不同C/N比和碳源種類條件下的SNAD生物膜脫氮性能

鄭照明,李 軍,楊京月,馬 靜,杜 佳

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不同C/N比和碳源種類條件下的SNAD生物膜脫氮性能

鄭照明,李 軍*,楊京月,馬 靜,杜 佳

(北京工業(yè)大學(xué)國家工程實(shí)驗(yàn)室,北京市污水脫氮除磷處理與過程控制工程技術(shù)研究中心,北京 100124)

通過批試實(shí)驗(yàn)研究了C/N比和碳源種類對SNAD生物膜厭氧氨氧化耦合反硝化脫氮性能的影響. SNAD生物膜反應(yīng)器以生活污水為進(jìn)水,以鮑爾環(huán)為生物膜載體,具有良好的SNAD脫氮性能.以乙酸鈉為碳源,研究了COD/NO2--N比對SNAD生物膜厭氧氨氧化耦合反硝化脫氮性能的影響.隨著COD/NO2--N比的增加,厭氧氨氧化亞硝態(tài)氮去除量占總亞硝態(tài)氮去除量的百分比逐漸減小. COD/NO2--N比分別為1、2、3、4和5實(shí)驗(yàn)組對應(yīng)的厭氧氨氧化亞硝態(tài)氮去除量占總亞硝態(tài)氮去除量的百分比分別為87.1%、52.2%、29.3%、23.7%和16.3%.當(dāng)COD/NO2--N比為0~2時(shí),厭氧氨氧化亞硝態(tài)氮去除量占總亞硝態(tài)氮去除量的百分比大于50%, SNAD生物膜可以實(shí)現(xiàn)良好的耦合脫氮.控制COD/NO2--N為5,研究了碳源種類對SNAD生物膜厭氧氨氧化耦合反硝化脫氮性能的影響.以甲酸鈉、乙酸鈉、丙酸鈉和葡萄糖為碳源實(shí)驗(yàn)組對應(yīng)的厭氧氨氧化亞硝態(tài)氮去除量占總亞硝態(tài)氮去除量的百分比分別為16.3%、37.1%、74.1%和76.8%.當(dāng)以丙酸鈉或葡萄糖為外加碳源并且COD/NO2--N=5時(shí), SNAD生物膜可以實(shí)現(xiàn)良好的耦合脫氮.

SNAD生物膜；碳源種類；碳氮比；脫氮性能

同步亞硝化、厭氧氨氧化和反硝化(SNAD)工藝是一種經(jīng)濟(jì)環(huán)保的脫氮工藝,在適宜的工況下,亞硝化菌、厭氧氨氧化菌和反硝化菌在一個(gè)反應(yīng)器中實(shí)現(xiàn)總氮和有機(jī)物的去除[1-2].關(guān)于SNAD工藝的研究多集中于高氨氮污水的處理,鮮有關(guān)于處理城市生活污水的報(bào)道[3-4].厭氧氨氧化菌在反應(yīng)器的自養(yǎng)脫氮中起著核心作用.當(dāng)反應(yīng)器中的有機(jī)物濃度較高時(shí),由于反硝化菌比厭氧氨氧化菌具有更強(qiáng)的亞硝態(tài)氮競爭能力,不利于厭氧氨氧化菌的生長.當(dāng)進(jìn)水C/N為2~4并且COD<400mg/L時(shí),厭氧氨氧化耦合反硝化反應(yīng)器可以取得良好的脫氮性能[5-6]. SNAD工藝適合處理C/N低于1.2并且COD<300mg/L的廢水[1,7].但近年來的研究表明通過控制間歇曝氣和高曝氣工況, SNAD工藝可以在較高有機(jī)物濃度和較高C/N條件下取得良好的脫氮性能[8-9].目前,有機(jī)物濃度和C/N比對SNAD污泥脫氮性能的影響都是在好氧的條件下進(jìn)行.但是在好氧條件下,異養(yǎng)菌會(huì)消耗大量的有機(jī)物,不能很好地反映不同C/N條件下SNAD污泥中厭氧氨氧化菌和反硝化菌的耦合脫氮性能.

