在線TOC驗(yàn)證報(bào)告(美國(guó) 休斯敦)

1、考慮到D/DBP（消毒劑/消毒副產(chǎn)物）的相關(guān)標(biāo)準(zhǔn)與規(guī)范要求，在沒(méi)有在線TOC分析儀的情況下，有任何企業(yè)或機(jī)構(gòu)愿意承擔(dān)高額的營(yíng)運(yùn)成本和風(fēng)險(xiǎn)嗎？當(dāng)在線監(jiān)測(cè)對(duì)比取樣監(jiān)測(cè)：其中的優(yōu)/劣勢(shì)何在？ WILLIAM J REAVIS, YING WEI, ERIC SABOLSICE; AND THOMAS HITCHCOCK公共事務(wù)與工程水質(zhì)監(jiān)控集團(tuán)，德克薩斯州·休斯敦市摘要The City of Houston, Texas has been aware of the implications that current and pending regulatory standards woul

2、d have on the operation of their four surface water treatment facilities. In particular, the City has closely monitored changes in regulations related to enhanced coagulation, total organic carbon (TOC) removal, and disinfection by-products (DBP) reduction. The City has, and continues, to conduct ex

3、tensive bench, pilot, and plant scale tests to determine how these regulatory changes would impact the operation of their surface water facilities. 德克薩斯州 休斯敦市一直關(guān)注著即將出臺(tái)的水質(zhì)監(jiān)測(cè)標(biāo)準(zhǔn)對(duì)該市四座水處理設(shè)施所帶來(lái)的潛在影響，同時(shí)，還更關(guān)注新標(biāo)準(zhǔn)在加強(qiáng)絮凝、提高TOC去除率、減少消毒副產(chǎn)物等方面的變化。為此，休斯敦市開展了一系列的實(shí)驗(yàn)室驗(yàn)證、試點(diǎn)及工廠測(cè)試等活動(dòng)，從而判斷這一調(diào)整對(duì)水處理設(shè)施的日常運(yùn)作所帶來(lái)的影響。The TOC con

4、tent of the source and finished water is the common attribute that significantly impacts each of the regulations of interest. TOC is perhaps the one water quality parameter that could impact the financial bottom line of a utility most. In most cases, a fully automated surface treatment facility stil

5、l measures TOC by collecting periodic grab samples for laboratory analysis. Making treatment decisions based on periodic TOC grab samples is comparable to flying a commercial airliner without instrumentation. 進(jìn)廠和出廠水的TOC含量通常對(duì)水質(zhì)處理和監(jiān)測(cè)結(jié)果有著重要的影響。同時(shí)，TOC參數(shù)還與處理廠經(jīng)濟(jì)效益密切相關(guān)。在大多數(shù)情況下，一座全自動(dòng)化的地表水處理工廠，仍采用定時(shí)取樣的方式，將水樣

6、送入實(shí)驗(yàn)室進(jìn)行分析，測(cè)出相應(yīng)的TOC值。但僅根據(jù)取樣所測(cè)得的TOC參數(shù)，來(lái)決定對(duì)應(yīng)的處理方案，其風(fēng)險(xiǎn)如同搭乘沒(méi)有儀表盤的商務(wù)航班，毫無(wú)保障。In a collaborative effort between the Water Quality Laboratory and the Operations Group at the Citys East Water Purification Complex (EWPC), an evaluation of on-line TOC equipment has been completed. After nearly a year of plant s

7、cale evaluation, the recommendation is being made that on-line TOC analyzers be purchased to enhance facility operations. During the trial, the instrument was used to monitor plant performance and to evaluate alternate coagulants and coagulant aids. The most interesting results of the study related

8、to how poorly the operators responded to changing raw water parameters when given daily grab sample results and how much better they were able to respond when allowed to utilize the on-line analyzer. The on-line TOC analyzer allowed the operators to track real time water quality changes and therefor

9、e respond much quicker than would be possible if grab samples were being used. Because the City of Houston has two raw water sources that are dramatically different (alkalinity, pH, turbidity, TOC concentration, and TOC composition), blends of the two raw water sources present special treatment chal

