NO2--N/NH4+-N及COD/NH4+-N對(duì)厭氧氨氧化耦合反硝化脫氮除碳的影響

趙鑫磊,邢嘉偉,付 雪,毛佩玥,安芳嬌,馬 嬌,陳永志

NO2--N/NH4+-N及COD/NH4+-N對(duì)厭氧氨氧化耦合反硝化脫氮除碳的影響

趙鑫磊,邢嘉偉,付 雪,毛佩玥,安芳嬌,馬 嬌,陳永志*

(蘭州交通大學(xué)環(huán)境與市政工程學(xué)院,甘肅省污水處理行業(yè)技術(shù)中心,甘肅省黃河水環(huán)境重點(diǎn)實(shí)驗(yàn)室,甘肅 蘭州 730070)

采用序批式反應(yīng)器-厭氧序批式反應(yīng)器(SBR-ASBR)組合工藝處理常溫低C/N比實(shí)際生活污水,通過(guò)調(diào)控SBR缺氧:好氧時(shí)間分別為80min:60min、120min:60min和150min:60min時(shí),實(shí)現(xiàn)半亞硝化,將其出水直接泵入ASBR反應(yīng)器中,考察不同進(jìn)水NO2--N/NH4+-N和COD/NH4+-N對(duì)厭氧氨氧化耦合反硝化同步脫氮除碳的影響,并采用響應(yīng)面法設(shè)計(jì)正交批次試驗(yàn).結(jié)果表明:在NO2--N/NH4+-N為1.55,COD/NH4+-N為4.22時(shí),出水NH4+-N、NO2--N和COD的濃度分別為2.79,0.47,38.37mg/L,其去除率分別高達(dá)87.56%,98.45%和62.69%.ΔNO2--N/ΔNH4+-N為2.23,生成的NO3--N的量比理論值小2.47mg/L,厭氧氨氧化和異養(yǎng)反硝化共同完成氮素去除,系統(tǒng)脫氮除碳性能最佳.當(dāng)NO2--N/NH4+-N和COD/NH4+-N分別由0.84增加到1.55和3.24增加到4.22時(shí),厭氧氨氧化和異養(yǎng)反硝化對(duì)脫氮貢獻(xiàn)率分別由80.40%降至53.33%和19.60%增加到46.67%.NO2--N/NH4+-N和COD/NH4+-N對(duì)TN和COD去除的正交影響顯著,均呈現(xiàn)正相關(guān),2分別為0.9243和0.9700.

半亞硝化；缺氧；好氧比；厭氧氨氧化耦合反硝化；脫氮除碳；響應(yīng)面法

厭氧氨氧化(ANAMMOX)反應(yīng)是指在厭氧或缺氧條件下,以NO2--N為電子受體,將NH4+-N直接氧化為N2的自養(yǎng)生物脫氮反應(yīng)過(guò)程.與傳統(tǒng)生物脫氮相比,因其具有無(wú)需有機(jī)碳源、節(jié)省25%曝氣量、反應(yīng)時(shí)間快、污泥產(chǎn)率低和脫氮效率高等優(yōu)勢(shì),成為目前最經(jīng)濟(jì)高效的污水脫氮工藝[1].然而, ANAMMOX只有在進(jìn)水中NO2--N和NH4+-N比值適當(dāng)?shù)那疤嵯?才能發(fā)揮其高效脫氮的優(yōu)勢(shì).因此,半亞硝化就成了ANAMMOX工藝的最合適前置工藝[2].由于在實(shí)際生活污水中部分亞硝化和厭氧氨氧化難以穩(wěn)定實(shí)現(xiàn)[3-4],故當(dāng)前大多數(shù)研究?jī)H局限于在高溫高氨氮廢水[5-8]和人工模擬廢水[9-11]條件下,探究單一因素對(duì)厭氧氨氧化脫氮的影響.而常溫條件下,用半亞硝化厭氧氨氧化組合工藝處理低C/N實(shí)際生活污水,同時(shí)探究雙因素對(duì)脫氮除碳交互影響的研究甚少.

