導讀：2020年(nian)(nian)9月,習總書記在第75屆聯合國(guo)大會上(shang)鄭重提(ti)出,“我國(guo)CO2排(pai)放力(li)爭于2030年(nian)(nian)前(qian)達到峰值,努力(li)爭取2060年(nian)(nian)前(qian)實現碳(tan)中和”。水務(wu)行業(ye)(ye)(ye)(ye)(ye)作為(wei)能(neng)耗較(jiao)密集的(de)行業(ye)(ye)(ye)(ye)(ye),對(dui)電力(li)、化(hua)學藥劑的(de)消耗都直(zhi)接(jie)或(huo)間接(jie)促使大量溫(wen)室氣體(ti)排(pai)放。因此(ci),盡快通(tong)過技術創新、能(neng)源(yuan)高效清(qing)潔利用(yong)(yong)、智能(neng)生產(chan)等手段(duan)實施低(di)碳(tan)變(bian)革(ge),降低(di)行業(ye)(ye)(ye)(ye)(ye)碳(tan)排(pai)放,有助于為(wei)全(quan)行業(ye)(ye)(ye)(ye)(ye)提(ti)供更(geng)為(wei)廣闊的(de)發展空間。同時,以(yi)清(qing)潔能(neng)源(yuan)替代化(hua)石能(neng)源(yuan)消耗,建立綠色電力(li)使用(yong)(yong)渠道,將有助于進一步抵消行業(ye)(ye)(ye)(ye)(ye)碳(tan)排(pai)放,賦能(neng)產(chan)業(ye)(ye)(ye)(ye)(ye)綠色低(di)碳(tan)轉(zhuan)型。

一、水務行業與碳(tan)排放緊(jin)密相關

水(shui)(shui)(shui)務(wu)行(xing)業(ye)是(shi)指(zhi)由原(yuan)水(shui)(shui)(shui)、供水(shui)(shui)(shui)、節水(shui)(shui)(shui)、排水(shui)(shui)(shui)、污(wu)(wu)(wu)水(shui)(shui)(shui)處(chu)理(li)(li)及(ji)水(shui)(shui)(shui)資(zi)源(yuan)回收(shou)利用等構成的(de)產(chan)業(ye)鏈(lian),如圖(tu)1所示。城市水(shui)(shui)(shui)務(wu)行(xing)業(ye)是(shi)城市發展、居(ju)民(min)生活和(he)工業(ye)生產(chan)等的(de)基礎,其行(xing)業(ye)上游(you)是(shi)原(yuan)水(shui)(shui)(shui)的(de)獲(huo)取(qu),水(shui)(shui)(shui)資(zi)源(yuan)獲(huo)取(qu)的(de)形(xing)式(地(di)(di)表水(shui)(shui)(shui)、地(di)(di)下水(shui)(shui)(shui))及(ji)水(shui)(shui)(shui)源(yuan)地(di)(di)的(de)品質情況直接影響著供水(shui)(shui)(shui)成本與能(neng)耗(hao);行(xing)業(ye)下游(you)是(shi)污(wu)(wu)(wu)水(shui)(shui)(shui)與污(wu)(wu)(wu)泥的(de)處(chu)理(li)(li)處(chu)置(zhi),城鎮居(ju)民(min)耗(hao)水(shui)(shui)(shui)量、節水(shui)(shui)(shui)情況及(ji)污(wu)(wu)(wu)水(shui)(shui)(shui)廠(chang)工藝技術和(he)智能(neng)化管理(li)(li)水(shui)(shui)(shui)平將直接影響污(wu)(wu)(wu)水(shui)(shui)(shui)處(chu)理(li)(li)的(de)綜合(he)能(neng)耗(hao)及(ji)藥劑消耗(hao)。

圖(tu)1 一種典(dian)型的城市水(shui)務(wu)行業(ye)系統

據(ju)數據(ju)統(tong)(tong)計,2020年全國(guo)城鎮(zhen)污水(shui)處理(li)全過程碳(tan)排放(fang)量為(wei)3 416.0萬t CO2,碳(tan)抵(di)消量為(wei)769.1萬t CO2,凈排放(fang)量為(wei)2 646.9萬t CO2,全國(guo)城鎮(zhen)供水(shui)系統(tong)(tong)碳(tan)排放(fang)量超過2 200萬t CO2。由此可見,水(shui)務行(xing)業實(shi)現碳(tan)減排對我國(guo)早(zao)日實(shi)現“碳(tan)達峰(feng)”“碳(tan)中和(he)”有(you)著重要意(yi)義。

