摘要:自行設(shè)計(jì)研發(fā)了以活性炭海綿作為膜基材的動(dòng)態(tài)膜生物反應(yīng)器,為污水處理的提標(biāo)排放及資源化利用提供了科學(xué)依據(jù)及實(shí)際參考價(jià)值。詳細(xì)考察了該反應(yīng)器對(duì)污染物的去除效果和運(yùn)行特性,通過(guò)和現(xiàn)有污水處理廠處理效果比較,探索活性炭海綿基材動(dòng)態(tài)膜生物反應(yīng)器用于城市污水提標(biāo)改造的可行性。結(jié)果表明,在水力停留時(shí)間8 h、污泥濃度8 000 mg/L的條件下,活性炭海綿動(dòng)態(tài)膜生物反應(yīng)器出水COD、NH3-N、TN和TP濃度分別≤35.0 mg/L、≤ 1.4 mg/L、≤10.2 mg/L和≤0.3 mg/L,出水達(dá)到《城鎮(zhèn)污水處理廠污染物排放標(biāo)準(zhǔn)》 GB189182002一級(jí)A標(biāo)準(zhǔn)?;钚蕴康奈叫阅芎秃>d的空間結(jié)構(gòu)特征協(xié)同作用強(qiáng)化了系統(tǒng)對(duì)污染物的去除效果,活性炭海綿動(dòng)態(tài)膜生物反應(yīng)器可完全取代現(xiàn)有污水廠深度處理工藝應(yīng)用于提標(biāo)改造。曝氣反沖洗可有效減緩出水通量下降,使系統(tǒng)出水通量穩(wěn)定在30 L/(m2·h)左右。
關(guān)鍵詞:活性炭海綿;動(dòng)態(tài)膜生物反應(yīng)器;污水處理;提標(biāo)改造
中圖分類號(hào):X 703.1;Q 503
文獻(xiàn)標(biāo)志碼:A
文章編號(hào):16744764(2014)02008905
Abstract:Dynamic membrane bioreactor (DMBR) based on activated carbon sponge materials was studied and developed independently. The pollutant removal efficiency and operational characteristics were investigated in detail, and the feasibility of DMBR application in transformation of real wastewater treatment plant (WWTP) was discussed by comparing the effluents. Results showed that the concentrations of COD, NH3N, TN and TP in effluents were below 35.0 mg/L, 1.4 mg/L, 10.2 mg/L and 0.3 mg/L, respectively, with the HRT of 8 h and MLSS of 8 000 mg/L. The ultimate effluent was qualified to standard A of “Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant” (GB 189182002). Adsorption of activated carbon and the spatial structure of sponge synergistically strengthen the pollutant removal. DMBR can be used in upgrading and transformation of WWTP by replacing the existing advanced treatment process. The flux of the DMBR was recovered by intensified aeration backwashing and maintained steadily at the level of 30 L/(m2·h).