10、lenges, especially related to coagulation efficiency and TOC removal. 在休斯敦水質(zhì)監(jiān)測(cè)實(shí)驗(yàn)室和EWPC工作組的共同努力下，完成了對(duì)在線TOC分析儀的綜合評(píng)估。經(jīng)過(guò)近一年的工廠實(shí)地驗(yàn)證，結(jié)果充分證明了在線TOC分析儀在污水處理廠日常運(yùn)營(yíng)中發(fā)揮的重要作用。在實(shí)驗(yàn)期間，分析儀被用于監(jiān)測(cè)工廠處理效果，以及過(guò)程中使用的絮凝劑和助凝劑。研究最具價(jià)值之處在于充分驗(yàn)證了，通過(guò)傳統(tǒng)取樣法，操作人員無(wú)法高效的轉(zhuǎn)換源水參數(shù)，工廠未能達(dá)到理想的處理效果，相反的是，通過(guò)使用在線分析儀，水質(zhì)處理效果明顯提高。實(shí)驗(yàn)表明，在線TOC分析儀可幫助操作人員把握

11、實(shí)時(shí)的水質(zhì)變化情況，相對(duì)傳統(tǒng)取樣法，更快的采取處理與應(yīng)對(duì)措施。由于休斯敦市的進(jìn)廠水來(lái)自兩大主要源頭，且在堿度、Ph值、濁度、有機(jī)碳含量和組成等方面有著截然的區(qū)別，混合后的進(jìn)場(chǎng)水，對(duì)工廠的處理工藝提出了更高的挑戰(zhàn)，特別在絮凝和TOC去除等方面。This paper will discuss the results of a variety of tests and it will examine the advantages and disadvantages of implementing continuous on-line TOC monitoring. When considering

12、the economic implication of applying enhanced coagulation measures, it becomes clear that the closer the operator is able to maintain the required TOC removal percentage without overfeeding, the lower the operation cost to the utility. Operating without the proper instrumentation costs money and res

13、ults in a lower quality water for the utility customers.本文將討論各種測(cè)試結(jié)果，并研究在線TOC監(jiān)測(cè)在實(shí)際應(yīng)用中的優(yōu)劣勢(shì)所在。關(guān)于加強(qiáng)絮凝所導(dǎo)致的經(jīng)濟(jì)影響，本文會(huì)讓我們清楚看到，在使用在線TOC分析儀情況下，不用額外增加絮凝劑，操作人員也能達(dá)到TOC目標(biāo)去除率，當(dāng)越接近所要求的去除率時(shí)，工廠的運(yùn)營(yíng)成本越低。同時(shí)也說(shuō)明了，分析儀器的選擇不當(dāng)，會(huì)造成更高的成本浪費(fèi)，且無(wú)法為客戶提供滿意的水質(zhì)保障。INTRODUCTION 背景介紹The City of Houstons Water Quality Group has been collect

14、ing data for several years on all phases of its water, from its watersheds through distribution. The data is extremely useful, but grab samples can not always provide data that can be used to track small fluctuations in water quality. For instance, chlorine, fluoride, turbidity, pH, and temperature

15、are water quality parameters that are currently tracked throughout the treatment process continuously by on-line monitoring equipment. The financial implications of operating in an enhanced coagulation mode to comply with the requirements of the D/DBP Rule makes it more prudent to track the TOC conc

16、entration throughout the treatment process. Management, Operations, and the Water Quality Group recognized that TOC removal would be a problem to contend with, but implementation of an on-line TOC monitoring program would require a financial commitment on the part of the City. In order to justify th

17、e purchase of on-line TOC monitoring equipment, the benefits of on-line TOC monitoring would have to be weighed against the cost, and in order to do this a plant scale test would be needed. 近年來(lái)休斯敦水質(zhì)監(jiān)控集團(tuán)堅(jiān)持從水源的各個(gè)階段采集數(shù)據(jù)，不管是從源頭，還是流經(jīng)的管網(wǎng)。雖然這些數(shù)據(jù)對(duì)于水質(zhì)監(jiān)測(cè)極為有用，但取樣的方法仍無(wú)法保證測(cè)得的數(shù)據(jù)，可隨時(shí)用于追蹤并監(jiān)測(cè)水質(zhì)的細(xì)微變化。例如氯、氟化物、濁度、pH值及溫

