非膜技術處理生物穩定滲濾液的效果及成本

劉婉瑩,呂 凡,3,仇俊杰,黃玉龍,章 驊,3,邵立明,3,何品晶,3*

非膜技術處理生物穩定滲濾液的效果及成本

劉婉瑩1,2,呂 凡1,2,3,仇俊杰1,2,黃玉龍1,2,章 驊1,2,3,邵立明1,2,3,何品晶1,2,3*

(1.同濟大學固體廢物處理與資源化研究所,上海 200092；2.同濟大學上海污染控制與生態安全研究院,上海 200092；3.同濟大學上海多源固廢協同處理和能源化工程技術研究中心,上海 200092)

以經厭氧-好氧處理的生物穩定滲濾液為研究對象,分別比較了其經活性炭吸附、混凝、芬頓和電解處理后的溶解性有機碳(DOC)、COD、溶解性氮(DN)和比紫外吸光度(SUV254)的變化,及去除單位COD的成本變化.研究發現,活性炭吸附、芬頓和混凝對生物穩定滲濾液的COD、DOC和DN的去除效率均隨藥劑投加量的增加而提高;包含化學氧化作用的芬頓和電解技術對芳構化有機物的去除效果更好,使得SUV254減少了60%～70%,且電流密度越大,去除效率越高;活性炭吸附去除單位毫克COD的價格最高,芬頓最低;對生物穩定滲濾液而言,活性炭投加量為5g/L、芬頓試劑投加量為0.605g/L、混凝劑投加量為4.92mmol/L Fe時,性價比較高,具體還應根據原水濃度與參考標準進行選擇.

吸附；混凝；芬頓；電解；非膜技術；生物穩定滲濾液；經濟分析

生活垃圾衛生填埋場產生的滲濾液,含有大量以有機質[1]、氨氮[2-3]、重金屬[4-5]和無機鹽[6]為主的污染物[7],也是釋放動物激素[8-9]、抗生素[10-11]、塑化劑[12-13]和微塑料[14]等各類新興污染物的重要源頭.根據各地降雨量、垃圾含水量的不同,我國每噸垃圾能產生70～950L滲濾液[15].

生物處理因其技術可靠、簡易且經濟的特點而被廣泛應用于處理新鮮垃圾滲濾液.根據反應條件,可分為好氧和厭氧兩大類.厭氧和好氧處理的生物穩定滲濾液一般無法達到《污水排入城鎮下水道水質標準》(GB/T 31962-2015)[16]、《生活垃圾填埋場污染控制標準》(GB 16889-2008)[17]等,還需采用吸附[18-19]、混凝[20-21]、芬頓[21]、電解[22]等非膜技術,或微濾、超濾、納濾、反滲透等[23]膜技術進行深度處理.研究表明[24],升流式厭氧污泥床(UASB)或活性污泥法組合反滲透幾乎可去除滲濾液中所有的COD和氨氮.微量污染物上,研究發現納濾能去除地表水中90%的天然有機物(NOM),以及近100%的三鹵甲烷生成潛能(THMFP)[25].然而,與此同時,分子質量、分子大小(長和寬)、酸解離常數、親疏水性和擴散系數等[26]因素均會影響納濾和反滲透的截留率,膜污染[27]及濃縮液[28]仍是亟待解決的問題.

隨著水處理工藝的發展,吸附、混凝、芬頓和電解等非膜技術展現出良好潛力,這使其替代膜技術成為可能,也為深度處理技術的比選與組合提供了更多選擇.活性炭吸附能去除生物穩定滲濾液中38%～90%的COD[29],且相比于COD和溶解性有機碳(DOC),對紫外光淬滅物質的去除效果更好[30].研究發現,在利用混凝-臭氧工藝處理生物穩定滲濾液時,混凝可去除67%的COD和96%的色度[31].而芬頓不僅能去除廢水中難降解的溶解性有機物(DOM)[32],提高其可生化性[33],還能去除填埋場滲濾液中的鄰苯二甲酸酯和雙酚A等內分泌干擾素[12].電解則能夠高效去除廢水中的COD、色度和各類新興污染物[34].

