Georgia Wastewater Class 2 Exam (pt 2)
What is the BOD contribution of a person per day?
0.17lb
1.2kw and 120 volts. Calculate the amps being used.
10 Amps
What is the minimum amount of oxygen to enter a confined space?
19.5%
How long is a COD test?
2-3 hours
How long is the BOD test?
5 days
What ratio of methane and carbon dioxide is found in digesters?
70% methane and 30% carbon dioxide
86% motor and 86% pump. What is the total efficiency?
74%
What is a RBC's speed controlled by?
Air volume
What is the first step if an accident occurs?
Check for injuries
What type of pump can pump 6% solids?
Positive displacement pump
This type of maintenance is used to extend equipment life, reduce maintenance cost, and increase reliability.
Preventative
What is the most important factor in preventing accidents at a wastewater plant?
attitude of the employee
A pump control's lights are on and looks ok but will not run. What is the cause?
blown fuse/tripped breaker
How is a valve named?
by the shape of its closing mechanism
Upon inspecting an idle centrifugal pump, you notice that the shaft is spinning backwards. What should bed the first thing you would check in this situation?
check valve
The addition of high strength anaerobic digester supernatant to the head of the aeration tank will...
decrease the D.O. concentration in the tank
How should digester supernatant be handled?
fed slowly back to the head of the plant to avoid shock loading or over-loading of nutrients
What type of bottle is used for COD samples?
glass
Plant influent appears black and has a foul odor each morning. The cause is traced to a pump station at a subdivision which is oversized for the current number of homes in the subdivision. What corrective action can you take?
lower the floats in the pump station so that the pumps will run frequently
What is the MOST LIKELY cause of excessive vibration in a pump?
misalignment
What is the process by which chlorine destroys bacteria?
oxidation
What is the advantage of using an egg shaped anaerobic digester over a traditional shape?
prevents scum accumulation
Chain of custody procedures follow a sample for what?
sample collection to sample disposal
What chemical neutralize a sour digester?
sodium hydroxide
What is the purpose of acidification of a sludge sampler during the determination of volatile acids?
to convert volatile acids salts to actual volatile acids
How does algae use the process of photosynthesis?
uses carbon dioxide to produce oxygen
When is sludge considered properly digested?
when 50% of organic matter gas has been destroyed and converted to gas