1.供水的碳排(pai)放

由水(shui)(shui)源處(chu)(chu)取得的原水(shui)(shui)在經過(guo)原水(shui)(shui)管網輸(shu)送(song)、水(shui)(shui)廠處(chu)(chu)理(li)(li)(li)、供水(shui)(shui)管網輸(shu)送(song)后送(song)入千家萬戶。原水(shui)(shui)管網輸(shu)送(song)、供水(shui)(shui)管網輸(shu)送(song)過(guo)程(cheng)(cheng)中需(xu)通(tong)過(guo)多級泵(beng)(beng)站、泵(beng)(beng)房處(chu)(chu)理(li)(li)(li),此過(guo)程(cheng)(cheng)中水(shui)(shui)泵(beng)(beng)消耗(hao)(hao)電能的間接(jie)排放是主要的溫室氣(qi)體排放形式。水(shui)(shui)廠處(chu)(chu)理(li)(li)(li)過(guo)程(cheng)(cheng)中一般(ban)不直接(jie)排放溫室氣(qi)體,其間接(jie)排放源于設備運行產生的能耗(hao)(hao),以及(ji)預處(chu)(chu)理(li)(li)(li)環節加(jia)氯、絮凝劑和消毒劑投加(jia)產生的藥耗(hao)(hao)。

趙榮(rong)欽等結(jie)合鄭州市(shi)水(shui)(shui)源(yuan)供給情況及相(xiang)關數據(ju)進行(xing)分析計算,結(jie)果表明,城(cheng)市(shi)依靠(kao)地(di)下水(shui)(shui)開采(cai)和(he)南水(shui)(shui)北調供水(shui)(shui)的(de)取水(shui)(shui)系統(tong)碳排(pai)放值達0.14 kg/m3,制水(shui)(shui)和(he)輸配水(shui)(shui)過(guo)程(cheng)(cheng)能源(yuan)強度分別為0.543 kW·h/m3和(he)0.320 kW·h/m3。依照2020年全國單位火(huo)電發電量CO2排(pai)放量換算,制水(shui)(shui)和(he)輸配水(shui)(shui)過(guo)程(cheng)(cheng)的(de)CO2排(pai)放量分別為0.452 kg/m3和(he)0.266 kg/m3,制水(shui)(shui)過(guo)程(cheng)(cheng)對碳排(pai)放的(de)貢(gong)獻率更大。

2.污(wu)水處理的(de)碳排放(fang)

生活(huo)污(wu)(wu)水處(chu)理(li)(li)的(de)碳排(pai)(pai)(pai)放(fang)(fang)形式主要分(fen)為直接(jie)排(pai)(pai)(pai)放(fang)(fang)和(he)間接(jie)排(pai)(pai)(pai)放(fang)(fang)。其(qi)中,直接(jie)排(pai)(pai)(pai)放(fang)(fang)一般為污(wu)(wu)水處(chu)理(li)(li)過(guo)程中,由于水中有機污(wu)(wu)染(ran)物被降解,釋放(fang)(fang)了(le)CO2、CH4和(he)N2O等(deng)溫室氣體,進入大氣;間接(jie)排(pai)(pai)(pai)放(fang)(fang)一般為污(wu)(wu)水處(chu)理(li)(li)過(guo)程中,所(suo)使用的(de)包括電、氣和(he)藥劑等(deng)所(suo)折算的(de)碳排(pai)(pai)(pai)放(fang)(fang)。

馬博(bo)雅等通(tong)過(guo)調研提出,相較(jiao)(jiao)(jiao)于(yu)直接排(pai)(pai)(pai)放(fang)(fang)(fang),目前對(dui)于(yu)間(jian)接排(pai)(pai)(pai)放(fang)(fang)(fang)方面(mian)的(de)研究較(jiao)(jiao)(jiao)為深入,技術方向(xiang)也較(jiao)(jiao)(jiao)明確(que),相關研究主要(yao)集中在節能(neng)降耗和污水(shui)(shui)能(neng)源回(hui)用兩個(ge)方面(mian)。北京(jing)城市排(pai)(pai)(pai)水(shui)(shui)集團(tuan)與深圳(zhen)水(shui)(shui)務集團(tuan)兩家規(gui)模較(jiao)(jiao)(jiao)大的(de)水(shui)(shui)務公司曾分別對(dui)污水(shui)(shui)處理過(guo)程(cheng)溫室(shi)氣體排(pai)(pai)(pai)放(fang)(fang)(fang)情況進行測算,結果表明在污水(shui)(shui)處理的(de)過(guo)程(cheng)中,因電力消耗導致的(de)間(jian)接排(pai)(pai)(pai)放(fang)(fang)(fang)及脫氮過(guo)程(cheng)中產生(sheng)的(de)氮氧化物直接排(pai)(pai)(pai)放(fang)(fang)(fang)是溫室(shi)氣體排(pai)(pai)(pai)放(fang)(fang)(fang)量的(de)主要(yao)組成,占排(pai)(pai)(pai)放(fang)(fang)(fang)總量的(de)80%～90%。