考慮到不同非膜技術的優勢和弊端,如何平衡去除效果與經濟成本,以使其更好地替代膜技術,成為問題的關鍵.以往研究除了膜技術[35],多局限于對電解[36]、混凝或芬頓[37]等同類技術的比較,或對單線處理流程的經濟分析[38],缺乏對多類非膜技術以及復雜流程的比較研究.而對各類非膜技術去除效率與經濟成本的分析,不僅能為處理過程中污染物去除的潛力提供依據,也能為技術的選擇或組合提供參考.本文以經厭氧-好氧處理的生物穩定滲濾液為研究對象,分別比較了其經活性炭吸附、混凝、芬頓和電解處理后DOC、COD、溶解性氮(DN)和比紫外吸光度(SUV254)的變化,及去除單位COD的成本變化,并以《污水排入城鎮下水道水質標準》(GB/T 31962-2015)[16]等為判別標準,篩選出了較好的非膜技術,針對每種技術給出了建議的藥劑投加量及電流密度,以期為生物穩定滲濾液非膜技術的比選與組合提供依據.

1 材料與方法

1.1 實驗材料

生物穩定滲濾液來自5L/d處理規模的產甲烷同時反硝化反應器(SDM-AS)[39].該反應器已穩定運行180d以上,進水來自上海市某生活垃圾焚燒廠的儲坑滲濾液(垃圾分類前),其性質與新鮮滲濾液相似.反應器的處理出水即為典型的生物穩定滲濾液,水質如表1所示.

1.2 裝置與藥劑

活性炭吸附所用試劑為粉末活性炭(PAC),將顆粒活性炭研磨、過篩(75μm)[40],取篩下物.其比表面積經BET測試(ASAP2460, Micromeritics Instrument Corporation, USA)確定為1420m2/g.取100mL滲濾液-活性炭(粉末)或水-活性炭(粉末)混合液于150mL錐形瓶中,將錐形瓶置于恒溫搖床中以200r/min震蕩5h,此后靜置12h(恒溫25℃),采用0.45μm聚醚砜針式過濾器過濾.粉末活性炭的投加量為2～10g/L[41],投加梯度為:0.5,1,2,5,10,20g/L.

表1 生物穩定滲濾液的典型水質特征

注:-為文章中未列出.

混凝所用裝置為六聯攪拌器(MY3000-6D,梅宇,中國),所用混凝劑為氯化鐵溶液(FeCl3·6H2O, 250g/L).分別向燒杯中加入400mL生物穩定滲濾液和超純水作為實驗組和空白組.向生物穩定滲濾液中加入鹽酸(質量分數15%～20%)以調節其pH(4.0± 0.2),250r/min攪拌30min去除大部分碳酸鹽及碳酸氫鹽;向超純水中加入等量鹽酸,同樣以250r/min攪拌30min,作為空白.然后,依次向燒杯中加入混凝劑和氫氧化鈉(12mol/L),啟動混凝程序,采用0.45 μm聚醚砜針式過濾器過濾.混凝劑的投加梯度為:0.3,0.9,1.9,3.7,4.9,6.9,11.1,14.8,18.5mmol Fe/L.

利用同一個六聯攪拌器(MY3000-6D,梅宇,中國)進行芬頓實驗,芬頓試劑包括硫酸亞鐵(FeSO4·7H2O, 250g/L)和過氧化氫(質量分數30%).向生物穩定滲濾液中加入適量硫酸(質量分數30%～40%)以調節pH(4.0±0.2),減少碳酸鹽和碳酸氫鹽對羥基自由基的捕捉效應[21];向等量超純水中加入等量硫酸,作為空白.通過預實驗確定硫酸亞鐵與過氧化氫的較優比例為2.5(數據未列出),在此比例下,分2次投加芬頓試劑,并改變其投加量如表2所示.

表2 芬頓試劑投加量

電解所用陽極和陰極分別為Ti/PbO2和不銹鋼,極板間距為10mm,陰極板在兩側,陽極板在中間,電流密度分別為2.5,5,10A/dm2,處理的生物穩定滲濾液體積為2.4L.首先,向生物穩定滲濾液中加入適量硝酸(質量分數15%～20%),將其pH調節至(4.0±0.2),快速攪拌,以去除大部分碳酸根離子和碳酸氫根離子;然后,定時取樣,并采用0.45μm聚醚砜針式過濾器過濾.由于鹽酸和硫酸均會產生相關自由基[46],本實驗最終采用硝酸調節樣品pH值.所有實驗均設置3組平行.