18、度等，在當(dāng)下，都是通過(guò)在線監(jiān)測(cè)設(shè)備對(duì)其進(jìn)行實(shí)時(shí)監(jiān)控。為達(dá)到D/DBP的相關(guān)規(guī)定，工廠需投入更多的成本，采用絮凝加強(qiáng)模式，對(duì)處理過(guò)程中的TOC含量進(jìn)行監(jiān)控。對(duì)此，管理部門、經(jīng)營(yíng)部門，及休斯敦城市水質(zhì)監(jiān)控集團(tuán)都意識(shí)到TOC的去除是處理過(guò)程中的一項(xiàng)難題，為了實(shí)施有效的在線TOC監(jiān)測(cè)方案，還需得到國(guó)家的財(cái)政支持。為證明采購(gòu)在線TOC監(jiān)測(cè)設(shè)備的重要性，還需對(duì)設(shè)備采購(gòu)成本與使用后的受益情況進(jìn)行綜合對(duì)比與分析，除此，在水處理工廠范圍內(nèi)的全面驗(yàn)證也是必不可少的程序。The first step in conducting a plant scale project is to determine a cour

19、se of study that is acceptable to all the parties, management, operations, and the technical staff conducting the trial. It could be argued that many times the research staff, state and federal regulatory agencies are not on the same page in the play book as the people responsible for operating the

20、production facility. The primary responsibility of the facility staff, including the technical staff, is to provide an adequate supply of potable, properly disinfected water, at an adequate pressure, while at the same time keeping costs to a minimum. Cost is the aspect of water treatment that most m

21、anagers and operators would argue that the technical staff has forgotten to factor in. In general, higher quality water must come at a higher operating cost, but when operations and the technical staff work together the additional cost can be minimized, and in some cases a cost savings can be realiz

22、ed. Two questions remains, “Is there a cost benefit to monitoring TOC on-line?” and “Can an on-line analyzer be used to help achieve the required TOC removal percentage?”開展全廠范圍測(cè)試的首要步驟是，制定一個(gè)被管理部門、營(yíng)運(yùn)部門、以及測(cè)試執(zhí)行人員所認(rèn)可的測(cè)試方案。當(dāng)研究人員、州及聯(lián)邦政府人員沒(méi)有共同作為設(shè)施負(fù)責(zé)人，且達(dá)成一致意見(jiàn)時(shí)，時(shí)常會(huì)出現(xiàn)意見(jiàn)分歧。水廠員工（含技術(shù)人員）的首要職責(zé)就是提供經(jīng)過(guò)消毒、水壓適當(dāng)?shù)某渥泔嬘盟?，同時(shí)

23、確保工廠的運(yùn)作成本最小化。成本也通常是管理層和運(yùn)作部門常提到的問(wèn)題，且總抱怨他們的技術(shù)人員沒(méi)有充分重視工廠處理成本的控制。總的來(lái)說(shuō)，優(yōu)質(zhì)的出廠水必將消耗更高的處理成本，但當(dāng)運(yùn)營(yíng)人員與技術(shù)人員目標(biāo)一致時(shí)，總能避免一些額外的成本浪費(fèi)，甚至找到降低運(yùn)營(yíng)成本的其他辦法。到此，仍然有兩個(gè)疑問(wèn)存在，“采用TOC在線監(jiān)測(cè)是否會(huì)帶來(lái)一定的成本收益？”“在線分析設(shè)備能使出廠水達(dá)到規(guī)定的TOC去除率嗎？”TREATMENT HISTORY AND WATERSHED BACKGROUND 水處理及水源地背景介紹The City of Houston has two raw water sources, the T

24、rinity River and the San Jacinto River. The raw water supplied by the two watersheds has uniquely different water quality characteristics that often require quite different treatment techniques. The Trinity River watershed is a larger and more stable raw water source. Its alkalinity averages 98 mg/L

