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Question 4. Multiple Choice section All multiple choice questions are worth [2.5 marks] (a) Transport due to bulk movement of fiuid is referred to as: 0 Diffusion (6) Advection (ii) Molecular diffusion (iv) Dispersion (b) A flux is a: () Transport due to bulk movement of fluid () volume per unit time (IT) mass divided by time, or concentration (C) multiplied by volumetric flow rate (0) (iv) rate of movement of a quantity like mass or heat normalised to area (C) If Sample C is a 1:10 dilution of B, which of the following is not correct: I A has more BOD than C Sample B needs to be diluted A has a BOD of 6 mg/l (iv) Sample C has a BOD of 40 mg/l Ess Dissolved Oxygen (mg/L) O NON B 1 2 3 4 Time (days) 5-day BOD test results (d) The following is the definition of "Is a measure of O, required by microorganisms to break down organic matter (0) BOD () DO (1) COD (iv) Oxidation-reduction potential (e) What is the most typical process ordering in a surface water treatment plant? (1) Filtration, Coagulation, Flocculation Settling (6) Coagulation Settling, Filtration, Flocculation Page 9 of 10
MACE20402 (1) Coagulation, Flocculation, Settling, Filtration (iv) Settling, Coagulation, Flocculation, Filtration (f) Which of the following is not a contaminant? 0) Turbidity (6) Microbiological (ID) Inorganic (iv) Organic (V) Hardness (9) The probability of a 100-year flood not being exceeded in the next 50 years is 0 40% (0) 60% 2% I (iv) 50% (h) Determine the probability that a 25-yr storm may occur in the next 10 years 0.542 () 0.04 (ili) 0.335 (iv) 0.4 (1) Return period (recurrence interval') is defined as: 0 Average number of years during which an event of given magnitude will be equalled or exceeded once (ii) Maximum number of years during which an event of given magnitude will be equalled or exceeded once (il) Median number of years during which an event of given magnitude will be equalled or exceeded once (iv) Minimum number of years during which an event of given magnitude will be equalled or exceeded once O) A hydropower storage station at a reservoir has a storage capacity of 7x10 m which can be released for generating electricity over a 5 hour period. If the effective head is 500m, and the generator efficiency is 90%, calculate the total electrical energy produced in 5 hours (0) 388.9 MW (11) 1.72 GW (iii) 1.72 GWh (iv) 8.6 GWh END OF EXAMINATION PAPER