課程名稱︰環境工程一 課程性質︰系定必修 課程教師︰張尊國 開課學院： 開課系所︰生工系 考試日期（年月日）︰97/11/19 考試時限（分鐘）：約180分鐘 是否需發放獎勵金：是 （如未明確表示，則不予發放） 試題 : 環境工程期中考試 試題 2008/11/19 1.試繪圖並說明混凝過程中界達電位(zeta potential)與膠體穩定之關係。混凝劑所扮演 之功能為何？常用之混凝劑有哪些？ 9% 2.Below is the process of a typical water treatment plant, please indicate units 1-7 and describe function of every unit. 9% 1:混合池 2:膠凝池 3:沉澱池 4:砂濾池 5:加氯消毒 6:清水池 7:抽水機 3.For a flocculant suspension, determine the removal efficiency for a basin 9 ft deep with an overflow rate Vo equal to 8 ft/h, using the laboratory settling data presented in the following table. 9% ─────────────────────────────────────── Percent suspended solids removed at indicated depth (in ft) ─────────────────────────────── Time,min 2 4 6 8 10 ─────────────────────────────────────── 20 61 30 71 63 55 40 81 72 63 61 57 50 90 81 73 67 63 60 - 90 80 74 68 70 - - 86 80 75 80 - - - 86 81 ─────────────────────────────────────── 4.Consider a first -order reaction, requiring 60% reduction in the concentration. Would a plug flow or a completely mixed flow resctor require the least reactor volume? How about when the reduction required 90%? 9% 5.A radioactive nuclide is reduced by 93% in 12 minutes. What is its half-life? 9% 6.A municipal wastewater treatment plant discharges into a stream that at some times of the year has no other flow. The characteristics of the waste are: 10% Flow = 0.1 m^3/sec Dissolves oxygen = 6 mg/L Temperature = 18℃ K1 = 0.23 day^-1 Ultimate BOD (L) = 280 mg/L DOs @ 18℃ = 9.54 mg/L The velocity in the stream is 0.5 m/sec and the reoxygenation constant K2 is assumed to be 0.45 day^-1 A.Will the stream maintain a minimum 4 mg/L if there is no other flow in the stream? B.If there is stream water above the outfall and this water has a temperature of 18℃ and no demand for oxygen and is saturated with DO, how great must the upstream flow be to assure a minimum dissolved oxygen of 4 mg/L downstream of the discharge? 7.a contaminant is removed by a first-order reaction (r =kC), with rate loss coefficient (k) of 0.24 hr^-1. Calculate the volume of a plug flow treatment system needed to achieve a 80% reduction in contaminant if the flow rate in the system is 0.002 m^3/s. 8.所謂折返加氯法並寫出過程中所有之化學反應，繪製之加氯量與餘氯量，圖中為何有一 段是朝下請說明。 9% 9.請說明濾床中之反沖洗順序。 9% 10.請導出顆粒沉澱之終端速度公式並說明在何種條件下可發展出Stoke's law? 9% 11.請說明沉澱池設計時溢流率 (overflow rate) 所代表的意義。 9% -- 一張好人卡可以換多少p幣啊 --

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