25、 as CaCO3, with a range of 71 and 114 mg/L as CaCO3. The Trinity Rivers TOC level averages 6.0 mg/L, and ranges between 4.2 and 8.6 mg/L. The San Jacinto watershed is a much smaller watershed and is subject to wide ranging seasonal fluctuations in water quality. Its alkalinity averages 50 mg/L as Ca

26、CO3, with an average TOC level of 8.7 mg/L. Compared to Trinity River water, the San Jacinto is generally more expensive and difficult to treat because of its low alkalinity and higher organic load. A majority of the Citys surface water is treated at the East Water Purification Complex (EWPC). The c

27、omplex houses three treatment facilities that supply water to two distribution entry points. The facilities treat a blend of the two raw water sources, generally a ratio of 90% Trinity River and 10% or less of San Jacinto water. Plants 1 and 2 get a majority of the San Jacinto water giving it a high

28、er raw TOC, and subsequently a higher TOC removal percentage. The higher raw TOC level does not equate to a much higher distribution TOC level. Percentage wise, Plants 1 and 2 achieve a higher TOC removal percentage than Plant 3, 34.8% vs. 31.3%, respectively.休斯敦市的水源主要來(lái)自Trinity和San Jacinto兩條河流。來(lái)自不同河

29、流的兩種源水有著不同的水質(zhì)特點(diǎn)，對(duì)水處理工藝要求也截然不同。Trinity河水域較寬，水源穩(wěn)定，其源水堿度為98 mg/L as CaCO3, 浮動(dòng)范圍在 71114 mg/L as CaCO3，TOC平均值為6.0 mg/L，浮動(dòng)范圍在4.2 and 8.6 mg/L。與之相反，San Jacinto河面較窄，且河流水質(zhì)受季節(jié)性變化影響較大，其堿度平均值為50 mg/L as CaCO3 TOC平均含量為8.7 mg/L。與Trinity相比，由于San Jacinto河流水域堿度較低、有機(jī)物含量較高，增加了其在處理過(guò)程中的難度與成本。休斯敦市大多數(shù)的地表水都是通過(guò)EWPC進(jìn)行處理，該機(jī)構(gòu)擁

30、有三大主要的水處理設(shè)施，并向城市的兩大配水管網(wǎng)輸送水源。這些處理廠的進(jìn)廠源水主要來(lái)城市的兩條河流，通常情況下90%左右的源水來(lái)自Trinity河，10%或更少的源水來(lái)自San Jacinto河。由于1、2號(hào)工廠主要對(duì)來(lái)自San Jacinto河的源水進(jìn)行處理，所以源水在進(jìn)廠時(shí)具有較高的TOC含量，經(jīng)過(guò)處理通常會(huì)達(dá)到較高的TOC去除率。由此可見(jiàn)，具有較高TOC含量的源水并不意味著出廠后仍有較高的TOC含量。為達(dá)到一致的處理效果，1、2號(hào)處理廠的TOC去除率通常會(huì)高于3號(hào)工廠，其去除率分別為34.8% vs. 31.3%。The organic makeup of the raw and dist

31、ribution waters has been studied extensively by the Citys Water Quality Research Group. The group conducted organic fractionation studies that were initiated in part, to answer questions that arose during the ICR data collection process. The group was interested in seeing which molecular weight comp

32、ounds contributed most to the formation of DBPs. Because the City had access to more than one type of TOC analyzer, raw and distribution water samples were measured using several analyzers, both High Temperature Combustion and UV Persulfate. 該市的水質(zhì)研究小組，對(duì)源水和出廠管網(wǎng)水的有機(jī)物組成情況，進(jìn)行了深入的研究。一定程度上，通過(guò)有機(jī)物分類研究的方法來(lái)解決

33、ICR數(shù)據(jù)采集過(guò)程中所遇到的問(wèn)題。同時(shí)，研究小組還十分關(guān)注DBP生成過(guò)程中，哪種分子量的化合物發(fā)揮了最大作用。由于休斯敦市并非采用單一的TOC分析儀,因此高溫燃燒和紫外硫酸鹽等原理的TOC分析儀被廣泛應(yīng)用于該市的源水與管網(wǎng)水監(jiān)測(cè)中。The analyzers were calibrated using the same standards, and when validation samples were run each of the instruments produced similar TOC values. However, raw water samples with comple