二(er)、水務行業(ye)碳(tan)減排可行性與(yu)路徑分析

1.供水過(guo)程的碳減排可行路(lu)徑

供水過程中的(de)碳(tan)(tan)排放主要集中在管網輸送(song)及處理設備用電(dian)、藥劑使用,減(jian)(jian)少(shao)藥劑消耗、推動節(jie)能(neng)減(jian)(jian)排、減(jian)(jian)少(shao)單位(wei)能(neng)耗碳(tan)(tan)排放量等措施(shi)均(jun)有(you)助于(yu)實現供水環節(jie)的(de)碳(tan)(tan)減(jian)(jian)排。

1.1 水(shui)源(yuan)保護

現(xian)代飲用水(shui)在加工處理過程(cheng)中,需經(jing)加氯消毒去除大部分(fen)微生(sheng)物,先后經(jing)混凝沉降、煤砂濾(lv)池、活性炭池的(de)(de)(de)過濾(lv)和吸附進行處理。因(yin)此(ci),優質(zhi)的(de)(de)(de)水(shui)源地將提供更高(gao)(gao)品質(zhi)的(de)(de)(de)原水(shui),相應地,其處理過程(cheng)所消耗的(de)(de)(de)藥劑量更低(di),碳(tan)排(pai)放更低(di)。強(qiang)化對水(shui)源地的(de)(de)(de)保護,不僅有助(zhu)于提高(gao)(gao)生(sheng)態環境質(zhi)量,還能夠降低(di)凈水(shui)處理過程(cheng)中間接碳(tan)排(pai)放。

1.2 新能源應用

提高非(fei)化石(shi)能(neng)(neng)源(yuan)發電(dian)(dian)(dian)(dian)(dian)量是(shi)電(dian)(dian)(dian)(dian)(dian)力(li)行(xing)業實(shi)(shi)現“碳(tan)達峰”的(de)(de)(de)(de)重要途徑(jing)。研究表明,水(shui)廠的(de)(de)(de)(de)能(neng)(neng)源(yuan)消(xiao)耗(hao)(hao)占到(dao)總(zong)(zong)成本的(de)(de)(de)(de)20%以(yi)上(shang),其中包括水(shui)泵、風機等在(zai)內(nei)的(de)(de)(de)(de)關(guan)鍵能(neng)(neng)耗(hao)(hao)設(she)(she)備耗(hao)(hao)能(neng)(neng)超過(guo)總(zong)(zong)能(neng)(neng)耗(hao)(hao)的(de)(de)(de)(de)85%。中電(dian)(dian)(dian)(dian)(dian)聯(lian)相關(guan)數據表明,2020年(nian)和(he)(he)2021年(nian)全國全口徑(jing)非(fei)化石(shi)能(neng)(neng)源(yuan)發電(dian)(dian)(dian)(dian)(dian)量分(fen)別為(wei)9.8×108 kW和(he)(he)1.11×109 kW,分(fen)別占到(dao)當(dang)年(nian)總(zong)(zong)發電(dian)(dian)(dian)(dian)(dian)裝機容量的(de)(de)(de)(de)44.7%與47%。提高水(shui)廠用(yong)電(dian)(dian)(dian)(dian)(dian)中非(fei)化石(shi)能(neng)(neng)源(yuan)的(de)(de)(de)(de)比例,可有效降低(di)凈水(shui)處理過(guo)程(cheng)(cheng)中的(de)(de)(de)(de)能(neng)(neng)耗(hao)(hao)與碳(tan)排(pai)放。東京自來水(shui)公司結合試(shi)運行(xing)計(ji)算與實(shi)(shi)際發電(dian)(dian)(dian)(dian)(dian)成效,評估太陽能(neng)(neng)發電(dian)(dian)(dian)(dian)(dian)設(she)(she)備和(he)(he)水(shui)力(li)發電(dian)(dian)(dian)(dian)(dian)設(she)(she)備的(de)(de)(de)(de)使用(yong)壽命分(fen)別為(wei)20年(nian)和(he)(he)22年(nian),在(zai)公共系統(tong)的(de)(de)(de)(de)支持下(xia),通過(guo)自用(yong)和(he)(he)售電(dian)(dian)(dian)(dian)(dian)獲利的(de)(de)(de)(de)方(fang)式,可適當(dang)降低(di)電(dian)(dian)(dian)(dian)(dian)力(li)成本、減少碳(tan)排(pai)放,有望在(zai)壽命期內(nei)收回建(jian)(jian)(jian)設(she)(she)和(he)(he)維護成本。豐(feng)順(shun)大(da)羅水(shui)廠的(de)(de)(de)(de)建(jian)(jian)(jian)設(she)(she)過(guo)程(cheng)(cheng)中充(chong)分(fen)利用(yong)了(le)廠區建(jian)(jian)(jian)筑物房頂及池體(ti),通過(guo)采(cai)用(yong)“門(men)式剛架屋面加蓋”等方(fang)式的(de)(de)(de)(de)光伏設(she)(she)備鋪(pu)設(she)(she),為(wei)廠區生產用(yong)電(dian)(dian)(dian)(dian)(dian)提供(gong)保障并(bing)抑制(zhi)了(le)池體(ti)內(nei)水(shui)藻生長。

