環(huán)境工程外文翻譯--生物-化學(xué)絮凝工藝處理城市的污水和生物作用的研究

1、<p>　　畢業(yè)設(shè)計(jì)(論文)外文資料翻譯</p><p>　　學(xué)院（系）： 資源與環(huán)境工程學(xué)院 </p><p>　　專 業(yè)： 環(huán)境工程 </p><p>　　姓 名： </p>&

2、lt;p>　　學(xué) 號(hào)： </p><p>　　外文出處： Journal of Environmental Sciences</p><p>　　附 件：1.外文資料翻譯譯文；2.外文原文。 </p><p>　　附錄1 外文資料翻譯譯文</p><p

3、>　　生物-化學(xué)絮凝工藝處理城市的污水和生物作用的研究</p><p>　　摘要： 本文介紹在處理上海城市的污水時(shí)證實(shí)生物-化學(xué)的絮凝工藝的中試實(shí)驗(yàn)的儀器和程序的可行性。并討論在此過(guò)程中生物的功能。最理想運(yùn)行的結(jié)果顯示，在反應(yīng)罐中，混合液懸浮固體(MLSS)是2g/L, 液壓的保持時(shí)間(HRT)是35min，聚合氯化鋁(PAC)是60mg/L，而濃度聚丙烯酰胺(PAM)是0.5mg/L.并且CODCr，TP

4、，SS和BOD5的平均濃度為分別是50mg/L，0.62mg/L，18mg/L，和17mg/L。這些設(shè)計(jì)的要求更好。此外，這個(gè)系統(tǒng)中的生物降解的存在有幾種方法證明。生物-化學(xué)的絮凝工藝的降解效率比在同樣的凝結(jié)劑中化學(xué)絮凝工藝提高20%。在不同的條件下進(jìn)行中試試驗(yàn)，為將來(lái)的設(shè)備操作提供最佳的參數(shù)和條件。</p><p>　　關(guān)鍵詞： 生物-化學(xué)絮凝工藝； 城市污水； 生物作用。</p><p&g

5、t;<b>　　1 試驗(yàn)</b></p><p>　　1.1 設(shè)計(jì)對(duì)項(xiàng)目進(jìn)行進(jìn)水和出水的濃度</p><p>　　根據(jù)顯示評(píng)價(jià)和標(biāo)準(zhǔn)的水規(guī)格，城市污水的設(shè)計(jì)進(jìn)水和出水的濃度見(jiàn)表格1。</p><p>　　表1 　工程設(shè)計(jì)進(jìn)水水質(zhì)</p><p>　　1.2 中試試驗(yàn)的流程圖</p><p>　　

6、生物-化學(xué)絮凝工藝中試試驗(yàn)的示意圖見(jiàn)圖1.</p><p><b>　　圖1 工藝流程圖</b></p><p>　　中試試驗(yàn)的設(shè)備包括一個(gè)小的混合罐，寬1.0m、高1.1m、長(zhǎng)2.2m的生物-化學(xué)絮凝罐, 兩個(gè)寬1.0m高2.9m、長(zhǎng)3.0m的沉淀池，寬0.6m、高6.5m、長(zhǎng)1.2m的硝化罐，空壓泵和水泵。生物-化學(xué)的絮凝罐被劃分成為三條廊道，在每一條廊道中加入曝

7、氣管。首先，城市污水被抽吸到混合罐中再進(jìn)入到生物-化學(xué)的絮凝罐中。水在每條廊道中反應(yīng)之后進(jìn)入第一沉淀池。然后水在澄清之后進(jìn)入水罐，它在外排前作為一個(gè)水庫(kù)或者進(jìn)一步反應(yīng)。水的一部分直接排出，而余下的水為了進(jìn)一步的處理被抽吸到硝化的罐中。伴隨著硝化菌，水進(jìn)水第二個(gè)沉淀池。在澄清之后水被排出。第一沉淀池為系統(tǒng)的生物-化學(xué)反應(yīng)提供回流污泥。曝氣系統(tǒng)向生物-化學(xué)絮凝反應(yīng)提供氧并且控制在不破壞絮凝團(tuán)的水平上?？諝饬魉僭谌齻€(gè)廊道內(nèi)分別是4m3/h，2

