環(huán)境工程專業(yè)英語unit7.ppt

Unit 7 Selection of Water Treatment Processes,05.12.2,Profession-related English,Watershed management should be considered part of the operation of a water-supply system, which（指代前面所說的事情） is very important to protect raw water quality. 流域管理應當被看作是供水系統(tǒng)運行的一部分，這對于保護原水質量十分重要。 Behind an intake structure, there comes water treatment process（倒裝結構）. 在取水工程后面，是水處理過程。,Profession-related English,Profession-related English,Current pretreatment processes in municipal water treatment are screening, presedimentation or desilting, chemical addition, and aeration. 目前市政水處理中的預處理工藝有篩分，預沉淀或沉砂，化學混凝和曝氣。 Presedimentation is regularly used to remove suspended matter from river water. 預沉淀習慣上用于從河水中去除懸浮物。,Chemical treatment, in advance of（在前面） in-plant coagulation, is most frequently applied to improve presedimentation, to pretreat hard-to remove substances, such as taste and odor compounds and color, and to reduce high bacterial concentrations. 在混凝處理前面，化學處理最頻繁地被用作改善預沉淀，或對難去除的物質進行預處理，例如嗅味物質、色度和減小高的細菌濃度。,Profession-related English,Conventional chemicals used with presedimentration are the polyelectrolytes and alum. 用來進行預沉淀處理的傳統(tǒng)的化學物質是高分子聚合物和鋁。,Profession-related English,Aeration is customarily the first step in treatment for the removal of iron and manganese from well waters and a standard way to separate dissolved gases such as hydrogen sulfide and carbon dioxide. 對于從井水中去除鐵和錳，習慣上曝氣作為處理的第一步。同時，曝氣也是分離諸如硫化氫和二氧化碳等溶解性氣體的標準方法。,Profession-related English,Treatment processes used in water plants depend on the raw-water source and quality of finished water desired. 水廠使用的處理工藝依賴于原水水源和對處理水的期望。 The specific chemicals selected for treatment are based on their effectiveness to perform the desired reaction and cost. 處理中所選用的藥劑是以它們的處理效果和費用為基礎的。,Profession-related English,For example, activated carbon, chlorine, chlorine dioxide, and potassium permanganate are all used for taste and odor control. 例如，活性碳、氯、二氧化氯和高錳酸鉀，都被用來控制嗅味。,Profession-related English,Excess chlorination, although least expensive, can create undesired trihalomethanes; activated carbon is the most effective chemical. 過量使用氯，盡管費用上增加很少，但產(chǎn)生不期望的三氯代甲烷；活性炭是最有效的化學劑。,Profession-related English,In surface-water treatment plants equipment for feeding two or three taste- and odor-removal chemicals is usually provided, so the operator can select the most effective and economic chemical applications. 在地表水處理廠，加藥裝置常常能用來投加兩種或三種的去嗅味的化學劑，因此，操作工能夠選擇使用最有效經(jīng)濟的化學藥品。,Profession-related English,There is no fixed rule for color removal applicable to all waters. 沒有適用于所有水的固定的色度去除法則。 Alum coagulation with adequate pretreatment, and applying oxidizing chemicals or activated carbon, may provide satisfactory removal. 經(jīng)過足夠的預處理后使用鋁絮凝劑、應用有氧化作用的化學品或活性炭，可以提供滿意的去除。,Profession-related English,On the other hand, a more expensive coagulant might（be？） prove to be more effective and reduce overall chemical costs. 另一方面，價格較貴的絮凝劑也許被證明效果較好，從而降低了總的藥劑費用。 Perhaps the most important consideration in designing water treatment processes is to provide flexibility. 也許，在進行水處理工藝設計的時候，最注重考慮的是它的適應性。,Profession-related English,The operator should have the means to change the point of application of certain chemicals. 操作工應當有辦法調節(jié)投加特定藥劑的點。 For example, chlorine feedlines are normally provided for pre-, intermediate-, and postchlorination. 例如，加氯的投藥管線通常設置成可滿足預氯化、中氯化和后氯化的要求。,Profession-related English,Multiple chemical feeders and storage tanks should be supplied so that various chemicals can be employed in the treatment process. 應當設置多個化學品進料器和儲存池，這樣在處理工藝中可以使用多種化學品。,Profession-related English,Degradation of the raw-water quality, or changes in costs of chemicals, may dictate a change in the type of coagulant or auxiliary chemicals used in coagulation. 原水質量下降，或化學品價格變化，可以改變絮凝劑的類型，或在絮凝處理時使用混凝劑。