摘要： 中國 正著手開(kai)展一(yi)(yi)項遠大的(de)開(kai)發計(ji)劃，來 發展 其污(wu)水處理的(de)基礎建設，以增進(jin)(jin)公眾健康和促進(jin)(jin)環境保(bao)護，同(tong)時(shi)還將(jiang)通過減小現(xian)有地表(biao)和地下水資(zi)源的(de)污(wu)染來擴(kuo)大水資(zi)源。這(zhe)(zhe)將(jiang)提供一(yi)(yi)個進(jin)(jin)一(yi)(yi)步利用(yong)(yong)水資(zi)源的(de)機(ji)會-水的(de)回收(shou)和利用(yong)(yong)。中國清楚地認識到(dao)了這(zhe)(zhe)一(yi)(yi)點，并(bing)積極地抓(zhua)住這(zhe)(zhe)一(yi)(yi)時(shi)機(ji)使回用(yong)(yong)水納入開(kai)發計(ji)劃之中。與(yu)此同(tong)時(shi)，中國也在努力地 學習(xi) 其他(ta)國家的(de)經驗，來實(shi)施該項計(ji)劃。

關(guan)鍵詞：再生回用(yong)水 回收和利用(yong) 環境保護

本文要(yao)講述三條有助(zhu)于中國實(shi)施這項計劃(hua)的指導性原則，即：

1. 回用水(shui)是(shi)整個(ge)(ge)水(shui)管理系統的一(yi)個(ge)(ge)組成部分。

2. 需要(yao)用系統(tong)的 方法(fa) 來評價(jia)水(shui)回用的 經濟 效益。

3. 有很多方法可以用來減小回用水對(dui)公眾健康和(he)環(huan)境(jing)造成的風險。

在(zai)本(ben)文中討論了每條原則對于在(zai)中國成功(gong)的實現(xian)廢水回用的適用性(xing)。

前言

中(zhong)國(guo)(guo)正在致力于開展一項有遠大的(de)開發(fa)(fa)(fa)計(ji)劃以發(fa)(fa)(fa)展其污(wu)水處理的(de)基礎建(jian)(jian)設(she)。結果不僅將增進公眾健康和(he)環(huan)境保護，同(tong)時(shi)(shi)還由于減輕了(le)現(xian)有地(di)表(biao)和(he)地(di)下(xia)水資(zi)(zi)源的(de)污(wu)染而擴大了(le)水資(zi)(zi)源。后者對于象中(zhong)國(guo)(guo)這樣(yang)人均水資(zi)(zi)源相對較(jiao)低的(de)國(guo)(guo)家(jia)(jia)來說尤(you)為重要(yao)。擴建(jian)(jian)廢水處理基礎設(she)施，也(ye)為中(zhong)國(guo)(guo)提(ti)供(gong)了(le)一個進一步利用(yong)水資(zi)(zi)源的(de)機會--污(wu)水的(de)回用(yong)。中(zhong)國(guo)(guo)清楚地(di)認識到(dao)了(le)這一點(dian)，并抓住時(shi)(shi)機將水回用(yong)列入到(dao)正在進行(xing)的(de)開發(fa)(fa)(fa)計(ji)劃之(zhi)中(zhong)。與此同(tong)時(shi)(shi)，中(zhong)國(guo)(guo)也(ye)在認真學習其他國(guo)(guo)家(jia)(jia)的(de)經驗，來實施該項計(ji)劃。

本文(wen)的(de)(de)目(mu)的(de)(de)是(shi)對中(zhong)國進(jin)行水(shui)回用(yong)提(ti)出一些(xie)(xie)建議(yi)。這些(xie)(xie)建議(yi)都(dou)是(shi)根據美國和(he)世(shi)界其他(ta)(ta)國家的(de)(de)廣(guang)泛(fan)經(jing)(jing)驗(yan)提(ti)出來的(de)(de)。本文(wen)不可能提(ti)供關于(yu)水(shui)回用(yong)的(de)(de)所有相關知識(shi)，在別的(de)(de) 文(wen)獻 (美國EPA,1998)和(he)這次會議(yi)的(de)(de)其他(ta)(ta)資料中(zhong)都(dou)有許(xu)多經(jing)(jing)驗(yan)需要我們學習。但是(shi)，這里提(ti)到的(de)(de)經(jing)(jing)驗(yan)是(shi)中(zhong)國決(jue)策者決(jue)定回用(yong)水(shui)計劃實(shi)施(shi)和(he) 應(ying)用(yong) 的(de)(de)關鍵。這些(xie)(xie)建議(yi)包括(kuo)三個指導性的(de)(de)原則，如(ru)表1所示(shi)。文(wen)章后面(mian)將對這三個指導性原則進(jin)行一一論(lun)述。

Paper Presented at " The 21st Century International Conference & Exhibition on Developing Strategy of Urban Wastewater Treatment and Reuse", Sponsored by the Chinese Ministry of Construction, The World Bank, and the United Nations Industrial Development Organization, BEijing, China, November 27-29, 2001.

6060 South Willow Drive, Greenwood Village, Colorado 80111, USA. gdaigger@ch2m.com.

指導(dao)性原(yuan)則之(zhi)一：水(shui)回用是整個水(shui)管理系(xi)統(tong)的一個組成部分

任何水(shui)(shui)(shui)(shui)回(hui)用(yong)計(ji)劃的(de)(de)(de)(de)(de)主要(yao)目的(de)(de)(de)(de)(de)之一(yi)是通過以回(hui)用(yong)水(shui)(shui)(shui)(shui)替代現(xian)有(you)的(de)(de)(de)(de)(de)使用(yong)水(shui)(shui)(shui)(shui)來(lai)擴大水(shui)(shui)(shui)(shui)資源。結(jie)果這些淡水(shui)(shui)(shui)(shui)資源被替代后(hou)就可另做它用(yong)。水(shui)(shui)(shui)(shui)回(hui)用(yong)就整個(ge)水(shui)(shui)(shui)(shui)資源來(lai)說得了(le)兩方面利(li)益(yi)。其一(yi)，很簡單，處理后(hou)的(de)(de)(de)(de)(de)水(shui)(shui)(shui)(shui)連同其所含的(de)(de)(de)(de)(de)污染物(wu)不(bu)(bu)再被排放，因(yin)此(ci)不(bu)(bu)污染現(xian)存(cun)的(de)(de)(de)(de)(de)水(shui)(shui)(shui)(shui)資源(即于(yu)水(shui)(shui)(shui)(shui)質有(you)益(yi))。其二，處理后(hou)的(de)(de)(de)(de)(de)水(shui)(shui)(shui)(shui)再回(hui)用(yong)減少(shao)了(le)為(wei)了(le)滿(man)足用(yong)水(shui)(shui)(shui)(shui)要(yao)求而(er)必須從環境中取水(shui)(shui)(shui)(shui)的(de)(de)(de)(de)(de)數量(即于(yu)水(shui)(shui)(shui)(shui)量有(you)益(yi))。

現有幾種不同目(mu)的(de)的(de)回(hui)用水方式(shi)，包括：

●農田灌溉

● 工業 用水(shui)

●城市非飲用水(澆灌，沖廁，環(huan)境修(xiu)復)

●非直接飲用(yong)性的回用(yong)