8、.5m3/h，和2m3/h。按這種方式，生物-化學(xué)反應(yīng)在同樣的罐內(nèi)迅速地和有效分解有機(jī)的污染物和TP(總磷)。從生物-化學(xué)的絮凝工藝的液壓的保持時(shí)間(HRT)對(duì)硝化作用來(lái)說(shuō)太短, 硝化罐懸浮過(guò)濾床(SFB)被用來(lái)提高氨氮的降解效率。在生物-化學(xué)的絮凝結(jié)果和機(jī)制在本文中作詳細(xì)討論。</p><p>　　中試試驗(yàn)中的無(wú)機(jī)的凝結(jié)劑和有機(jī)的大分子凝結(jié)劑的選擇在中試試驗(yàn)中有很大的幫助。首先，助凝劑按要求的濃度被添加到一個(gè)反

9、應(yīng)罐中。接著，助凝劑和絮凝劑的選擇的用量用計(jì)量泵(MILTONROY，美國(guó))加到罐中。在其中助凝劑和絮凝劑的增加量是可調(diào)整的。在這個(gè)系統(tǒng)中，聚合氯化鋁(PAC)被用作絮凝劑，而助凝劑是聚丙烯酰胺(PAM)。PAC被注入到罐中在第一條廊道的入口，和第二條廊道的入口加入PAM。</p><p><b>　　分析和監(jiān)控</b></p><p>　　項(xiàng)目測(cè)量評(píng)估見(jiàn)表格2。水質(zhì)

10、量監(jiān)控使用的方法見(jiàn)表格3。</p><p>　　表2 　分析測(cè)試項(xiàng)目</p><p>　　1.4 生物作用分析</p><p>　　生物作用研究使用一個(gè)特制的密封的反應(yīng)器、充氧氣泵、電磁攪拌器，Leici JPB~607便攜式的溶解氧計(jì)量器，和一個(gè)秒表。生物的功能的分析被劃分成為兩個(gè)步驟。首先，1000 ml水樣放到特制的密封的反應(yīng)器中，溶解氧是用充氧氣泵將空氣注入

11、到樣品中。接著，充氣設(shè)備被移去，反應(yīng)器的蓋子蓋緊并且連接到溶解氧計(jì)量器。對(duì)溶解氧濃度進(jìn)行連續(xù)記錄。做出溶解氧的消耗的曲線。</p><p>　　表3 　水質(zhì)指標(biāo)的分析方法</p><p><b>　　結(jié)果和討論</b></p><p>　　2.1　中試試驗(yàn)結(jié)果</p><p>　　為了對(duì)操作結(jié)果進(jìn)行詳細(xì)分析將其劃分成為六

12、個(gè)階段見(jiàn)表4。不同的階段的時(shí)間間隔表現(xiàn)出了PAC的用量趨勢(shì)和PAC的注入位置。</p><p>　　表 4 生物化學(xué)絮凝在六個(gè)操作期的測(cè)定結(jié)果</p><p>　　正如表4所示，PAC的用量從高到適中，然后到低，由計(jì)量器控制。隨著PAC劑量的減少?gòu)亩３諧OD的降解效率，而出水的TP濃度在很大程度的增加。通過(guò)觀察當(dāng)PAC用量在60mg/L的時(shí)候出水的TP濃度輕微超出正常的標(biāo)準(zhǔn)。結(jié)論，PAC

13、用量為70mg/L是這個(gè)工藝的最佳用量。5時(shí)期是用來(lái)測(cè)驗(yàn)去除COD，TP和SS的最佳加藥量。6時(shí)期是用來(lái)測(cè)驗(yàn)PAC的最佳注入位置的。當(dāng)PAC的用量是100mg/L時(shí)，結(jié)果證明反應(yīng)不充分。</p><p>　　2.2　最佳操作條件</p><p>　　表格4表明試驗(yàn)顯示的最佳操作條件是：在絮凝罐中的藥劑的用量MLSS 2g/L；HRT 35min; 液態(tài)的PAC 70mg/L；PAM (分子

14、量從2百萬(wàn)到3百萬(wàn) )的用量為0.5mg /L在這樣的操作條件下的結(jié)果在下列的段落中分別被論述。</p><p>　　2.2.1 　去除COD</p><p>　　在COD去除的最佳條件下操作的超過(guò)25天見(jiàn)圖2。正如圖2所示，進(jìn)水的COD濃度一天天變化。進(jìn)水的COD通常在124mg/L到266mg/L之間。出水的COD通常在24mg/L到74mg/L之間，平均的流出物是50mg/L，去除率