在反硝化過程中,理論上每1mg NO3--N被還原為氮?dú)庑枰?.86mg COD.考慮到細(xì)菌的生長,實(shí)際上每1mg NO3--N被還原為氮?dú)庑枰?.5~4.5mg COD[10].當(dāng)水中的碳源不足以進(jìn)行完全反硝化時(shí),將揮發(fā)性脂肪酸應(yīng)用于反硝化脫氮有助于提高生物脫氮效率,解決碳源不足的技術(shù)難題[11].對于SNAD工藝,也可以考慮投加揮發(fā)性脂肪酸等有機(jī)物來調(diào)控反硝化過程,提高反應(yīng)器的總氮去除率.許多研究人員研究了甲醇、乙醇、葡萄糖和揮發(fā)性脂肪酸對微生物反硝化速率的影響[12-14].研究表明碳源代謝途徑越復(fù)雜,其消耗速率越低,污泥的反硝化速率越低[11,15].因此有必要研究碳源種類對SNAD污泥中厭氧氨氧化菌和反硝化菌耦合脫氮性能的影響.

采用處理生活污水的SNAD生物膜反應(yīng)器,通過批試實(shí)驗(yàn)在厭氧條件下評價(jià)C/N、碳源種類對SNAD污泥中厭氧氨氧化菌和反硝化菌耦合脫氮性能的影響.以期為SNAD工藝在城市污水處理中的工程應(yīng)用提供指導(dǎo).

1 材料和方法

1.1 SNAD生物膜反應(yīng)器

SNAD生物膜反應(yīng)器如圖1所示.反應(yīng)器為圓柱形結(jié)構(gòu),有效容積為89.5L(高徑比為2.07).反應(yīng)器采用SBR運(yùn)行方式,周期運(yùn)行完畢之后馬上進(jìn)行下一個(gè)周期,反應(yīng)器內(nèi)填充鮑爾環(huán)作為生物膜載體(K3載體, AnoxKaldnes,北京),鮑爾環(huán)堆積體積為34L,反應(yīng)器有效盛水容積為77.7L,排水比為81%.鮑爾環(huán)的直徑為25mm,分成多個(gè)小格,每個(gè)小格的直徑為4mm,鮑爾環(huán)表面生物膜厚度為1~2mm.反應(yīng)器底部設(shè)置曝氣盤,采用溫度控制箱在線監(jiān)測并控制反應(yīng)器內(nèi)水溫,反應(yīng)器側(cè)壁(距底部以上20cm處)安裝水力攪拌器,排水口設(shè)置在底部以上20cm處,排水口直徑為20mm.在反應(yīng)器穩(wěn)定運(yùn)行階段,曝氣量控制為500L/h,溫度控制為30℃.

1.2 SNAD生物膜反應(yīng)器運(yùn)行工況

反應(yīng)器進(jìn)水采用北京工業(yè)大學(xué)家屬區(qū)生活污水,主要水質(zhì)指標(biāo)如下: CODCr200~300mg/L; NH4+-N 60~80mg/L; NO2--N <1mg/L; NO3--N <1mg/L; TOC 50~ 60mg/L; TN 100~140mg/L; pH為7.5~8.0;堿度300~400mg/L.周期運(yùn)行工況為:進(jìn)水(5min),間歇曝氣循環(huán)(曝氣20min/混合20min),后曝氣(20min),沉淀(10min),排水(10min),靜置(1min).間歇曝氣循環(huán)次數(shù)為6次.在混合階段,曝氣停止,水力攪拌器啟動(dòng),使載體在反應(yīng)器內(nèi)處于流化狀態(tài),增加微生物和底物的接觸.曝氣階段反應(yīng)器內(nèi)的溶解氧濃度5.6mg/L,曝氣結(jié)束10min左右反應(yīng)器內(nèi)的溶解氧濃度降低為0mg/L.反應(yīng)器的脫氮性能和有機(jī)物去除性能良好,出水NH4+-N, NO3--N和總無機(jī)氮(TIN)濃度平均值分別為2,7,11mg/L, TIN去除率為80%~90%, TIN平均去除負(fù)荷為0.22kg TIN/(m3·d).出水COD濃度平均值為45mg/L,COD平均去除率為71%.

SNAD生物膜具有良好的脫氮性能.生物膜的厭氧氨氧化、反硝化和好氧亞硝態(tài)氮氧化活性分別為0.267kg TIN/(kg VSS·d)、0.211kg NO2--N/ (kg VSS·d)和0.053kg NO2--N/(kg VSS·d).