1.3 技術(shu)創新

少(shao)人/無(wu)人化(hua)水(shui)(shui)(shui)(shui)(shui)廠(chang)是當前現代化(hua)水(shui)(shui)(shui)(shui)(shui)廠(chang)發展的(de)(de)主(zhu)要(yao)目標之一(yi),為實(shi)現高(gao)(gao)效(xiao)、少(shao)人工、自(zi)(zi)動化(hua)的(de)(de)設備運(yun)(yun)行,將電(dian)氣(qi)自(zi)(zi)動化(hua)及人工智能運(yun)(yun)用(yong)于水(shui)(shui)(shui)(shui)(shui)廠(chang),將有(you)(you)助于提(ti)(ti)高(gao)(gao)生(sheng)(sheng)產管理(li)效(xiao)率(lv),保障(zhang)供水(shui)(shui)(shui)(shui)(shui)可(ke)靠(kao)性(xing),降(jiang)低(di)誤差、減(jian)少(shao)能耗(圖(tu)2)。以蘇州吳中(zhong)水(shui)(shui)(shui)(shui)(shui)廠(chang)為例,該廠(chang)通過(guo)電(dian)氣(qi)自(zi)(zi)動化(hua)控(kong)制系統(tong)的(de)(de)應用(yong),實(shi)現精準(zhun)排泥,同時自(zi)(zi)動加(jia)藥系統(tong)能夠與水(shui)(shui)(shui)(shui)(shui)源(yuan)地水(shui)(shui)(shui)(shui)(shui)質(zhi)(zhi)、過(guo)程水(shui)(shui)(shui)(shui)(shui)水(shui)(shui)(shui)(shui)(shui)質(zhi)(zhi)、出(chu)廠(chang)水(shui)(shui)(shui)(shui)(shui)水(shui)(shui)(shui)(shui)(shui)質(zhi)(zhi)實(shi)現多參數聯動,通過(guo)數據指導(dao)生(sheng)(sheng)產管理(li),有(you)(you)效(xiao)降(jiang)低(di)了(le)(le)能耗,提(ti)(ti)高(gao)(gao)了(le)(le)工作效(xiao)率(lv)。其自(zi)(zi)研的(de)(de)管網補氯(lv)一(yi)體化(hua)裝(zhuang)置可(ke)實(shi)現聯網全自(zi)(zi)動化(hua)運(yun)(yun)行,降(jiang)低(di)前端余(yu)(yu)氯(lv)指標,有(you)(you)效(xiao)提(ti)(ti)升下游管網余(yu)(yu)氯(lv),提(ti)(ti)升用(yong)水(shui)(shui)(shui)(shui)(shui)品質(zhi)(zhi)(圖(tu)3)。武漢余(yu)(yu)氏墩水(shui)(shui)(shui)(shui)(shui)廠(chang)在自(zi)(zi)動化(hua)改(gai)造中(zhong),建設了(le)(le)采用(yong)PLC控(kong)制的(de)(de)自(zi)(zi)動加(jia)藥控(kong)制系統(tong)、進排水(shui)(shui)(shui)(shui)(shui)自(zi)(zi)動控(kong)制系統(tong)等,實(shi)現均勻(yun)配水(shui)(shui)(shui)(shui)(shui)、穩定出(chu)水(shui)(shui)(shui)(shui)(shui),降(jiang)低(di)了(le)(le)能耗。

圖2 自動(dong)化智能加藥(yao)投加系統使沉淀池出水渾濁度(du)波(bo)動(dong)減(jian)少(shao)50%,出水余氯指標(biao)波(bo)動(dong)減(jian)少(shao)45%