15、達(dá)到70%。因此得出結(jié)論這個(gè)工藝能有效的去除COD并且達(dá)到標(biāo)準(zhǔn)。</p><p>　　圖2 對(duì)COD的去除效果</p><p>　　2.2.2　去除TP</p><p>　　正如圖3所示，進(jìn)水的TP濃度變化從1.63mg/L到 3.25mg/L，平均濃度為2.37mg/L。簡(jiǎn)言之，出水的濃度在1mg/L以下的TP出水濃度是0.62mg/L，而去除率達(dá)到最佳操作條件的

16、74.3%。如果進(jìn)水的濃度太高，出水的TP濃度將超過(guò)1mg/L。</p><p>　　2.2.3　去除懸浮固體(SS)</p><p>　　如圖4所示，超過(guò)設(shè)計(jì)濃度150mg/L的 SS濃度的變化從70mg/L到 380mg/L，平均值濃度為2.7mg/L。所有出水的SS濃度在40mg /L以下，出水的SS的平均濃度為18mg/L，去除率達(dá)到88.6 %。在研究工藝中出水的SS濃度都保持在

17、一個(gè)較低的水平，而且非常穩(wěn)定。竹園城市污水處理設(shè)備(ZMWTP)去除SS的目的很容易實(shí)現(xiàn)。</p><p>　　圖3 對(duì)TP的去除效果</p><p>　　圖4 對(duì)SS的去除效果</p><p>　　2.3生物作用分析測(cè)試</p><p>　　2.3.1不同的模擬反應(yīng)系統(tǒng)的設(shè)計(jì)</p><p>　　為了證實(shí)在生物-化

18、學(xué)絮凝罐中的生物活動(dòng)，試驗(yàn)中設(shè)計(jì)使用不同的系統(tǒng)。所有的試驗(yàn)條件見(jiàn)表格5。</p><p>　　表5 不同反應(yīng)條件對(duì)比</p><p>　　2.3.2　研究結(jié)果</p><p>　　工況1結(jié)果表明ZMWTP 污水本身對(duì)溶解氧消耗十分少。在開(kāi)始時(shí)，溶解氧的濃度為8mg/L。在12分鐘之后，濃度保持在7mg/L到8mg/L，其消耗量不超過(guò)1mg/L?？梢酝茢喑鲈跒樘幚淼奈?/p>

19、水中有生物存在。對(duì)于工況2，增加化學(xué)凝結(jié)劑，開(kāi)始時(shí)的濃度為6 mg/L，20分鐘之后極少微生物消費(fèi)溶解氧不超過(guò)1mg/L。工況3，用類比的方法模擬沒(méi)有曝氣過(guò)程，開(kāi)始時(shí)溶解氧濃度為6mg/L，并且在20分鐘之后濃度的變化超過(guò)1mg/L。如果前二個(gè)條件沒(méi)有回流污泥那么在絮凝期間，即使供氣，這個(gè)系統(tǒng)溶解氧的消耗量是輕微的。當(dāng)回流污泥增加時(shí)，如果不曝氣的話這個(gè)系統(tǒng)的溶解氧的消耗仍然很低。因此，在在這三個(gè)工況下都有微量的微生物存在。工況4用類比的

20、方法模擬有污泥回流和曝氣的絮凝工藝。在20分鐘后溶解氧的濃度約為2.8 mg/L。由于耗氧微生物的存在，如果不曝氣，即使有污泥回流效果仍然不是很好。結(jié)論得出系統(tǒng)有一定的微生物分解作用。</p><p>　　工況5、6、7的溶解氧的消耗曲線見(jiàn)圖6. 如圖5所示，如果活躍的回流污泥(從上海竹園城市污水處理系統(tǒng))存在于生物-化學(xué)的絮凝工藝中，因?yàn)槲⑸锏幕顒?dòng)溶解氧的消耗量增加6.4mg。明顯地，溶解氧的需求量十分高。根

21、據(jù)圖6，試驗(yàn)結(jié)果顯示出實(shí)際運(yùn)行的中試裝置第一、二廊道在5～7分鐘內(nèi)的耗氧量為5 mg/L左右,溶解氧的消耗量大約為5mg/L。由此可以判斷在竹園污水的中試裝置中存在較好的生物作用</p><p>　　圖5 工況5下的溶解氧消耗曲線</p><p>　　圖6 工況6和7下的溶解氧消耗曲線</p><p>　　2.3.3生物的活動(dòng)分析的測(cè)試數(shù)據(jù)</p>