1.3 批試實(shí)驗(yàn)裝置及其運(yùn)行條件

批試實(shí)驗(yàn)采用1000mL燒杯,燒杯內(nèi)放置50個(gè)鮑爾環(huán),進(jìn)行3次平行重復(fù)實(shí)驗(yàn).鮑爾環(huán)取自穩(wěn)定運(yùn)行的SNAD生物膜反應(yīng)器,實(shí)驗(yàn)前將鮑爾環(huán)置于30℃自來水中洗去表面的殘留基質(zhì).采用模擬廢水,配水氮素組分為NH4Cl和NaNO2.采用鹽酸和氫氧化鈉調(diào)節(jié)pH值,初始pH值控制為7.0.

1.3.1 SNAD生物膜好氧亞硝態(tài)氮氧化,厭氧氨氧化和反硝化活性測定 SNAD生物膜的好氧亞硝態(tài)氮氧化,厭氧氨氧化和反硝化活性測定方法參照文獻(xiàn)[16].各脫氮活性測定時(shí)的配水組分參照文獻(xiàn)[17].

1.3.2 COD/NO2--N比實(shí)驗(yàn) 以乙酸鈉為碳源,考察COD/NO2--N比對SNAD生物膜厭氧氨氧化耦合反硝化脫氮性能的影響.初始NH4+-N和NO2--N濃度均為70mg/L,乙酸鈉按需添加,使批試裝置內(nèi)的COD/NO2--N比分別為0、1、2、3、4和5.

批試過程步驟: (1)配置泥水混合液; (2)啟動(dòng)恒溫磁力攪拌器,轉(zhuǎn)速為500r/min,通氮?dú)?0min(氮?dú)饧兌?9.999%); (3)停止通氮?dú)? 用保鮮膜密封燒杯口,將燒杯連同磁力攪拌器放入30℃的恒溫培養(yǎng)箱中.每隔一定時(shí)間取樣測定主要組分濃度.以氨氮或亞硝態(tài)氮濃度低于10mg/L的取樣時(shí)刻為計(jì)時(shí)終點(diǎn),污泥生物活性計(jì)算根據(jù)公式(1).

式中:濃度單位為mg/L;計(jì)時(shí)終點(diǎn)單位為min;揮發(fā)性物質(zhì)質(zhì)量單位為g.計(jì)時(shí)終點(diǎn)的確定:若在取樣的時(shí)間內(nèi),批試裝置內(nèi)的NH4+-N或NO2--N濃度低于10mg/L,則以NH4+-N或NO2--N濃度剛低于10mg/L的取樣時(shí)刻為計(jì)時(shí)終點(diǎn);若在取樣的時(shí)間內(nèi),批試裝置內(nèi)的NH4+-N或NO2--N濃度始終高于10mg/L,則以取樣結(jié)束的時(shí)刻為計(jì)時(shí)終點(diǎn).污泥活性單位為kg N/(kg VSS·d).

污泥濃度的確定:用牙簽刮落鮑爾環(huán)表面附著較為松散的生物膜,將殘留有生物膜的鮑爾環(huán)放于燒杯中,盛適量水,采用超聲設(shè)備處理,待鮑爾環(huán)表面的生物膜完全脫落,將超聲后的泥水混合液和前面的松散污泥混合用濾紙過濾,將截留污泥的濾紙經(jīng)烘箱和馬弗爐處理,烘干時(shí)間及溫度與常規(guī)污泥濃度測量條件相同,得到這50個(gè)鮑爾環(huán)的干物質(zhì)量和揮發(fā)性物質(zhì)質(zhì)量.

1.3.3 碳源種類實(shí)驗(yàn) 分別以甲酸鈉、乙酸鈉、丙酸鈉和葡萄糖為碳源,考察碳源種類對SNAD生物膜反硝化以及厭氧氨氧化耦合反硝化脫氮性能的影響.初始NO2--N濃度為70mg/L,控制COD/NO2--N為5.0.在反硝化實(shí)驗(yàn)以及厭氧氨氧化耦合反硝化實(shí)驗(yàn)中,初始NH4+-N濃度分別為0,70mg/L.批試過程步驟和污泥活性計(jì)算方法同1.3.2.