表(biao)2列舉(ju)(ju)了每一(yi)種水(shui)(shui)(shui)(shui)回(hui)(hui)(hui)用(yong)(yong)(yong)(yong)的(de)(de)例子，表(biao)明了在(zai)發達國(guo)家如(ru)美國(guo)、新加坡每一(yi)種水(shui)(shui)(shui)(shui)回(hui)(hui)(hui)用(yong)(yong)(yong)(yong)的(de)(de)方(fang)式(shi)(shi)都得(de)(de)到廣泛的(de)(de)應(ying)(ying)用(yong)(yong)(yong)(yong)。這(zhe)(zhe)些應(ying)(ying)用(yong)(yong)(yong)(yong)都是以水(shui)(shui)(shui)(shui)處(chu)(chu)理(li)技(ji)(ji)術(shu)(shu)(shu)(shu)作為支(zhi)持(chi)的(de)(de)。總(zong)之(zhi)，采取可利(li)用(yong)(yong)(yong)(yong)的(de)(de)水(shui)(shui)(shui)(shui)處(chu)(chu)理(li)技(ji)(ji)術(shu)(shu)(shu)(shu)來支(zhi)持(chi)每一(yi)種水(shui)(shui)(shui)(shui)回(hui)(hui)(hui)用(yong)(yong)(yong)(yong)的(de)(de)方(fang)式(shi)(shi)，使水(shui)(shui)(shui)(shui)超過(guo)或(huo)達到(就水(shui)(shui)(shui)(shui)質(zhi)而言)非直接(jie)飲用(yong)(yong)(yong)(yong)的(de)(de)要求，而非飲用(yong)(yong)(yong)(yong)水(shui)(shui)(shui)(shui)的(de)(de)增加也(ye)就直接(jie)地(di)增加了供(gong)(gong)(gong)水(shui)(shui)(shui)(shui)量(liang)(無(wu)論是如(ru)表(biao)2所列舉(ju)(ju)的(de)(de)地(di)表(biao)水(shui)(shui)(shui)(shui)供(gong)(gong)(gong)給還是地(di)下水(shui)(shui)(shui)(shui)供(gong)(gong)(gong)給)。因此(ci)，合適的(de)(de)回(hui)(hui)(hui)用(yong)(yong)(yong)(yong)水(shui)(shui)(shui)(shui)處(chu)(chu)理(li)技(ji)(ji)術(shu)(shu)(shu)(shu)的(de)(de)可行(xing)性使水(shui)(shui)(shui)(shui)回(hui)(hui)(hui)用(yong)(yong)(yong)(yong)不受限(xian)制(zhi)。隨著(zhu)膜(mo)(mo)技(ji)(ji)術(shu)(shu)(shu)(shu)的(de)(de)發展這(zhe)(zhe)將變為現(xian)實。膜(mo)(mo)技(ji)(ji)術(shu)(shu)(shu)(shu)包括兩(liang)個方(fang)面，其(qi)(qi)一(yi)是在(zai)二級處(chu)(chu)理(li)后的(de)(de)膜(mo)(mo)處(chu)(chu)理(li)技(ji)(ji)術(shu)(shu)(shu)(shu)，即(ji)應(ying)(ying)用(yong)(yong)(yong)(yong)微濾(lv)或(huo)超濾(lv)，再緊接(jie)著(zhu)應(ying)(ying)用(yong)(yong)(yong)(yong)反滲透的(de)(de)技(ji)(ji)術(shu)(shu)(shu)(shu)(AWWA，1996);其(qi)(qi)二是應(ying)(ying)用(yong)(yong)(yong)(yong)膜(mo)(mo)生物反應(ying)(ying)器(qi)(Gunder,2001;Stephenson,等，2000)。這(zhe)(zhe)些技(ji)(ji)術(shu)(shu)(shu)(shu)將在(zai)本(ben)次會議的(de)(de)其(qi)(qi)他論文(wen)中進行(xing)詳(xiang)細的(de)(de)討論。當(dang)需(xu)求高質(zhi)量(liang)的(de)(de)回(hui)(hui)(hui)用(yong)(yong)(yong)(yong)水(shui)(shui)(shui)(shui)時，應(ying)(ying)當(dang)使處(chu)(chu)理(li)水(shui)(shui)(shui)(shui)平得(de)(de)到極大的(de)(de)提高。

當處(chu)(chu)(chu)理(li)(li)方(fang)式和(he)系(xi)(xi)統(tong)(tong)構造成(cheng)為回(hui)(hui)用(yong)(yong)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)總體(ti)布置考慮(lv)的(de)(de)(de)(de)(de)一(yi)個因素(su)時(shi)，廢水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)的(de)(de)(de)(de)(de)收(shou)(shou)集(ji)(ji)和(he)分配系(xi)(xi)統(tong)(tong)的(de)(de)(de)(de)(de)也是一(yi)個要著重考慮(lv)的(de)(de)(de)(de)(de)因素(su)。圖1表示(shi)的(de)(de)(de)(de)(de)是加利福(fu)尼亞州洛(luo)杉(shan)磯(ji)(ji)市(shi)的(de)(de)(de)(de)(de)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)回(hui)(hui)用(yong)(yong)系(xi)(xi)統(tong)(tong)的(de)(de)(de)(de)(de)布置情況：回(hui)(hui)用(yong)(yong)的(de)(de)(de)(de)(de)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)來自洛(luo)杉(shan)磯(ji)(ji)、Glendale、Donald C.Tillman和(he)西(xi)部流域(yu)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)回(hui)(hui)用(yong)(yong)廠(chang)(chang)(WRPs)。洛(luo)杉(shan)磯(ji)(ji)、Glendale、Donald C.Tillman回(hui)(hui)用(yong)(yong)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)廠(chang)(chang)處(chu)(chu)(chu)理(li)(li)系(xi)(xi)統(tong)(tong)由基(ji)本(ben)的(de)(de)(de)(de)(de)初(chu)級(ji)處(chu)(chu)(chu)理(li)(li)、二級(ji)處(chu)(chu)(chu)理(li)(li)、過(guo)(guo)濾(lv)和(he)高(gao)級(ji)消毒系(xi)(xi)統(tong)(tong)組成(cheng)。他們利用(yong)(yong)收(shou)(shou)集(ji)(ji)系(xi)(xi)統(tong)(tong)收(shou)(shou)集(ji)(ji)原(yuan)污(wu)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)并進(jin)(jin)行(xing)處(chu)(chu)(chu)理(li)(li)，再利用(yong)(yong)雙配水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)系(xi)(xi)統(tong)(tong)將(jiang)經過(guo)(guo)處(chu)(chu)(chu)理(li)(li)的(de)(de)(de)(de)(de)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)分配到(dao)(dao)(dao)(dao)附近(jin)的(de)(de)(de)(de)(de)地區進(jin)(jin)行(xing)使(shi)用(yong)(yong)。他們將(jiang)處(chu)(chu)(chu)理(li)(li)過(guo)(guo)程中(zhong)產(chan)生(sheng)(sheng)的(de)(de)(de)(de)(de)固體(ti)廢物返回(hui)(hui)到(dao)(dao)(dao)(dao)收(shou)(shou)集(ji)(ji)系(xi)(xi)統(tong)(tong)，然后運送到(dao)(dao)(dao)(dao)Hiperion污(wu)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)處(chu)(chu)(chu)理(li)(li)廠(chang)(chang)(WWTP)對其進(jin)(jin)行(xing)充分的(de)(de)(de)(de)(de)去除和(he)處(chu)(chu)(chu)置。Hiperion污(wu)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)處(chu)(chu)(chu)理(li)(li)廠(chang)(chang)位于(yu)洛(luo)杉(shan)磯(ji)(ji)市(shi)的(de)(de)(de)(de)(de)工(gong)業(ye)區，同Terminal島污(wu)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)處(chu)(chu)(chu)理(li)(li)廠(chang)(chang)一(yi)樣，收(shou)(shou)集(ji)(ji)到(dao)(dao)(dao)(dao)的(de)(de)(de)(de)(de)污(wu)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)多(duo)數是城(cheng)市(shi)里產(chan)生(sheng)(sheng)的(de)(de)(de)(de)(de)工(gong)業(ye)污(wu)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)，也收(shou)(shou)集(ji)(ji)到(dao)(dao)(dao)(dao)了沒(mei)有被上游的(de)(de)(de)(de)(de)WRPs回(hui)(hui)收(shou)(shou)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)廠(chang)(chang)處(chu)(chu)(chu)理(li)(li)的(de)(de)(de)(de)(de)污(wu)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)。洛(luo)杉(shan)磯(ji)(ji)、Glendale、Donald C.Tillman回(hui)(hui)用(yong)(yong)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)廠(chang)(chang)(WRPs)位于(yu)生(sheng)(sheng)活區污(wu)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)截留(liu)管(guan)的(de)(de)(de)(de)(de)附近(jin)，這樣就會使(shi)處(chu)(chu)(chu)理(li)(li)后的(de)(de)(de)(de)(de)污(wu)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)所含的(de)(de)(de)(de)(de)工(gong)業(ye)廢水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)較少。西(xi)部流域(yu)回(hui)(hui)用(yong)(yong)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)廠(chang)(chang)與此不(bu)同，它收(shou)(shou)集(ji)(ji)的(de)(de)(de)(de)(de)是Hiperion WWTP的(de)(de)(de)(de)(de)二級(ji)出(chu)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)，對其進(jin)(jin)行(xing)一(yi)系(xi)(xi)列的(de)(de)(de)(de)(de)處(chu)(chu)(chu)理(li)(li)后，將(jiang)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)用(yong)(yong)于(yu)非限(xian)制性(xing)城(cheng)鎮澆灌用(yong)(yong)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)，或注入(ru)地下(xia)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)以(yi)防(fang)止(zhi)海水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)入(ru)侵地下(xia)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)含水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)層(ceng)，或用(yong)(yong)于(yu)工(gong)業(ye)冷卻用(yong)(yong)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)。隨著人們對回(hui)(hui)用(yong)(yong)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)質水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)量需求的(de)(de)(de)(de)(de)提高(gao)，西(xi)部流域(yu)回(hui)(hui)用(yong)(yong)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)廠(chang)(chang)長期(qi)以(yi)來不(bu)斷(duan)地進(jin)(jin)行(xing)改造。上述的(de)(de)(de)(de)(de)例子說明決定(ding)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)回(hui)(hui)用(yong)(yong)系(xi)(xi)統(tong)(tong)布置的(de)(de)(de)(de)(de)方(fang)面(mian)有許多(duo)，主要包括以(yi)下(xia)幾個方(fang)面(mian)：