1.3 分析方法

DOC和DN的測試由總有機碳分析儀(TOC- VCPH,島津,日本)和總氮分析儀(TNM-l,島津,日本)完成,因生物穩定滲濾液及其處理后出水均經0.45μm聚醚砜濾膜過濾,故測試所得總有機碳(TOC)及總氮(TN)即為DOC和DN;COD的測試由分光光度計(DRB200,哈希,美國)完成;氯離子濃度由瓶口滴定器(Titrette 50mL,普蘭德,德國)測定;SUV254等于紫外吸光度(ultraviolet absorbance at 254nm,UV254)比DOC,其值代表了生物穩定滲濾液及其處理后出水的芳構化程度[47],UV254的測試采用紫外分光光度計(UV-1800,島津,日本).

1.4 數據處理

本文中各類非膜技術對污染物的去除率公式如下式(1);去除污染物的成本計算如下式(2),單位為元/mg COD.

2 結果與分析

2.1 活性炭吸附

如圖1所示,粉末活性炭對DOC、COD和DN的吸附去除率均隨投加量增加而提高,且其對DOC的去除率最高.就DOC而言,當粉末活性炭的投加量為5g/L時,去除率接近80%;其后,隨著粉末活性炭投加量增加,去除率的增加明顯趨緩;當投加量為20g/L時,去除率最高達89.1%.因經歷了好氧硝化過程,生物穩定滲濾液中的氨氮濃度較低,亞硝酸鹽、硝酸鹽和有機氮構成了DN的主要部分,粉末活性炭對此部分氮去除率最高僅為11.5%(投加量20g/L).

粉末活性炭不能降解污染物,而主要通過空間位阻、范德華力和親疏水性去除污染物[48],其吸附容量隨分子尺寸的減少而增加[49].根據不同活性炭投加量下DOC和COD的濃度,可由吸附容量(表3),計算得到DOC和COD的Fruendlich吸附等溫式.DOC的吸附等溫式中,e, DOC為本文獲得的PAC對DOC的吸附容量(見表3),mg DOC/g PAC;DOC為與吸附比表面積、溫度有關的系數,本文經計算為0.1052;DOC為與溫度有關的常數,本文經計算為0.6567;DOC為吸附平衡時DOC濃度,mg/L.

COD的吸附等溫式中,e, COD為本文研究獲得的PAC對COD的吸附容量(表3),mg COD/g PAC;COD為與吸附比表面積、溫度有關的系數,本文經計算為9.616×10-13;COD為與溫度有關的常數,本文經計算為0.1808;COD為吸附平衡時COD濃度,mg/L.

圖1 不同粉末活性炭投加量下的污染物去除效果

表3 不同粉末活性炭投加量下的DOC和COD吸附容量

注:e,DOC為本文獲得的PAC對DOC的吸附容量,mg DOC/g PAC;e,COD為本文獲得的PAC對COD的吸附容量,mg COD/g PAC.

2.2 混凝

因鐵鹽對于天然有機物的去除效果優于鋁鹽[50],本實驗采用三氯化鐵作為混凝劑.由圖2可知,隨著混凝劑投加量的增加,DOC和COD的去除率先快速提高,后逐漸變緩.當FeCl3的投加量大于14.77mmol/L時,DOC的去除率從72.4%下降至62.4%,COD的去除率從62.3%下降至61.6%,這可能與混凝機理的變化有關.此外,DN的去除率變化不明顯,在混凝劑投加量最大時(FeCl3=18.46mmol/ L),DN去除率仍僅為6.2%.

圖2 不同混凝劑投加量下污染物去除效果

2.3 芬頓

芬頓包括氧化和混凝2個過程,氧化過程中,有機物被部分降解;混凝過程中,有機物從水相轉移至鐵泥中.由圖3可知,隨著投加量增加,DOC、DN和COD的去除率逐漸提高.其中,DOC的去除率從58.7%提高至81.0%,增幅與混凝及活性炭吸附相比較小.COD的去除率從42.9%提高至58.0%,范圍與多數文獻一致[21,29,51],變化幅度也較小,這可能與過氧化氫及硫酸亞鐵的比例固定有關[21,52];此外,當2種藥劑的比例不同時,氧化和混凝對COD去除的貢獻不相同[53],對有機物的處理效果也具有選擇性[54].DN的去除率從4.8%提高至11%.僅0.605g/L的投加量即可去除58.7%的DOC和42.9%的COD;且芬頓與混凝及活性炭吸附類似,對DN的去除率較低.

圖3 不同芬頓試劑投加量下的污染物去除效果

2.4 電解

主要考察電流密度對電解效果的影響.采用恒電流模式,由于電解過程中生物穩定滲濾液的體積變化較小,近似認為極水比(電極面積與處理水量之比)不變.由圖4可知,隨著電流密度增大,電解對COD和DOC的去除率明顯提高.180min后,電流密度分別為2.5,5,10A/dm2的電解對COD和DOC的去除率分別達到79.8%、94.7%、92.5%和23.0%、37.5%、47.4%.電解結束時,COD和DOC的濃度分別為151,41,59mg/L和130,116,91mg/L.