基于此,本試驗(yàn)采用序批式反應(yīng)器-厭氧序批式反應(yīng)器(SBR-ASBR),進(jìn)行半亞硝化厭氧氨氧化耦合異養(yǎng)反硝化組合工藝處理實(shí)際生活污水,通過(guò)控制SBR缺氧:好氧時(shí)間實(shí)現(xiàn)半亞硝化,并將其出水直接作為厭氧氨氧化的進(jìn)水,探究不同NO2--N/NH4+-N和COD/NH4+-N對(duì)厭氧氨氧化耦合反硝化脫氮除碳的影響,并采用響應(yīng)面法設(shè)計(jì)批次實(shí)驗(yàn)優(yōu)化分析2個(gè)參數(shù)對(duì)脫氮除碳的交互作用,得出系統(tǒng)脫氮除碳效果最佳的NO2--N/NH4+-N和COD/NH4+-N,以期為該工藝的實(shí)際應(yīng)用提供一定的理論參考.

1 材料與方法

1.1 實(shí)驗(yàn)裝置

SBR和ASBR反應(yīng)器均采用圓柱形有機(jī)玻璃制成,SBR反應(yīng)器直徑16cm,高45cm,有效容積5L,取樣口安裝于反應(yīng)器側(cè)壁.實(shí)驗(yàn)過(guò)程中通過(guò)溫控儀調(diào)節(jié)溫度,同時(shí)底部安裝有曝氣裝置,通過(guò)流量計(jì)來(lái)調(diào)控溶解氧,采用定時(shí)器來(lái)調(diào)控間歇運(yùn)行模式及缺氧/好氧時(shí)間.ASBR反應(yīng)器直徑14cm,高48cm,有效容積為5L,取樣口安裝于反應(yīng)器的側(cè)壁,反應(yīng)器上部有排氣孔,使氣體能夠通過(guò)水封瓶排出,反應(yīng)器的底部安裝有排泥口,反應(yīng)器的外壁包裹黑色塑料布遮光.半亞硝化SBR和厭氧氨氧化ASBR組合工藝如圖1所示.

圖1 半亞硝化耦合厭氧氨氧化組合工藝示意

1.原水箱;2.進(jìn)水泵;3.曝氣泵;4.氣體流量計(jì);5.攪拌器;6.排泥口;7.取樣口;8.中間水箱;9.DO/pH儀;10.溫控儀

1.2 接種污泥

半亞硝化試驗(yàn)的接種污泥取實(shí)驗(yàn)室培養(yǎng)的短程硝化污泥,污泥脫氮性能良好,MLSS為3550mg/L,污泥MLVSS/MLSS(值)為0.70,SV30為40%～55%.

厭氧氨氧化試驗(yàn)的接種污泥取自已成功啟動(dòng)且穩(wěn)定運(yùn)行的厭氧氨氧化活性污泥,其MLSS為3360mg/L,MLVSS為2550mg/L,具有良好的脫氮性能.

1.3 實(shí)驗(yàn)用水水質(zhì)及檢測(cè)方法

半亞硝化試驗(yàn)用水取自蘭州交通大學(xué)家屬區(qū)實(shí)際生活污水,厭氧氨氧化進(jìn)水為SBR半亞硝化反應(yīng)的出水,生活污水水質(zhì)指標(biāo)見(jiàn)表1.

表1 生活污水水質(zhì)

MLSS采用濾紙稱重法,所測(cè)水樣經(jīng)0.45μm濾紙過(guò)濾后根據(jù)國(guó)家標(biāo)準(zhǔn)方法[12]測(cè)定:COD采用快速消解分光光度法測(cè)定,NH4+-N采用納氏試劑分光光度法測(cè)定,NO2--N采用N-1(1-萘基)-乙二胺光度法測(cè)定,NO3--N采用麝香草酚分光光度法測(cè)定,pH值和DO采用Multi3420儀測(cè)定.

1.4 運(yùn)行工況

本試驗(yàn)在室溫(24.0±0.5)℃,SRT=25d,曝氣量100L/h下,SBR反應(yīng)器采用了3種缺氧:好氧時(shí)間(80min:60min、120min:60min和150min:60min)運(yùn)行工況實(shí)現(xiàn)半亞硝化;然后以半亞硝化出水分別作為ASBR厭氧氨氧化反應(yīng)進(jìn)水,在HRT=33h時(shí)探究不同進(jìn)水NO2--N/NH4+-N和COD/NH4+-N對(duì)厭氧氨氧化耦合反硝化同步脫氮除碳的影響.具體運(yùn)行工況如表2所示,其中SBR半亞硝化反應(yīng)器進(jìn)出水周期為進(jìn)水15min,缺氧攪拌分別為80,120,150min,好氧均為60min,反應(yīng)停止沉淀30min后排水,排水比為75%.

