Private On-Site Wastewater

It is known that some pathogenic organisms will survive from less than ___ day(s) in heat and more than ___ in freezing moist soil

1 day and 2 years

Trickling filters can remove 90 to 95 % of ___ found in soil, water, and wastewater

Bacteria, viruses, and cholera vibrio

Primary sedimentation can remove ____ found in soil, water, and wastewater

50-90 % of the bacteria, 30-50% of ascaris, and 80% of schistosomes

Chemical coagulation, flocculation, sedimentation, and filtration remove …

Most bacteria, most viruses and protozoa, and most helminths

Chlorination of untreated wastewater is typically NOT an effective treatment for …

Entamoeba histolytica cysts, giardia cysts, and tapeworms (protozoas)

Wastewater is the used water from a home or community and the strength is expressed in terms of …

Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD), and suspended solids

A storm sewer is used to

Remove sewage and storm water

Stream pollution is sometimes apparent by

A zone of degradation (decomp and recovery)

A young lake is considered to be

Oligiotrophic

Nutrients associated with eutrophication include

phosphates, nitrogen, and organic carbon

The National Pollutant Discharge Elimination System (NYPDES) prohibits the discharge of pollutants into US waters unless a permit is issued by

The EPA or State

The favored method of disposal of domestic wastewater (grey water) is

connection to the public sewer system

The wastewater from a water closet and latrine or aqua privy flushing is referred to as

Black water

The permeability of soil is directly related to the ___ of the soil

Chemical composition, color / texture, and granular structure

Permeability means

The ability of the soil to absorb and allow water and air to pass through

The most accurate estimates of sewage flow are based on

Annual water-meter readings

Grease traps are installed for the purpose of minimizing grease in the sewer system. The trap

is not of proven value in many commercial applications

The septic tank primarily functions as a

Biological treatment system, sedimentation tank, and conditions

The detention time for wastewater in a septic tank is recommended to be

24 to 72 hours (no less)

If the septic tank will have a garbage disposal unit feeding into it

The size of tanks should be increased by 50%

Septic tanks serving commercial operations should be inspected for the need for cleaning

Twice a year

Septage is best defined as

A mixture of sludge, scum, and grey

If a septic tank is pumped in a wet period

The tank may float into the ground

How often should a septic tank for a private home is serviced

Every 3 to 5 years

Human disease from aerosols of wastewater

Is related primarily to wastewater treatment by the activated sludge, trickling filter, and spray irrigation processes

The plans for an area to be sewage should

Be prepared by a licensed professional engineer, include specifications and an engineering report, include the problem, objectives, and design details

Final disposal of sludge may include

composting, sanitary landfill, and land application

Chemical coagulation, flocculation, sedimentation, and filtration will remove nearly all bacteria, viruses, protozoa, and helminths if supplemented by

Chlorination

Why should sewage sludge not be used as a soil builder or fertilizer supplement for crops for forage if it has not been properly tested?

It may result in higher levels of toxic metals in vegetation and in the animals eating the vegetation

Loam is a mixture of gravel, sand, silt, and clay containing what?

Decaying plant and animal matter

The degree of eutrophication of a lake is indicated by

The quantity of planktonic algae, reduced water transparency / clarity, and dissolved oxygen in the water near the surface

What is the best assurance of satisfactory operation of a properly designed and constructed septic tank system?

Proper maintenance

After a septic tank has been cleaned, it should not be scrubbed and disinfected. Why?

The sludge sticking to the insides would have a seeding effect and assist in renewing the bacteria activity

One of the most important factors contributing to disease transmission of microbiological agents is

Concentration or dose of microorganisms

When storm water and domestic sewage enter the same sewer it is known as a

Combined sewer

Loam is composed of

Sand, gravel, and silt

A watertight tank designed to slow down the movement of raw sewage and wastes passing through to the soils is known as a

Septic tank

What is the most common method of applying wastewater to land?

Spray irrigation

Plants employing tricking filters, activated sludge, and spray irrigation present a possible health hazard to their employees due to

Inhalation of airborne microorganisms

Which of the following is NOT an explosive component of sewer gas?

Carbon Dioxide (explosive: carbon monoxide, hydrogen sulfide, and methane)

Which of the following is NOT true concerning sewage and disease hazards?

Entamoeba histolytica, hepatitis virus, and giardia cysts are EASILY destroyed by normal chlorination of sewage (very hard to destroy)

Which of the following soils would be most suitable for subsurface absorption of wastewater?

Yellow, brown, or red soil (air and water is able to pass through)

Which of the following are the LEAST important in reducing sewage to “soil", liquids, and gases?

Anaerobic bacteria (Top soil / most important: earthworms, protozoa, and aerobic bacteria)

The amount of dissolved oxygen required in aerobic bacterial decomposition, measured in ppm or mg/1 and used in determining the strength of wastewater is

Biochemical Oxygen Demand (BOD) (difference between initial dissolved oxygen and second sample)

The reliability and interpretation of the soil percolation test are affected by all of the following EXCEPT

Shape of test hole (verses: the evaluation of site investigation, soil profile, and suitability; size and diameter of the test hole, and the saturation of the soil)

Disinfection or chlorination of sewage effluent is

An added safeguard to reduce the risk of disease transmission where the probability exists

Plants absorb certain constituents of wastewater for irrigation of consumable plant products may present a health hazard to humans if the water contains

Cadmium

A measure of the relativity constant rate at which clear water, maintained at a relatively constant depth, will seep out of a standard size test hole that has been previously saturated is the

Soil percolation test

The ability of a soil to absorb and allow water and air to pass through is related to all of the following EXCEPT

Cation exchange capacity (other answers: chemical composition, texture / color, and granular structure)

The ability of the soil to absorb and allow water and air to pass through is called

Permeability

The most effective method discovered for running a percolation test is

to make tests in holes that have been filled with water overnight

Deep sludge depth, thick fog layer, and the appearance of particles of solids in the effluent from a septic tank is an indication of what?