圖4 不同電流密度下電解處理污染物的去除效果

與活性炭吸附及混凝不同,電解可以降解有機物,其作用分為完全礦化和部分氧化[46].完全礦化時,有機物可被徹底降解為CO2;部分氧化時,有機物的氧化態變高,但仍留存于樣品中[46,55].如圖4(c)和(d)所示,DOC的去除率低于50%,表明電解只完全礦化了不到50%的有機物;而COD的去除率超過90%,表明幾乎所有的有機物都被部分氧化成小分子,但在后續階段,只有一部分被完全礦化成CO2.

由于生物穩定滲濾液的氨氮濃度較低(2～ 21mg/L),而電解對氮的去除主要體現在氨氮上[45],本文不討論電解對氮的去除效果.因此,為避免引入氯離子產生氯的自由基,或引入硫酸根離子產生過硫酸基[46],實驗采用稀硝酸調節溶液pH值,以阻止碳酸鹽、碳酸氫鹽捕獲羥基自由基[21].電解體系引入了硝酸根離子,貢獻了DN.

3 討論

3.1 不同深度處理技術出水的SUV254

其中電解2.5A/dm2、電解5A/dm2和電解10A/dm2分別表示電流密度為2.5,5,10A/dm2的處理效果.對于活性炭吸附和混凝,生物穩定滲濾液的SUV254分別從3.79L/(mg×m)下降至2.02,2.49L/ (mg×m),而后有所上升;這表明出水中芳構化有機物的比例先下降,其后隨著DOC下降有所上升[47].芬頓處理后,生物穩定滲濾液的SUV254從3.79L/ (mg×m)下降至0.59L/(mg×m),表明親水性小分子有機物的比例增加,這與芬頓的氧化作用相關[56].

圖5 PAC、混凝、Fenton和電解處理出水的SUV254

經3種(2.5,5和10A/dm2)電流密度電解后,與芬頓處理后的出水相似, 3種電流密度下,出水SUV254均從2.5L/(mg×m)左右快速下降至0.5L/(mg×m),再緩慢上升至0.75～1.0L/(mg×m).電流密度越大,SUV254下降至最低值所需的時間越短,即氧化速率越快(圖6).

上述結果表明,均存在氧化反應的芬頓和電解,出水SUV254的下降幅度較大,為60%～70%;只存在相際遷移的活性炭吸附和混凝,出水SUV254的下降幅度較小,為40%～50%.

3.2 不同技術的最佳去除率及成本分析

根據不同滲濾液處理設施的規模與工藝,考慮到設備折舊、人工及污泥處理等費用的復雜性,本文主要討論藥劑及部分電耗成本的直接運行成本;并根據各種藥劑的市場價格及電費標準.由圖7比較可得,活性炭吸附去除單位毫克COD的價格最高,且與10A/m2的電解數量級相當,均比其他技術高出一個數量級.由于藥劑選擇等原因,芬頓去除單位毫克COD的價格比混凝更低.此外,對于活性炭吸附、芬頓和混凝而言,去除單位COD的價格與藥劑投加量基本呈正相關;而對于2.5,5和10A/m2的電解而言,去除單位COD的價格與電解時間呈凸函數關系.

圖7(a)中,當活性炭投加量分別為2,5,10g/L時,DOC和COD的去除率分別為65.4%、79.5%、85.8%和44.6%、57.7%、49.2%,DOC和COD的濃度分別為59,35,24mg/L,377,288,345mg/L,價格分別為3.1×10-5,5.9×10-5和1.4×10-4元/mg COD;其中,DOC的去除率先增加了14.1%、后增速放緩,COD的去除率先增加后降低,COD的濃度在活性炭投加量為5g/L時低于《污水排入城鎮下水道水質標準》(GB/T 31962-2015)C級標準300mg/L[16],去除單位毫克COD的價格則先增加了2.8×10-5元、后增速提高.上述結果表明,對于生物穩定滲濾液,活性炭投加量為5g/L時的性價比最高,此時DOC和COD的去除率分別接近80%和60%.