表2 SBR、ASBR運(yùn)行工況

1.5 批次試驗(yàn)

批次試驗(yàn)是在HRT=33h下,同一個(gè)ASBR厭氧氨氧化耦合反硝化系統(tǒng)中,不同時(shí)間點(diǎn)以TN和COD去除率為研究對(duì)象,以NO2--N/NH4+-N和COD/NH4+-N為2個(gè)影響因素,采用Central Composite響應(yīng)面設(shè)計(jì)正交批次實(shí)驗(yàn)分別運(yùn)行[13-14],探究NO2--N/NH4+-N和COD/NH4+-N對(duì)TN和COD去除率的交互影響,具體實(shí)驗(yàn)方案見(jiàn)表3.

表3 響應(yīng)面批次實(shí)驗(yàn)設(shè)計(jì)

1.6 計(jì)算分析方法

氨氧化率(AOR)和亞硝化率(NAR)按下式計(jì)算:

式中:(NH4+-Nin)和(NH4+-Neff)分別為SBR反應(yīng)器進(jìn)、出水NH4+-N濃度,mg/L;D(NO2--N)和Δ(NO3-- N)分別為SBR反應(yīng)器進(jìn)出水NO2--N和NO3--N的濃度差,mg/L.

厭氧氨氧化在系統(tǒng)中對(duì)脫氮的貢獻(xiàn)率及反硝化脫氮的貢獻(xiàn)率的計(jì)算,參考魏思佳等[15]提出的公式:

式中:(NH4+-N)rem、(NO2--N)rem、分別為ASBR反應(yīng)器中NH4+-N和NO2--N去除量,mg/L;DNO3--N為ASBR反應(yīng)器NO3--N的變化量,mg/L.

2 結(jié)果與討論

2.1 缺氧:好氧工況下半亞硝化穩(wěn)定性的實(shí)現(xiàn)

由圖2可知,3種工況下SBR反應(yīng)器進(jìn)水中NH4+-N和NO2--N的平均濃度分別為95.71和0.20mg/L,氨氧化率和亞硝化率在整個(gè)過(guò)程均呈現(xiàn)上升趨勢(shì).工況Ⅰ(缺氧:好氧等于80min:60min)時(shí),出水中NH4+-N和NO2--N的濃度分別為34.93和29.20mg/L,氨氧化率由最初的41.98%上升至63.74%,亞硝化率由83.09%增大到85.12%,NO2--N/ NH4+-N≈0.84.這是因?yàn)槿毖鯐r(shí)間較短,對(duì)NOB的抑制較弱,一部分氨氮轉(zhuǎn)換為NO3--N且系統(tǒng)內(nèi)消耗COD發(fā)生了異養(yǎng)反硝化,導(dǎo)致亞硝化率上升緩慢[16].工況Ⅱ(缺氧:好氧為120min:60min)時(shí),運(yùn)行至53d氨氧化率和亞硝化率分別上升至71.84%和90.36%,出水NO2--N/NH4+-N=1,即實(shí)現(xiàn)穩(wěn)定的半亞硝化.最后出水NO2--N/NH4+-N≈1.18.工況Ⅲ(缺氧:好氧為150min:60min)時(shí),第80d NO2--N/NH4+-N達(dá)到理論值1.32,此時(shí)氨氧化率和亞硝化率分別達(dá)到73.99%和95.66%.之后出水NH4+-N和NO2--N濃度分別為22.38和34.67mg/L,NO2--N/NH4+-N≈1.55并保持穩(wěn)定,亞硝化率高達(dá)97%左右.分析原因:在缺氧/好氧曝氣模式下,缺氧環(huán)境中AOB和NOB活性都會(huì)受到一定程度的影響,其中,AOB具有“飽食饑餓”特性,而NOB不具備此特性,曝氣間隔的增加,即缺氧時(shí)間的相對(duì)延長(zhǎng),增加了對(duì)NOB的抑制,使得AOB逐漸成為優(yōu)勢(shì)菌種;因此在一定的缺氧/好氧比范圍內(nèi),缺氧時(shí)間所占的比例越大越有利于亞硝酸鹽的積累[17-18].