34、x matrixes produced inconsistent results when the dispersion of natural organic material (NOM) was comprised mainly of small organic compounds 儀器在校準(zhǔn)時(shí)采用同樣的檢測(cè)標(biāo)準(zhǔn)，通過(guò)對(duì)同一校準(zhǔn)液進(jìn)行測(cè)量，并測(cè)出相近的TOC參數(shù)。但在成分復(fù)雜的源水中，特別是富含天然有機(jī)物（且主要由小分子有機(jī)化合物組成，如富里酸、氨基酸等）的源水中，很難測(cè)得穩(wěn)定的TOC參數(shù)。(富里酸和氨基酸). The High Temperature Combustion instrume

35、nts often produced values higher than those obtained using the UV Persulfate instruments. In particular, there seemed to be a greater difference in the measured TOC levels in Trinity River samples collected during dry weather conditions. Fractionation studies proved that Trinity River water had a hi

36、gher concentration of small NOM, organics that are more difficult to oxidize. The problem associated with the UV Persulfate analyzer was that incomplete oxidation of the non-purgable organics resulted in lower, inconsistent, and inaccurate measurements. With proper sample preparation, extending UV e

37、xposure time, and the use of a stronger oxidant, the problems associated with the UV Persulfate instrument were corrected. Being able to recognize and correct the problems associated with the UV Persulfate analyzer makes it best choice for most laboratories. The UV Persulfate analyzer is much simple

38、r to operate, easier to maintain, and more trouble free than the High Temperature Combustion analyzer. 通過(guò)高溫燃燒法測(cè)得的參數(shù)值通常高于紫外硫酸鹽法。特別是在測(cè)量枯水期從Trinity所采取的水樣時(shí)，以上兩種原理的分析儀所測(cè)得的TOC參數(shù)存在明顯的差異。分離研究表明Trinity河含有較高濃度的小分子有機(jī)化合物，因此有機(jī)物成分更難被氧化。紫外硫酸鹽法測(cè)試儀的問(wèn)題主要在于non-purgable有機(jī)物無(wú)法完全氧化，從而導(dǎo)致測(cè)出的TOC參數(shù)偏低、不穩(wěn)定，無(wú)法完成精確的測(cè)量，但如果更適當(dāng)?shù)販?zhǔn)備水樣

39、，延長(zhǎng)紫外曝光時(shí)間，使用更強(qiáng)的氧化劑，就可解決紫外硫酸鹽TOC分析儀所存在的問(wèn)題。想要了解并解決紫外硫酸鹽TOC分析儀所存在的問(wèn)題，最佳方法是將其應(yīng)用于實(shí)驗(yàn)室測(cè)量中。紫外硫酸鹽TOC分析儀擁有操作簡(jiǎn)便，易保養(yǎng)等特點(diǎn)，相對(duì)高溫燃燒分析儀而言，問(wèn)題更少，穩(wěn)定性更佳。Based on the alkalinity and raw water TOC concentration, the City of Houston would be required to achieve a TOC removal percentage that ranges between 30 and 50 percent.

40、 This depends greatly on the raw water blend and seasonal water quality conditions. Achieving the required TOC removal percentage is much easier during wet weather (winter) conditions. Both raw water sources require higher coagulant dosages during wet weather conditions to achieve adequate turbidity

41、 removal. The higher coagulant dose combined with an increased organic load of large humic substances, due to runoff into the watershed, make it much easier to achieve the required TOC removal percentage.根據(jù)源水堿度與TOC濃度特點(diǎn)，休斯敦市的處理廠需達(dá)到30%-50%的TOC去除率，但這也絕大意義上取決于源水中的混合物，以及水質(zhì)的季節(jié)性變化。通常在雨水較多的季節(jié)（冬天），更容易達(dá)到規(guī)定的TO

42、C去除率。在雨季，為達(dá)到更好的脫濁效果，需在源水中加入更多的絮凝劑，同時(shí)，因?yàn)榻邓?，大量的腐殖質(zhì)被沖入河流源水中，增加了水中的有機(jī)物含量，此時(shí)的有機(jī)物會(huì)與加量的絮凝劑充分結(jié)合，使處理工藝更易達(dá)到理想的TOC去除率。The greatest unknown for management and operations staff has been whether the required TOC removal percentage could be achieved during dry weather operating conditions, and if so, how could it