22、<p>　　一些帶有相似用量的操作條件的結(jié)果列在表6中和測(cè)試具有相同BOD5列在表7中。</p><p>　　表6 　 COD和TP在不同條件下的數(shù)據(jù)統(tǒng)計(jì)表</p><p>　　表7 　本工況進(jìn)出水BOD5/COD 測(cè)定結(jié)果</p><p>　　在凝結(jié)-絮凝工藝中，污水中的磷的去除機(jī)制可能有兩種: 懸浮的磷酸鹽凝聚成固體并在沉降的過(guò)程中將磷去除。由金屬離

23、子組成的水解物中的磷酸鹽離子進(jìn)行直接吸附。形成的在金屬鹽中的磷酸鹽在去除過(guò)程中作絮凝劑。磷酸鹽的去處過(guò)程受到一些因素的影響 ,例如堿度, 有機(jī)的物質(zhì)含量和其他金屬的存在。參加磷的降解過(guò)程的基本的反應(yīng)如下:</p><p>　　這個(gè)反應(yīng)相關(guān)對(duì)它的一些次要的反應(yīng)。假設(shè)，磷以正磷酸鹽的形式伴隨著金屬離子被磷酸鹽降解，總磷以更復(fù)雜的吸附反應(yīng)吸附絮凝成微粒被去除。</p><p>　　正如表格4中所

24、示，在操作條件2、3和4中的用量分別為70mg/L，70mg/L和60mg/L。但是，在工況3、4中的單位凝結(jié)劑有機(jī)物質(zhì)去除率超過(guò)工況2的35%,同時(shí)，工況3、4中TP的去除率超過(guò)工況2的20%。一種解釋是在相同的用量, 由于生物-化學(xué)作用的作用生物-化學(xué)的絮凝工藝中的污染物的去除率比化學(xué)絮凝工藝中的高20%。如果生物-化學(xué)的絮凝工藝被使用，要達(dá)到相同的去除率，藥劑用量可以減少20 %。</p><p>　　如表

25、格7中所示進(jìn)水中流出物的BOD5與COD的平均值分別是0.4和0.3。由于生物作用，出水的BOD5與COD濃度小于進(jìn)水濃度的25%。根據(jù)表格7，BOD5的平均的去除率的72%，這是化學(xué)絮凝工藝所不能達(dá)到的。去除率表明生物作用對(duì)整個(gè)系統(tǒng)的穩(wěn)定變得越來(lái)越重要。這大大地提高可溶性BOD5的去除率。</p><p>　　作為一個(gè)結(jié)論，由于生物-化學(xué)的作用，磷和有機(jī)的物質(zhì)的化學(xué)去除效率被改進(jìn)。當(dāng)生物-化學(xué)的絮凝工藝成穩(wěn)定的

26、運(yùn)行時(shí)，化學(xué)作用對(duì)磷去除很重要，而生物的功能對(duì)有機(jī)物的去除更重要, 諸如BOD5，COD等等。</p><p><b>　　3　結(jié)論</b></p><p>　　生物-化學(xué)的絮凝工藝處理上海城市污水是可行的，用空氣攪拌代替機(jī)械攪拌是可以完成化學(xué)混合反應(yīng)的。在反應(yīng)罐中，MLSS的濃度是2g/L，HRT是35min，液態(tài)的PAC的用量70 mg/L，并且濃度PAM是0.5

27、mg/L。并且CODCr，TP，SS的平均的出水的濃度BOD5是50mg/L，0.62mg/L，18mg/L，和17mg/L分別。因此，結(jié)果滿足上海的城市污水處理中的設(shè)計(jì)的要求。</p><p>　　根據(jù)絮凝劑和凝集沉降劑當(dāng)前的價(jià)格，用量費(fèi)用是少于0.1RMB元每立方米污水。</p><p>　　在相同的用量，因?yàn)樯锖突瘜W(xué)工藝的共同作用，其去除率超過(guò)單獨(dú)使用生物-化學(xué)的絮凝工藝和化學(xué)絮凝

