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CORK INSTITUTE OF TECHNOLOGY
INSTITIÚID TEICNEOLAÍOCHTA CHORCAÍ
Autumn Examinations 2010/
Module Title: BS Environmental Services
Module Code: EPRO
School: School of Mechanical & Process Engineering
Programme Title: Bachelor of Engineering in Building Services Engineering
Programme Code: EBSEN_7_Y
External Examiner(s): Mr. C. Leddy, Dr. B. Costello Internal Examiner(s): Mr. W.M. Corr
Instructions: Answer any 3 questions. All questions carry equal marks.
Duration: 2 Hours
Sitting: Autumn 2011
Requirements for this examination:
Note to Candidates: Please check the Programme Title and the Module Title to ensure that you have received the correct examination. If in doubt please contact an Invigilator.
Q1. (a) Write a detailed note on the uses of activated carbon in water treatment. Your note should address: Source, size, type, dose, uses Mode of application Mode of operation (7 marks)
(b) Describe the design philosophy and operation of multimedia filter beds. (4 marks)
(c) Drinking water for a scheme to supply a town of 50,000 people is to be filtered through a dual filter of anthracite and sand with design data as follows:
Table 1 Constituent Size mm Density g/cc Sphericity Depth mm Porosity % Anthracite 1.3 1.60 0.52 720 45 Sand 0.65 2.65 0.75 360 55
(i) Size the bed As for a loading of 300 m^3 /day per m^2. (3 marks) (ii) Calculate the total clean bed head loss. (6 marks)
s d eq
Lh Kg ^1 ^3 S^2 AQ , S ^6
2
Take K = 5 μ = 0.001 Pa.S
Q3. (a) Describe in detail the unit operations involved in the pre-treatment of municipal or industrial wastewaters. (8 marks)
(b) (i) Design a primary settling tank for the new (large) wastewater treatment plant at Little Island. Assume a treatment load of 250,000 persons equivalent. (8 marks)
(ii) Sketch ideal and thermal stratified (dead zone) flow patterns along the tank. (4 marks)
Q4. (a) Describe a temperature inversion and sketch the effect it has on atmospheric plume dispersion. (4 marks) (b) It is estimated that a burning dump emits 3g/s of NOx. What is the concentration of NOx directly downwind from this source at distances of 0.5 and 5 km on an overcast night with a wind speed of 7 m/s? Assume the dump to be a ground-level point source with no plume rise. (6 marks) (c) (i) The owner of the dump suggests things would be much better if a 20-m stack were erected on the dump: it could then be considered a point source at an elevation of 20 m. Repeat part (b) for this condition. (7 marks) (ii) Is the owner right? (3 marks)
Refer to Table 6.1 and Figures 6.7 and 6.
Q5. (a) Describe the operation of a typical MSW incinerator and list the key operating parameters. (6 marks)
(b) Describe the content and disposal of the four key effluent streams. (5 marks)
(c) What technologies are available for flue gas treatment? (3 marks)
(d) MSW from a city of 200,000 households comprises combustible: water: inert in the ratio 50:30:20 by mass. (i) Estimate the calorific value of the waste. Will it burn unassisted? (3 marks) (ii) Estimate the primary energy output in MW. (2 marks) (ii) How might the calorific value be increased in winter-time? (1 mark)