1. 廢水(shui)收集系(xi)統布置在工業極少的服(fu)務區內。

2. 回用(yong)水(shui)廠(chang)廠(chang)址應選(xuan)在接收的(de)廢水(shui)中少有或沒(mei)有工業組分的(de)地(di)方。

3. 回用水(shui)廠廠址應選在靠近現在或將(jiang)來應用回用水(shui)的(de)地(di)方，將(jiang)雙配水(shui)系(xi)統的(de)配水(shui)距(ju)離 減至(zhi)最小。

廢水(shui)(shui)收集系統(tong)和水(shui)(shui)分配(pei)系統(tong)的(de)經濟壽命很長，一(yi)般是(shi)100年(nian)或更長，因此(ci)許多年(nian)來(lai)原有的(de)收集系統(tong)的(de)布(bu)置和處(chu)(chu)理設施(shi)的(de)位置在幾十年(nian)內(nei) 影響(xiang) 著水(shui)(shui)的(de)回用。另一(yi)方面，每隔20年(nian)，處(chu)(chu)理設施(shi)需要進行革(ge)新。不但如此(ci)，為了(le)提高處(chu)(chu)理水(shui)(shui)平(ping)，水(shui)(shui)廠也需要革(ge)新。因此(ci)，對回用水(shui)(shui)的(de)計劃(hua)影響(xiang)最大的(de)不是(shi)現有的(de)處(chu)(chu)理方法，而是(shi)回用水(shui)(shui)廠的(de)整體布(bu)置。

現有(you)的(de)(de)整體系(xi)(xi)(xi)統(tong)(tong)結構也能(neng)夠被(bei)利用(yong)(yong)(yong)(yong)。城鎮(zhen)農(nong)業回(hui)(hui)用(yong)(yong)(yong)(yong)水(shui)(shui)系(xi)(xi)(xi)統(tong)(tong)要具備對污水(shui)(shui)和(或者)處(chu)(chu)理(li)后(hou)水(shui)(shui)的(de)(de)收集(ji)和長距離運輸的(de)(de)能(neng)力。農(nong)業回(hui)(hui)用(yong)(yong)(yong)(yong)低質的(de)(de)經處(chu)(chu)理(li)的(de)(de)城鎮(zhen)污水(shui)(shui)，可將(jiang)原來用(yong)(yong)(yong)(yong)于農(nong)業的(de)(de)淡水(shui)(shui)用(yong)(yong)(yong)(yong)于城鎮(zhen)生活使用(yong)(yong)(yong)(yong)。由于農(nong)業回(hui)(hui)用(yong)(yong)(yong)(yong)水(shui)(shui)系(xi)(xi)(xi)統(tong)(tong)所(suo)需的(de)(de)處(chu)(chu)理(li)費用(yong)(yong)(yong)(yong)較(jiao)低和(或)所(suo)產生的(de)(de)水(shui)(shui)資(zi)源價值彌補了輸送(song)設施的(de)(de)費用(yong)(yong)(yong)(yong)。非(fei)直(zhi)接飲(yin)用(yong)(yong)(yong)(yong)回(hui)(hui)用(yong)(yong)(yong)(yong)水(shui)(shui)系(xi)(xi)(xi)統(tong)(tong)與此不同(tong)，既然回(hui)(hui)用(yong)(yong)(yong)(yong)水(shui)(shui)同(tong)原有(you)的(de)(de)供水(shui)(shui)相混和，經過(guo)(guo)后(hou)續的(de)(de)處(chu)(chu)理(li)設施的(de)(de)處(chu)(chu)理(li)，是(shi)通過(guo)(guo)現有(you)的(de)(de)飲(yin)用(yong)(yong)(yong)(yong)配水(shui)(shui)系(xi)(xi)(xi)統(tong)(tong)的(de)(de)分(fen)配可用(yong)(yong)(yong)(yong)于非(fei)直(zhi)接飲(yin)用(yong)(yong)(yong)(yong)回(hui)(hui)用(yong)(yong)(yong)(yong)，那(nei)么輸水(shui)(shui)系(xi)(xi)(xi)統(tong)(tong)和配水(shui)(shui)系(xi)(xi)(xi)統(tong)(tong)的(de)(de)費用(yong)(yong)(yong)(yong)將(jiang)達到(dao)最小。但是(shi)，在非(fei)直(zhi)接飲(yin)用(yong)(yong)(yong)(yong)回(hui)(hui)用(yong)(yong)(yong)(yong)水(shui)(shui)系(xi)(xi)(xi)統(tong)(tong)中，為了保(bao)護公眾供水(shui)(shui)水(shui)(shui)源不受污染(ran)，就需要對回(hui)(hui)用(yong)(yong)(yong)(yong)水(shui)(shui)進行高(gao)度處(chu)(chu)理(li)，這樣處(chu)(chu)理(li)費用(yong)(yong)(yong)(yong)將(jiang)最高(gao)。

總的(de)(de)說來，回(hui)用水(shui)(shui)系(xi)統提高(gao)了現有的(de)(de)水(shui)(shui)資源水(shui)(shui)質和可利(li)用的(de)(de)水(shui)(shui)量，因而增大了現有的(de)(de)水(shui)(shui)資源量。回(hui)用水(shui)(shui)系(xi)統由集水(shui)(shui)、處(chu)理和配水(shui)(shui)系(xi)統組成。由于集水(shui)(shui)和配水(shui)(shui)系(xi)統的(de)(de)使用期(qi)較(jiao)長，所以選(xuan)擇合(he)適(shi)的(de)(de)回(hui)用水(shui)(shui)系(xi)統時，集水(shui)(shui)和配水(shui)(shui)系(xi)統的(de)(de)布(bu)置比(bi)處(chu)理系(xi)統更(geng)重(zhong)要。現在已有幾(ji)個模式適(shi)合(he)于特殊的(de)(de)應用。

指導性原則2：評估回用水經濟效益需要(yao)系統方法

通常情(qing)況下，人們希望(wang)在簡(jian)單的(de)(de)(de)(de)(de)基礎上(shang)對(dui)回用(yong)(yong)(yong)水(shui)(shui)(shui)(shui)進(jin)行(xing)評估，即確定水(shui)(shui)(shui)(shui)回用(yong)(yong)(yong)的(de)(de)(de)(de)(de)處理(li)和(he)配(pei)水(shui)(shui)(shui)(shui)費(fei)用(yong)(yong)(yong)后(hou)，同水(shui)(shui)(shui)(shui)的(de)(de)(de)(de)(de)商(shang)業價(jia)格進(jin)行(xing)對(dui)比。如(ru)(ru)果回用(yong)(yong)(yong)水(shui)(shui)(shui)(shui)經過處理(li)和(he)分配(pei)的(de)(de)(de)(de)(de)費(fei)用(yong)(yong)(yong)比現(xian)(xian)有的(de)(de)(de)(de)(de)用(yong)(yong)(yong)水(shui)(shui)(shui)(shui)價(jia)格較低,那(nei)么(me)水(shui)(shui)(shui)(shui)的(de)(de)(de)(de)(de)回用(yong)(yong)(yong)是可行(xing)的(de)(de)(de)(de)(de)和(he)經濟(ji)(ji)(ji)(ji)有效的(de)(de)(de)(de)(de)。如(ru)(ru)果回用(yong)(yong)(yong)水(shui)(shui)(shui)(shui)處理(li)和(he)分配(pei)的(de)(de)(de)(de)(de)費(fei)用(yong)(yong)(yong)比現(xian)(xian)有的(de)(de)(de)(de)(de)水(shui)(shui)(shui)(shui)的(de)(de)(de)(de)(de)商(shang)業價(jia)格高，那(nei)么(me)水(shui)(shui)(shui)(shui)的(de)(de)(de)(de)(de)回用(yong)(yong)(yong)是不經濟(ji)(ji)(ji)(ji)的(de)(de)(de)(de)(de)。然(ran)而(er)，這樣的(de)(de)(de)(de)(de)經濟(ji)(ji)(ji)(ji)估算忽略了回用(yong)(yong)(yong)水(shui)(shui)(shui)(shui)對(dui)現(xian)(xian)有供水(shui)(shui)(shui)(shui)系統(tong)的(de)(de)(de)(de)(de)增(zeng)大的(de)(de)(de)(de)(de)作用(yong)(yong)(yong)。當然(ran)，必須把用(yong)(yong)(yong)于再生回用(yong)(yong)(yong)的(de)(de)(de)(de)(de)投資與擴建供水(shui)(shui)(shui)(shui)系統(tong)所需增(zeng)加的(de)(de)(de)(de)(de)一般都(dou)超過平均(jun)水(shui)(shui)(shui)(shui)價(jia)或(huo)商(shang)業水(shui)(shui)(shui)(shui)價(jia)的(de)(de)(de)(de)(de)費(fei)用(yong)(yong)(yong)進(jin)行(xing)比較，上(shang)述的(de)(de)(de)(de)(de)這種簡(jian)單的(de)(de)(de)(de)(de)水(shui)(shui)(shui)(shui)再生回用(yong)(yong)(yong)經濟(ji)(ji)(ji)(ji) 計算 方法將(jiang)為(wei)回用(yong)(yong)(yong)水(shui)(shui)(shui)(shui)的(de)(de)(de)(de)(de)應用(yong)(yong)(yong)確立機會。