1.4 分析方法

NH4+-N:納氏試劑光度法;NO2--N:N-(1-萘基)-乙二胺分光光度法;NO3--N:麝香草酚分光光度法;DO、溫度:WTW/Multi 3420測定儀;堿度和CODCr:按中國國家環(huán)保局和美國環(huán)境總署發(fā)布的標(biāo)準(zhǔn)方法測定[18].采用vario TOC測定儀測定TN和TOC.取NH4+-N, NO2--N和NO3--N濃度之和為TIN濃度.

1.5 計(jì)算方法

考慮到NO2--N對COD測定的影響,COD的計(jì)算根據(jù)公式(2)[19].

式中:COD和NO2--N濃度單位為mg/L.

結(jié)合SNAD生物膜的厭氧氨氧化批試氮素降解特性,在SNAD生物膜厭氧氨氧化耦合反硝化脫氮的氮素平衡分析中:厭氧氨氧化亞硝態(tài)氮去除量=氨氮去除量×1.45;反硝化亞硝態(tài)氮去除量=總亞硝態(tài)氮去除量—厭氧氨氧化亞硝態(tài)氮去除量.

2 結(jié)果和討論

2.1 SNAD生物膜的厭氧氨氧化活性

圖2中,初始NH4+-N和NO2--N濃度都為70mg/L,隨著反應(yīng)的進(jìn)行, NH4+-N和NO2--N濃度逐漸降低,硝態(tài)氮濃度逐漸上升.△NO2--N/ △NH4+-N=1.45,△NO3--N/△NH4+-N=0.29,和Strous等的研究結(jié)果相近[20].生物膜的厭氧氨氧化活性為0.267kg TIN/(kg VSS·d).

2.2 COD/NO2--N比對SNAD生物膜厭氧氨氧化耦合反硝化脫氮性能的影響

由圖3、圖4可見,當(dāng)COD/NO2--N為0時(shí), SNAD生物膜主要進(jìn)行厭氧氨氧化,批試過程中NH4+-N和NO2--N濃度逐漸降低, NO3--N濃度逐漸增加,取樣結(jié)束時(shí)刻的NO3--N濃度為13.6mg/L.當(dāng)COD/NO2—N>0時(shí), SNAD生物膜可以同時(shí)進(jìn)行厭氧氨氧化和反硝化,批試過程中NH4+-N和NO2--N濃度逐漸降低, NO3--N濃度一直小于2mg/L. COD/NO2--N分別為0、1、2、3、4和5實(shí)驗(yàn)組對應(yīng)的氨氮去除速率分別為0.121,0.145, 0.101,0.079,0.062,0.040kg N/(kg VSS·d);亞硝態(tài)去除速率分別為0.180,0.242, 0.281,0.392,0.379, 0.358kg N/(kg VSS·d).隨著COD/NO2--N的增加, SNAD生物膜的氨氮去除速率總體呈逐漸減小的趨勢,亞硝態(tài)氮去除速率逐漸上升,表明生物膜的厭氧氨氧化活性總體呈逐漸減小的趨勢,亞硝態(tài)氮反硝化活性逐漸增強(qiáng).其原因分析如下:首先,反硝化菌和厭氧氨氧化菌主要位于SNAD生物膜的內(nèi)部[21-22],生物膜對于底物的傳質(zhì)具有阻礙作用[23];其次,反硝化菌利用碳源將硝態(tài)氮或亞硝態(tài)氮還原為氮?dú)?隨著COD/NO2--N的增加,反硝化菌對生物膜中亞硝態(tài)氮的奪取能力逐漸增強(qiáng),生物膜內(nèi)可供厭氧氨氧化菌利用的亞硝態(tài)氮濃度逐漸降低,所以生物膜的厭氧氨氧化活性表現(xiàn)為逐漸減小.但是COD/NO2--N為1對應(yīng)實(shí)驗(yàn)組的氨氮去除速率大于COD/NO2--N為0對應(yīng)實(shí)驗(yàn)組的氨氮去除速率,其原因分析如下:生物膜厭氧氨氧化過程會(huì)產(chǎn)生硝態(tài)氮,由于碳源數(shù)量的限制,反硝化菌無法將硝態(tài)氮完全還原為氮?dú)?在生物膜內(nèi)部積累了亞硝態(tài)氮,生物膜內(nèi)可供厭氧氨氧化菌利用的亞硝態(tài)氮濃度增加,所以生物膜的厭氧氨氧化活性增加.表1為不同COD/NO2--N條件下SNAD生物膜厭氧氨氧化耦合反硝化的氮素平衡分析. COD/NO2--N比分別為1、2、3、4和5實(shí)驗(yàn)組對應(yīng)的厭氧氨氧化亞硝態(tài)氮去除量占總亞硝態(tài)氮去除量的百分比分別為87.1%、52.2%、29.3%、23.7%和16.3%.隨著COD/NO2--N比的增加,厭氧氨氧化亞硝態(tài)氮去除量占總亞硝態(tài)氮去除量的百分比逐漸降低.當(dāng)COD/NO2--N比為0~2時(shí),厭氧氨氧化亞硝態(tài)氮去除量占總亞硝態(tài)氮去除量的百分比大于50%,厭氧氨氧化菌比反硝化菌具有更強(qiáng)的亞硝態(tài)競爭能力,SNAD生物膜可以實(shí)現(xiàn)良好的耦合脫氮.當(dāng)COD/NO2--N比大于2時(shí),厭氧氨氧化菌在亞硝態(tài)的競爭過程中處于劣勢,不利于SNAD生物膜的耦合脫氮.

