CE 351 Final

Select all of the correct statements with respect to eutrophication: (4)

- Eutrophication is a natural aging process of lakes - One control method is to reduce limiting nutrient concentration - Cultural eutrophication is attributed to human activities - Rate of photosynthesis is higher in eutrophic lakes

Which one of the following are assumptions made in developing the 1-D stream DO model: (4)

- Steady state conditions - DO is replenished only through natural reactions - Discharging of oxygen demanding wastes is the only factor responsible for DO removal - There is no dispersion of wastes in the direction of flow

Select all of the correct statements regarding thermal stratification of lakes (4)

- The hypolimnion of an eutrophic lake can become anaerobic during the summer - Thermal stratification in lakes is caused by water density differences at different depth - Thermocline is the layer with the greatest rate of change in temperature - Thermal stratification may disappear in the spring and fall

Identify all of the attached growth wastewater treatment processes (2)

- Trickling filters - Rotating biological contactors (RBC)

One kg of a MSW has a moisture content of 25%, and 10% of the dry mass is hydrogen. The amount of moisture in kg generated from hydrogen during combustion of this waste is most likely:

0.7

A wastewater has a TKN of 5 mg/L, what is its NBOD in mg/L?

22.9

A sample of wastewater is diluted by a factor of 1:10. The diluted wastewater has an initial dissolved oxygen concentration of 7.0 mg/L. After 5 d it has a dissolved oxygen concentration of 3.0 mg/L. The 5-day BOD of the initial undiluted wastewater is most nearly

40 mg/L

A wastewater has 10 mg/L of NH3 -N, what is its NBOD in mg/L?

45.7

Which unit process in a municipal wastewater treatment plant is most likely to consume the most energy and emit the most green house gases:

Activated sludge process

Which of the following is NOT a unit process in a typical surface water treatment plant:

Aeration

Composting

Aerobic degradation of organic matter under controlled conditions

Which one of the following is the first stage of decomposition of landfill materials

Aerobic phase

Flocculation

Agitation of chemically treated water to induce agglomeration of finely divided suspended matter by physical mixing

The water quality assessments of 1992 showed that the most significant source of impairment of surface water quality in the United Sates is:

Agriculture

Volatile organic compounds

Among the most commonly found contaminants; often used as solvents in industrial processes

Life cycle analysis

Analyzing a products entire life cycle from an environmental point of view

Which one of the following products has the highest recycling rate

Auto batteries

What can be expected from the measured 5-day biochemical oxygen demand (BOD 5) and the ultimate BOD (BOD u) of the same wastewater?

BOD 5 < BOD u

Microbial standards

Based on testing water for evidence of any fecal contamination

Types of oxygen demanding wastes (3)

Biodegradable substances in municipal wastewaters, biodegradable substances in industry effluents, oxidizable inorganic compounds

Methemoglobinemia

Blue baby syndrome, hemoglobin + NO2

Total BOD

CBOD + NBOD

Which one of the following green house gases has the highest global warming potential?

CFC-11

6 criteria pollutants

CO, Pb, NO2, O3, SO2, particulate matter (PM10, PM2.5)

Thermal stratification in lakes

Caused by the density differences between surface water and the water near the bottom

Nutrients

Chemicals essential to the growth of living things (ie carbon, sulfur, calcium, nitrogen,etc)

Recycling

Collection, processing, repurposing, composting

Disposal

Combustion with or without energy recovery, landfills

Secondary pollutants

Created by various physical processes and chemical reactions that take place in the atmosphere

The amount of DO that water can hold ____________ with temperature.

Decreases

Which one of the following is a TOXIC substance emitted from combustion of municipal solid waste:

Dioxins

Pathogens

Disease causing organisms that grow and multiply within the host

Salts

Dissolved solids (Na 2+, Ca 2+, Mg 2+, etc)

Environmental impacts of combustion (3)

Emissions of air pollutants, toxic substances, incinerator ash

Clean air act (1990)

Established NAAQSs, required SIPs, and established emission standards

The major source of mercury in municipal solid waste is most likely:

Fluorescent lamps

Steps of LCA

Goal/scope definition, inventory analysis, impact assessment

Clean water act

Governs the regulation of wastewater effluents and water quality in the receiving body of water

A water has a hardness of 135 mg/L as CaCO3, the water is classified as

Hard

Eutrophic lake

High nutrient content and high plant productivity

Which one of the following is NOT a factor affecting waste composting:

Hydrogen

Impact assessment

Identify all the environmental impacts associated with the inputs and outputs detailed in the inventory analysis

CO sources

Incomplete combustion of a carbonaceaous fuel

Water samples are analyzed for the coliform group of bacteria because these bacteria

Indicate the possible presence of disease-causing organisms

The Comprehensive Environmental Response, Compensation, and Liability Act (Also known as Superfund Act) was enacted by Congress in 1980 in response to the threat of hazardous waste sites originated from:

Industrial waste

Which one of the following is the second step in life cycle analysis (LCA):

Inventory analysis

In a standard five-day BOD test, why is it sometimes necessary to seed the sample?