圖2簡單的(de)(de)說(shuo)明(ming)(ming)了一種(zhong)(zhong)應當被采用(yong)的(de)(de)估算回(hui)用(yong)水(shui)(shui)(shui)(shui)(shui)(shui)可行(xing)的(de)(de)方法。比如(ru)對(dui)社區(qu)(qu)現有的(de)(de)四個(ge)水(shui)(shui)(shui)(shui)(shui)(shui)源(yuan)(yuan)進行(xing)考慮，其(qi)中兩(liang)個(ge)是(shi)區(qu)(qu)域(yu)井水(shui)(shui)(shui)(shui)(shui)(shui)供(gong)給，注(zhu)明(ming)(ming)區(qu)(qu)域(yu)井水(shui)(shui)(shui)(shui)(shui)(shui)A和(he)(he)B;另兩(liang)個(ge)是(shi)地表(biao)(biao)(biao)水(shui)(shui)(shui)(shui)(shui)(shui)源(yuan)(yuan)供(gong)給，注(zhu)明(ming)(ming)地表(biao)(biao)(biao)水(shui)(shui)(shui)(shui)(shui)(shui)源(yuan)(yuan)A和(he)(he)B。每一種(zhong)(zhong)水(shui)(shui)(shui)(shui)(shui)(shui)源(yuan)(yuan)供(gong)水(shui)(shui)(shui)(shui)(shui)(shui)的(de)(de)費(fei)(fei)用(yong)包括(kuo)從(cong)環境(jing)中取水(shui)(shui)(shui)(shui)(shui)(shui)的(de)(de)費(fei)(fei)用(yong)、貯(zhu)水(shui)(shui)(shui)(shui)(shui)(shui)(原水(shui)(shui)(shui)(shui)(shui)(shui)或處(chu)理后的(de)(de)水(shui)(shui)(shui)(shui)(shui)(shui)的(de)(de)貯(zhu)存)費(fei)(fei)用(yong)、處(chu)理費(fei)(fei)用(yong)和(he)(he)配(pei)水(shui)(shui)(shui)(shui)(shui)(shui)費(fei)(fei)用(yong)。取水(shui)(shui)(shui)(shui)(shui)(shui)步(bu)驟(zou)包括(kuo)鑿井(區(qu)(qu)域(yu)井水(shui)(shui)(shui)(shui)(shui)(shui)供(gong)給)和(he)(he)地表(biao)(biao)(biao)水(shui)(shui)(shui)(shui)(shui)(shui)的(de)(de)引入(地表(biao)(biao)(biao)水(shui)(shui)(shui)(shui)(shui)(shui)的(de)(de)供(gong)給)。貯(zhu)水(shui)(shui)(shui)(shui)(shui)(shui)包括(kuo)建造地表(biao)(biao)(biao)水(shui)(shui)(shui)(shui)(shui)(shui)的(de)(de)貯(zhu)存池(chi)和(he)(he)處(chu)理后水(shui)(shui)(shui)(shui)(shui)(shui)的(de)(de)儲(chu)存池(chi)。處(chu)理步(bu)驟(zou)包括(kuo)對(dui)地下水(shui)(shui)(shui)(shui)(shui)(shui)要進行(xing)簡單的(de)(de)消毒(du)處(chu)理，或者(zhe)建造地表(biao)(biao)(biao)水(shui)(shui)(shui)(shui)(shui)(shui)處(chu)理水(shui)(shui)(shui)(shui)(shui)(shui)廠。配(pei)水(shui)(shui)(shui)(shui)(shui)(shui)費(fei)(fei)用(yong)用(yong)于配(pei)水(shui)(shui)(shui)(shui)(shui)(shui)系(xi)統的(de)(de)建造、運行(xing)和(he)(he)維護方面。這四種(zhong)(zhong)水(shui)(shui)(shui)(shui)(shui)(shui)源(yuan)(yuan)的(de)(de)相(xiang)對(dui)費(fei)(fei)用(yong)情況(kuang)如(ru)圖2所(suo)示(shi)(shi)。假定用(yong)水(shui)(shui)(shui)(shui)(shui)(shui)費(fei)(fei)用(yong)建立在費(fei)(fei)用(yong)平(ping)均的(de)(de)基(ji)礎(chu)上(shang)，那么(me)消費(fei)(fei)者(zhe)的(de)(de)用(yong)水(shui)(shui)(shui)(shui)(shui)(shui)價(jia)格(ge)是(shi)這四種(zhong)(zhong)水(shui)(shui)(shui)(shui)(shui)(shui)源(yuan)(yuan)費(fei)(fei)用(yong)的(de)(de)平(ping)均價(jia)格(ge)，如(ru)圖2所(suo)示(shi)(shi)。平(ping)均價(jia)格(ge)是(shi)相(xiang)對(dui)費(fei)(fei)用(yong)的(de)(de)55%。