圖3 全自動(dong)管網(wang)補氯一體化裝置實現凈水消毒及(ji)自動(dong)檢測

在(zai)(zai)工(gong)(gong)(gong)作(zuo)(zuo)實踐中(zhong),電氣自(zi)動化(hua)控制(zhi)技術(shu)對(dui)(dui)提高生(sheng)產效率、減少勞動力(li)(li)成本、降低能(neng)源與材(cai)料的(de)消耗(hao)等有(you)著較為明顯(xian)的(de)積極作(zuo)(zuo)用(yong)(yong),然(ran)而其在(zai)(zai)面對(dui)(dui)部(bu)分(fen)生(sheng)產預警(jing)時,相(xiang)比于工(gong)(gong)(gong)作(zuo)(zuo)閱歷豐富(fu)的(de)熟練技術(shu)工(gong)(gong)(gong)、工(gong)(gong)(gong)程師,存(cun)在(zai)(zai)處理上(shang)的(de)滯(zhi)后(hou)性,且對(dui)(dui)于突發性問題(ti)的(de)解決(jue)能(neng)力(li)(li)有(you)限(xian),仍需人力(li)(li)介入。因此,推動發展(zhan)供水(shui)行業(ye)人工(gong)(gong)(gong)智能(neng)技術(shu)尤(you)為重(zhong)要,可依(yi)托人工(gong)(gong)(gong)神經網絡與自(zi)我學習能(neng)力(li)(li),預測用(yong)(yong)水(shui)需求并智能(neng)化(hua)調控設(she)備功率,實時依(yi)照水(shui)源質量(liang)調節(jie)工(gong)(gong)(gong)藝確保出水(shui)穩定(ding),智能(neng)預測水(shui)質波動并及時預警(jing)等。

1.4 節水措施(shi)

我國供(gong)水(shui)管(guan)(guan)(guan)(guan)網建設(she)年代跨度大,管(guan)(guan)(guan)(guan)道類型普遍有(you)鋼管(guan)(guan)(guan)(guan)、鑄(zhu)鐵、球(qiu)墨鑄(zhu)鐵、預應(ying)力混凝(ning)土、塑料等,管(guan)(guan)(guan)(guan)道布置日益(yi)復雜緊密,受地質(zhi)變化、路面沉降、施工、材(cai)料老化、道路振動等因素(su)影(ying)響,自來水(shui)管(guan)(guan)(guan)(guan)道滲(shen)漏(lou)(lou)難以避免。滲(shen)漏(lou)(lou)導致的(de)凈水(shui)外泄將進一步(bu)提(ti)高水(shui)廠面對同等用水(shui)需求時的(de)處理水(shui)量(liang),有(you)必要(yao)對管(guan)(guan)(guan)(guan)網巡查、檢漏(lou)(lou)專業工作人(ren)員強化學(xue)習(xi),并更新檢測(ce)技(ji)術,進而(er)確保供(gong)水(shui)管(guan)(guan)(guan)(guan)網運行穩(wen)定。

2.排水(shui)過程的碳減排可行路(lu)徑(jing)

與(yu)鋼鐵、有(you)色(se)金屬行(xing)(xing)業等(deng)高耗(hao)能(neng)(neng)的行(xing)(xing)業相(xiang)比,污水處(chu)理(li)系統的能(neng)(neng)耗(hao)因其相(xiang)對較低(di)(di),被(bei)人們長期忽視,但實際上污水處(chu)理(li)也屬于能(neng)(neng)耗(hao)密集(ji)型行(xing)(xing)業。通過強化(hua)(hua)資(zi)源(yuan)再利(li)用、優化(hua)(hua)污水處(chu)理(li)工藝與(yu)技術、降低(di)(di)單(dan)位用電碳排(pai)放等(deng)有(you)助于污水廠(chang)實現節能(neng)(neng)減排(pai)。

2.1 廢(fei)水回用

對(dui)于經處理后(hou)達(da)到非飲用(yong)水(shui)(shui)標準的尾水(shui)(shui),可在檢測后(hou)確保其達(da)到相(xiang)關回用(yong)水(shui)(shui)質要求,用(yong)于不(bu)與(yu)人體(ti)直接接觸(chu)的用(yong)水(shui)(shui),例(li)如可用(yong)于廠區/園區綠化(hua)用(yong)水(shui)(shui)、風機(ji)冷卻(que)循環水(shui)(shui)及帶式(shi)脫水(shui)(shui)機(ji)的濾(lv)帶沖洗(xi)水(shui)(shui)等。

2.2 技(ji)術創新(xin)