A septic tank in need of cleaning

Which of the following is non-toxic to aquatic organisms, a good virucide, and adds oxygen to treated wastewater effluents?

Ozone

The suitability of soil for the subsurface disposal of sewage and other wastewater can be determined by a study of soil characteristics and the

Soil percolation test

A soil which is mottled brown and red would indicate

A tight soil is probably due to a fluctuating water table or a lack of aeration

Sand filters, elevated systems in suitable fill, evapotranspiration absorption systems, evapotranspiration beds, aeration systems, stabilization ponds or lagoons, recirculating toilets and the like, are

Sometimes used where soil is unsuitable

In order to obtain “reproducible results” with a soil percolation test, it is very important to

Soak the gravel with water before the test is made (saturation of the soil is essential; the constant rate of water drop in the test hole)

Ozone disinfection has many advantages. Which of the following is NOT TRUE?

Ozone is approximately equal in cost to chlorine (more expensive) (True: non-toxic to aquatic organisms, source of dissolved oxygen, and is a good virucide)

By USEPA Standards, the pH of secondary treatment effluent shall be in the range of

6 to 9

Which of the following would be a cause of septic-tank failure?

Lack of cleaning of the tank, leaking plumbing fixtures, and improper design/construction or the absorption system

The effectiveness of disinfection depends on

The degree of treatment the sewerage has received, the amount of chlorine used and the residual chlorine maintained, and the mixing and retention period

Facultative bacteria can

Line under both aerobic and anaerobic conditions

Man-made organic compounds that degrade very slowly are referred to as

refractory organics (Ex: chlordane, endrin, DDT, and lindane)

The sand filter is used to

Remove suspended solids from water and remove bacteria from water

Sewer gas may contain

Hydrogen sulfide (H2S), methane, and chlorine

Brine from water softening units as low as ___ may inhibit bacterial action in septic tanks

1.2% (tends to build us in sludge)

Which of the following is TRUE regarding the use of septic-tank cleaners?

Their use is not advised

The use of a cesspool is prohibited due to

greater potential for groundwater contamination

The typical limitation of use of the septic tank absorption field system is due to

Soil type and size requirements

The NODAK system is designed to

Protect ground water

Common causes of failure of septic tank seepage field systems include improper sizing, non-suitable soil, non-servicing, and

leaking fixtures

The tradition absorption field should be laid in trenches not more than ___ below the ground surface

24 inches

The top of the absorption field gravel should be covered with …

6 inches of top soil / permeable material

The field distribution piping should be surrounded with ___ and at least 2 inches deep under the pipe

Washed gravel, ¾ inches to 2 ½ inches or crushed stone

The distance between the field lines or tiles must be a minimum of ___ in a treatment absorption field arrangement

6 feet

(T or F) The recommended backfill over the absorption field is 12 inches

True

(T or F) The recommended distance from the bottom of the trench to the ground water table or rock is 62 inches

False - it is 24 inches

(T or F) The recommended maximum length of the system materials is 75 feet

True

(T or F) The placement of the distribution box is not critical as long as it is water tight

False

The use of serial distribution system is considered to have disadvantages over the use of distribution boxes

False - it has advantages

Yeast added to a new septic tank speeds up digestion by a factor of 2.7

False

(T or F) The depth of septic tanks and ratio of width to length recommended by most health departments are very similar

True

(T or F) Soil containing loam will remove most of the phosphorus in sewage effluent

False

(T or F) A lump of soil with good characteristic will break apart with little pressure along definite cleavage plains and should be blue or grayish in color

False - should be yellow, brown, or red in color

What are the two factors commonly used to determine soil permeability or ability to absorb wastewater?

Soil characteristics and watershed

Which would not be considered suitable for disposal of sewage by subsurface means?

Clay - doesn’t drain well

What two factors determine the groundwater contamination potential from a septic tank?

Soil characteristics and depth to groundwater

What step listed below must be done in order to obtain reproducible results in the soil perc test?

Totally saturated soil before beginning the test

Which is correct regarding septic tanks?

They will slow down the flow rate that solids can settle out

Detention time for septic tanks should NOT be less than

24 hours

How often should residential septic tanks be inspected?

Annually

Which should not be added to septic tanks?

Salt and brine (results in less effective system), Sulphuric acid (H2S and releases toxic fumes and fatal), Chlorine bleach or ammonia (creates caustic soda (lye) could cause injury, permanent damage, or death)

Which statement is true in regards to outlets and inlets on distributions boxes in sewage disposal systems?

Inlet must be 6 inches higher than the outlet

Which of the following is NOT a factor in the satisfactory operation of a septic tank / sand filter system?

Ratio of septic tank size to sand filter size

Which method if most common method of applying wastewater to land?

Spray irrigation

Which gas is found in sewers but is NOT considered explosive?

CO2 (Explosive: Methane, hydrogen, and carbon monoxide)

Which is considered to be the best single-strength measure of wastewater polluted water containing degradable waste?

5-day BOD

Another name for a mature or balanced lake

Mesotrophic (Oligotrophic- young, Eutrophophic- most mature)

Name the three zones of stream pollution, in order of normal chain of events

Degradation, decomposition, and recovery

What is the permissible 8-hour threshold limit value for H2S Hydrogen Sulfide?

20 ppm (50 ppm for 10 min; 300ppm is fatal)