如(ru)圖2所示，回(hui)(hui)(hui)用(yong)(yong)(yong)(yong)(yong)(yong)(yong)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)的(de)(de)(de)(de)(de)價格(ge)(ge)是(shi)(shi)居民用(yong)(yong)(yong)(yong)(yong)(yong)(yong)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)價格(ge)(ge)或用(yong)(yong)(yong)(yong)(yong)(yong)(yong)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)率(即(ji)平均用(yong)(yong)(yong)(yong)(yong)(yong)(yong)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)價格(ge)(ge))的(de)(de)(de)(de)(de)一小部分。原(yuan)因(yin)是(shi)(shi)人們通常認為回(hui)(hui)(hui)用(yong)(yong)(yong)(yong)(yong)(yong)(yong)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)不(bu)象(xiang)飲用(yong)(yong)(yong)(yong)(yong)(yong)(yong)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)那(nei)樣有(you)價值，對(dui)(dui)其(qi)使(shi)(shi)用(yong)(yong)(yong)(yong)(yong)(yong)(yong)需要某種(zhong)動機。回(hui)(hui)(hui)用(yong)(yong)(yong)(yong)(yong)(yong)(yong)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)的(de)(de)(de)(de)(de)價格(ge)(ge)取決于其(qi)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)質同(tong)飲用(yong)(yong)(yong)(yong)(yong)(yong)(yong)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)的(de)(de)(de)(de)(de)比較。然而，回(hui)(hui)(hui)用(yong)(yong)(yong)(yong)(yong)(yong)(yong)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)的(de)(de)(de)(de)(de)價格(ge)(ge)相當(dang)于飲用(yong)(yong)(yong)(yong)(yong)(yong)(yong)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)的(de)(de)(de)(de)(de)70~80%也并不(bu)少見(jian)。但這種(zhong)價格(ge)(ge)并不(bu)能反應出(chu)回(hui)(hui)(hui)用(yong)(yong)(yong)(yong)(yong)(yong)(yong)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)的(de)(de)(de)(de)(de)價值。總(zong)的(de)(de)(de)(de)(de)說來，水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)的(de)(de)(de)(de)(de)再(zai)生(sheng)回(hui)(hui)(hui)用(yong)(yong)(yong)(yong)(yong)(yong)(yong)是(shi)(shi)增(zeng)大(da)供(gong)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)系(xi)統的(de)(de)(de)(de)(de)一種(zhong)方法。當(dang)為了這個目(mu)的(de)(de)(de)(de)(de)而使(shi)(shi)用(yong)(yong)(yong)(yong)(yong)(yong)(yong)回(hui)(hui)(hui)用(yong)(yong)(yong)(yong)(yong)(yong)(yong)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)時(shi)(shi)，只(zhi)要水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)再(zai)生(sheng)回(hui)(hui)(hui)用(yong)(yong)(yong)(yong)(yong)(yong)(yong)的(de)(de)(de)(de)(de)總(zong)費(fei)(fei)(fei)用(yong)(yong)(yong)(yong)(yong)(yong)(yong)少于自來水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)供(gong)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)的(de)(de)(de)(de)(de)總(zong)體費(fei)(fei)(fei)用(yong)(yong)(yong)(yong)(yong)(yong)(yong)(包括取水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)、貯(zhu)存、處理和配水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)費(fei)(fei)(fei)用(yong)(yong)(yong)(yong)(yong)(yong)(yong))，采用(yong)(yong)(yong)(yong)(yong)(yong)(yong)回(hui)(hui)(hui)用(yong)(yong)(yong)(yong)(yong)(yong)(yong)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)系(xi)統供(gong)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)是(shi)(shi)可(ke)行的(de)(de)(de)(de)(de)。所以，對(dui)(dui)于圖2中的(de)(de)(de)(de)(de)例(li)子，供(gong)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)總(zong)費(fei)(fei)(fei)用(yong)(yong)(yong)(yong)(yong)(yong)(yong)為100%時(shi)(shi)，回(hui)(hui)(hui)用(yong)(yong)(yong)(yong)(yong)(yong)(yong)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)費(fei)(fei)(fei)用(yong)(yong)(yong)(yong)(yong)(yong)(yong)占40%。回(hui)(hui)(hui)用(yong)(yong)(yong)(yong)(yong)(yong)(yong)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)除去(qu)增(zeng)加供(gong)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)外，還有(you)一個潛在的(de)(de)(de)(de)(de)作用(yong)(yong)(yong)(yong)(yong)(yong)(yong)是(shi)(shi)代(dai)替了現有(you)的(de)(de)(de)(de)(de)供(gong)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)資源(yuan)。在這種(zhong)情(qing)形下，如(ru)果水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)回(hui)(hui)(hui)用(yong)(yong)(yong)(yong)(yong)(yong)(yong)費(fei)(fei)(fei)用(yong)(yong)(yong)(yong)(yong)(yong)(yong)比最昂貴的(de)(de)(de)(de)(de)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)源(yuan)供(gong)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)費(fei)(fei)(fei)用(yong)(yong)(yong)(yong)(yong)(yong)(yong)低(di)，那(nei)么水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)的(de)(de)(de)(de)(de)回(hui)(hui)(hui)用(yong)(yong)(yong)(yong)(yong)(yong)(yong)也就降低(di)了成(cheng)本，例(li)如(ru)圖2中地表水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)源(yuan)B相對(dui)(dui)費(fei)(fei)(fei)用(yong)(yong)(yong)(yong)(yong)(yong)(yong)最大(da)為75%，。因(yin)此，對(dui)(dui)回(hui)(hui)(hui)用(yong)(yong)(yong)(yong)(yong)(yong)(yong)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)的(de)(de)(de)(de)(de)使(shi)(shi)用(yong)(yong)(yong)(yong)(yong)(yong)(yong)進行評估(gu)時(shi)(shi)，僅僅考慮(lv)那(nei)些比用(yong)(yong)(yong)(yong)(yong)(yong)(yong)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)價格(ge)(ge)少的(de)(de)(de)(de)(de)情(qing)形，將要忽略回(hui)(hui)(hui)用(yong)(yong)(yong)(yong)(yong)(yong)(yong)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)的(de)(de)(de)(de)(de)真正(zheng)經濟效益。例(li)如(ru)，假定使(shi)(shi)用(yong)(yong)(yong)(yong)(yong)(yong)(yong)回(hui)(hui)(hui)用(yong)(yong)(yong)(yong)(yong)(yong)(yong)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)的(de)(de)(de)(de)(de)費(fei)(fei)(fei)用(yong)(yong)(yong)(yong)(yong)(yong)(yong)同(tong)地表水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)源(yuan)供(gong)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)B費(fei)(fei)(fei)用(yong)(yong)(yong)(yong)(yong)(yong)(yong)相等，那(nei)么水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)的(de)(de)(de)(de)(de)回(hui)(hui)(hui)用(yong)(yong)(yong)(yong)(yong)(yong)(yong)對(dui)(dui)社區來說是(shi)(shi)經濟有(you)效的(de)(de)(de)(de)(de)。由于供(gong)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)的(de)(de)(de)(de)(de)增(zeng)長，用(yong)(yong)(yong)(yong)(yong)(yong)(yong)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)率有(you)時(shi)(shi)不(bu)得不(bu)增(zeng)長，或許(xu)達到相對(dui)(dui)費(fei)(fei)(fei)用(yong)(yong)(yong)(yong)(yong)(yong)(yong)的(de)(de)(de)(de)(de)60%左右，此時(shi)(shi)回(hui)(hui)(hui)用(yong)(yong)(yong)(yong)(yong)(yong)(yong)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)的(de)(de)(de)(de)(de)費(fei)(fei)(fei)用(yong)(yong)(yong)(yong)(yong)(yong)(yong)占45%。

最后，對水(shui)再(zai)生(sheng)回(hui)用(yong)(yong)成本(ben)進行(xing)評(ping)估。通常情(qing)況下，合理的(de)(de)廢水(shui)管理需要(yao)采用(yong)(yong)一些(xie)處理方式以保證(zheng)廢水(shui)的(de)(de)排(pai)入環境(jing)(jing)而不會使(shi)環境(jing)(jing)受(shou)到危害(hai)。這些(xie)成本(ben)同水(shui)的(de)(de)再(zai)生(sheng)回(hui)用(yong)(yong)沒有(you)聯(lian)系起來， 自(zi)然 沒包括在水(shui)的(de)(de)再(zai)生(sheng)回(hui)用(yong)(yong)的(de)(de)經濟(ji)評(ping)估之(zhi)中。而通常僅把(ba)廢水(shui)的(de)(de)額外處理的(de)(de)費用(yong)(yong)，即超(chao)出了排(pai)入環境(jing)(jing)的(de)(de)要(yao)求(qiu)的(de)(de)處理的(de)(de)費用(yong)(yong)，包括在回(hui)用(yong)(yong)水(shui)的(de)(de)經濟(ji) 分析 之(zhi)內。

總的說(shuo)來，水(shui)再(zai)生回(hui)用的經濟(ji)評估需要包括以下幾個(ge)方面：

1. 所有的(de)供水費用進行(xing)評估，包(bao)括取水、貯水、處(chu)理和配水的(de)費用。

2. 再生回用(yong)水(shui)(shui)費(fei)(fei)用(yong)同下一個(ge)最(zui)值得(de)花(hua)費(fei)(fei)的(de)擴建(jian)社(she)區供水(shui)(shui)方案的(de)總的(de)供水(shui)(shui)費(fei)(fei)用(yong)相比 較。

3.水的價(jia)格通常基于(yu)所有(you)社區供水費(fei)用的平(ping)均價(jia)格，并不指最(zui)大的費(fei)用。

4.回(hui)用水(shui)(shui)的(de)價格通常(chang)占用水(shui)(shui)價格的(de)一小部分，有(you)時沒有(you)提供足夠的(de)收(shou)益(yi)資助再(zai)(zai)生回(hui)用水(shui)(shui)系統(tong)。然而，即使回(hui)用水(shui)(shui)水(shui)(shui)價不為再(zai)(zai)生回(hui)用水(shui)(shui)系統(tong)提供資助，但是從供水(shui)(shui)系統(tong)整體背(bei)景來說水(shui)(shui)的(de)再(zai)(zai)生回(hui)用也(ye)是有(you)效益(yi)的(de)。

4. 通常(chang)水(shui)再生(sheng)回用(yong)費(fei)用(yong)定為比(bi)排放(fang)環境所需的水(shui)處理(li)的費(fei)用(yong)多出來費(fei)用(yong)。

