃度增加而增大，而大環(huán)內(nèi)酯類的去除率大小與污泥濃度無關(guān)。Dorival-Garcia等[42]發(fā)現(xiàn)將污泥濃度從7 g/L增大到15 g/L時(shí)，喹諾酮類抗生素的去除率和生物降解途徑占比均有顯著提高。他還指出，較高的污泥濃度雖然使微生物對(duì)抗生素的吸附能力降低，但其可為抗生素提供更多的吸附位點(diǎn)，從而使得抗生素的吸附總量增加。Fernandez-Fontaina等[24]比較了MBR和CAS的吸附和生物降解能力，發(fā)現(xiàn)MBR中抗生素的Kbiol和Kd值并無明顯提高，因此他認(rèn)為MBR的去除優(yōu)勢(shì)主要在于高濃度的污泥濃度使得去除總量增大。

3.4污泥齡污泥齡是污水處理廠工藝設(shè)計(jì)的重要指標(biāo)，它影響著污泥濃度、生物多樣性、微生物的活性和優(yōu)勢(shì)菌群，同時(shí)它也是影響MBR去除抗生素效果的重要因素。在較長(zhǎng)的污泥齡下，慢速生長(zhǎng)自養(yǎng)菌(如硝化細(xì)菌)能夠緩慢增殖，同時(shí)微生物種類更為復(fù)雜，其可通過直接代謝或共代謝的方式加強(qiáng)抗生素的降解[29]。一般來說，MBR的污泥齡比CAS的要大，MBR對(duì)抗生素的去除效果更好。長(zhǎng)泥齡、較低污泥負(fù)荷能夠提高污泥生物多樣性，有助于抗生素在污泥共代謝作用下的去除；短泥齡會(huì)導(dǎo)致污泥濃度下降、絮體尺寸變大以及比表面積減小，從而降低抗生素的去除效果[29]。因此，適當(dāng)延長(zhǎng)污泥齡可以提高M(jìn)BR對(duì)抗生素的去除率。然而，也有學(xué)者觀察到在相同污泥齡條件下，與CAS相比，MBR對(duì)抗生素的去除并無優(yōu)勢(shì)，這可能與其他因素(如污泥濃度、食微比等)的影響有關(guān)[73]。

3.5水力停留時(shí)間一般來說，提高水力停留時(shí)間能夠增加微生物和污水的接觸時(shí)間，從而提高抗生素的去除效果。

當(dāng)水力停留時(shí)間過短時(shí)，污泥生物降解抗生素速率的提高無法抵消增大的進(jìn)水負(fù)荷，此時(shí)去除效率就會(huì)下降。Fernandez-Fontaina等[66]在研究中觀察到紅霉素隨著水力停留時(shí)間的縮短，其通過生物降解作用去除的比例先是增大，隨后隨進(jìn)水負(fù)荷的提高而減小，而羅紅霉素隨著水力停留時(shí)間的縮短，其生物降解去除率減小，表明不同抗生素在相同水力停留時(shí)間下有著不同的動(dòng)力學(xué)和計(jì)量學(xué)限制。Gros等[61]和García-Galán等[74]基于偽一級(jí)動(dòng)力學(xué)模型，提出處理工藝需要滿足最小水力停留時(shí)間(t1/2)來保證足夠的時(shí)間進(jìn)行吸附和生物降解以達(dá)到去除效果。Kbiol值較高及Kd值較低的抗生素(即疏水性較差)更易受到水力停留時(shí)間的影響，而Kbiol值較低及Kd值較高的抗生素更易受到污泥齡的影響。