28、工藝的20%。由于生物作用，在生物-化學(xué)的絮凝工藝的作用下BOD的平均去除率能達(dá)到72%，這不是化學(xué)絮凝工藝所能單獨(dú)地實(shí)現(xiàn)的。</p><p>　　不同的模擬條件下的耗氧量的結(jié)果表明在城市污水處理過(guò)程中不僅只有生物作用, 化學(xué)絮凝過(guò)程的作用，還包括沒(méi)有曝氣的回流污泥的化學(xué)絮凝過(guò)程的作用。然而，生物-化學(xué)的絮凝工藝的耗氧量是很明顯的，這表明在反應(yīng)罐中有很好的生物作用。</p><p>　　當(dāng)

29、生物-化學(xué)的絮凝工藝成穩(wěn)定的運(yùn)行時(shí)，化學(xué)作用對(duì)磷去除很重要，而生物的功能對(duì)有機(jī)物的去除更重要。</p><p><b>　　附錄2 外文原文</b></p><p>　　Chemical and biological flocculation process to treat municipal sewage and analysis of biological fu

30、nction</p><p>　　XIA Si-qing, YANG Dian-hai , XU Bin , ZHAO Jian-fu</p><p>　　(State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092, China. Email: siqin

31、gxia@mail.Tongji.edu.cn)</p><p>　　Abstract: The pilot-scale experimental apparatus and the procedure of the chemical and biological flocculation process to verify the feasibility in treating Shanghai municip

32、al sewage were introduced in this paper. In addition, the biological function of the process was discussed. The results of optimal running showed that in the reaction tank, the concentration of mixed liquor suspended sol

33、id(MLSS) was 2g/L , hydraulic retention time (HRT) was 35min , do sage of liquid polyaluminium chloride (PA</p><p>　　Keywords: chemical and biological flocculation process; municipal water; biological functi

34、on</p><p>　　1 　Experimental</p><p>　　1.1 　Designed influent and effluent concentrations of the project</p><p>　　According to the demonstration evaluation and standard water quality

35、requirements, the designed influent and effluent concentrations of the municipal sewage are shown in Table 1. </p><p>　　Table 1 　Designed influent and effluent concentrations</p><p>　　1.2 　Flow

36、sheet of the pilot-scale experiment</p><p>　　A schematic drawing of the pilot-scale chemical and biological flocculation process employed is shown in Fig. 1. </p><p>　　Fig. 1 Scheme of the pilot

37、-scale experimental apparatus (the flow rate was 50m3/d)</p><p>　　Equipments for the pilot-scale study included a small mixing tank, a 1.1m high chemical and biological flocculation tank with a width of 1.0m

38、 and a length of 2.2m, two 2.9m high sedimentation tanks with a width of 1.0m and a length of 3.0m, a 6.5m high nitrifying tank with a width of 0.6m and a length of 1.2m, and air and water pumps. The chemical and biologi

39、cal flocculation tank was divided into three galleries, with one aeration pipe in each gallery. First, the municipal sewage was pumped into</p><p>　　Inorganic coagulant and organic macromolecule coagulant ai

40、ds, selected by laboratory-scale evaluation, were used in this pilot-scale experiment. First, the coagulant and aid were added to the demand concentration in a solution tank. Second, the selected dosages of coagulant and

41、 flocculant were added into the tank by a metering pump (MILTONROY, made in USA). The point at which the coagulant and flocculant were added was adjustable. In this system, polyaluminium chloride (PAC) was used as the fl

42、oc</p><p>　　1.3 　Analyses and monitoring</p><p>　　The items measured to evaluate performance are shown in Table 2. The methods employed for water quality monitoring are presented in Table 3.<

43、/p><p>　　Table 2 　Parameters of the water quality</p><p>　　1.4 　Analysis of biological function</p><p>　　Biological function was evaluated using a tailored sealed reactor, oxygen pump,

44、 magnetic mixer, Leici JPB~607 portable dissolved oxygen meter, and a stopwatch. The analysis for biological function was divided into two steps. First, 1000 ml water samples were put into the tailored sealed reactor, an

45、d dissolved oxygen was added to the samples by aeration using an air pump. Second, the aeration devices were removed and the lid of reactor was tightened and was connected to a dissolved oxygen meter. </p><p&g

46、t;　　Table 3 　Monitoring methods for water quality analysis</p><p>　　2 　Results and discussion</p><p>　　2.1 　Pilot-scale performance</p><p>　　The operating results are divided into s