指導性原(yuan)則(ze)3：采取(qu)可利用(yong)的方法以(yi)減輕水(shui)回用(yong)對(dui)公眾健(jian)康和環境造成的風險

人們(men)對使用回(hui)用水(shui)的(de)(de)安全性很關(guan)心。廢水(shui)中(zhong)含(han)有(you)(you)許(xu)多 影響(xiang) 公眾(zhong)健(jian)康(kang)和環境(jing)(jing)的(de)(de)污(wu)(wu)(wu)染物(wu)質。去除廢水(shui)中(zhong)主要(yao)污(wu)(wu)(wu)染物(wu)是(shi)減輕其對公眾(zhong)健(jian)康(kang)和環境(jing)(jing)影響(xiang)的(de)(de)主要(yao)措施(shi)，這(zhe)樣就(jiu)需要(yao)對實施(shi)再(zai)生回(hui)用水(shui)計劃所需的(de)(de)污(wu)(wu)(wu)水(shui)處(chu)理 方法 進行嚴格的(de)(de)規定。然(ran)而(er)，必須(xu)認識到，幾(ji)種方法對減輕回(hui)用水(shui)對公眾(zhong)健(jian)康(kang)和環境(jing)(jing)影響(xiang)都是(shi)有(you)(you)效的(de)(de)，如表3所示。

我們還要(yao)(yao)關(guan)注工業污(wu)水(shui)(shui)(shui)中有(you)毒和其(qi)他污(wu)染物(wu)(wu)(wu)質(zhi)潛在(zai)(zai)(zai)的(de)(de)危(wei)害(hai)，這(zhe)些污(wu)染物(wu)(wu)(wu)有(you)可能(neng)存在(zai)(zai)(zai)于原污(wu)水(shui)(shui)(shui)中，因此(ci)也(ye)就有(you)可能(neng)存在(zai)(zai)(zai)于回(hui)(hui)用水(shui)(shui)(shui)中。去除這(zhe)些污(wu)染物(wu)(wu)(wu)質(zhi)是消除其(qi)威脅的(de)(de)一種方(fang)法。而另(ling)一種方(fang)法是控(kong)制水(shui)(shui)(shui)源，以減少(shao)污(wu)染物(wu)(wu)(wu)質(zhi)進(jin)入回(hui)(hui)用水(shui)(shui)(shui)的(de)(de)機會。例如，作(zuo)為回(hui)(hui)用水(shui)(shui)(shui)水(shui)(shui)(shui)源的(de)(de)服務區限定(ding)在(zai)(zai)(zai)主要(yao)(yao)是生活性污(wu)水(shui)(shui)(shui)區域(yu)，避免(mian)明顯的(de)(de)工業排(pai)放物(wu)(wu)(wu)的(de)(de)影(ying)響。對那些已存在(zai)(zai)(zai)的(de)(de)工廠排(pai)放的(de)(de)廢水(shui)(shui)(shui)，應該進(jin)行嚴格控(kong)制，使其(qi)排(pai)入要(yao)(yao)再生廢水(shui)(shui)(shui)中的(de)(de)污(wu)染物(wu)(wu)(wu)質(zhi)減到最少(shao)。這(zhe)就需要(yao)(yao)成熟的(de)(de)處理技術來去除這(zhe)些污(wu)染物(wu)(wu)(wu)質(zhi)，處理結(jie)果(guo)能(neng)使回(hui)(hui)用水(shui)(shui)(shui)系(xi)統更加可靠和安全。

將(jiang)回用(yong)(yong)(yong)(yong)(yong)水(shui)(shui)(shui)和(he)飲用(yong)(yong)(yong)(yong)(yong)水(shui)(shui)(shui)系(xi)統分開(kai)是消除對公眾(zhong)健(jian)康和(he)環境威(wei)脅的(de)(de)另(ling)一種(zhong)(zhong)方法(fa)。在這種(zhong)(zhong)情(qing)形下，將(jiang)回用(yong)(yong)(yong)(yong)(yong)水(shui)(shui)(shui)用(yong)(yong)(yong)(yong)(yong)于(yu)風險比較低的(de)(de)情(qing)況(kuang)，例如用(yong)(yong)(yong)(yong)(yong)于(yu)工業生(sheng)產過程(cheng)用(yong)(yong)(yong)(yong)(yong)水(shui)(shui)(shui)、灌溉用(yong)(yong)(yong)(yong)(yong)水(shui)(shui)(shui)和(he)衛生(sheng)間沖洗用(yong)(yong)(yong)(yong)(yong)水(shui)(shui)(shui)。回用(yong)(yong)(yong)(yong)(yong)水(shui)(shui)(shui)配水(shui)(shui)(shui)系(xi)統的(de)(de)使用(yong)(yong)(yong)(yong)(yong)數量(liang)和(he)范圍，以及公眾(zhong)同(tong)回用(yong)(yong)(yong)(yong)(yong)水(shui)(shui)(shui)接觸(chu)的(de)(de)隔離程(cheng)度不(bu)僅決定(ding)這種(zhong)(zhong)回用(yong)(yong)(yong)(yong)(yong)系(xi)統的(de)(de)費用(yong)(yong)(yong)(yong)(yong)，而且還決定(ding)著對公眾(zhong)健(jian)康和(he)環境的(de)(de)保(bao)護程(cheng)度。然(ran)而，這種(zhong)(zhong)回用(yong)(yong)(yong)(yong)(yong)系(xi)統的(de)(de)費用(yong)(yong)(yong)(yong)(yong)和(he)風險的(de)(de)減少程(cheng)度同(tong)所選擇的(de)(de)處理(li)方式有關。

還有一(yi)種(zhong)消(xiao)減風險的方法是將回(hui)用(yong)(yong)水(shui)(shui)(shui)與可能(neng)暴露(lu)的途(tu)徑隔離(li)開(kai)來。例如(ru)， 應用(yong)(yong) 回(hui)用(yong)(yong)水(shui)(shui)(shui)進行澆(jiao)灌(guan)(guan)公共(gong)綠地時(shi)，使(shi)用(yong)(yong)滴(di)灌(guan)(guan)系(xi)統灌(guan)(guan)溉比使(shi)用(yong)(yong)噴灑系(xi)統安全(quan)(quan)。同(tong)樣，回(hui)用(yong)(yong)水(shui)(shui)(shui)用(yong)(yong)于澆(jiao)灌(guan)(guan)直接(jie)食用(yong)(yong)的作物(wu)時(shi)，使(shi)用(yong)(yong)漫灌(guan)(guan)或滴(di)灌(guan)(guan)灌(guan)(guan)溉比使(shi)用(yong)(yong)噴灑系(xi)統安全(quan)(quan)。原因(yin)是這種(zhong)措施減少了回(hui)用(yong)(yong)水(shui)(shui)(shui)同(tong)作物(wu)中(zhong)的糧食直接(jie)接(jie)觸的機會。

將(jiang)(jiang)低(di)(di)質(zhi)水(shui)(shui)(shui)同高(gao)質(zhi)水(shui)(shui)(shui)相混(hun)(hun)和(he)，可(ke)以(yi)減少(shao)(shao)低(di)(di)質(zhi)水(shui)(shui)(shui)源中的(de)(de)(de)污染物(wu)質(zhi)濃(nong)度，從而減少(shao)(shao)了低(di)(di)質(zhi)水(shui)(shui)(shui)帶來的(de)(de)(de)危險(xian)。例如，如果回用(yong)(yong)(yong)(yong)(yong)(yong)水(shui)(shui)(shui)用(yong)(yong)(yong)(yong)(yong)(yong)于飲用(yong)(yong)(yong)(yong)(yong)(yong)目的(de)(de)(de)時，在(zai)其進行(xing)(xing)分配(pei)之前可(ke)同高(gao)質(zhi)的(de)(de)(de)飲用(yong)(yong)(yong)(yong)(yong)(yong)水(shui)(shui)(shui)相混(hun)(hun)和(he)。非(fei)直(zhi)接(jie)飲用(yong)(yong)(yong)(yong)(yong)(yong)水(shui)(shui)(shui)回用(yong)(yong)(yong)(yong)(yong)(yong)方法一(yi)般是將(jiang)(jiang)回用(yong)(yong)(yong)(yong)(yong)(yong)水(shui)(shui)(shui)同原水(shui)(shui)(shui)源混(hun)(hun)和(he)，混(hun)(hun)合后(hou)的(de)(de)(de)水(shui)(shui)(shui)再進入(ru)水(shui)(shui)(shui)廠經過處理(li)，然(ran)后(hou)通(tong)過配(pei)水(shui)(shui)(shui)系(xi)(xi)統供(gong)給用(yong)(yong)(yong)(yong)(yong)(yong)戶。直(zhi)接(jie)飲用(yong)(yong)(yong)(yong)(yong)(yong)水(shui)(shui)(shui)回用(yong)(yong)(yong)(yong)(yong)(yong)方式(shi)與此不同，回用(yong)(yong)(yong)(yong)(yong)(yong)水(shui)(shui)(shui)直(zhi)接(jie)進入(ru)配(pei)水(shui)(shui)(shui)系(xi)(xi)統而沒(mei)有(you)進行(xing)(xing)混(hun)(hun)和(he)。這樣(yang)的(de)(de)(de)回用(yong)(yong)(yong)(yong)(yong)(yong)水(shui)(shui)(shui)使(shi)(shi)用(yong)(yong)(yong)(yong)(yong)(yong)方式(shi)將(jiang)(jiang)導致(zhi)一(yi)部分用(yong)(yong)(yong)(yong)(yong)(yong)戶使(shi)(shi)用(yong)(yong)(yong)(yong)(yong)(yong)的(de)(de)(de)是大量的(de)(de)(de)回用(yong)(yong)(yong)(yong)(yong)(yong)水(shui)(shui)(shui)，而一(yi)部分使(shi)(shi)用(yong)(yong)(yong)(yong)(yong)(yong)的(de)(de)(de)是少(shao)(shao)量的(de)(de)(de)回用(yong)(yong)(yong)(yong)(yong)(yong)水(shui)(shui)(shui)，從而對健康(kang)形(xing)成(cheng)不同的(de)(de)(de)威脅。