Key words:Activated carbon sponge; Dynamic membrane bioreactor; Wastewater treatment; Upgrading and reconstruction
膜生物反應(yīng)器(Membrane bioreactor, MBR)因其出水水質(zhì)好、剩余污泥少、占地面積省在污水深度處理及提標(biāo)改造中日益得到廣泛關(guān)注和推廣[17],但膜材料價(jià)格和膜污染仍然是限制該技術(shù)大范圍應(yīng)用的瓶頸[810]。為解決傳統(tǒng)MBR的不足,動(dòng)態(tài)膜生物反應(yīng)器(Dynamic membrane bioreactor, DMBR)應(yīng)運(yùn)而生。DMBR是建立在傳統(tǒng)MBR基礎(chǔ)之上的新型生物反應(yīng)器,以無(wú)紡布、篩網(wǎng)等粗孔材料為膜基材,通過(guò)活性污泥過(guò)濾過(guò)程中形成的生物動(dòng)態(tài)膜實(shí)現(xiàn)近似于微濾膜的過(guò)濾效果,該技術(shù)具有基建及運(yùn)行費(fèi)用低、膜污染易控制等優(yōu)點(diǎn)[1112]。Seo等[13]、Hong[14]等研究發(fā)現(xiàn),DMBR在處理效果和懸浮物截留均表現(xiàn)出很好的效果。武小鷹等[15]認(rèn)為DMBR的工作壓力更小,膜材料具有再生性,通過(guò)水力沖洗可使膜通量恢復(fù)90%以上。
膜基材是DMBR的重要組成部分,會(huì)直接影響系統(tǒng)運(yùn)行特性和污染物去除效果。國(guó)內(nèi)外學(xué)者分別對(duì)篩網(wǎng)[1620]、無(wú)紡布[2123] 、織物[24] 、陶瓷[25]等作為膜基材進(jìn)行了廣泛的研究。本課題組前期分別考察了以聚酯無(wú)紡布、聚丙烯無(wú)紡布、聚酯篩網(wǎng)、聚酰胺篩網(wǎng)、海綿等作為膜基材,發(fā)現(xiàn)所構(gòu)成的DMBR對(duì)有機(jī)物和NH3-N均有較好的去除效果[2627]。
為了進(jìn)一步改善出水水質(zhì),結(jié)合既往研究成果,將活性炭海綿作為DMBR的膜基材?;钚蕴亢>d作為DMBR的膜基材,可將活性炭的吸附性能和海綿的過(guò)濾性能有機(jī)結(jié)合?;钚蕴亢>d是采用高分子粘結(jié)材料將優(yōu)質(zhì)、吸附性能較強(qiáng)粉狀催化活性炭附載于聚氨酯發(fā)泡載體上制成的過(guò)濾材料,其含炭量在30%~50%,具有良好的吸附性能;同時(shí),活性炭海綿具有海綿的一些特性,如較高的孔隙率、良好的過(guò)濾性能等,使得抗膜污染能力得到增強(qiáng)。主要考察以活性炭海綿作為膜基材的DMBR的處理效果和運(yùn)行特性,并將其處理效果和現(xiàn)有污水處理廠深度處理出水對(duì)比,探索該DMBR應(yīng)用于實(shí)際污水處理廠提標(biāo)改造的可行性。
1試驗(yàn)裝置與方法
1.1試驗(yàn)裝置
中試裝置位于江蘇常州某城市污水處理廠,中試處理規(guī)模50 t/d,停留時(shí)間8 h,進(jìn)水為該廠缺氧池出水,中試裝置通過(guò)回轉(zhuǎn)式鼓風(fēng)機(jī)提供氧氣,曝氣系統(tǒng)采用穿孔布?xì)猓瑲馑瓤刂圃?0∶1。接種污泥取自污水廠好氧池,穩(wěn)定運(yùn)行過(guò)程中控制污泥濃度在8 000 mg/L左右。出水采用重力出流,水頭壓差約1 m。
實(shí)驗(yàn)采用80塊面積和構(gòu)造相同的平板膜組件,每塊膜組件尺寸為1.0 m×0.5 m,總有效過(guò)水面積約70 m2。膜材料采用活性炭海綿,孔徑約為500 μm,厚1 cm;膜組件的排列方式為橫向、縱向各2排,每排單獨(dú)出水。
1.2原水水質(zhì)
實(shí)驗(yàn)原水為污水處理廠缺氧池出水,其水質(zhì)條件見(jiàn)表1。
1.3分析項(xiàng)目與方法
定期分別對(duì)DMBR進(jìn)出水、膜池上清液、污水廠二沉池出水、轉(zhuǎn)盤濾池出水進(jìn)行采樣分析。測(cè)定項(xiàng)目包括pH值、溫度、濁度、MLSS、COD、NH3-N、NO-3-N、NO-2N、TN、TP等,均采用中國(guó)標(biāo)準(zhǔn)方法[28]。
2結(jié)果與討論
2.1污染物去除效果