圖7(b)中,當芬頓試劑的投加量分別為0.605,4.086g/L時,DOC和COD的去除率分別為58.7%、79.4%和42.9%、60.4%,DOC和COD的濃度分別為70,35mg/L和383,265mg/L,其中,COD的濃度分別低于《污水排入城鎮下水道水質標準》(GB/T 31962-2015)A、B級和C級標準[16],去除單位毫克COD的價格分別為1.8×10-6和1.1×10-5元/mg COD,比臭氧協同雙氧水氧化滲濾液的成本更低[57].而隨著芬頓試劑投加量的增加,去除單位毫克COD的價格直線上升,但與其他技術相比增幅較小;如前所述,DOC、COD和DN去除率的增幅較小,但前兩者的去除率仍分別大于58%和40%.由此可見,芬頓具有較大的價格優勢,可推廣于實際應用,但同時也應考慮處理流程的成本及操作難度.

如圖7(c),當混凝劑的投加量分別為1.85,3.69, 4.92,6.90mmol/L Fe時,DOC和COD的去除率分別為39.9%、44.5%、57.6%、66.7%和62.4%、58.3%、62.8%、62.5%,DOC和COD的濃度分別為102,94, 72,57mg/L和504,559,498,503mg/L,價格分別為2.910-6,6.1×10-6,7.6×10-6和1.1×10-5元/mg COD.其中,DOC的去除率在混凝劑的投加量分別為3.69和4.92mmol/L Fe之間時變化最大,COD的去除率維持在60%左右,COD的濃度在混凝劑投加量為4.92mmol/L Fe時低于《污水排入城鎮下水道水質標準》(GB/T 31962-2015)A、B級標準500mg/L[16],去除單位毫克COD的價格基本呈直線變化.由此可見,對于生物穩定滲濾液,混凝劑投加量為4.92mmol/L Fe時性價比最高,具體情況還應視原水濃度與達標要求而定.

在圖7(d)、(e)和(f)中,電解技術去除單位毫克COD的價格均在15min時增速變緩,這可能與作用自由基的變化有關;而分別在120,90,90min時增速變快,這與DOC去除率的變化趨勢相反.根據焦耳定律,恒電流電解時,消耗的電能與電阻和時間呈正相關,由此可見,去除的DOC影響了電解體系的電阻,這可能與滲濾液中的腐殖酸相關.此外,由于凸函數的特性,與芬頓和混凝相比,電解較難在低于1.0×10-5元/mg COD時獲得較好的去除效果.

圖7 不同技術去除單位毫克COD的價格隨藥劑量或電解時間的變化

4 結論

4.1 活性炭吸附、芬頓和混凝對生物穩定滲濾液的COD、DOC和DN的去除效率均隨藥劑投加量的增加而提高,對DN的去除率均低于15%.

4.2 SUV254的結果表明,包含化學氧化的芬頓和電解對芳構化有機物的去除效果更好,SUV254減少了60%～70%,且電流密度越大,去除效率越高;只存在相際遷移的活性炭吸附和混凝效果較差,SUV254減少了40%～50%.

4.3 在活性炭吸附、芬頓、混凝和電解(電流密度分別為2.5,5,10A/m2)4種技術中,活性炭吸附去除單位毫克COD的價格最高,芬頓最低.對生物穩定滲濾液而言,活性炭投加量為1g/136mgCOD、芬頓試劑投加量為1g/1372mgCOD、混凝劑投加量為1mmol Fe/169mgCOD時,性價比較高,具體還應根據原水濃度與參考標準進行選擇.

[1] He P J, Xue J F, Shao L M, et al. Dissolved organic matter (DOM) in recycled leachate of bioreactor landfill [J]. Water Research, 2006,40(7): 1465-1473.

[2] He P J, Shao L M, Guo H D, et al. Nitrogen removal from recycled landfill leachate by ex situ nitrification and in situ denitrification [J]. Waste Management, 2006,26(8):838-845.

[3] He P J, Shao L M, Guo H D, et al. Nitrogen removal from landfill leachate using single or combined processes [J]. Environmental Technology, 2005,26(4):373-380.

[4] He P J, Xiao Z, Shao L M, et al. In situ distributions and characteristics of heavy metals in full-scale landfill layers [J]. Journal of Hazardous Materials, 2006,137(3):1385-1394.

[5] Qu M, He P J, Shao L M, et al. Heavy metals mobility in full-scale bioreactor landfill: Initial stage [J]. Chemosphere, 2008,70(5):769- 777.

[6] Xia Y, He P J, Pu H X, et al. Inhibitory effect of high calcium concentration on municipal solid waste leachate treatment by the activated sludge process [J]. Waste Management & Research, 2017, 35(5):508-514.

