Module 14 - Onsite Wastewater Treatment Systems

Question 1

How do unsaturated soil conditions affect virus retention in an effluent drain field (check ALL that apply)?

They result in higher pore water velocities than under saturated conditions.
They increase the partitioning of viruses to the air-water interface.
They establish a water potential gradient that causes water to enter smaller soil pores, allowing for more opportunities for contact between virus particles and soil particle surfaces.
They increase the contact of viral particles with the soil.

Answer 1

They increase the partitioning of viruses to the air-water interface.
They establish a water potential gradient that causes water to enter smaller soil pores, allowing for more opportunities for contact between virus particles and soil particle surfaces.
They increase the contact of viral particles with the soil.

Question 2

What is the minimum horizontal distance between an effluent drain field and wells and potable springs?
25 feet.
15 feet.
100 feet.
5 feet.

Answer 2

100 feet.

Question 3

A small flow Onsite Wastewater Treatment System is a system with a design flow of:
1500 gallon per day or more.
900 gallon per day or less.
1,800 gallon per day or less.
600 gallon per day or less.

Answer 3

1,800 gallon per day or less.

Question 4

What is the minimum horizontal distance between an effluent drain field and a property line?
25 feet.
5 feet.
15 feet.
20 feet.

Answer 4

5 feet.

Question 5

Viruses can cause salmonellosis.

TRUE
FALSE

Answer 5

FALSE

Question 6

What is the potential fate of ammonia (NH4+) in an effluent drain field (check ALL that apply)
It is mineralized by microbes.
It is oxidized to nitrate.
It is reduced to nitrogen gas (N2).
It is uptaken by a plant.

Answer 6

It is mineralized by microbes.
It is oxidized to nitrate.
It is uptaken by a plant.

Question 7

Which organisms are predators of bacteria (check ALL that apply)?
Nematodes
Protozoa
Earth worms

Answer 7

Nematodes
Protozoa

Question 8

Conventional onsite wastewater treatment systems are typically only driven by gravity.
FALSE
TRUE

Answer 8

TRUE

Question 9

In general, viruses are …
10 times larger than bacteria.
10 times smaller than bacteria.
100 times larger than bacteria.
100 times smaller than bacteria.

Answer 9

100 times smaller than bacteria.

Question 10

The daily design flow is …
150 gallons per day (gpd) times the number of bedrooms times two.
150 gallons per day (gpd) times the number of bedrooms.
1000 gallon for a 4-bedroom-home.
150 gallons per day (gpd) times the number of residents.

Answer 10

150 gallons per day (gpd) times the number of bedrooms.

Question 11

Which of the following is true for an effluent drain field in a sloped area?
The trenches are installed level with the contour and are connected with an overflow pipe.
The trenches are installed perpendicular to the contour in a herringbone fashion.
The trenches are leveled, and septic effluent is fed to them by pumping.
Effluent drain fields are not permitted on sloped soils.

Answer 11

The trenches are installed level with the contour and are connected with an overflow pipe.

Question 12

What are the permit requirements for repairs of Onsite Wastewater Treatment Systems in Alabama?
A permit is required from the Alabama Department of Public Health.
There is no general permit requirement for repairs only for new installations.
No permit is required if repairs are being performed by a licensed engineer.
A permit is required from the Local Health Department.

Answer 12

A permit is required from the Local Health Department.

Question 13

Redox features in a soil … (check ALL that apply)
May affect the minimum separation depth.
Are an indicator for seasonal groundwater levels.
Indicate that reducing conditions may be present during at least part of the year.
Increase retention of viruses.

Answer 13

May affect the minimum separation depth.
Are an indicator for seasonal groundwater levels.
Indicate that reducing conditions may be present during at least part of the year.

Question 14

Both, biotic and abiotic processes in the septic and in the soil contribute to removal of contaminants from wastewater.
FALSE
TRUE

Answer 14

TRUE

Question 15

Bacteria can cause cholera.

TRUE
FALSE

Answer 15

TRUE

Question 16

How many U.S. households are connected to an onsite wastewater treatment system (OWTS)?
>25,000,000
<25,000,000
>50,000,000
10,000,000

Answer 16

> 25,000,000

Question 17

Soil structure affects virus transport removal by controlling preferential flow, which allows percolating effluent to bypass large volumes of soil under saturated conditions.
TRUE
FALSE

Answer 17

TRUE

Question 18

Straining and adsorption are mechanisms to remove …
Viruses.
Bacteria.
Bacteria and viruses.

Answer 18

Bacteria

Question 19

A shallow placement system is a Conventional Onsite Wastewater Treatment System in that the trench bottom and sidewalls are located in unaltered natural soil, but that requires some amount of fill material above the effluent drain field in order to provide a minimum soil cover of 12 inches over the effluent drain field.
TRUE
FALSE

Answer 19

TRUE

Question 20

What is the minimum horizontal distance between an effluent drain field and a surface water body?
50 feet.
15 feet.
25 feet.
20 feet.