2.1.1COD去除效果圖2為中試裝置對(duì)COD的去除效果。由圖可知,進(jìn)水COD在60.0~141.0 mg/L變化時(shí),出水COD濃度穩(wěn)定在35.0 mg/L以下,對(duì)應(yīng)平均去除率為73.2%。由圖還可發(fā)現(xiàn),膜池上清液COD濃度高于出水,基本穩(wěn)定在22.0~58.0 mg/L。經(jīng)計(jì)算,動(dòng)態(tài)膜組件對(duì)COD去除的平均貢獻(xiàn)率約為11.3%(出水去除率與上清液去除率之差值)。COD去除率較既往研究略低。分析認(rèn)為,主要是由原水水質(zhì)濃度波動(dòng)較大和進(jìn)水含有部分工業(yè)廢水兩方面原因所致。
3結(jié)論
1)以活性炭海綿為膜基材的DMBR將活性炭的吸附性能和海綿的空間結(jié)構(gòu)特征有機(jī)結(jié)合,取得了較好的污染物去除效果,系統(tǒng)出水COD、NH3-N、TN和TP濃度分別≤35.0 mg/L、≤1.4 mg/L、≤10.2 mg/L和≤0.3 mg/L,出水達(dá)到GB18918—2002(一級(jí)A)標(biāo)準(zhǔn);對(duì)應(yīng)平均去除率分別為73.2%、91.3%、50.3%和60.7%。其中,膜基材及其表面附著的微生物對(duì)COD、TN和TP等污染物具有較大去除貢獻(xiàn),平均貢獻(xiàn)率分別為11.3%、11.1%和10.7%。
2)與現(xiàn)有污水處理廠處理效果比較,活性炭海綿DMBR對(duì)COD和TN具有一定的去除優(yōu)勢(shì);就NH3-N和TP而言,DMBR和污水處理廠均取得了較好的去除效果?;钚蕴亢>dDMBR對(duì)污染物的去除效果優(yōu)于污水處理廠二沉池出水,可完全取代現(xiàn)有污水廠深度處理工藝。
3)活性炭海綿DMBR運(yùn)行一個(gè)月左右,其膜通量由啟動(dòng)初期的48 L/(m2·h)下降至20 L/(m2·h),此后通過(guò)加大曝氣反沖洗使通量得到一定恢復(fù),并最終穩(wěn)定在30 L/(m2·h)左右。
參考文獻(xiàn):
[1]劉銳,黃霞,劉若鵬,等.膜生物反應(yīng)器和傳統(tǒng)活性污泥工藝的比較[J].環(huán)境科學(xué),2001,22(3):2024.
[2]Guoa W S,Vigneswarana S. The role of a membrane performance enhancer in a membrane bioreactor: a comparison with other submerged membrane hybrid systems [J]. Desalination, 2008, 231(1/2/3): 305313.
[3]Liu Z Q,Zhang X M. A pilot study on domestic wastewater treatment with A/OMBR systems [C]//The 4th International Conference on Bioinformatics and Biomedical Engineering(iCBBE 2010): Chengdu,June 1820,2010.
[4]董良飛,薛濤,郗曉敏.A2/O/A/MBR中試裝置的除污效能研究[J].中國(guó)給水排水,2009,25(23):611.
[5]張傳政,宋爽.平板膜生物反應(yīng)器用于生活污水處理工程改造[J].中國(guó)給水排水,2010,26(20):100103.
[6]周慧,徐得潛,馬常仁,等.A/O膜生物反應(yīng)器工藝運(yùn)用于城市污水處理廠出水提標(biāo)改造的研究[J].環(huán)境污染與防治,2011,33(12):1322.
[7]Lesjean B,Huisjeslow E H. Survey of the European MBR market: trends and perspectives [J]. Desalination, 2008, 231(13): 7181.
[8]Khan M T, Takizawa S, Lewandowski Z, et al. Membrane fouling due to dynamic particle size changes in the aerated hybrid PAC MF system [J]. Journal of Membrane science, 2011, 366(1): 1724.
[9]Mishima I,Nakajima J. Control of membrane fouling in membrane bioreactor process by coagulant addition [J]. Water Science and Technology, 2009, 59(6): 12551262.