[7] 何品晶.固體廢物處理與資源化技術 [M]. 北京:高等教育出版社, 2011: 399-401.

He P J. Treatment and recycling technologies of solid waste [M]. Beijing: Higher education press, 2011:399-401.

[8] Zhang H, Chang C H, Lu F, et al. Estrogenic activity of fractionate landfill leacahte [J]. Science of the Total Environment, 2009,407(2): 879-886.

[9] Zhang H, Chang C H, Lu F, et al. Fluorescent characteristics of estrogenic compounds in landfill leachate [J]. Environmental Technology, 2009,30(9):953-961.

[10] He P J, Huang J H, Yu Z F, et al. Antibiotic resistance contamination in four Italian municipal solid waste landfills sites spanning 34years [J]. Chemosphere, 2021,266:129182.

[11] Yu Z F, He P J, Shao L M, et al. Co-occurrence of mobile genetic elements and antibiotic resistance genes in municipal solid waste landfill leachates: A preliminary insight into the role of landfill age [J]. Water Research, 2016,106:583-592.

[12] He P J, Zheng Z, Zhang H, et al. PAEs and BPA removal in landfill leachate with Fenton process and its relationship with leachate DOM composition [J]. Science of the Total Environment, 2009,407(17): 4928-4933.

[13] Zheng Z, He P J, Shao L M, et al. Phthalic acid esters in dissolved fractions of landfill leachates [J]. Water Research, 2007,41(20):4696- 4702.

[14] He P J, Chen L Y, Shao L M, et al. Municipal solid waste (MSW) landfill: A source of microplastics?-Evidence of microplastics in landfill leachate [J]. Water Research, 2019,159:38-45.

[15] Yang N, Damgaard A, Kjeldsen P, et al. Quantification of regional leachate variance from municipal solid waste landfills in China [J]. Waste Management, 2015,46:362-372.

[16] GB/T31962-2015 污水排入城鎮下水道標準 [S].

[17] GB/T31962-2015 Wastewater quality standards for discharge to municipal sewers [S].

[18] GB 16889-2008 生活垃圾填埋場污染控制標準[S].

[19] GB 16889-2008 Standard for pollution control on the landfill site of municipal solid waste [S].

[20] Xiang Y J, Xu Z Y, Wei Y Y, et al. Carbon-based materials as adsorbent for antibiotics removal: mechanisms and influencing factors [J]. Journal of Environmental Management, 2019,237:128-138.

[21] Talebi A, Razali Y S, Ismail N, et al. Selective adsorption and recovery of volatile fatty acids from fermented landfill leachate by activated carbon process [J]. Science of the Total Environment, 2020,707: 134533.

[22] Tatsi A A, Zouboulis A I, Matis K A, et al. Coagulation– flocculation pretreatment of sanitary landfill leachates [J]. Chemosphere, 2003, 53(7):737-744.

[23] Deng Y, Englehardt J D. Treatment of landfill leachate by the Fenton process [J]. Water Research, 2006,40(20):3683-3694.

[24] Sarkka H, Bhatnagar A, Sillanpaa M. Recent developments of electro-oxidation in water treatment - a review [J]. Journal of Electroanalytical Chemistry, 2015,754:46-56.

[25] Zhang B L, Shan C, Hao Z N, et al. Transformation of dissolved organic matter during full-scale treatment of integrated chemical wastewater: molecular composition correlated with spectral indexes and acute toxicity [J]. Water Research, 2019,157:472-482.

[26] Kurniawan T A, Lo W H, Chan G Y S. Physico-chemical treatments for removal of recalcitrant contaminants from landfill leachate [J]. Journal of Hazardous Materials, 2006,129(1-3):80-100.

[27] De La Rubia A, Rodriguez M, Leon V M, et al. Removal of natural organic matter and THM formation potential by ultra- and nanofiltration of surface water [J]. Water Research, 2008,42(3):714- 722.

[28] Bellona C, Drewes J E, Xu P, et al. Factors affecting the rejection of organic solutes during NF/RO treatment - a literature review [J]. Water Research, 2004,38(12):2795-2809.

[29] Tang C Y, Chong t H, Fane A G. Colloidal interactions and fouling of NF and RO membranes: A review [J]. Advances in Colloid and Interface Science, 2011,164(1/2):126-143.

[30] Van Der Bruggen B, Lejon L, Vandecasteele C. Reuse, treatment, and discharge of the concentrate of pressure-driven membrane processes [J]. Environmental Science & Technology, 2003,37(17):3733-3738.