43、be achieved, and at what cost. During dry periods, water quality conditions in both watersheds change significantly. Turbidity in the raw water drops, making it easier to achieve the target finished water turbidity, but at the same time the TOC levels drop making it more difficult to achieve the req

44、uired TOC removal percentage. This is why achieving the required TOC removal percentage during dry weather conditions will be the most difficult challenge facing the water production staff at the City of Houston. 對(duì)于水處理廠管理和操作人員而言，在旱季是否可以達(dá)到規(guī)定的TOC去除率仍是最大的疑問(wèn)，如果可以，要如何實(shí)現(xiàn)，運(yùn)行成本如何？在旱季，休斯敦兩條河流的水質(zhì)情況都會(huì)發(fā)生較大的變化。源

45、水中的濁度會(huì)大幅下降，使工廠很簡(jiǎn)單就可以達(dá)到出廠水濁度標(biāo)準(zhǔn)。但同時(shí)，TOC含量的下降也為達(dá)到規(guī)定的去除率增加了不少難度，這也是為什么在旱季，達(dá)到規(guī)定的TOC去除率，是休斯敦水廠所面臨的頭號(hào)難題。INSTRUMENTATION 介紹A Hach 1950 Plus On-line TOC analyzer was used during this study. The 1950 Plus utilizes the UV/Persulfate analysis method. The City of Houstons decision to purchase this instrument was

46、 based on several parameters, including its ability to analyze multiple streams, the relative ease of operation, easy access for maintenance, separation of wetted area from electronics, and the ability to automatically perform validations and calibrations at prescribed time intervals. The most impor

47、tant consideration however, was the analyzers ability to detect organics that oxidize more slowly. This is achieved through the addition of multiple UV chambers. The more slowly oxidized organics are given the chance to completely oxidize by increasing the UV exposure, thus increasing the accuracy o

48、f reported TOC values. For the City of Houston, the addition of a second UV chamber was required to adequately to meet the oxidation requirements. In raw water sources that have a relatively low TOC value, incomplete oxidation could result in the under estimation of the raw water TOC, thus significa

49、ntly reducing the reported TOC removal value. Anyone considering the purchase of an on-line or laboratory TOC analyzer should determine the organic makeup of their source water prior to purchasing an instrument.1950+在線TOC分析儀被用于了此項(xiàng)重要研究。該款儀器采用了紫外硫酸鹽分析原理，休士頓市購(gòu)買此儀器的原因是基于，該儀器可同時(shí)測(cè)量多組水樣，操作簡(jiǎn)單，便于維護(hù)，電子組件與濕區(qū)分離

50、，并可以按時(shí)進(jìn)行定期的校準(zhǔn)與驗(yàn)證，但最主要的原因還是因?yàn)閮x器可測(cè)定緩慢氧化的有機(jī)物。這取決于儀器額外增加了UV反應(yīng)艙，這使緩慢氧化的有機(jī)物更長(zhǎng)時(shí)間曝露于紫外光中，達(dá)到徹底氧化的效果，從而提高了儀器對(duì)TOC參數(shù)測(cè)量的準(zhǔn)確性。對(duì)于休斯敦所選用的儀器而言，增加的第二個(gè)紫外反應(yīng)艙必須使有機(jī)物得到重分氧化。在TOC含量相對(duì)較低的源水中，不完全的氧化可造成對(duì)源水TOC含量判斷過(guò)低，從而嚴(yán)重影響實(shí)際去除的TOC數(shù)量。所以在決定購(gòu)買在線或?qū)嶒?yàn)室TOC分析儀之前，應(yīng)清楚認(rèn)識(shí)你所測(cè)源水中的有機(jī)物組成情況。STUDY PLAN 研究計(jì)劃Over several years, the laboratory staff

51、 at the City of Houston has conducted hundreds of jar tests and numerous pilot studies. These tests have provided insight as to how the required TOC removal percentage might be achieved. Unfortunately, jar tests and pilot studies can only provide an indication of what might be expected in the full-s