生活(huo)污(wu)(wu)水(shui)(shui)的(de)處理(li)技術(shu)(shu)多(duo)種多(duo)樣,但目前應用(yong)廣泛、技術(shu)(shu)成熟(shu)的(de)處理(li)技術(shu)(shu)一(yi)般是通(tong)過(guo)外(wai)部(bu)添加能(neng)源、碳(tan)源或藥(yao)劑對(dui)(dui)污(wu)(wu)染(ran)物(wu)(wu)進(jin)行降解,此過(guo)程(cheng)會向(xiang)外(wai)界環(huan)境排放大量(liang)溫(wen)室氣(qi)體,減少額外(wai)能(neng)量(liang)、碳(tan)源的(de)輸(shu)(shu)(shu)入(ru),將有(you)助于(yu)降低污(wu)(wu)水(shui)(shui)廠(chang)碳(tan)排放。在(zai)副產品利(li)(li)用(yong)方面,當前的(de)工(gong)(gong)藝(yi)技術(shu)(shu)中多(duo)采用(yong)焚(fen)燒發(fa)(fa)(fa)電(dian)(dian)、厭氧消化(hua)(hua)產出甲(jia)烷、生物(wu)(wu)產氫等(deng)途(tu)徑,對(dui)(dui)污(wu)(wu)水(shui)(shui)處理(li)過(guo)程(cheng)中其副產物(wu)(wu)污(wu)(wu)泥進(jin)行能(neng)源轉化(hua)(hua)。例(li)如,日(ri)本(ben)部(bu)分(fen)污(wu)(wu)水(shui)(shui)廠(chang)將熱能(neng)用(yong)于(yu)供暖及(ji)融雪工(gong)(gong)程(cheng);德國卡地茨污(wu)(wu)水(shui)(shui)處理(li)廠(chang)綜(zong)合利(li)(li)用(yong)太陽(yang)(yang)能(neng)發(fa)(fa)(fa)電(dian)(dian)、廢水(shui)(shui)發(fa)(fa)(fa)電(dian)(dian)、熱能(neng)發(fa)(fa)(fa)電(dian)(dian)、沼(zhao)氣(qi)發(fa)(fa)(fa)電(dian)(dian)4種發(fa)(fa)(fa)電(dian)(dian)方式解決廠(chang)區(qu)自身電(dian)(dian)能(neng)需求;青島光威污(wu)(wu)水(shui)(shui)處理(li)廠(chang)、六圩污(wu)(wu)水(shui)(shui)處理(li)廠(chang)利(li)(li)用(yong)沼(zhao)氣(qi)發(fa)(fa)(fa)電(dian)(dian)技術(shu)(shu)減少外(wai)部(bu)輸(shu)(shu)(shu)入(ru)電(dian)(dian)能(neng)。Schaubroeck等(deng)與(yu)Besson等(deng)將生命周期評估法(fa)應用(yong)于(yu)奧地利(li)(li)Strass污(wu)(wu)水(shui)(shui)處理(li)廠(chang)的(de)工(gong)(gong)藝(yi)研究,表明污(wu)(wu)泥消化(hua)(hua)產生的(de)沼(zhao)氣(qi)等(deng)可生產充足電(dian)(dian)力并對(dui)(dui)外(wai)輸(shu)(shu)(shu)出并網,獲取一(yi)定經(jing)濟(ji)利(li)(li)益。圖4展示了(le)美國格(ge)雷沙(sha)姆污(wu)(wu)水(shui)(shui)處理(li)廠(chang)通(tong)過(guo)工(gong)(gong)藝(yi)優化(hua)(hua)提高(gao)沼(zhao)氣(qi)產量(liang),使用(yong)燃氣(qi)發(fa)(fa)(fa)電(dian)(dian)機組將可再(zai)生沼(zhao)氣(qi)熱電(dian)(dian)聯產與(yu)太陽(yang)(yang)能(neng)發(fa)(fa)(fa)電(dian)(dian)協(xie)同(tong)利(li)(li)用(yong),實現能(neng)源凈零,厭氧發(fa)(fa)(fa)酵(jiao)池的(de)副產品仍可作為肥料回用(yong)于(yu)農田。

圖4 美國俄勒岡州格(ge)雷沙姆污水處理廠(chang)建設熱電聯(lian)產系(xi)統,通過可再生(sheng)沼氣熱電聯(lian)產和太(tai)陽能(neng)發(fa)電實現能(neng)源自給

王京凡等的研究也指出(chu),未來可持(chi)續(xu)的工藝(yi)是(shi)新型AB工藝(yi),即(ji)A段負責高效碳(tan)捕獲,目的是(shi)使污(wu)水(shui)中的有(you)機(ji)物(wu)在生物(wu)氧化之前(qian)被捕獲,后續(xu)用(yong)于能量(liang)回收,B段實施(shi)低碳(tan)新技術(shu)(如使用(yong)厭(yan)氧氨氧化技術(shu)減(jian)少(shao)外加碳(tan)源),進一步去除污(wu)水(shui)中的污(wu)染(ran)物(wu)。

