Georgia Wastewater Class 2 Exam (pt1)
In addition to the worker entering a confined space, what is the maximum number of people required to be present during a confined space entry?
1
How often should the temperature change on an anaerobic digester?
1 Fahrenheit per day
What is the carbon-nitrogen-phosphorous ratio?
100:5:1
What is the holding time for pH, DO, and chlorine residual test?
15 minutes or "immediately"
Suction lift on a centrifugal pump should not exceed ____ feet.
25
What is the COD sample holding time?
28 days
Lab records must be kept on file for ___ years.
3
Solids records must be kept on file for ___ years.
5
When pumping a corrosive liquid, what should the pressure differential range of the seal water line be compared to the pump's discharge pressure?
5.0 to 9.9 psi (34.5 to 68.2 kPa)
In an anaerobic digester, gas pressure is maintained by a controlling mechanism that commonly regulates what?
6-8 inches of water column pressure
Orifice has to do with what?
Air gas flow meter and trickling filter arm holes
What is a difference between COD and BOD tests?
COD is a faster test and tends to have higher results than BOD
What gas has the LOWEST exposure limit?
H2S (Hydrogen Sulfide)
What is the unit for electrical resistance?
Ohm
Open channel flow measurements devices are primarily what?
Parshall Flume
In conducting an oxygen uptake test, the feed sample consists of what?
Return Activated Sludge (RAS)
During morning checks, an operator notices that the bearings in the pump are running hot. What can cause this?
The bearings are over lubricated
What method is used to determine D.O.?
Winkler titration
When working in confined spaces where flammable gases may be present, use only tools made of ___________.
a non-sparking alloy
Wastewater flows with large objects should be pumped by what?
a pump with a closed impeller
Facultative ponds are made up of what?
aerobic top layer and anaerobic bottom layer
If a centrifugal pump vibrates and is noisy, what could be the cause?
air is in the pump
What type of pump is used to decrease the overall specific weight of a confined column of a gas-water mixture?
air lift
Chlorine leaks may be detected by ____________.
ammonia solution
The best back flow prevention device is __________.
an air gap
The beveled edge of a weir is located where?
at the top face of the weir
What gas, often found in digester startups, lowers pH?
carbon dioxide
What are the 2 most prominent gases at a digester start-up?
carbon dioxide and nitrogen
What is a common maintenance procedure for UV?
check and clean the quartz sleeves
What should you do if the mechanical bar screen rake is inoperative but the motor runs?
check/replace broken sheer pin
Maintenance required for capacitance level indicators include what?
checking and cleaning the connections
What does amperometric titration measure?
chlorine residual
Ammonia sample preservation and hold time consists of what?
cool sample to <6°C, lower pH to <2 with H2SO4 (sulfuric acid), 28 day hold time
When using an evaporator in disinfection, the chlorine pressure reducing valve should be located where?
down stream of the evaporator
What does a trip tap do on a digester?
drain condensation from gas piping
What explains how to handle a chlorine release?
emergency response plan
During normal operation of a positive pressure open-circuit self-contained breathing apparatus, the bypass valve should be ________.
fully closed
Fecal coliform is recorded as ___________.
geometric mean
Typically, in the presence of light, stiff, billowy white foam on the surface of an aeration tank is an indicator of what?
high F:M ratio. decrease wasting immediately
A large increase of effluent chlorine demand can be cause by what?
high concentration of nitrates
What are the 3 types of alkalinity?
hydroxide, bicarbonate, and carbonate
Most of the measurable active chlorine residual, when added to wastewater is in the form of _____________.
hypochlorous ions
When collecting nocardia samples, where is it high concentrated?
in the foam
As the temperature increases, the oxygen transfer rate ____________.
increases
What is the most likely cause of fluctuating discharge output in a progressive cavity pump?
leak in suction line
If an air compressor is cycling on and off frequently, what is most likely the cause?
leaky valve
What is the easiest way to determine if progressive cavity's internal elements are worn?
low discharge pressure
An increase in carbon dioxide content in wastewater will ______ the pH.
lower
To achieve an overall threat rating for a specific emergency event, a wastewater utility should consider the frequency of past occurrences, the probability of future occurrences, and the ______________.
magnitude of impact
Ammonia is added to chlorine to _________________.
maintain the chlorine residual for a longer period of time
What is the threshold limit time weighted average?
max allowable exposure for 8 hours with no harmful effects
What should you do to assure a pump is delivering designed flows and pressures?
measure flows and pressures, compare to manufacture pump curve
What is added to a COD sample to prevent chlorine interference?
mercury sulfate
An auto flow of proportional chlorination system is working properly. However, in the morning hours when the flow is increasing, the operator is unable to obtain a chlorine residual. What is causing the problem?
nitrates in the effluent
What 2 materials are found in wastewater that is used to make fertilizer?
nitrogen and phosphorus
What is the most significant problem in using an activated sludge process to treat seasonal cannery waste?
nutrient imbalance
Where do you place the chlorine leak on a leaking chlorine container?
on top (chlorine is heavier than air)
A recently rebuilt centrifugal pump has just been returned to service and is now drawing more amps than usual. What is most likely the problem?
packing is too tight
What is a probe used with a portable D.O. meter?
polarographic
Uniforms, I.D., and system logos on wastewater system vehicles are critical components of what?
public awareness and security program
Emergency lists should be verified _____.
quarterly
What do you do to adjust your sample before ammonia distillation?
raise the pH
Improper rotation in a centrifugal pump may cause what?
reduced flow or no flow
What is the purpose of a fecal bath?
regulate temperature
What device is used to measure chlorine flow rates?
rotameter
If there is foaming in an anaerobic digester, what should you do?
slow the feed rate down
What chemicals reduce or eliminate chlorine residual?
sulfur dioxide and sodium metabisulfide
A lift station that is controlled by a bubbler system has a low water level, but the indicator is reading high and the pump is running constantly. What is the most likely the problem?
the bubbler tube is blocked
For security, SCADA should not be connected to ________.
the internet
A pump station with variable frequency drives and two complete pumping units are provided. What flow should each pumping unit be capable of delivering?
the max daily design flow of the station
2 pumps of the same capacity operate together with a single main. The discharge will be _______.
the same as one pump
If a pin shears on a piece of equipment, what do you replace it with?
the same type of pin
Constant weight is obtained when _____________.
the weight change is less than 4% of the previous weighing, or it is 0.5mg
Besides viscosity, what is an important consideration in the selection of lubricating oil?
thermal range
What is the easiest way to determine whether the rotor or stator on a progressive cavity pump is worn?
track the discharge flow rate over time
In electrical circuits, what is used to reduce voltage when necessary?
transformer
Materials purchased and received by the utility should be what?
verified against the purchase order
What is the primary indicator of an upset anaerobic digester?
volatile acid increase/alkalinity decrease
What is electrical pressure available to cause flow of current when an electrical circuit is closed?
voltage
From a security perspective, manholes, pump stations, and neighborhood assets are considered a _____________.
vulnerability
Systematic process for evaluating the susceptibility of critical facilities to potential threats and identifying corrective actions that can reduce or mitigate the risk of serious consequences associated with these threats?
vulnerability
When determining the suction head or lift of a centrifugal pump, measure the distance from the __________________.
water surface to the center line of the impeller
What does a gravimetric belt feeder use to measure?
weight
