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API- mixing zone modeling and dilution analysis for water-quality-based NPDES permit limits

Quiz Questions:

   
1. EPA water quality criteria guidance includes some components for each regulated pollutant. They are:
       
    Magnitude (the allowed concentration in ambient water)
    Duration (the averaging period over which the ambient pollutant concentration is compared to the allowed value)
    Frequency (how often the criterion may be exceeded)
    All of the above
       
2. Mixing zone implementation differs widely across the United States. Some states have very prescriptive policies and procedures for establishing mixing zones and calculating dilution factors.
       
    True
    False
       
3. What does USGS stand for?
       
    United States Geological Survey
    United Standard Geological Survey
    None of the above
    United States Geological Standard
       
4. The harmonic mean flow used to evaluate ambient water quality against human health criteria is a long-term mean value for the receiving water calculated according to procedures outlined by Rossman and EPA.
       
    True
    False
       
5. After determining effluent dilution under critical conditions for a bay or estuary, EPA (1991) also recommends checking a non-critical condition (e.g., higher river inflow or lower stratification) that encompasses the period of maximum ambient velocity during a tidal cycle.
       
    True
    False
       
6. EPA's minimum requirement is that water quality within mixing zones should result in lethality to migrating fish, drifting organisms moving through a plume, or sessile organisms that may attempt to reside within a mixing zone.
       
    True
    False
       
7. States fall into two categories with regard to the overall process of establishing mixing zones. In the first category, a state sets the dimensions of the mixing zone and calculates dilution factors for the discharger. The second category of states require the discharger to submit a mixing zone study which establishes the dilution factor.
       
    True
    False
       
8. What does table 2-1 illustrate about?
       
    Mixing Zone Regulations of Selected States
    Florida Department of Environmental Protection
    Permitting Authority
    None of the above
       
9. The results of the reasonable potential analysis are also used to determine the maximum size of the mixing zone.
       
    True
    False
       
10. The physics of effluent mixing and dilution involve the principles of conservation of mass, momentum, and energy.
       
    True
    False
       
11. What does figure 3-1 illustrate about?
       
    Illustrations of Plumes and Jets
    Pure Plume in uniform crossfire
    Effects of ambient conditions on discharge
    None of the above
       
12. Negatively buoyant discharges will rise regardless of discharge hydraulics until reaching the surface or entraining sufficient ambient water to equal the density of the receiving body
       
    True
    False
       
13. The term "outfall pipe" is typically used to refer to the pipe extending from the wastewater treatment plant to the first port.
       
    True
    False
       
14. Lateral mixing in rivers occurs over relatively longer distances and is dependent on factors such as current speed, channel morphology, and the presence or absence of bottom roughness and rapids.
       
    True
    False
       
15.

For buoyant discharges, research has shown that the dilution of a multi-port diffuser in un-stratified waters increases in proportion to the length raised to the 2/3 powers, as indicated below

What does Q stand for in the above equation?

       
    Design discharge rate
    Tube coefficient
    Height of the tube
    None of the above
       
16. Peak flow conditions must be evaluated to ensure that sufficient head exists to discharge effluent at the design high water level without adversely impacting treatment plant hydraulics.
       
    True
    False
       
17. Risk of infrastructure damage can come from causes including storms, currents, shipping, seismic failures, debris, sediment, and plant growth.
       
    True
    False
       
18. One-dimensional models consider changes in pollutant concentration over a single dimension in space, typically the axis of the discharge jet or plume
       
    True
    False
       
19. Steady state models predict receiving water concentrations in response to model inputs (e.g., effluent flows, concentrations) that remain constant over time.
       
    True
    False
       
20. A more rigorous tool is available for predicting maximum in-stream concentrations downstream of a discharge as well as attenuation due to ambient dilution. This desktop equation is:

What does W stand for in the above equation?

       
    Stream width
    Discharge
    Diameter of the tube
    None of the above
       
   
 
 

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