最(zui)后，利用成熟的(de)(de)(de)和多重的(de)(de)(de)處(chu)理(li)(li)技(ji)術(shu)可減(jian)少回用水(shui)對公(gong)眾(zhong)和環(huan)境的(de)(de)(de)影響。但是由于處(chu)理(li)(li)技(ji)術(shu)不可能(neng)(neng)達到(dao)100%的(de)(de)(de)去(qu)除和完(wan)全(quan)的(de)(de)(de)可靠，可能(neng)(neng)會(hui)使一些污染(ran)物穿(chuan)過處(chu)理(li)(li)系統(tong)出(chu)來，因此處(chu)理(li)(li)技(ji)術(shu)本(ben)身也存在著一定的(de)(de)(de)風險。正因為如此，采用一種以上的(de)(de)(de)去(qu)除相同污染(ran)物的(de)(de)(de)處(chu)理(li)(li)技(ji)術(shu)去(qu)除污染(ran)物質，可以改(gai)善污染(ran)和處(chu)理(li)(li)過程的(de)(de)(de)可靠性。

上述這些(xie)消(xiao)減(jian)回用(yong)(yong)(yong)水(shui)對(dui)(dui)公眾健(jian)康和(he)(he)環境(jing)風(feng)(feng)(feng)險的(de)(de)(de)方(fang)(fang)法便引(yin)出了多級屏(ping)障的(de)(de)(de)概念。在回用(yong)(yong)(yong)水(shui)系(xi)(xi)(xi)(xi)(xi)統(tong)(tong)(tong)(tong)設(she)計中(zhong)，可(ke)(ke)以(yi)(yi)采(cai)(cai)用(yong)(yong)(yong)多種(zhong)屏(ping)障方(fang)(fang)法來(lai)減(jian)少(shao)風(feng)(feng)(feng)險，也就(jiu)(jiu)(jiu)是(shi)說，當(dang)一種(zhong)屏(ping)障方(fang)(fang)式(shi)的(de)(de)(de)有效性是(shi)暫時的(de)(de)(de)話，那(nei)么(me)就(jiu)(jiu)(jiu)可(ke)(ke)以(yi)(yi)采(cai)(cai)用(yong)(yong)(yong)另一種(zhong)屏(ping)障的(de)(de)(de)方(fang)(fang)法保(bao)證回用(yong)(yong)(yong)系(xi)(xi)(xi)(xi)(xi)統(tong)(tong)(tong)(tong)的(de)(de)(de)可(ke)(ke)靠(kao)性和(he)(he)效用(yong)(yong)(yong)。例如(ru)(ru)，我們可(ke)(ke)以(yi)(yi)選擇(ze)適當(dang)的(de)(de)(de)處(chu)理方(fang)(fang)法對(dui)(dui)水(shui)進(jin)行處(chu)理使其滿足(zu)特(te)別(bie)的(de)(de)(de)用(yong)(yong)(yong)途，但是(shi)回用(yong)(yong)(yong)水(shui)系(xi)(xi)(xi)(xi)(xi)統(tong)(tong)(tong)(tong)收集的(de)(de)(de)廢水(shui)是(shi)來(lai)自于工(gong)(gong)廠很少(shao)的(de)(de)(de)服務(wu)區，而使整個(ge)系(xi)(xi)(xi)(xi)(xi)統(tong)(tong)(tong)(tong)的(de)(de)(de)可(ke)(ke)靠(kao)性得以(yi)(yi)提高。另外，如(ru)(ru)果(guo)由于某種(zhong)原因，處(chu)理系(xi)(xi)(xi)(xi)(xi)統(tong)(tong)(tong)(tong)只是(shi)暫時有效，但是(shi)因為(wei)沒(mei)有工(gong)(gong)業污染物(wu)質(zhi)，回用(yong)(yong)(yong)水(shui)的(de)(de)(de)安(an)全(quan)性仍可(ke)(ke)得到(dao)保(bao)證。與此相同，如(ru)(ru)果(guo)灌溉系(xi)(xi)(xi)(xi)(xi)統(tong)(tong)(tong)(tong)中(zhong)不僅采(cai)(cai)用(yong)(yong)(yong)適當(dang)的(de)(de)(de)處(chu)理方(fang)(fang)式(shi)，并(bing)且能有效地減(jian)少(shao)灌溉系(xi)(xi)(xi)(xi)(xi)統(tong)(tong)(tong)(tong)(比如(ru)(ru)淹沒(mei)式(shi)滴流系(xi)(xi)(xi)(xi)(xi)統(tong)(tong)(tong)(tong))的(de)(de)(de)用(yong)(yong)(yong)水(shui)同公眾或食用(yong)(yong)(yong)性作物(wu)的(de)(de)(de)接觸機會(hui)，那(nei)么(me)整個(ge)灌溉系(xi)(xi)(xi)(xi)(xi)統(tong)(tong)(tong)(tong)的(de)(de)(de)安(an)全(quan)性就(jiu)(jiu)(jiu)提高了。這樣(yang)的(de)(de)(de)話，對(dui)(dui)回用(yong)(yong)(yong)系(xi)(xi)(xi)(xi)(xi)統(tong)(tong)(tong)(tong)的(de)(de)(de)效用(yong)(yong)(yong)進(jin)行評價要基于系(xi)(xi)(xi)(xi)(xi)統(tong)(tong)(tong)(tong)的(de)(de)(de)表(biao)現形(xing)式(shi)。這分(fen)為(wei)兩(liang)種(zhong)情(qing)形(xing)，或者系(xi)(xi)(xi)(xi)(xi)統(tong)(tong)(tong)(tong)的(de)(de)(de)所(suo)有組成部分(fen)運行良好，或者一個(ge)或多個(ge)組成部分(fen)運行沒(mei)有達到(dao)預期目(mu)的(de)(de)(de)。回用(yong)(yong)(yong)系(xi)(xi)(xi)(xi)(xi)統(tong)(tong)(tong)(tong)對(dui)(dui)公眾健(jian)康和(he)(he)環境(jing)影響的(de)(de)(de)消(xiao)減(jian)程度也可(ke)(ke)以(yi)(yi)根(gen)據這些(xie)進(jin)行評估和(he)(he)對(dui)(dui)比。通過采(cai)(cai)用(yong)(yong)(yong)不同的(de)(de)(de)風(feng)(feng)(feng)險減(jian)輕辦(ban)法可(ke)(ke)逐步(bu)改(gai)進(jin)處(chu)理系(xi)(xi)(xi)(xi)(xi)統(tong)(tong)(tong)(tong)帶來(lai)的(de)(de)(de)風(feng)(feng)(feng)險。既然回用(yong)(yong)(yong)系(xi)(xi)(xi)(xi)(xi)統(tong)(tong)(tong)(tong)的(de)(de)(de)某些(xie)單(dan)元(yuan)(特(te)別(bie)是(shi)處(chu)理單(dan)元(yuan))可(ke)(ke)以(yi)(yi)分(fen)階段的(de)(de)(de)實(shi)施，因此，逐步(bu)實(shi)施這些(xie)單(dan)元(yuan)，就(jiu)(jiu)(jiu)可(ke)(ke)以(yi)(yi)逐步(bu)地減(jian)少(shao)對(dui)(dui)公眾和(he)(he)環境(jing)的(de)(de)(de)風(feng)(feng)(feng)險。