3.6氧化還原電位諸多文獻(xiàn)報(bào)道了抗生素在好氧硝化、缺氧反硝化以及厭氧條件下的去除效率，對(duì)于大多數(shù)抗生素來說好氧條件下其去除率較高。Suarez 等[75]對(duì)好氧硝化條件和缺氧反硝化條件下MBR對(duì)抗生素的去除效果進(jìn)行了比較，結(jié)果表明羅紅霉素、紅霉素在硝化條件下去除率分別為91%和89%左右，而在缺氧條件下其去除率分別僅為15%和20%左右。也有文獻(xiàn)報(bào)道在厭氧條件下某些抗生素去除效果較佳的情況，如Suarez 等[75]研究發(fā)現(xiàn)，好氧條件下磺胺甲惡唑去除率僅為22%左右，而Monsalvo等[76]和Wijekoon等[52]的研究結(jié)果顯示，磺胺甲惡唑在厭氧MBR中幾乎被完全去除。Xue等[77]在研究中也發(fā)現(xiàn)甲氧芐氨嘧啶在厭氧池中幾乎被完全去除。分析原因可能是：①回流使厭氧池抗生素濃度下降；②污泥吸附造成的下降；③厭氧污泥自身具有較強(qiáng)的降解抗生素的能力。而紅霉素在污泥相的濃度在好氧池達(dá)到最低，這可能是由于好氧池下生物降解的作用。

4　MBR組合工藝

MBR對(duì)絕大多數(shù)抗生素具有較佳的去除效果，但出水中依然有相當(dāng)?shù)臍堄唷Ｒ虼嗽S多學(xué)者研究MBR組合工藝對(duì)抗生素的強(qiáng)化去除效果，如粉末活性炭-膜生物反應(yīng)器工藝(PAC-MBR)[43]、膜生物反應(yīng)器-臭氧工藝(MBR-O3)[43]、膜生物反應(yīng)器-紫外光/H2O2工藝(MBR-UV/H2O2)[78]、膜生物反應(yīng)器-反滲透/納濾工藝(MBR-RO/NF)[79]等。MBR及其組合工藝對(duì)抗生素的去除效果見表4。由表4可以看出，MBR組合工藝比單獨(dú)的MBR具有更佳的去除效果。此外，還有學(xué)者將酶催降解與MBR結(jié)合用于去除微量有機(jī)污染物[80]。

表4　MBR及其組合工藝對(duì)抗生素的去除效果

粉末活性炭-膜生物反應(yīng)器工藝主要利用活性炭的吸附能力以提高去除效果。Baumgarten等[43]在研究中將粉末活性炭(投加量<50 mg/L)加入到MBR反應(yīng)器，環(huán)丙沙星、恩諾沙星和莫西沙星的去除率分別從73%、56%、78%提高到96%左右。Serrano 等[83]研究發(fā)現(xiàn)，粉末活性炭的加入可使反應(yīng)器內(nèi)氨氧化菌增多，從而提高了生物降解抗生素的能力；MBR中加入1 g/L的粉末活性炭便幾乎可以完全去除紅霉素和羅紅霉素。活性炭加入初期能夠提高去除效果，但運(yùn)行一段時(shí)間后活性炭吸附能力喪失，去除效果就會(huì)下降；對(duì)于難降解的物質(zhì)，活性炭有限的吸附容量是限制其去除效果的重要因素[84]?；钚蕴康募尤胄枰ㄆ谠偕蚋鼡Q，會(huì)增大產(chǎn)泥量。反滲透/納濾膜的去除原理主要為分子截留[48,85]，靜電作用也發(fā)揮一定作用。大量研究表明反滲透/納濾膜有去除微量有機(jī)污染物的能力[86]，MBR與反滲透/納濾膜的互補(bǔ)結(jié)合能夠強(qiáng)化處理效果、拓寬工藝的適用范圍。Alturki等[81]研究發(fā)現(xiàn)，膜生物反應(yīng)器-反滲透/納濾工藝幾乎能夠完全去除磺胺甲惡唑，其中MBR反應(yīng)器對(duì)磺胺甲惡唑的去除率可達(dá)85%以上，其余部分主要為反滲透/納濾膜發(fā)揮作用；Alturki等[81]認(rèn)為MBR能夠去除疏水性強(qiáng)和生物降解能力強(qiáng)的物質(zhì)，而對(duì)于親水性強(qiáng)的組分去除率則比較分散，這一部分隨后被反滲透/納濾膜有效去除。臭氧、紫外光、二氧化鈦光催化等高級(jí)氧化技術(shù)歷來被認(rèn)為是處理難降解有機(jī)物的有效方法，其可幫助去除MBR無法有效去除的抗生素。紫外光或二氧化鈦光催化氧化受到水質(zhì)條件(如濁度)和有機(jī)物的影響較為嚴(yán)重[87]，MBR較好的出水水質(zhì)能夠有效解決這一問題。然而，采用高級(jí)氧化技術(shù)強(qiáng)化去除抗生素的過程中，抗生素的毒性可能會(huì)增強(qiáng)[88]。需要指出的是，有關(guān)MBR與高級(jí)氧化聯(lián)用技術(shù)去除抗生素的應(yīng)用研究依然較少，副產(chǎn)物的產(chǎn)生以及毒性增強(qiáng)的問題依然存在，這也成為其應(yīng)用的一大限制。