2.3 新能源應(ying)用

國內污水(shui)廠(chang)(chang)的(de)耗電(dian)(dian)量普遍達0.29 kW·h/m3,相較于(yu)美國的(de)污水(shui)廠(chang)(chang)耗電(dian)(dian)量(0.2 kW·h/m3)而言(yan),該數據顯然遠超發達國家。通過工藝改進(jin),在(zai)(zai)降(jiang)(jiang)低單位廢水(shui)處理耗電(dian)(dian)量的(de)同時,減(jian)少的(de)單位電(dian)(dian)耗碳排放量將(jiang)(jiang)有(you)助于(yu)降(jiang)(jiang)低廠(chang)(chang)區整體(ti)碳排放量。污水(shui)廠(chang)(chang)占地(di)(di)較大(da)、樓層較低,采用太陽能、風能等(deng)新(xin)能源(yuan)將(jiang)(jiang)有(you)助于(yu)減(jian)少廠(chang)(chang)區所用市(shi)電(dian)(dian)需(xu)求量(圖5),Goswami等(deng)研究了(le)在(zai)(zai)污水(shui)處理系(xi)統(tong)(tong)(tong)中開發浮動太陽能光(guang)伏(fu)(FSPV)系(xi)統(tong)(tong)(tong),將(jiang)(jiang)光(guang)伏(fu)組件漂浮在(zai)(zai)水(shui)面上實(shi)(shi)現太陽能發電(dian)(dian),15 MW太陽能光(guang)伏(fu)系(xi)統(tong)(tong)(tong)可(ke)向電(dian)(dian)網供能26 465.7 MW·h/年,減(jian)少蒸發788萬m3的(de)水(shui),減(jian)少CO2排放量近52萬t,有(you)助于(yu)污水(shui)廠(chang)(chang)向可(ke)持續發展轉型。劉(liu)玉濤等(deng)對山(shan)東某(mou)地(di)(di)下污水(shui)廠(chang)(chang)開展實(shi)(shi)例分(fen)析,論證了(le)通過建設包含光(guang)伏(fu)發電(dian)(dian)、沼(zhao)氣發電(dian)(dian)等(deng)在(zai)(zai)內的(de)多能互補綜合能源(yuan)系(xi)統(tong)(tong)(tong),可(ke)實(shi)(shi)現污水(shui)廠(chang)(chang)的(de)穩定(ding)供電(dian)(dian),每年可(ke)節約標準煤2 855 t,減(jian)排CO2以及其他(ta)大(da)氣污染物(wu)排放7 699 t。

圖(tu)5 建設污水廠光伏電(dian)站提供綠色(se)清潔電(dian)能

三、總結與(yu)建議

1.打造(zao)“低碳水務”是邁向水務“碳中和”的必由之路

水(shui)是人類日常生(sheng)活和社會(hui)發(fa)展(zhan)不(bu)可(ke)或缺的(de)(de)重要物質資源,污水(shui)直(zhi)排(pai)所產生(sheng)的(de)(de)黑臭水(shui)體在厭氧(yang)環境中(zhong)(zhong)會(hui)增加大量(liang)(liang)碳(tan)排(pai)放。水(shui)務(wu)行業(ye)的(de)(de)減(jian)碳(tan)舉措既(ji)能(neng)(neng)夠直(zhi)接推進水(shui)環境治理環節的(de)(de)碳(tan)排(pai)放協同(tong)控(kong)制,又可(ke)有(you)效覆蓋全行業(ye)用水(shui)過程的(de)(de)碳(tan)減(jian)排(pai)。“低碳(tan)水(shui)務(wu)”可(ke)通過新(xin)技術的(de)(de)應(ying)用降低單位用電量(liang)(liang)和藥劑投加量(liang)(liang),從而(er)減(jian)少額(e)外能(neng)(neng)量(liang)(liang)和碳(tan)源的(de)(de)輸入,同(tong)時(shi)依靠廠區(qu)內新(xin)能(neng)(neng)源的(de)(de)使(shi)用、副產物能(neng)(neng)源轉化等方式實現供排(pai)水(shui)行業(ye)“碳(tan)中(zhong)(zhong)和”目(mu)標(biao)。