47、ix periods for detailed analysis as indicated in Table 4. The time intervals for the periods were chosen based upon performance trends for dosage of PAC and the position PAC injected. </p><p>　　As shown in T

48、able 4, the dosage of PAC was varied from high to moderate, and then to low, as controlled by a meter pump. With the decreased dose of PAC, the removal efficiencies of COD were maintained; however the effluent TP concent

49、ration significantly increased. It was observed that the effluent TP concentration slightly exceeded the regular standard when the PAC dosage was 60mg/L. The conclusion was drawn that 70mg/L was the favorable dosage of P

50、AC for this process. Period 5 was set to verify</p><p>　　Table 4 Chemical and biological flocculation process performance during six operating periods</p><p>　　2.2 　Typical operating conditions&

51、lt;/p><p>　　Table 4 indicates that the typical operating conditions for practical performance were: MLSS 2g/L in the flocculation tank; the HRT 35min; dosage of liquid PAC 70mg/L; and dosage of PAM (molecular w

52、eight is from 2million to 3million) 0. 5mg/L. The results under these operating conditions are discussed individually in the following sections.</p><p>　　2.2.1 　Removal of COD</p><p>　　COD remov

53、al over 25d of operation under typical operating conditions is shown in Fig. 2.</p><p>　　As shown in Fig. 2, the influent COD concentration varied day by day. The influent COD was normally between 124 mg/L a

54、nd 266mg/L. The effluent COD was normally between 24mg/L and 74mg/L, the average effluent was 50mg/L, and removal efficiencies were measured up to 70 %. It is therefore concluded that this process had favorable capacity

55、 to remove COD and reach the standards successfully.</p><p>　　2.2.2 Removal of TP</p><p>　　As seen in Fig. 3, the influent TP concentration ranged from 1.63mg/L to 3.25 mg/L, and the average v

56、alue was 2.37 mg/L. In general, the effluent concentrations were below 1 mg/L. The average effluent TP concentration was 0.62 mg/L, and the removal efficiencies were observed up to 74.3 % under typical operating conditio

57、ns. The effluent TP concentration, however, would exceed the standard of 1 mg/L if the influent concentration were too high.</p><p>　　2.2.3 　Removal of suspended solid(SS)</p><p>　　As shown in F

58、ig. 4, the influent SS concentration ranged from 70mg/L to 380mg/L, and the average was 2.7 mg/L, which is over the designed concentration of 150 mg/L. All effluent SS concentrations were below 40mg/L. The average efflue

59、nt SS concentration was 18mg/L, and the removal efficiencies were up to 88.6 %. The effluent SS concentration was maintained at a low level throughout the study and the effect was stable. SS removal goals for Zhuyuan Mun

60、icipal Wastewater Treatment Plant (ZMWTP) could</p><p>　　2.3 　Analytic test of biological function</p><p>　　2.3.1 Design of different analog reaction system</p><p>　　In order to ve

61、rify biological activity in the chemical and biological flocculation tanks, different system designs were employed in experiments. All conditions are summarized in Table 5.</p><p>　　2.3.2 　Discussion of resu

62、lts</p><p>　　The operating condition 1 shows very little DO consumption by ZMWTP wastewater. At the beginning, the concentration of DO was 8 mg/L. After 12min, the value remained at 7 mg/L to 8 mg/L, and the

63、 reduction was not more than 1 mg/L. It could be concluded that there was little biological activity in the raw wastewater. For operating condition 2, the chemical coagulant was added, the value was 6 mg/L at the beginni

64、ng, and the consumption of DO was also not more than 1 mg/L after 20 min due to few mi</p><p>　　Table 5 　Different analog reaction systems</p><p>　　Operating condition 4 simulated the process wh

65、ich had chemical return sludge mixed with air for coagulation by analogy. The consumption of DO was about 2.8 mg/L after 20min. It is obvious that although the return sludge was not active sludge, with aeration, the DO w

66、as consumed because of the existence of aerobic microorganisms. It could be concluded that the biological metabolism existed in this system. </p><p>　　The DO consumption curves for operating conditions 5, 6,

67、 and 7 are shown in Fig. 5 and Fig. 6. As shown in Fig. 5, if the active return sludge (from Shanghai Quyang Minicipal Wastewater Treatment Plant) was used in the analogizing of the chemical and biological flocculation p