其他研究人員通過長期實(shí)驗(yàn)考察了C/N比對厭氧氨氧化耦合反硝化反應(yīng)器脫氮性能的影響. Chamchoi等[5]的研究表明,當(dāng)進(jìn)水COD為200~300mg/L(COD/NOX--N比為2~3)時(shí),厭氧氨氧化耦合反硝化反應(yīng)器中的厭氧氨氧化菌活性良好,當(dāng)進(jìn)水COD超過300mg/L (COD/NOX--N比大于3)時(shí),反應(yīng)器中厭氧氨氧化菌的脫氮性能惡化,和本研究結(jié)果相近.此外,Tang等[6]的研究表明,當(dāng)進(jìn)水COD為300mg/L(COD/NO2--N比為1.25)時(shí),厭氧氨氧化耦合反硝化顆粒污泥反應(yīng)器中的厭氧氨氧化菌活性良好,厭氧氨氧化亞硝態(tài)氮去除量占總亞硝態(tài)氮去除量的55.3%;當(dāng)進(jìn)水COD為700mg/L (COD/NO2--N比為2.92)時(shí),反應(yīng)器中厭氧氨氧化菌的脫氮性能惡化,厭氧氨氧化亞硝態(tài)氮去除量占總亞硝態(tài)氮去除量百分比降低至2.1%,和本研究結(jié)果相近.Ni等[24]的研究表明,當(dāng)進(jìn)水COD為400mg/L(COD/ NO2--N比為4)時(shí),厭氧氨氧化耦合反硝化反應(yīng)器中的厭氧氨氧菌活性良好,反應(yīng)器對有機(jī)物的耐受能力高于本實(shí)驗(yàn)的研究結(jié)果.同時(shí),一些研究人員通過長期實(shí)驗(yàn)考察了COD和C/N比對SNAD反應(yīng)器脫氮性能的影響.Chen等[1]的研究表明,當(dāng)進(jìn)水COD為100mg/L (COD/NH4+-N比為0.5)時(shí), SNAD生物膜反應(yīng)器的總氮去除率為70%;當(dāng)進(jìn)水COD為150mg/L (COD/NH4+-N比為0.75)時(shí),反應(yīng)器的總氮去除率降低至40%.Li等[7]的研究表明當(dāng)進(jìn)水COD為245~295mg/L (COD/NH4+-N比為1.2)時(shí), SNAD生物膜反應(yīng)器中反硝化菌去除的氮素質(zhì)量占反應(yīng)器總氮去除量的49.22%.綜上所述, SNAD反應(yīng)器對有機(jī)物的耐受能力比厭氧氨氧化耦合反硝化反應(yīng)器更低.其原因可能為厭氧氨氧化菌和反硝化菌對亞硝態(tài)氮的競爭能力和菌種的數(shù)量有關(guān), SNAD反應(yīng)器內(nèi)的污泥由亞硝化菌、厭氧氨氧化菌、反硝化菌和異養(yǎng)菌組成,污泥中厭氧氨氧化菌的豐度較低,在低濃度有機(jī)物環(huán)境中,污泥中厭氧氨氧化菌對亞硝態(tài)氮的競爭能力較低.其次,SNAD反應(yīng)器中存在一定濃度的溶解氧,溶解氧會(huì)抑制厭氧氨氧化菌活性,進(jìn)一步降低厭氧氨氧化菌的亞硝態(tài)氮競爭能力[25].