總結 和結論

總(zong)的(de)(de)(de)說(shuo)來， 中(zhong)國(guo) 正在著手(shou)于一(yi)項(xiang)有遠見的(de)(de)(de)宏偉計劃，該項(xiang)計劃將(jiang)擴(kuo)大污水(shui)(shui)處(chu)理的(de)(de)(de)基礎(chu)設施(shi)，這不僅(jin)能夠減少地(di)表水(shui)(shui)和地(di)下(xia)水(shui)(shui)資(zi)源的(de)(de)(de)污染(ran)，而且(qie)還能夠加強對公眾健(jian)康(kang)和環境的(de)(de)(de)保護。這將(jiang)為另一(yi)個水(shui)(shui)資(zi)源，即(ji)回用(yong)水(shui)(shui)的(de)(de)(de)使用(yong)提(ti)供機會。中(zhong)國(guo)已經(jing)意識到了這樣(yang)的(de)(de)(de)機會，并且(qie)積極地(di)將(jiang)水(shui)(shui)回用(yong)納入正在實施(shi)的(de)(de)(de)計劃中(zhong)。同時，中(zhong)國(guo)為了完成這項(xiang)宏偉的(de)(de)(de)計劃，也(ye)在認真地(di) 學習 其(qi)他(ta)國(guo)家的(de)(de)(de)經(jing)驗。

 這篇文(wen)章討(tao)論了三個指(zhi)導(dao)性(xing)原則，以幫助中國實施水回用的(de)計劃。它(ta)們是(shi)：

1. 回用水(shui)是整個水(shui)管理系統(tong)的一部分。

2. 需要一種系統方(fang)法來評價回用水的 經濟 可行(xing)性。

3. 可以(yi)采用許多方式和(he)方法來消減回用水對公眾健康(kang)和(he)環境風險。

水(shui)的(de)(de)(de)回(hui)(hui)用(yong)既減(jian)少(shao)了對水(shui)資(zi)源的(de)(de)(de)污染，也減(jian)少(shao)了必(bi)(bi)須從環境中(zhong)去(qu)除的(de)(de)(de)水(shui)量，因此，水(shui)的(de)(de)(de)回(hui)(hui)用(yong)就(jiu)是(shi)增加(jia)了水(shui)資(zi)源。有些水(shui)回(hui)(hui)用(yong)的(de)(de)(de)模式是(shi)可行的(de)(de)(de)，可以根據當地的(de)(de)(de)情形不同而(er)采用(yong)不同的(de)(de)(de)回(hui)(hui)用(yong)模式。由(you)于(yu)廢水(shui)收集(ji)(ji)和分(fen)配系(xi)(xi)(xi)統(tong)同處(chu)理(li)系(xi)(xi)(xi)統(tong)相(xiang)比，其(qi)使(shi)用(yong)期更長，所以確定收集(ji)(ji)和配水(shui)系(xi)(xi)(xi)統(tong)的(de)(de)(de)形式比處(chu)理(li)系(xi)(xi)(xi)統(tong)更為重要(yao)。如果必(bi)(bi)要(yao)的(de)(de)(de)話(hua)，處(chu)理(li)系(xi)(xi)(xi)統(tong)可以分(fen)階段建(jian)造。而(er)對于(yu)收集(ji)(ji)和分(fen)配系(xi)(xi)(xi)統(tong)分(fen)階段建(jian)造則很困(kun)難。

對回(hui)用(yong)(yong)(yong)(yong)水(shui)(shui)(shui)(shui)進行經(jing)濟(ji)評估要求全面了解整個供水(shui)(shui)(shui)(shui)系(xi)統的(de)(de)(de)(de)(de)經(jing)濟(ji)性。水(shui)(shui)(shui)(shui)再(zai)生回(hui)用(yong)(yong)(yong)(yong)的(de)(de)(de)(de)(de)費(fei)(fei)用(yong)(yong)(yong)(yong)必須同社(she)區即(ji)將采用(yong)(yong)(yong)(yong)的(de)(de)(de)(de)(de)費(fei)(fei)用(yong)(yong)(yong)(yong)最(zui)高的(de)(de)(de)(de)(de)供水(shui)(shui)(shui)(shui)系(xi)統總費(fei)(fei)用(yong)(yong)(yong)(yong)相比(bi)(bi)較。供水(shui)(shui)(shui)(shui)的(de)(de)(de)(de)(de)費(fei)(fei)用(yong)(yong)(yong)(yong)包(bao)括環(huan)境中去除的(de)(de)(de)(de)(de)水(shui)(shui)(shui)(shui)量的(de)(de)(de)(de)(de)費(fei)(fei)用(yong)(yong)(yong)(yong)(地(di)表引水(shui)(shui)(shui)(shui)和(he)井群)、貯水(shui)(shui)(shui)(shui)費(fei)(fei)用(yong)(yong)(yong)(yong)(貯存原水(shui)(shui)(shui)(shui)及(ji)生產出(chu)的(de)(de)(de)(de)(de)水(shui)(shui)(shui)(shui))、處理費(fei)(fei)用(yong)(yong)(yong)(yong)和(he)配水(shui)(shui)(shui)(shui)費(fei)(fei)用(yong)(yong)(yong)(yong)。如果(guo)再(zai)生回(hui)用(yong)(yong)(yong)(yong)水(shui)(shui)(shui)(shui)比(bi)(bi)擴建的(de)(de)(de)(de)(de)供水(shui)(shui)(shui)(shui)系(xi)統費(fei)(fei)用(yong)(yong)(yong)(yong)低(di)，那(nei)么它就(jiu)是(shi)(shi)經(jing)濟(ji)的(de)(de)(de)(de)(de)。然而，擴建供水(shui)(shui)(shui)(shui)系(xi)統的(de)(de)(de)(de)(de)費(fei)(fei)用(yong)(yong)(yong)(yong)通(tong)常比(bi)(bi)平均水(shui)(shui)(shui)(shui)價高。既(ji)然回(hui)用(yong)(yong)(yong)(yong)水(shui)(shui)(shui)(shui)的(de)(de)(de)(de)(de)價格(ge)定位在某種程度上低(di)于(yu)飲用(yong)(yong)(yong)(yong)水(shui)(shui)(shui)(shui)價，出(chu)售(shou)回(hui)用(yong)(yong)(yong)(yong)水(shui)(shui)(shui)(shui)直(zhi)接得(de)到的(de)(de)(de)(de)(de)收入也將低(di)于(yu)再(zai)生回(hui)用(yong)(yong)(yong)(yong)水(shui)(shui)(shui)(shui)系(xi)統的(de)(de)(de)(de)(de)建造(zao)費(fei)(fei)用(yong)(yong)(yong)(yong)，即(ji)使(shi)如此(ci)，回(hui)用(yong)(yong)(yong)(yong)水(shui)(shui)(shui)(shui)系(xi)統是(shi)(shi)經(jing)濟(ji)有效(xiao)的(de)(de)(de)(de)(de)。

消(xiao)減(jian)回(hui)用水系統(tong)對公(gong)眾健康(kang)和環境的(de)(de)風(feng)(feng)險(xian)(xian)的(de)(de)許多(duo)(duo)可行的(de)(de)方法(fa)，提(ti)高(gao)了實施的(de)(de)回(hui)用水系統(tong)的(de)(de)可靠性。這樣的(de)(de)回(hui)用水系統(tong)通常是由(you)多(duo)(duo)級安(an)全(quan)屏(ping)蔽組成的(de)(de)，包括處理和其他步驟(zou)。實施新(xin)增的(de)(de)單元(yuan)，可以(yi)使風(feng)(feng)險(xian)(xian)進一步降低(di)。

參考 文獻

American Water Works Association, Water Treatment Membrane Processes, McGraw-Hill, New York, 1996.

Gunder, B., The Membrane-Coupled Activated Sludge Process in Municipal Wastewater Treatment, Technomic Publishing Co., Lancaster, PA, 2001.

Stephenson, T., S Judd, B. Jefferson, and K. Brindle, Membrane Bioreactors for Wastewater Treatment, IWA Publishing, London, 2000.

United States Environmental Protection Agency, Guidelines for Water Reuse, EPA/625/R-92/004, 1992.

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