Sewage treatment plants

Question 1

Advantages of having STP on board

Answer 1

Reduce ship side openings
Simplify pipe runs
Heads can be lower on ship
Also be used in dry dock

Question 2

Explain aerobic digestion

Answer 2

Digesting the sewage

Question 3

Explain anaerobic digestion

Answer 3

When air supply fails the organisms begin to die and give off H2S which is known as anaerobic

Question 4

How would you detect anaerobic digestion at low levels

Answer 4

H2S moniter or can smell it

Question 5

Purpose of coarse screen

Answer 5

To take out any foreign matter

Question 6

Purpose of primary and secondary air lifts

Answer 6

To transfer liquid from aeration tank into settlement , then is returned to aeration by second air lift (sludge return)

Question 7

Purpose of the aeration diffuser

Answer 7

Pump air into the aeration tank across the base of compartment

Question 8

Explain the Collect hold and transfer system

Answer 8

Is a collecting system consisting of either two or three tanks only and a series of pumps

Question 9

What is effect of 
0.03 
150-400
1000+
PPM

Answer 9

By odour
Injury - loss smell
Death

Question 10

Hazards associated with raw sewage

Answer 10

Health conditions like typhoid , hepatitis

Question 11

Hazards associated with STPs

Answer 11

Dangerous chemicals
Raw sewage
Dangerous gases (H2S methane)