表1 不同C/N比條件下SNAD生物膜厭氧氨氧化耦合反硝化脫氮特性

2.3 碳源種類對SNAD生物膜反硝化活性的影響

圖5中,COD/NO2--N=5,以甲酸鈉、乙酸鈉、丙酸鈉和葡萄糖為碳源時(shí),SNAD生物膜的亞硝態(tài)氮反硝化去除速率分別為0.293,0.211,0.159, 0.074kg N/(kg VSS·d). Elefsiniotis等[15]通過批試實(shí)驗(yàn)表明,乙酸作為外加碳源時(shí),污泥的硝態(tài)氮反硝化去除速率高于丙酸,和本研究結(jié)果一致. Yang等[11]通過批試實(shí)驗(yàn)表明,乙酸作為外加碳源時(shí),污泥的硝態(tài)氮反硝化去除速率高于葡萄糖,和本研究結(jié)果一致.在生物反硝化過程中,碳源被用于反硝化,合成細(xì)胞物質(zhì)和轉(zhuǎn)化為細(xì)胞內(nèi)碳源[26-27].不同種類的碳源需要經(jīng)過不同的代謝途徑才能被反硝化菌用于反硝化,從而造成了反硝化速率的差異[11,15].乙酸鈉的代謝途徑較為簡單,可與輔酶A結(jié)合形成乙酰輔酶A直接進(jìn)入TCA循環(huán)[28].丙酸鈉和葡萄糖的代謝途徑較為復(fù)雜.丙酸鈉需先與輔酶A結(jié)合形成丙酰輔酶A,然后通過一系列的反應(yīng)被轉(zhuǎn)化為琥珀酰輔酶A并進(jìn)入TCA循環(huán).葡萄糖需首先轉(zhuǎn)化為丙酮酸,丙酮酸被轉(zhuǎn)化為乙酰輔酶A并進(jìn)入TCA循環(huán)[14,28].甲酸鈉需轉(zhuǎn)化為乙酰輔酶A才能進(jìn)入TCA循環(huán),代謝途徑比乙酸鈉復(fù)雜,但是本研究中甲酸鈉的反硝化速率比乙酸鈉高.和乙酸鈉相比,甲酸鈉是單碳化合物,合成細(xì)胞組分的能量需求較大,微生物的細(xì)胞產(chǎn)率較低,有機(jī)物的利用率較高,所以甲酸鈉的反硝化速率大于乙酸鈉的反硝化速率[29].

2.4 碳源種類對SNAD生物膜厭氧氨氧化耦合反硝化脫氮性能的影響

由圖6、圖7可見,以甲酸鈉、乙酸鈉、丙酸鈉和葡萄糖為外加碳源實(shí)驗(yàn)組對應(yīng)的氨氮去除速率分別為0.040,0.057,0.070,0.082kg N/(kg VSS·d);亞硝態(tài)氮去除速率分別為0.358,0.222, 0.136,0.154kg N/(kg VSS·d).以甲酸鈉、乙酸鈉、丙酸鈉和葡萄糖為碳源時(shí),SNAD生物膜的反硝化活性依次減小,反硝化菌對亞硝態(tài)氮的利用能力逐漸降低.生物膜內(nèi)可供厭氧氨氧化菌利用的亞硝態(tài)氮底物濃度逐漸增加,所以生物膜的厭氧氨氧化活性逐漸增強(qiáng).表2中,以甲酸鈉、乙酸鈉、丙酸鈉和葡萄糖為外加碳源實(shí)驗(yàn)組對應(yīng)的厭氧氨氧化亞硝態(tài)氮去除量占總亞硝態(tài)氮去除量的百分比分別為16.3%、37.1%、74.1%和76.8%.當(dāng)以丙酸鈉或葡萄糖為外加碳源并且COD/NO2--N=5時(shí),厭氧氨氧化亞硝態(tài)氮去除量占總亞硝態(tài)氮去除量的百分比大于50%,厭氧氨氧化菌比反硝化菌具有更強(qiáng)的亞硝態(tài)競爭能力, SNAD生物膜可以實(shí)現(xiàn)耦合脫氮.當(dāng)以甲酸鈉或乙酸鈉為外加碳源并且COD/NO2--N=5時(shí),厭氧氨氧化菌在亞硝態(tài)的競爭過程中處于劣勢.