張艷輝等[19]在缺氧/好氧為180min:60min時(shí),在連續(xù)流中實(shí)現(xiàn)穩(wěn)定半亞硝化,氨氧化率為57.01%,亞硝化率為92.01%.劉宏等[20]在缺氧/好氧=60min: 30min條件下,交替5次,在SBR反應(yīng)器中可以實(shí)現(xiàn)穩(wěn)定的短程硝化,出水氨氮幾乎為零,亞硝化率為99.75%.王桃等[21]在缺氧/好氧=30min:30min條件下,交替運(yùn)行4次,氨氮去除率達(dá)95.44%,亞硝化率達(dá)99.30%.上述研究主要實(shí)現(xiàn)了短程硝化,而本試驗(yàn)實(shí)現(xiàn)半亞硝化的目的在于為后續(xù)厭氧氨氧化反應(yīng)提供合適的進(jìn)水基質(zhì)條件,即NO2--N/NH4+-N接近厭氧氨氧化反應(yīng)理論計(jì)量比1.32.因此,將其出水直接作為厭氧氨氧化反應(yīng)的進(jìn)水.

圖2 SBR中不同缺氧:好氧時(shí)間比對(duì)半亞硝化穩(wěn)定性影響

2.2 不同進(jìn)水條件對(duì)厭氧氨氧化耦合反硝化脫氮的影響

①當(dāng)進(jìn)水NO2--N/NH4+-N=0.84,COD/NH4+- N=3.24時(shí),由圖3a可知,出水NH4+-N濃度逐漸由18.79mg/L降至10.90mg/L,去除率由47.71%上升到68.80%,此階段進(jìn)水NO2--N的濃度相對(duì)NH4+-N的濃度較小,在一定程度上NO2--N決定著厭氧氨氧化反應(yīng)的進(jìn)程,進(jìn)而影響NH4+-N的去除量;出水NO2--N和NO3--N的平均濃度分別為0.46和5.99mg/L.本階段DNO2--N/ΔNH4+-N由1.65逐漸降低并穩(wěn)定至1.30左右(圖3b),其平均值為1.33,與化學(xué)計(jì)量比一致;出水NO3--N的量比理論值低1.49mg/L,這是因?yàn)橄到y(tǒng)中存在COD發(fā)生了異養(yǎng)反硝化.②當(dāng)進(jìn)水NO2--N/NH4+-N=1.18,COD/NH4+- N=3.83時(shí),出水NH4+-N濃度降至5.97mg/L,其去除率達(dá)77.80%,這是由于進(jìn)水NH4+-N比前一工況低且基質(zhì)比更接近理論值1.32[22],更多的NH4+-N和NO2--N通過(guò)厭氧氨氧化反應(yīng)轉(zhuǎn)化為N2.DNO2--N/DNH4+-N平均值為1.71,出水NO3--N的量比理論值低2.35mg/L,這是因?yàn)镃OD/NH4+-N增加,系統(tǒng)異養(yǎng)反硝化有所增強(qiáng),對(duì)NON(NO2--N+NO3--N)的消耗增加.③當(dāng)進(jìn)水NO2--N/NH4+-N=1.55,COD/ NH4+-N=4.22時(shí),出水NH4+-N平均濃度2.79mg/L,去除率達(dá)87.56%,NO2--N出水平均濃度為0.47mg/L,去除率高達(dá)98%以上,出水NO3--N的平均濃度為4.29mg/L,此時(shí)系統(tǒng)脫氮效果最佳.

DNO2--N/DNH4+-N平均值為2.23,出水NO3-- N的量比理論值低2.47mg/L,均高于前2個(gè)工況,這是由于進(jìn)水基質(zhì)比高于理論值,過(guò)量的NO2--N及厭氧氨氧化產(chǎn)生的NO3--N為異養(yǎng)反硝化提供了充足的底物,且COD/NH4+-N增加,異養(yǎng)反硝化碳源充足,反硝化作用增強(qiáng).

