Environmental engineering midterm

How many core units are in SI

7

What are the core 7 units

meter

kilogram

second

ampere

kelvin

candela

mole

mole

unit for measuring small entities

avogadro’s number

6.022×10^(23)

Atomic weight

mass of an atom/element

Molecular Weight

the mass of one mole of a molecule

atom

molecule

Ideal gas law

volume that a particular mass of a gas takes up depends on the system's temperature and pressure

pv=nrt

gas constant

.0821 atm*L/mol*k

8.314 J/mol*k

stoichiometry

the calculation of relative quantities of reactants and products in chemical reactions

chemical reactions must be

balanced

A chemical reaction must follow the law of conservation of

mass

Contaminant transport in groundwater can be slowed by chemical reactions with the soil matrix.

True

Which of the following processes does not significantly affect contaminant transport in groundwater?

Hydraulic head

Which of the following conditions would result in the highest groundwater velocity?

High hydraulic conductivity and high hydraulic gradient

Which of the following parameters directly affect Darcy’s velocity? (Select all that apply.)

Hydraulic gradient

Hydraulic conductivity

Q

Volumetric Flow rate

v

darcy velocity

v’

linear velocity

n

porosity

k

hydraulic conductivity

dh/dL

hydraulic gradient

Groundwater flow rate is proportional to:

Q=-kA dh/dl

darcy velocity

v=-k dh/dl

average linear velocity

v’=v/n

Hydraulic conductivity (coefficient of permeability)

permeability constant

least permeable clays and granite

k=0.0004 m/d

most permeable gravel

k=4100 m/d

homogenous (uniform)

same k throughout

heterogeneous (non-uniform)

different k values

porosity

ratio: volume of voids to total volume of material

porosity(n)

(Vvoids)/(Volume void+Volume of material

volume of water stored

porosity*volume of material

hydraulic head

distance from datum to water table

units: ft, m

Gradient

slope of the watertable

units: unitless

Hydraulic Gradient

change in head/horizontal distance

(h2-h1)/L

An ____aquifer is located below the water table.

unconfined

In which zone are all the spaces filled with water: 

saturated zone

unconfined

aquifer present below the water table above an aquifer

confined aquifer

both above and below is an aquifer

perched

confirming layer in the middle of an unsaturated zone

unsaturated (vadose) zone:

air and water within crevices

saturated zone

all spaces are filled with water

water table

upper layer of saturated zone

confining bed

aquifer, impermeable layer, restricts flow

Aquifer

saturated layer that water can flow through easily

DO is an abbreviation for____oxygen

dissolved

Which zone has the least amount of oxygen?

septic

Which type of equilibrium reaction governs the saturation concentration of oxygen in the water (DO_sat)?

air-water

DO_act

The actual dissolved oxygen concentration.

D

The difference between the actual concentration and the saturation concentration.

DO_sat

The oxygen concentration at equilibrium.

After an oxygen deficit occurs in a river, causes it to recover

aeration

Water pollutants can be classified into how many general categories?

4

Point source

Examples:

domestic sewage

industrial waste

non-point source

agricultural runoff

urban runoff

Nitrogen and phosphorus are considered pollutants when present at any concentration.

False

Salts that do not evaporate are called total ___solids.

dissolved

PPCPs is an acronym for ____and personal care _____.

pharmaceuticals

products

Which of the following is NOT one of the four processes affecting dissolved oxygen levels in water?

Filtration

Warmer water holds more dissolved oxygen than cooler water.

False

Pesticides are easily biodegraded by bacteria in the environment.

False

Identify the reactants for an aerobic respiration reaction.

oxygen

glucose

In the photosynthesis reaction, light energy is transformed by the chlorophyll in plants and algae. The energy is then stored in the bonds of which compound?

carbohydrates

The technical term for the food that is consumed to obtain energy is

substrate

methionine

organic

cysteine

organic

sulfate

inorganic

nitrate

inorganic

guanine

organic

alanine

organic

carbon dioxide

inorganic

carbonate

inorganic

benzene

organic

The theoretical oxygen demand is calculated from the____ of the reaction.

stoichiometry

The incubation time for the BOD5 test is:

5 days

Biochemical Oxygen Demand (BOD) is an important parameter in water quality assessment. Which of the following statements are true regarding BOD? (Select all that apply.)

High BOD values indicate good water quality with minimal organic pollution.

BOD measures the amount of oxygen required for microbial decomposition of organic matter in water.

BOD is used to assess the effectiveness of wastewater treatment processes.

According to the video, what percent of the Earth is covered by water?

70

Most of the Earth's water is contained in:

oceans

On a global basis, water is mostly used for which purpose?

agricultural

According to the textbook, water is transferred to the earth's atmosphere through which two processes?

evaporation and transpiration

A graphical representation of the discharge of a stream at a single gaging station is called a:

hydrograph

The rational method formula in U.S. customary units shows that in/hr*acre is approximately equation to:

1 cubic foot per second

categories of water use

Industrial, municipal/domestic, agricultural

Evapotranspiration (12%)

evaporation of water and transpiration of water from leaves

Evaporation of ocean water (88%)

desalination process

over ocean

less precipitation than evaporation

over land

more precipitation than evaporation

watershed (or Drainage Basin)

The land area that drains to a point of concern

What influences surface runoff?

Type of soil

Land slope

Rainfall intensity

development

Risks of high runoff rates

higher flow rates in rivers that can cause erosion of banks and resuspension of bottom sediment

Transport of pollutants (nonpoint source)

Assumptions of a CSTR are that the concentration within the control volume is the same:

as the exit concentration

throughout the control volume

mass balance equation

dm/dt=min-mout+mrxn

Each term of the mass balance equation has dimensions of:

[M]/[T]

Steady State

that the conditions do not change with time.

Which part(s) of the mass balance equation is affected when assessing whether a system is at steady-state or not?

dm/dt

Which part(s) of the mass balance equation is affected when assessing whether a system is conservative or not?

mrxn

Which part(s) of the mass balance equation is affected when assessing whether a system has flows in and/or out?

min

mout

Which is NOT a synonym for effluent?

incoming