表2 不同碳源種類條件下生物膜厭氧氨氧化耦合反硝化脫氮特性

3 結(jié)論

3.1 以乙酸鈉為外加碳源時(shí),隨著COD/NO2--N比的增加, SNAD生物膜的厭氧氨氧化活性總體呈逐漸減小的趨勢,反硝化活性逐漸增加.當(dāng)COD/NO2--N比分別為0、1、2、3、4和5時(shí), SNAD生物膜的氨氮去除速率分別為0.121,0.145, 0.101,0.079,0.062,0.040kg N/(kg VSS·d);亞硝態(tài)去除速率分別為0.180,0.242,0.281,0.392,0.379, 0.358kg N/(kg VSS·d).

3.2 控制COD/NO2--N比為5,以甲酸鈉、乙酸鈉、丙酸鈉和葡萄糖為碳源時(shí), SNAD生物膜的反硝化活性依次減小,其亞硝態(tài)氮反硝化去除速率分別為0.293,0.211,0.159,0.074kg N/(kg VSS·d).碳源的代謝途徑是影響反硝化速率的關(guān)鍵因素.

3.3 厭氧氨氧化耦合反硝化批試過程中,控制COD/NO2--N為5,以甲酸鈉、乙酸鈉、丙酸鈉和葡萄糖為碳源時(shí),SNAD生物膜的氨氮去除速率分別為0.040,0.057,0.070,0.082kg N/(kg VSS·d);亞硝態(tài)氮去除速率分別為0.358,0.222,0.136, 0.154kg N/(kg VSS·d).當(dāng)以丙酸鈉或葡萄糖為外加碳源并且COD/NO2--N比為5時(shí), SNAD生物膜可以實(shí)現(xiàn)良好的耦合脫氮.

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The nitrogen removal performance of the SNAD biofilm with different C/N ratios and carbon sources.

ZHENG Zhao-ming, LI Jun*, YANG Jing-yue, MA Jing, DU Jia

(National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Engineering Research Center of Beijing, Beijing University of Technology, Beijing 100124, China).

The effect of carbon sources and chemical oxygen demand (COD)/NO2--N ratios on the anammox- denitrification coupling process of the simultaneous partial nitrification, anammox and denitrification (SNAD) biofilm was studied in batch tests. The SNAD biofilm reactor was fed with domestic wastewater and filled with Kaldnes rings. During the stable running period, good SNAD performance was achieved. The effect of COD/NO2--N ratios on the anammox-denitrification coupling process was studied with the carbon source of sodium acetate. Consequently, the NO2--N consumption via anammox was found to be reduced with the increase of COD/NO2--N ratio. With the COD/NO2--N ratios of 1, 2, 3, 4 and 5, the corresponding NO2--N consumption via anammox were 87.1%, 52.2%, 29.3%, 23.7% and 16.3%, respectively. With the COD/NO2--N ranges of 0 to 2, the NO2--N consumption via anammox was above 50%, which indicated that good nitrogen removal performance was obtained. Besides, the effect of carbon sources on the anammox-denitrification coupling process was studied with the COD/NO2--N ratio of 5. With the carbon sources of sodium formate, sodium acetate, sodium propionate and glucose, the corresponding NO2--N consumption via anammox were 16.3%, 37.1%, 74.1% and 76.8%, respectively. The SNAD biofilm could operate good nitrogen removal performance with the carbon sources of sodium propionate or glucose at the COD/NO2--N ratio of 5.

SNAD biofilm；carbon source；C/N ratios；nitrogen removal performance

X703.5

A

1000-6923(2017)04-1331-08

2016-08-31

國家水體污染控制與治理科技重大專項(xiàng)(2015ZX 07202-013)

鄭照明(1989-),男,浙江嵊州市人,北京工業(yè)大學(xué)博士研究生,主要從事厭氧氨氧化,亞硝化和SNAD工藝研究.發(fā)表論文4篇.

* 責(zé)任作者, 教授, jglijun@bjut.edu.cn

, 2017,37(4)：1331~1338