5　結(jié)語

抗生素的大量使用所引發(fā)的人類健康和環(huán)境安全問題不容忽視。大量文獻(xiàn)報(bào)道了城市污水廠進(jìn)水、出水和污泥中抗生素的檢出，表明傳統(tǒng)活性污泥法不能有效去除抗生素。MBR對(duì)各類抗生素的去除效果較佳，其在城市污水廠中的應(yīng)用必將大大降低天然環(huán)境中抗生素的流入。MBR中抗生素主要通過生物降解和吸附這2種途徑去除，二者受到抗生素的分子結(jié)構(gòu)、親疏水性的制約。影響因素研究是提高M(jìn)BR對(duì)抗生素去除效果的前提和基礎(chǔ)，對(duì)于優(yōu)化MBR運(yùn)行條件具有重要的理論和現(xiàn)實(shí)意義。去除效果受到溫度、pH、污泥濃度、污泥齡、水力停留時(shí)間、氧化還原電位等多方面的影響，其中學(xué)者應(yīng)重點(diǎn)關(guān)注污泥濃度、污泥齡。此外，MBR組合工藝的開發(fā)和應(yīng)用能夠完善城市污水廠的處理工藝，從而進(jìn)一步增強(qiáng)抗生素的去除效果，這也值得學(xué)者進(jìn)行更深入地研究。

目前，學(xué)者對(duì)MBR去除抗生素的去除機(jī)理、影響因素研究仍然不夠全面、深入?？股胤N類繁多、性質(zhì)各異，學(xué)者應(yīng)著眼于更大種類范圍的抗生素，進(jìn)一步研究其在MBR的去除機(jī)理與效果。有關(guān)MBR中抗生素通過生物降解和吸附途徑去除的比例的相關(guān)報(bào)道依然較少，以吸附為主要途徑的抗生素依然會(huì)殘留在泥相中，從而造成污泥安全處置問題，因此有必要開展泥相中抗生素的行為和歸趨研究。

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Research Progress of Treatment of Antibiotic Wastewater by MBR

CHENG Xue-ting,YANG Dian-hai*

(College of Environmental Science and Engineering,Tongji University,Shanghai 200092)

Removal efficiency of antibiotics from wastewater by membrane bioreactor (MBR) was reviewed,and removal pathways (biodegradation and adsorption) were deeply analyzed.Meanwhile,the effects of influencing factors including temperature,pH,mixed liquor suspended solids (MLSS),sludge retention time (SRT),hydraulic retention time (HRT) and redox potential on the removal effect of antibiotics were emphatically discussed,and the strengthening removal effect of antibiotics by MBR combined processes was introduced,aiming to provide a reference for the design and optimization of operating condition of MBR processes for treating antibiotic wastewater.

Membrane bioreactor; Antibiotics; Removal effect; Removal ways; Influencing factors

國家自然科學(xué)基金(51408425)；國家水體污染控制與治理科技重大專項(xiàng)(2011ZX07316-002)。

程雪婷(1991- )，女，河北邯鄲人，碩士研究生，研究方向：水污染控制技術(shù)。*通訊作者，教授，博士生導(dǎo)師，從事水污染控制技術(shù)研究。

2016-05-20

X 703

A

0517-6611(2016)23-060-07