由圖3c可知,進(jìn)水總氮在56.13～67.88mg/L之間波動(dòng),出水總氮呈現(xiàn)逐級(jí)遞減趨勢(shì),并在NO2--N/ NH4+-N=1.55,COD/NH4+-N=4.22時(shí),協(xié)同脫氮效果最佳,總氮去除率達(dá)到最高值86.90%,平均值達(dá)到81.68%,高于前2個(gè)工況總氮的平均去除率68.71%、75.97%.安芳嬌等[23]研究發(fā)現(xiàn),當(dāng)進(jìn)水中NO2--N/ NH4+-N在1.4～1.6之間時(shí),厭氧氨氧化系統(tǒng)脫氮的效能最佳,其中NH4+-N、NO2--N和TN的出水濃度分別為2.13,1.08和10.87mg/L,三者的去除率分別為93.60%、97.80%和81.68%.閭剛等[24]研究表明,當(dāng)進(jìn)水NO2--N/NH4+-N為1.34時(shí),厭氧氨氧化系統(tǒng)中NO2--N和NH4+-N去除率均可達(dá)99.99%,TN去除率達(dá)87%.這是由于厭氧氨氧化菌與反硝化菌生長(zhǎng)條件相似,在厭氧氨氧化反應(yīng)過(guò)程中伴隨有異養(yǎng)反硝化作用,導(dǎo)致NO2--N/NH4+-N較理論值大.而傅金祥等[25]采用人工配水研究基質(zhì)比對(duì)厭氧氨氧化生物膜工藝脫氮效能的影響時(shí),發(fā)現(xiàn)最佳NO2--N/ NH4+-N為1.2,NO2--N和NH4+-N去除率分別為98%和96%.這是因?yàn)樯锬ず突钚晕勰嘈螒B(tài)中菌群結(jié)構(gòu)有所不同,導(dǎo)致基質(zhì)比小于理論值[26].此外,本試驗(yàn)與魏思佳等[15]研究發(fā)現(xiàn)當(dāng)COD/NH4+-N= 4.25～5.25時(shí)系統(tǒng)厭氧氨氧化耦合反硝化脫氮效果最佳結(jié)果一致.

2.3 不同進(jìn)水條件下厭氧氨氧化和異養(yǎng)反硝化脫氮貢獻(xiàn)率及COD的去除

由圖4得知,在NO2--N/NH4+-N=0.84,COD/ NH4+-N=3.24時(shí),厭氧氨氧化和異養(yǎng)反硝化對(duì)脫氮的貢獻(xiàn)率分別為80.40%和19.60%,COD平均出水濃度68.91mg/L,COD平均去除率僅為39.03%.在NO2--N/NH4+-N=1.18,COD/NH4+-N=3.38時(shí),厭氧氨氧化脫氮貢獻(xiàn)率由83.86%下降至67.81%,出水COD濃度降至53.59mg/L,COD平均去除率為50.03%.當(dāng)進(jìn)水條件為NO2--N/NH4+-N=1.55,COD/NH4+-N= 4.22時(shí),厭氧氨氧化與反硝化在系統(tǒng)中的脫氮貢獻(xiàn)率分別為53.33%和46.67%,出水COD濃度為38.37mg/L,COD去除率為62.69%,此時(shí)系統(tǒng)耦合脫氮效果最佳(圖3c).

亞硝酸鹽氮既是厭氧氨氧化反應(yīng)的電子受體,又是反硝化反應(yīng)的電子受體,因此厭氧氨氧化和反硝化反應(yīng)對(duì)亞硝酸鹽氮存在競(jìng)爭(zhēng)關(guān)系[27].在NO2--N/NH4+-N=0.84,COD/NH4+-N=3.24時(shí),厭氧氨氧化基質(zhì)比遠(yuǎn)小于理論值1.32,系統(tǒng)中氨氮處于充足狀態(tài),可為厭氧氨氧化反應(yīng)提供足夠的電子供體,此環(huán)境相對(duì)反硝化菌而言更有利于厭氧氨氧化菌生長(zhǎng)[13].此外,COD/NH4+-N較小,不能為反硝化提供足夠的驅(qū)動(dòng)力去爭(zhēng)奪NO2--N,因此厭氧氨氧化菌與反硝化菌在競(jìng)爭(zhēng)NO2--N的過(guò)程中處于優(yōu)勢(shì)[28-29],所以厭氧氨氧化對(duì)脫氮的貢獻(xiàn)率較高.當(dāng)NO2--N/ NH4+-N=1.18,COD/NH4+-N=3.38;NO2--N/NH4+-N=1.55,COD/NH4+-N=4.22時(shí),厭氧氨氧化對(duì)脫氮的貢獻(xiàn)率持續(xù)下降,異養(yǎng)反硝化對(duì)脫氮貢獻(xiàn)率不斷上升,這是因?yàn)榘钡獫舛冉档?亞硝酸鹽濃度升高,COD相對(duì)充足,厭氧氨氧化菌對(duì)NO2--N競(jìng)爭(zhēng)優(yōu)勢(shì)被削弱,在第87周期后二者對(duì)脫氮的貢獻(xiàn)各自穩(wěn)定在53%和47%.本研究結(jié)果與文獻(xiàn)[15,23,30]一致.COD去除率在整個(gè)周期呈上升趨勢(shì),因?yàn)镃OD/ NH4+-N增加,異養(yǎng)反硝化加強(qiáng),系統(tǒng)內(nèi)COD降解速率加快.