2.實現(xian)水務行業“碳(tan)中和”的關鍵是管(guan)理策(ce)略與技術創新

(1)明確階段發展目標,提高從(cong)業(ye)人員對水務行業(ye)實現(xian)“碳(tan)中和(he)”的共識。

水(shui)務(wu)行(xing)(xing)業(ye)實(shi)現(xian)“碳(tan)(tan)中(zhong)(zhong)(zhong)(zhong)和(he)(he)”不是一(yi)蹴而(er)就的(de),既要(yao)(yao)避免運動式的(de)“碳(tan)(tan)沖鋒”,也要(yao)(yao)避免全(quan)行(xing)(xing)業(ye)從業(ye)者對實(shi)現(xian)“碳(tan)(tan)中(zhong)(zhong)(zhong)(zhong)和(he)(he)”的(de)“事不關己”。需要(yao)(yao)明確階段性(xing)(xing)發展目(mu)標,優(you)先減少廠區(qu)能(neng)耗(hao)(hao)、物耗(hao)(hao),結(jie)合(he)技術(shu)(shu)創新、工(gong)(gong)藝改(gai)良(liang)實(shi)現(xian)“碳(tan)(tan)達峰(feng)”,再進一(yi)步(bu)(bu)通(tong)過引入新能(neng)源、降低(di)單位水(shui)處理(li)碳(tan)(tan)排(pai)放過渡至“碳(tan)(tan)中(zhong)(zhong)(zhong)(zhong)和(he)(he)”。通(tong)過階段性(xing)(xing)目(mu)標的(de)設立及(ji)從業(ye)人員培訓,逐(zhu)步(bu)(bu)提(ti)高水(shui)務(wu)行(xing)(xing)業(ye)工(gong)(gong)作人員對實(shi)現(xian)“碳(tan)(tan)中(zhong)(zhong)(zhong)(zhong)和(he)(he)”必(bi)要(yao)(yao)性(xing)(xing)、緊迫性(xing)(xing)的(de)認識,自上而(er)下與(yu)自下而(er)上同步(bu)(bu)提(ti)高全(quan)行(xing)(xing)業(ye)探(tan)索節能(neng)減排(pai)技術(shu)(shu)與(yu)管理(li)措施及(ji)積(ji)極性(xing)(xing)。

(2)研發低碳處置(zhi)技術,促進(jin)產業轉型與升級。

進一步研發(fa)凈(jing)水處(chu)理(li)、污水處(chu)置過程(cheng)中(zhong)的新(xin)技術(shu)、新(xin)設備,提高處(chu)理(li)運行(xing)(xing)效率、減少能(neng)耗與藥耗、增(zeng)加能(neng)源(yuan)回收利用(yong)比例,積極開(kai)發(fa)包括太(tai)陽(yang)能(neng)、風能(neng)等適用(yong)于水務行(xing)(xing)業的可再生(sheng)能(neng)源(yuan),推動工藝(yi)過程(cheng)無人化(hua)、處(chu)理(li)裝置智能(neng)化(hua),實現水務行(xing)(xing)業處(chu)理(li)廠穩(wen)定運行(xing)(xing)、節約外(wai)能(neng)輸入、資源(yuan)再利用(yong),使相關(guan)處(chu)理(li)過程(cheng)由能(neng)源(yuan)消耗型轉化(hua)為能(neng)源(yuan)外(wai)溢型,實現“碳(tan)中(zhong)和(he)”運行(xing)(xing),促進包括溫室氣體減排技術(shu)在內(nei)的研發(fa)與應用(yong)。

(3)開展全生命周期評價,推動行業全產業鏈碳減排。

全(quan)生命周期(qi)(qi)評(ping)價(jia)有(you)助于(yu)清晰量化(hua)各流程(cheng)中物質流動(dong)時碳(tan)排(pai)(pai)放(fang)(fang)情(qing)況,分析碳(tan)足跡,評(ping)估(gu)不同(tong)流程(cheng)、不同(tong)技術下廠(chang)區(qu)溫室(shi)氣體(ti)(ti)排(pai)(pai)放(fang)(fang)潛能。應進(jin)一步健(jian)全(quan)水(shui)(shui)務行業全(quan)鏈(lian)條(tiao)產品(pin)生命周期(qi)(qi)評(ping)價(jia),實(shi)現“水(shui)(shui)源-凈水(shui)(shui)處置-終(zhong)端(duan)用水(shui)(shui)-污水(shui)(shui)處置-排(pai)(pai)水(shui)(shui)”全(quan)過程(cheng)碳(tan)排(pai)(pai)放(fang)(fang)評(ping)價(jia),為開發綠色(se)低碳(tan)水(shui)(shui)務產品(pin)、進(jin)一步降低水(shui)(shui)務行業碳(tan)排(pai)(pai)放(fang)(fang)提供支撐。

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