It ensures a supply of oxygen and does not limit the degradation of organic matter

Which one of the following is incorrect regarding to alkalinity:

It is responsible for the soap curd that makes a ring around the bathtub

In a standard five-day BOD test, why isn't ultimate BOD measured?

It takes a long time to determine and the BOD5 is what is typically measured

Select all correct statements regarding the ultimate BOD (2)

It will change with the type of wastes, it will not change with temperature

Lead sources

Lead, smelters, battery manufacturing, waste incineration

Major sources of groundwater contamination (5)

Leaking underground storage tanks, industrial waste, home septic systems, landfills, ag chemicals

Oligotrophic lake

Low nutrient content and low plant productivity

Discarded materials

MSW materials left after recovered for recycling and composting

Primary standards

Maximum contaminant levels based on health-related criteria

Heavy metals

Metals with specific gravity greater than about 4 or 5

What does the BOD reaction rate constant k depend on?

Nature of the waste and temperature

Which of the following may cause the "blue baby" syndrome in infant

Nitrate

Limiting __________ and _________ can help control eutrophication

Nitrogen and phosphorous

Which one of the following should NOT be expected in landfill gases:

Nitrogen dioxide

Secondary standards

Non-enforceable guidelines based on aesthetics and non-aesthetic characteristics

BODu

Oxygen required to completely degrade a sample of waste

Sinks of DO (3)

Oxygen-demanding wastes, plant respiration in the night, sediment oxygen demand

Sources of DO (3)

Photosynthesis in the day, tributaries, natural reaeration

What is the difference between the primary standards and the secondary standards of drinking water?

Primary standards relate to health effects, while secondary standards relate to aesthetic concerns

Eutrophication

Process of nutrient enrichment

NAAQSs primary standards

Protect public health

NAAQSs secondary standards

Protect public welfare

Which one of the followings is NOT an in situ groundwater treatment technology:

Pump and treat

Inventory analysis

Quantify what comes in and what goes out, including the energy and materials associated with each stage

Which one is not a mechanism involve in the rapid sand filtration process:

Rapid mixing

Under the same water temperature, which one of the following sample has the highest value of the BOD reaction rate constant

Raw sewage

Source reduction

Reduce toxicity, less packaging, product reuse, more durable products, on site mulching and composting

Primary treatment of wastewater

Reduces settleable solids

Safe drinking water act

Regulates drinking water quality

Sedimentation

Removal of solid particles from suspension by gravity

RCRA

Resource conservation recovery act (1976)

Which one of the following should be given the highest priority in the integrated solid waste management approach:

Source reduction

Primary pollutants

Substances that are emitted directly into the atmosphere

Oxygen Demanding Wastes

Substances that oxidize in the receiving body of water, and thus reduce the amount of DO in the water

Which one of the following can be the precursor for "acid rain":

Sulfur dioxide

Which one of the following emissions from a coal-fired power station can be controlled by a scrubber using limestone

Sulfur dioxide

Which one of the following is a REGULATED primary air pollutant:

Sulfur dioxide

Which one of the following is not a green house gas?

Sulfur dioxide

Thermal pollution

Temperature rise caused by heat released into a receiving water

Select the incorrect statement regarding the oxygen sag curve

The DO deficit will increase with distance after the critical point

In a standard five-day BOD test, why is it usually necessary to dilute the sample?

The only oxygen available to the organisms is the dissolved oxygen in the water

NBOD

The oxygen needed to convert ammonia to nitrate

CBOD

The oxygen needed to oxidize organic carbon to carbon dioxide

Emerging contaminants

Their fate and toxic impacts are not yet clear

Why are coliform bacteria used as the indicator organisms? (3)

They are excreted in large numbers in feces, pathogenic organisms originate in fecal discharges, contaminated water is potentially dangerous by the presence of coliform bacteria

Rapid mixing

To blend chemicals

Goal of green engineering

To minimize adverse impacts while simultaneously maximizing benefits to the economy, society, and environment

In a standard five-day BOD test, why is the test run in the dark?

To prevent photosynthesis when adding oxygen and to disprove the findings for oxygen consumption

What is the purpose of municipal water supply systems?

To provide potable water than is safe for human consumption and has adequate quality for industrial users

In a standard five-day BOD test, why is the BOD bottle stoppered?

To remove and prevent air bubbles in the solution

BOD5

Total amount of oxygen consumed by microorganisms during the first five days of biodegradation

Coliform bacteria

Used as indicator organisms whose presence suggests that the water is contaminated

What is the limitation of using coliform as an indicator?

Viruses, protozoal cysts, and helminth eggs are more persistent than coliform bacteria

Seeded BOD test

With added microbial seed