Answer 20

50 feet.

Question 21

The maximum depth of a trench of an effluent drain field in Alabama is:
120 inches.
48 inches.
2 feet.
60 inches.

Answer 21

60 inches.

Question 22

Nitrogen is mostly present in form on nitrate in wastewater.
TRUE
FALSE

Answer 22

FALSE

Question 23

A socially-dosed Onsite Wastewater Treatment System receives wastewater based on the water use practices of the house occupants.
FALSE
TRUE

Answer 23

TRUE

Question 24

The scum layer can be found …
neither of these places.
in a septic tank and on the outside perimeter of a drainage trench.
in a septic tank.
on the outside perimeter of a drainage trench.

Answer 24

in a septic tank.

Question 25

The oxygen demand of wastewater refers to the amount of oxygen consumed as compounds present in water are oxidized chemically or biochemically. Which of the following is correct (Check all that apply)?
Carbonaceous BOD (cBOD) is the amount of O2 consumed in a wastewater sample when microbial oxidation of NH4+ is suppressed
The biochemical oxygen demand is larger than the chemical oxygen demand.
The biochemical oxygen demand is determined by incubation for 5 days.
The biochemical oxygen demand is smaller than the chemical oxygen demand.

Answer 25

Carbonaceous BOD (cBOD) is the amount of O2 consumed in a wastewater sample when microbial oxidation of NH4+ is suppressed

Question 26

The actual flow of wastewater is typically …
larger than the design flow.
equal to the design flow.
smaller than the design flow.

Answer 26

smaller than the design flow.

Question 27

What is the minimum horizontal distance between an effluent drain field and a basement or in-ground storm shelter?
15 feet.
10 feet.
50 feet.
25 feet.

Answer 27

15 feet.

Question 28

Just like wastewater treatment plants, Onsite Wastewater Treatment Systems are monitored by the Public Health Department on a regular basis.
TRUE
FALSE

Answer 28

FALSE

Question 29

Grazing on bacteria by protozoa and nematodes in soil - and by protozoa in sewage - exerts an important control on bacterial populations and communities.
TRUE
FALSE

Answer 29

TRUE

Question 30

The pH in a soil environment … (check ALL that apply)

facilitates the retention of viruses if the pH is below the isoelectric point of the virus.
determines the presence/absence of an energy minimum in the diffuse double layer.
affects the retention of phosphorus.
affects the cation exchange capacity of soil.

Answer 30

facilitates the retention of viruses if the pH is below the isoelectric point of the virus.
affects the retention of phosphorus.
affects the cation exchange capacity of soil.

Question 31

Viruses vary in shape, and their diameter ranges from …
200 to 300 nm.
2 to 3,000 nm.
20 to 3,000 nm.
20 to 300 nm.

Answer 31

20 to 300 nm.

Question 32

What is the minimum lot size for establishing an Onsite Wastewater Treatment System?
25,000 square feet
25,000 square feet
0.5 acres
15,000 square feet

Answer 32

15,000 square feet

Question 33

Conventional onsite wastewater treatment systems typically contain:
A septic tank, a distribution box, and a soil treatment area.
A septic tank, and a soil treatment area.
A septic tank, a pump, and a soil treatment area.
A septic tank, secondary treatment, a distribution box, and a soil treatment area.

Answer 33

A septic tank, a distribution box, and a soil treatment area.

Question 34

The main function of the septic tank is to retain the solids present in wastewater.
FALSE
TRUE

Answer 34

TRUE

Question 35

What is the minimum horizontal distance between an effluent drain field and a building foundation?
15 feet.
10 feet.
20 feet.
5 feet.

Answer 35

5 feet.

Question 36

Determination of Chemical Oxygen Demand involves incubating a water sample with a known amount of a strong chemical oxidant under acidic conditions. The amount of oxidant consumed by the reaction is expressed as equivalents of O2 consumed per L of the sample.

TRUE
FALSE

Answer 36

TRUE

Question 37

Precipitation or irrigation events can result in saturated flow in the drain field, which can remobilize adsorbed viruses.

FALSE
TRUE

Answer 37

TRUE

Question 38

An Onsite Wastewater Treatment System shall be designed by an engineer under the following conditions or circumstances (check ALL that apply):
Slopes over 25 percent.
The system has a design flow of more than 1,800 gpd of sewage.
For systems which need to be designed for correct gravity flow.
For any Conventional Onsite Wastewater Treatment System.
The lot is smaller than the minimum lot size requirements.

Answer 38

Slopes over 25 percent.
The system has a design flow of more than 1,800 gpd of sewage.
The lot is smaller than the minimum lot size requirements.

Question 39

What is the minimum horizontal distance between an effluent drain field and a potable (drinkable) water line?
10 feet.
20 feet.
5 feet.
15 feet.

Answer 39

5 feet.

Question 40

What is the minimum hydraulic retention time of wastewater in a septic tank for particle separation to occur?
12 hours
2 days
3 days
1 day

Answer 40

2 days