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