圖4 ASBR中厭氧氨氧化和異養(yǎng)反硝化對(duì)脫氮貢獻(xiàn)率及COD的去除特征

2.4 不同進(jìn)水條件對(duì)厭氧氨氧化耦合反硝化脫氮除碳的影響

在厭氧氨氧化耦合反硝化系統(tǒng)中,以TN和COD去除率為研究對(duì)象,以NO2--N/NH4+-N和COD/ NH4+-N為2個(gè)影響因素,采用Central Composite響應(yīng)面[31]設(shè)計(jì)正交批次實(shí)驗(yàn),實(shí)驗(yàn)結(jié)果見(jiàn)表4和表5.

表4 響應(yīng)面批次實(shí)驗(yàn)TN去除率

表5 響應(yīng)面批次實(shí)驗(yàn)COD去除率

以TN和COD去除率為響應(yīng)值,回歸方程分別為1= + 75.35 + 4.63 ×+ 1.61 ×- 0.15 ××,2= 0.9243;2= + 45.40 + 3.41 ×+ 7.99 ×+ 2 ××,2= 0.9700,方差分析見(jiàn)表6和表7.由表可知,兩個(gè)模型的值分別為17.10和45.30,值均小于0.05,表明NO2--N/NH4+-N和COD/NH4+-N對(duì)TN和COD去除率影響均顯著.

表6 TN去除率方差分析

表7 COD去除率方差分析

圖5 TN去除率和COD去除率的等高線圖及響應(yīng)面

分析了3種不同曝氣模式下SBR出水中NO2--N/NH4+-N和COD/NH4+-N對(duì)厭氧氨氧化耦合反硝化脫氮除碳的影響.由表6、表7可知, NO2--N/NH4+-N及COD/NH4+-N對(duì)TN去除及COD去除均有顯著影響.分析圖5可知,隨NO2--N/ NH4+-N的增加,TN去除率逐漸升高且受COD/ NH4+-N影響較小;NO2--N/NH4+-N較高時(shí),隨COD/ NH4+-N的增加COD去除率升高更加明顯.原因是在NO2--N/NH4+-N較低的情況下,厭氧氨氧化菌不能得到足夠的NO2--N進(jìn)行反應(yīng),導(dǎo)致生成的NO3--N量較少,同時(shí)COD/NH4+-N較低,導(dǎo)致異養(yǎng)反硝化受到抑制,因此,系統(tǒng)厭氧氨氧化耦合反硝化脫氮除碳性能較差[32].當(dāng)NO2--N/NH4+-N增加且逐漸接近理論值,厭氧氨氧化反應(yīng)充分生成更多的N2和NO3--N,當(dāng)NO2--N/NH4+-N大于理論值,厭氧氨氧化剩余的NO2--N和生成的NO3--N為反硝化提供基質(zhì)底物.而COD/NH4+-N的適當(dāng)增加,為異養(yǎng)反硝化提供充足的碳源,保證了異養(yǎng)反硝化的正常進(jìn)行,降解COD的同時(shí)也可以解除有機(jī)物對(duì)厭氧氨氧化反應(yīng)的抑制,并且產(chǎn)生CO2為厭氧氨氧化提供了無(wú)機(jī)碳源,進(jìn)而達(dá)到良好協(xié)同脫氮除碳作用[33-36].最終在NO2--N/NH4+-N為1.55、COD/NH4+-N為4.22時(shí),系統(tǒng)脫氮除碳效果最佳.

3 結(jié)論

3.1 在SBR反應(yīng)器中,溫度為24℃,缺氧:好氧時(shí)間分別為80min:60min、120min:60min和150min: 60min時(shí),均可以實(shí)現(xiàn)良好的半亞硝化.其出水NO2--N/NH4+-N和COD/NH4+-N分別為0.84和3.24; 1.18和3.83;1.55和4.22.