[31] Renou S, Givaudan J G, Poulain S, et al. Landfill leachate treatment: review and opportunity [J]. Journal of Hazardous Materials, 2008, 150(3): 468-493.

[32] Deng Y, Jung C I, Zhao R Z, et al. Adsorption of UV-quenching substances (UVQS) from landfill leachate with activated carbon [J]. Chemical Engineering Journal, 2018,350:739-746.

[33] Monje-Ramirez I, Orta De Velasquez M T. Removal and transformation of recalcitrant organic matter from stabilized saline landfill leachates by coagulation-ozonation coupling processes [J]. Water Research, 2004,38(9):2358-2366.

[34] Sun G X, Zhang Y, Gao Y X, et al. Removal of hard COD from biological effluent of coking wastewater using synchronized oxidation-adsorption technology: performance, mechanism, and full- scale application [J]. Water Research, 2020,173:115517.

[35] De Morais J L, Zamora P P. Use of advanced oxidation processes to improve the biodegradability of mature landfill leachates [J]. Journal of Hazardous Materials, 2005,123(1-3):181-186.

[36] Oturan N, Van Hullebusch E D, Zhang H, et al. Occurrence and Removal of Organic Micropollutants in Landfill Leachates Treated by Electrochemical Advanced Oxidation Processes [J]. Environmental Science & Technology, 2015,49(20):12187-12196.

[37] Ribera-Pi J, Badia-Fabregat M, Espi J, et al. Decreasing environmental impact of landfill leachate treatment by MBR, RO and EDR hybrid treatment [J]. Environmental Technology, 2020:1-15.

[38] Mandal P, Dubey B K, Gupta A K. Review on landfill leachate treatment by electrochemical oxidation: Drawbacks, challenges and future scope [J]. Waste Management, 2017,69:250-273.

[39] Amor C, De Torres-Socias E, Peres J A, et al. Mature landfill leachate treatment by coagulation/flocculation combined with Fenton and solar photo-Fenton processes [J]. Journal of Hazardous Materials, 2015,286: 261-268.

[40] Di Maria F, Sisani F. A life cycle assessment of conventional technologies for landfill leachate treatment [J]. Environmental Technology & Innovation, 2017,8:411-422.

[41] Qiu J J, Lu F, Zhang H, et al. Persistence of native and bio-derived molecules of dissolved organic matters during simultaneous denitrification and methanogenesis for fresh waste leachate [J]. Water Research, 2020,175:115705.

[42] Welander U, Henrysson T. Physical and chemical treatment of a nitrified leachate from a municipal landfill [J]. Environmental Technology, 1998,19(6):591-599.

[43] Foo K Y, Hameed B H. An overview of landfill leachate treatment via activated carbon adsorption process [J]. Journal of Hazardous Materials, 2009, 171(1-3):54-60.

[44] Zhao J S, Ouyang F, Yang Y X, et al. Degradation of recalcitrant organics in nanofiltration concentrate from biologically pretreated landfill leachate by ultraviolet-Fenton method [J]. Separation and Purification Technology, 2020,235:116076.

[45] Qiu J J, Lu F, Zhang H, et al. UPLC Orbitrap MS/MS-based fingerprints of dissolved organic matter in waste leachate driven by waste age [J]. Journal of Hazardous Materials, 2020,383:121205.

[46] Zheng Z, Zhang H, He P J, et al. Co-removal of phthalic acid esters with dissolved organic matter from landfill leachate by coagulation and flocculation process [J]. Chemosphere, 2009,75(2): 180-186.

[47] Fernandes A, Santos D, Pacheco M J, et al. Nitrogen and organic load removal from sanitary landfill leachates by anodic oxidation at Ti/Pt/PbO2, Ti/Pt/SnO2-Sb2O4and Si/BDD [J]. Applied Catalysis B: Environmental, 2014,148:288-294.

[48] Panizza M, Cerisola G. Direct and mediated anodic oxidation of organic pollutants [J]. Chemical Reviews, 2009,109(12):6541-6569.

[49] Weishaar J L, Aiken G R, Bergamaschi B A, et al. Evaluation of specific ultraviolet absorbance as an indicator of the chemical composition and reactivity of dissolved organic carbon [J]. Environmental Science & Technology, 2003,37(20):4702-4708.

[50] Phungsai P, Kurisu F, Kasuga I, et al. Changes in dissolved organic matter composition and disinfection byproduct precursors in advanced drinking water treatment processes [J]. Environmental Science & Technology, 2018,52 (6):3392-3401.

