Ich2304:Waste Management Question Paper
Ich2304:Waste Management
Course:Bachelor Of Science In Public Health
Institution: Meru University Of Science And Technology question papers
Exam Year:2011
INSTRUCTIONS: Answer questions one in section A and any other two question sin section B
SECTION A – COMPULSORY
QUESTION ONE (30 MARKS)
When treating waste water, both anaerobic and an aerobic bacteria require nitrogen for their
nutrients. Nitrogen is therefore necessary for synthesis. However, only 50% of organic nitrogen
is available for synthesis. One milligram (1mg) of Nitrogen requires 4.57mg/l of oxygen to be
broken down by aerobic bacteria. Some waste water contains ammonia nitrogen. All ammonia
nitrogen unlike organic nitrogen is 100% available for synthesis. How much oxygen will be
required in waste water that contains;
a) 40mg/l of organic nitrogen? (5 Marks)
b) 30mg/l of ammonia nitrogen? (5 Marks)
c) What are the concerns of developed countries as pertains to waste water treatment as
opposed to developing countries? (5 Marks)
d) What criteria do we need to use in order to determine sustainable waste water treatment
options? (5 Marks)
e) Explain how microbial action takes place in these categories giving examples in each
case. (5 Marks)
SECTION B
QUESTION TWO (20 MARKS)
Describe the environmental factors necessary for maximum efficiency in a tropical waste water
treatment plant, giving the range of temperatures when growth of micro organisms is highest,
when growth declines and eventually, the micro – organisms die. (20 Marks)
2
QUESTION THREE (20 MARKS)
The design criteria of a trickling filter is such that the BOD removal at the primary sedimentation
is 30-40%. Zero point one (0.1)kg of BOD requires 1M3 volume in a trickling filter. The media
depth is 2M, while the rotating arm is to the manufacturer’s design. During design, one filter
should be designed to be on standby. Design a trickling filter for a population of 5000 people
whose water consumption per capital per day is 200L and a BOD of 0.6kg/Capital/day.
(20 Marks)
QUESTION FOUR (20 MARKS)
Write short notes on:
i. Sewage (3 Marks)
ii. Primary treatment of waste water. (5 Marks)
iii. Secondary treatment. (5 Marks)
iv. Tertiary treatment (5 Marks)
v. Disposal of screenings. (2 Marks)
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