52、cale production facility. Therefore, a plant scale study was conducted at the City of Houstons East Water Purification Complex during dry weather operating conditions. The study also provided an opportunity to evaluate how effectively the operating staff could achieve and maintain the required TOC r

53、emoval percentage through the use of an on-line TOC monitoring device. 經(jīng)過(guò)數(shù)年的研究，休斯敦的實(shí)驗(yàn)室人員進(jìn)行了無(wú)數(shù)次的燒杯實(shí)驗(yàn)和試點(diǎn)研究。實(shí)驗(yàn)證明，規(guī)定的TOC去除率是可以達(dá)到的，但結(jié)果卻僅說(shuō)明了為達(dá)到規(guī)定的去除率，在水廠中哪些工藝或設(shè)備是必須的。因此休斯敦市在在EWPC水廠，開展了一次旱季作業(yè)條件下的全面研究。這次研究讓大家看到，通過(guò)使用在線TOC分析儀，操作人員是如何達(dá)到并維持規(guī)定的TOC去除率的。The study plan was relatively simple. First, determine if the

54、 target removal percentage can be attained. Second, explain to the operators how the target removal percentage can be achieved. Third, evaluate the operators performance to see if they can achieve and maintain the target removal percentage without the aid of the on-line TOC analyzer. Fourth, allow t

55、he operator to use the on-line analyzer and see if their performance improves. And finally, determine the benefits of using an on-line analyzer. This trial was started in mid summer after an extended period of dry weather, raw water turbidity and TOC levels had dropped significantly, thus requiring

56、lower chemical dosages to achieve the target finished water turbidity. The study was conducted on a single treatment train at the East Water Purification Complex. At the time of the study a blend of 90% Trinity River water and 10% San Jacinto River water was being treated at the facility. The flow r

57、ate through the treatment train was held constant at 40 mgd (a 0.6 gal/min/ft2 surface overflow rate). In addition to monitoring the TOC on-line, pH, total chlorine, turbidity, lime feed rate, streaming current, and coagulant (alum) dose were monitored on-line. An alkalinity grab sample was collecte

58、d on the raw water each shift by the operations staff. 這項(xiàng)研究計(jì)劃相對(duì)簡(jiǎn)單，首先是為了判定目標(biāo)去除率是否可以達(dá)到，其次，讓操作人員了解是如何實(shí)現(xiàn)目標(biāo)去除率的，第三，評(píng)估操作人員工作情況，如果在沒(méi)有在線TOC分析儀的情況下，是否能達(dá)到或維持目標(biāo)去除率，第四，讓操作人員使用在線分析儀，并清楚了解使用后的工作改進(jìn)情況，最后，研究將總結(jié)使用在線TOC分析儀的獲益。該研究開始于持續(xù)晴熱天氣后的盛夏，此時(shí)的源水濁度與TOC含量都大幅下降，為達(dá)到出廠濁度，工廠只需投入少量的化學(xué)藥劑。該研究在EWPC單獨(dú)的一條處理線進(jìn)行，其中90%的源水來(lái)自Trinit

59、y河，10%來(lái)自San Jacinto河，水處理線流動(dòng)率保持在40 mgd (a 0.6 gal/min/ft2 surface overflow rate)。除了監(jiān)測(cè)在線的TOC參數(shù)，還對(duì)pH、總氯、濁度、lime feed rate、流動(dòng)電流、絮凝劑（礬）等參數(shù)進(jìn)行在線監(jiān)測(cè)。此外，每個(gè)班次的現(xiàn)場(chǎng)操作人員，也通過(guò)不定時(shí)取樣的方式對(duì)源水堿度進(jìn)行檢測(cè)。PRELIMINARY TREATMENT EVALUATION 預(yù)處理方案評(píng)估STAGE 1: ALUM ADJUSTMENT WITH LIME AND POLYMER ADDITION 階段1 絮凝劑（明礬）與石灰、聚合物進(jìn)行調(diào)節(jié)A preliminary treatment evaluation was conducted to determine if the required TOC removal percentage could be achieved on a plant scale. The first step was to establish a normal o