68、rocess , the consumption of DO increased to 6.4mg due to microbe activity. Obviously, the demand for oxygen consumption was very high. According to Fig. 6, after 5 to 7 min, oxygen consumption in the first and second gal

69、lery</p><p>　　2.3.3 Analyses of biological activity by testing data</p><p>　　The results of some operating conditions with similar dosage are listed in Table 6 and some BOD5 tested are included

70、 in Table 7.</p><p>　　Table 6 　Statistical data of COD and TP removal for several operating conditions</p><p>　　In the coagulation-flocculation process, the removal of phosphorus in the wastewat

71、er may be due to two mechanisms: the phosphates being incorporated to solids in suspension and the reduction of these solids during the process including the removal of the phosphorus. The direct adsorption of phosphate

72、ions in the hydrolysis products was formed by the metal ion used as a coagulant. Removal through the formation of phosphate precipitates with the metal salts was used as coagulants. The removal of p</p><p>　

73、　Table 7 　BOD5/COD measured in influent and effluent during pilot-scale experiment</p><p>　　This reaction has a number of secondary reactions associated to it. It is generally assumed that the phosphorus in

74、the form of orthophosphate is removed by precipitation of phosphate with the metal ion while the total phosphorus is removed by a more complicated combination of interaction and adsorption with the flocculated particles.

75、</p><p>　　As shown in Table 6, the dosages in operating conditions 2, 3 and 4 were 70 mg/L , 70 mg/L and 60 mg/L respectively. But the organic substance removal of unit coagulant in operating conditions 3 an

76、d 4 exceeded that of operating condition 2 by 35 %, and the TP removal of unit coagulant in operating conditions 3 and 4 exceeded that of operating condition 2 by 20 %. An explanation is that at the same dosage, the remo

77、val efficiencies of pollutants in the chemical and biological flocculation process </p><p>　　Table 7 shows that the average of BOD5/COD in the influent and effluent was 0.4 and 0.3 respectively. As a result

78、of biological function, the effluent BOD5/COD value is 25 % less than the influent value. According to Table 7, the average removal efficiency of BOD5 was 72 %, which could not be attained by the chemical flocculation pr

79、ocess. The removal efficiencies indicated that the biological function become more and more significant with the stability of system. This enhanced the removal effici</p><p>　　As a conclusion, because of the

80、 cooperation of chemical and biological, both the chemical precipitation efficiency for phosphorus removal and organic substance removal were improved. The chemical function was more important for phosphorus removal and

81、the biological function was more important for solved organic matter, such as BOD5, COD etc., as the chemical and biological flocculation process became a stable run condition.</p><p>　　3 　Conclusions</p&

82、gt;<p>　　It is feasible to treat Shanghai municipal water by a chemical and biological flocculation process. Mechanical mixing can be substituted by air mixing to perform the reaction of chemical mixing. In the re

83、action tank, the concentration of MLSS was 2g/L, HRT was 35min, dosage of liquid PAC was 70 mg/L and the concentration of PAM was 0.5mg/L. The average effluent concentrations of CODCr, TP, SS and BOD5 were 50mg/L, 0.62mg

84、/L, 18 mg/L, and 17mg/L respectively. Therefore, the results were measured u</p><p>　　Given the current price of coagulants and flocculants, the dosage cost is less than 0.1RMB Yuan per cubic meter wastewate

85、r.</p><p>　　At the same dosage, the removal efficiencies due to chemical and biological flocculation process exceeded that of the chemical flocculation process alone by 20% due to the cooperating action of c

86、hemical and biological activity.</p><p>　　As a result of biological activity , the average removal efficiencies of BOD in the chemical and biological flocculation process could as high as 72% , which cannot

87、be achieved by the common chemical flocculation process alone.</p><p>　　The results of oxygen consumption rate under different simulated conditions indicated there is only light biological activity in the mu

88、nicipal wastewater, chemical flocculation process, and chemical flocculation process including return sludge without aeration. However, oxygen consumption in the chemical and biological flocculation process was distinct,

89、 which indicated a good biological activity in the reaction tank.</p><p>　　Chemical function was more important for phosphorus removal and biological function was more important for solved organic matter, as

90、 the chemical and biological flocculation process became a stable run condition.</p><p>　　References:</p><p>　　1. Aguilar M I, Saez J, Lorens M et al., 2002. Nutrient removal sludge production i

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