[10]Tian Y, Chen I, Zhang S, et al.Correlating membrane fouling with sludge characteristics in membrane bioreactors: an especial interest in EPS and sludge morphology analysis [J]. Bioresource Technology, 2011, 102(19): 88208827.
[11]范彬,黃霞,文湘華,等.動(dòng)態(tài)膜生物反應(yīng)器對(duì)城市污水的處理[J].環(huán)境科學(xué),2002,23(6):5156.
[12]Wu Y, Huang X, Wen X, et al. Fuction of dynamic membrane in selfforming dynamic membrane coupled with bioreactor [J].Water Science and Technology,2005, 51(6/7): 107114.
[13]Seo G T, Moon B H. Filtration characteristics of immersed coarse pore filters in an activated sludge system for domestic wastewater reclamation [J].Water Science and Technology, 2007,55(1/2):5158.
[14]Hong S K, IN S S. Fullscale study on dynamic state membrane bioreactor with modified intermittent aeration [J]. Desalination, 2007, 202(1/2/3): 99105.
[15]武小鷹,鄭平,徐紅亮.動(dòng)態(tài)膜技術(shù)及其在環(huán)境工程中的應(yīng)用[J].膜科學(xué)與技術(shù),2003,23(6): 4953.
[16]Chu L, Li S. Filtration capability and operational characteristics of dynamic membrane bioreactor for municipal wastewater treatment [J]. Separation and Purification Technology, 2006, 51(2): 173179.
[17]Satyawali Y,Balakrishnan M. Treatment of distillery effluent in a membrane bioreactor(MBR)equipped with mesh filter [J]. Separation and Purification Technology, 2008, 63(2): 278286.
[18]Jeison D, Diaz I,Lier J B. Anaerobic membrane bioreactors: are membranes really necessary [J]. Electronic Journal of Biotechnology, 2008, 11(4):17.
[19]Walker M, Banks C J, Heaven S. Development of a coarse membrane bioreactor for twostage anaerobic digestion of biodegradable municipal solid waste [J]. Water Science and Technology, 2009, 259(4): 729735.
[20]Zhang X, Wang Z, Wu Z, et al. Formation of dynamic membrane in an anaerobic membrane bioreactor for municipal wastewater treatment [J]. Chemical Engineering Science, 2010, 165(1): 175183.
[21]Seo G T, Moon B H, Park Y M K, et al. Filtration characteristics of immersed coarse pore filters in an activated sludge system for domestic wastewater reclamation [J]. Water Science and Technology, 2007, 55(1/2): 5158.
[22]An Y,Wang Z,Wu Z, et al. Characterization of membrane foulants in an anaerobic nonwoven fabric membrane bioreactor for municipal wastewater treatment [J]. Chemical Engineering Science, 2009, 155(3): 709715.
[23]Ren X,Shon H K, Jang N, et al.Novel membrane bioreactor(MBR)coupled with a nonwoven fabric filter for household wastewater treatment [J]. Water Research, 2010, 44(3): 751760.
[24]Liu H,Yang C, Pu W, et al. Formation mechanism and structure of dynamic membrane in the dynamic membrane bioreactor [J]. Chemical Engineering Science, 2009,148(2/3): 12901295.
[25]Li F, Chen J, Deng C. The kinetics of crossflow dynamic membrane bioreactor [J].Water SA, 2006,32(2): 199203.
[26]傅大放,林玉嬌.幾種不同基材動(dòng)態(tài)膜生物反應(yīng)器污泥層性質(zhì)分析[J].化工學(xué)報(bào),2008,59(10):25962600.
[27]李澄.海綿基材動(dòng)態(tài)膜生物反應(yīng)器及其對(duì)二氯酚降解性能[D].南京:東南大學(xué),2011.
[28]魏復(fù)盛.水和廢水監(jiān)測(cè)分析方法[M].4版.北京:中國(guó)環(huán)境科學(xué)出版社,2002.
(編輯呂建斌)