,Profession-related English,In the case of （在情況）surface-water treatment plants it is desirable to provide space for the construction of additional pretreatment facilities. 在地表水廠，預留空間用來建造附加的預處理設施，這是所期望的。,Profession-related English,The flow in river may change due to construction of dams, channel improvements, or upstream water use. 由于修建水壩，修繕渠道，或上游使用水，河流中的水流也許會改變。 The quality of water changes due to human alteration and occupation of the watershed. 由于人類在流域內的改造活動，水質發(fā)生改變。,Profession-related English,Concentrations of pollutants（主語） from disposal of municipal and industrial wastes and agricultural land-runoff may increase（謂語）. 來自于市政、工業(yè)廢物和農(nóng)田徑流中的污染物質濃度也許增加。 Lakes can become more eutrophic. 湖泊變得更富營養(yǎng)化。,Profession-related English,The treatment plant described in Fig.2-2 is a groundwater plant with provisions for iron and manganese removal and lime softening. 圖2-2中所表示的處理廠是一個地下水廠，包含鐵、錳去除工藝和石灰軟化處理。,Profession-related English,Profession-related English,氯化：抑制鐵細菌的生長和鐵、錳的初級氧化。,曝氣：增加DO，氧化鐵、錳，去除二氧化碳。,氯化：氧化還原殘留的錳。,停留：允許氧化的完成。,去除鐵、錳的去除。,氨：將殘留的分子態(tài)氯轉變成結合態(tài)的氯。,氟硅酸：氟化反應。,After installation, the plant capacity（設備生產(chǎn)能力） has been expanded and the treatment process converted to only iron and manganese removal by increasing the aerator capacity, adding chlorine feed after the aeration, and using the settling basin as a detention tank. 設備安裝完成以后，水廠產(chǎn)量擴大，進而修正處理工藝，采取增加曝氣量、在曝氣之后投加氯，以及使用沉淀設備充當接觸停留池等措施，只進行鐵和錳的去除 。,Profession-related English,At present (現(xiàn)在,目前) this plant is only capable of（有能力) performing oxidation by aeration and chlorination for iron and manganese removal and disinfection. 目前，這個廠子只是借助曝氣和氯化的氧化作用去除鐵和錳，并進行消毒。,Profession-related English,Finished water quality is excellent all year round because of the stable character of the well supply. 由于井水水質穩(wěn)定,處理水的水質全年優(yōu)質。 The treatment plant in Fig.2-3 is a typical conventional plant for surface water treatment built in 1950 s. 圖2-3所示的處理廠建于19世紀50年代，是一座典型的常規(guī)地表水處理廠。,Profession-related English,Profession-related English,Lake,Chlorine: to establish residual,Intake with screen,Chlorine: for disinfection as necessary,Activated carbon: as necessary for taste and odor control and color removal,Mixing tank,Auxiliary chemicals: to aid coagulation as necessary,Sand filter,Activated carbon: as necessary for taste and odor control,Sodium fluoride: for fluoridation,sedimentation,Fig.2-3 Conventional treatment plant for surface-water with taste and odor problem,Settling filter,Flocculation,Alum: for coagulation,Flocculation,Filtration of nonsettled floc,氯化：根據(jù)需要而消毒,活性炭：根據(jù)需要去除嗅味和色度,鋁：為了絮凝而投放,助凝劑：根據(jù)需要添加,絮凝,活性炭：根據(jù)嗅味去除的需要,沉淀,氟化鈉：氟化處理,未沉淀絮體的過濾,加氯：并保持一定殘留,Since then the lake-water source has become increasingly eutrophic, and additional facilities for taste and odor control have been provided. 自從湖泊水源變得富營養(yǎng)化以來,處理廠增加了針對嗅味和色度的處理設施.,Profession-related English,Activated carbon, chlorine dioxide, and various auxiliary chemicals（主語） for improved chemical treatment are now available（謂語） to the operator during critical periods of poorer raw-water quality. 在水源水質較差的緊急時期,活性炭、二氧化氯和其它輔助的化學品在改善化學處理方面是操作人員可以使用的措施。,Profession-related English,During most of the year the finished water is very palatable, but tastes and odors cannot be completely removed during spring and fall lake overturns. 一年中大多數(shù)時間里，水廠的處理水質量都好，但在春季和秋季湖水翻塘的時候，嗅味就不能完全去除。,Profession-related English,For a turbid and polluted river with highly variable quality, a complex, flexible treatment system should be employed. 對于渾濁的被污染的河流，其水質變異大，需要復雜和靈活多變的處理系統(tǒng)。,Profession-related English,A general treatment scheme consists of plain sedimentation for desilting; 為了避免被淤塞，一般的處理流程包括自然沉淀。 mixing following by sedimentation, suing coagulants as necessary; 混合緊接在沉淀之后，同時按照需要加入絮凝劑。,Profession-related English,split treatment for partial