3.2 以SBR半亞硝化出水作為厭氧氨氧化的進(jìn)水,當(dāng)進(jìn)水中NO2--N/NH4+-N為1.55、COD/NH4+-N為4.22時(shí),ASBR反應(yīng)器出水中NH4+-N、NO2--N和COD濃度分別為2.79mg/L、0.47mg/L和38.37mg/L,其去除率分別高達(dá)87.56%、98.45%和62.29%;DNO2--N/DNH4+-N平均值為2.23,NO3--N實(shí)際生成量與理論生成量平均差值為2.47mg/L,厭氧氨氧化耦合反硝化協(xié)同脫氮除碳效果最佳.

3.3 隨ASBR進(jìn)水NO2--N/NH4+-N和COD/NH4+- N增加,ASBR中厭氧氨氧化和異養(yǎng)反硝化對(duì)脫氮的的貢獻(xiàn)率分別為由80.40%降至53.33%和19.60%增加到46.67%,出水TN濃度為7.95mg/L,去除率達(dá)86.90%.表明厭氧氨氧化協(xié)同異養(yǎng)反硝化共同完成氮素去除.

3.4 響應(yīng)面法批次實(shí)驗(yàn)結(jié)果表明,兩個(gè)模型值均小于0.05,NO2--N/NH4+-N和COD/NH4+-N對(duì)TN和COD去除均有影響,且都呈現(xiàn)正相關(guān).其中,NO2-- N/NH4+-N對(duì)TN去除率影響更顯著,COD/NH4+-N對(duì)COD去除率影響更顯著.

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Effect of NO2--N/NH4+-N and COD/NH4+-N on anaerobic ammonia oxidation coupled denitrification nitrogen and carbon removal.

ZHAO Xin-lei, XING Jia-wei, FU Xue, MAO Pei-yue, AN Fang-jiao, MA Jiao, CHEN Yong-zhi*

(School of Environmental and Municipal Engineering,Technical Center of Sewage Treatment Industry in Gansu, Key Laboratory of Yellow River Water Environment in Gansu, Lanzhou 730070, China)., 2021,41(6)：2586～2594

The Sequencing Batch Reactor-Anaerobic Sequencing Batch Reactor (SBR-ASBR) combined processwas used to treat actual domestic sewage with low C/N ratio at normal temperature,the partial nitritation was achieved by regulating SBR hypoxia: aerobic time was 80min:60min, 120min:60min and 150min:60min respectively. Then the effluent was pumped into the ASBR reactor,investigate the effect of different influent NO2--N/NH4+-N and COD/ NH4+-N on removal of nitrogen and carbon by anaerobic ammonia oxidation coupled denitrification, and response surface methodology was used to design orthogonal batch test. The results showed that: NO2--N/NH4+-N was 1.55 and COD/NH4+-N was 4.22, the effluent concentrations of NH4+-N, NO2--N and COD were 2.79, 0.47 and 38.37mg/L respectively, and their removal rates were as high as 87.56%, 98.45% and 62.69% respectively. ΔNO2--N/ΔNH4+-N was 2.23, the quantity of generated NO3--N was smaller than the theoretical value by 2.47mg/L, nitrogen was removed by the joint action of anammox and denitrifying, the nitrogen and carbon removal performance of the system was best. When NO2--N/NH4+-N and COD/NH4+-N increased from 0.84 to 1.55 and 3.24 to 4.22, respectively, the contribution of anammox and heterotrophic denitrification to nitrogen removal decreased from 80.40% to 53.33% and 19.60% increased to 46.67%. NO2--N/NH4+-N and COD/NH4+-N had significant interactive effects on the removal of TN and COD, and both showed a positive correlation,2were 0.9243 and 0.9700 respectively.

semi-nitrosation；ratio of anoxic and aerobic；anaerobic ammonia oxidation and denitrification；removal of nitrogen and carbon；response surface analysis

X703

A

1000-6923(2021)06-2586-09

趙鑫磊(1992-),男,內(nèi)蒙古自治區(qū)呼和浩特人,蘭州交通大學(xué)碩士研究生,主要研究方向?yàn)樗廴究刂评碚撆c技術(shù).

2020-10-23

國(guó)家自然科學(xué)基金資助項(xiàng)目(51668033);甘肅省自然科學(xué)基金資助項(xiàng)目(18JR3RA126);甘肅省高等學(xué)校特色專業(yè)-環(huán)境工程項(xiàng)目(101004)

* 責(zé)任作者, 教授, 476411589@qq.com