[51] Velten S, Knappe D R U, Traber J, et al. Characterization of natural organic matter adsorption in granular activated carbon adsorbers [J]. Water Research, 2011,45(13):3951-3959.

[52] Matilainen A, Vepsalainen M, Sillanpaa M. Natural organic matter removal by coagulation during drinking water treatment: a review [J]. Advances in Colloid and Interface Science, 2010,159(2):189-197.

[53] 王 杰,馬溪平,唐鳳德,等.微波催化氧化法預處理垃圾滲濾液的研究 [J]. 中國環境科學, 2011,31(7):1166-1170.

Wang J, Ma X P, Tang F D, et al. Study on pretreatment of landfill leachate by microwave catalytic oxidation [J]. China Environmental Science, 2011,31(7):1166-1170.

[54] Umar M, Aziz H A, Yusoff M S. Trends in the use of Fenton, electro-Fenton and photo-Fenton for the treatment of landfill leachate [J]. Waste Management, 2010,30(11):2113-2121.

[55] Deng Y. Physical and oxidative removal of organics during Fenton treatment of mature municipal landfill leachate [J]. Journal of Hazardous Materials, 2007,146(1/2):334-340.

[56] He P J, Liu W Y, Qiu J J, et al. Improvement criteria for different advanced technologies towards bio-stabilized leachate based on molecular subcategories of DOM [J]. Journal of Hazardous Materials, 2021,414: 125463.

[57] Moreira F C, Boaventura R A R, BRILLAS E, et al. Electrochemical advanced oxidation processes: A review on their application to synthetic and real wastewaters [J]. Applied Catalysis B: Environmental, 2017,202:217-261.

[58] 陳煒鳴,張愛平,李 民,等.O3/H2O2降解垃圾滲濾液濃縮液的氧化特性及光譜解析 [J]. 中國環境科學, 2017,37(6):2160-2172.

Chen W M, Zhang A P, Li M, et al. Oxidation characteristics and spectral analysis of concentrated leachate degraded by O3/H2O2[J]. China Environmental Science, 2017,37(6):2160-2172.

Cost-benefit analysis of different non-membrane based technologies for the treatment of bio-stabilized leachate.

LIU Wan-ying1,2, Lü Fan1,2,3, QIU Jun-jie1,2, HUANG Yü-long1,2, ZHANG Hua1,2,3, SHAO Li-ming1,2,3, HE Pin-jing1,2,3*

(1.Institute of Waste Treatment and Reclamation, Tongji University, Shanghai 200092, China；2.Shanghai Institute of Pollution Control and Ecological Security, Tongji University, Shanghai 200092, China；3.Shanghai Multi-source Solid Waste Collaborative Treatment and Energy Engineering Technology Research Center, Tongji University, Shanghai 200092, China)., 2022,42(2)：644～653

In this paper, four non-membrane based techniques, including activated carbon adsorption, coagulation, Fenton and electrolysis, were applied to treat the anaerobic-aerobic stabilized leachate. The respective water quality parameters, such as dissolved organic carbon (DOC), chemical oxygen demand (COD), dissolved nitrogen (DN) and specific ultraviolet absorbance at 254nm (SUV254), were determined for comparison. Cost change curve of removing unit COD was also depicted. When activated carbon adsorption, Fenton and coagulation were employed, the removal efficiencies of COD, DOC and DN increased with enhancing the dosages of agents. Fenton and electrolysis as chemical oxidation techniques shows superior performance on the removal of aromatized organics, resulting in 60%～70% reduction of SUV254. In addition, the removal efficiency linearly increased with the current density. For every unit of COD removal, the cost for applying activated carbon adsorption is highest among all the tested techniques while the expense of Fenton will be minimal. To make these techniques economical, it is recommended that 5g/L of activated carbon, 0.605g/L of Fenton reagent and 4.92mmol/L Fe of coagulant were used for each process. When applied in practical application, it is worth noting that the actual dosage need be optimized on basis of the properties of on-site leachate and the local discharge standards.

Adsorption；Coagulation；Fenton；Electrolysis；Non-membrane based technology；Bio-stabilized leachate；Cost-benefit analysis

X703.5

A

1000-6923(2022)02-0644-10

劉婉瑩(1997-),女,湖北潛江人,碩士,主要從事固體廢物處理與資源化利用的相關研究.發表論文3篇.

2021-07-12

國家重點研發計劃項目(2018YFD1100600);國家自然科學基金資助項目(22076145)

* 責任作者, 教授, solidwaste@tongji.edu.cn