Environmental Previous Exams

At what temp is water most dense

4 degrees celsius

individuals infected with which of the following pathogens can spread the disease via dormant cysts, but are only 5-10% likely to show symptoms

Giardia

Hydrobromic acid (HBr) is a strong acid. If sodium bromide (NaBr) is added to water at pH 7 and completely dissociates, what will happen to the pH

pH will not change

Which of the following is an example of an oppurtunistic pathogen

Legionella pneumophila

the Pka of 1-propanol (Ch3CH2CH2OH) is 16.9 at normal pH range ~(6-8) which can we assume is present at negligible concentration - protonated or deprotonated (CH3CH2CH2O-)

Deprotonated

What is the formula for the sulfate anion

SO4²-

which of the following pollutants is associated with agriculture

all (nitrogen, salts, phosphorous)

Which of the following parameters is used to quantify the amount of suspended solid particles in water

Turbidity

Chemical elements are defined by the atoms containing a certain number of what

Protons

Which of the following statements apply to endocrine disruptors

can have toxicological effects even at low concentrations, can interfere with hormone function

Which of the following is regulated by a secondary drinking water standard, as part of the Safe Drinking Water Act

taste and odor

What is the main goal of coagulation in drinking water treatment

To neutralize surface charge of colloidal particles

How do granular media filters remove colloidal particles from water

the colloids collide with media particles and stick to them

This molecule is an example of what

PFAS

Contamination from agricultural runoff or road salts are example of what

nonpoint source pollution

Which of the following waterborne illnesses is caused by a blood fluke

Schistosomiasis

Covalent bonding involves the sharing of electrons among atoms

True

Which of the contaminants is known to bioaccumulate

Mercury (Hg)

Toluene is an example of what type of molecule

Aromatic, Organic

Primary standards of the safe water drinking act come in which two forms

Maximum contaminant levels and treatment techniques

Adjusting the flow ratio between return (RAS) and waste (WAS) lines in the activated sludge process affects which of the following

All (Ratio of BOD conversions to CO2 v. Biomass, Food to microbe ratio (F/M), Cell retention time (thetac)

The conversion of N2 gas to nitrogen-containing nutrients such as nitrate and ammonia is known as

Nitrogen Fixation

Which is a characteristic of combined chlorine disinfection

All (Involves both addition of free chlorine and ammonia, leads to fewer byproducts than free chlorine, provides a relatively long-lasting residual in the distribution system)

Which of the following is an alternative process to activated sludge for BOD removal

Membrane Bioreactor

Which organism is most resistant to inactivation by chemical oxidants

Cryptosporidium parvum cysts

An activated sludge process with high BOD removal ratio, high aeration requirements, and poor settle ability of solids is characteristic of what type of cell (solids) retention time

High (>6d)

What role do anerobic digestors play in wastewater treatment

None (removal of recalcitrant dissolved organic compounds, disinfection of treated waste water, ammonia removal prior to activated sludge treatment)

Which of the following can be removed from wastewater by precipitating as a solid, followed by sedimentation

Phosphorous

What type of reactor can be used to determine the rate constant (k) of a chemical reaction

Batch reactor

If only organic compounds are present with no external electron acceptors such as O2 or SO4²-, which type of metabolism could microbes use to obtain energy

Fermentation

A water sample is collected from a polluted river and analyzed for BOD5 using the appropriate methods. Which of the following would affect the result

The biodegradability of the organic compounds in water

Why does organic nitrogen contribute minimally to BOD5

it takes longer than 5 days for bacteria to begin using it as an electron donor

Consider a point source discharging oxygen-demanding wastes into a river. Which of the following can affect the distance of the critical point (DO min) downstream from the discharge point

All (Stream Velocity, Altitude, Turbulent white water v. non-turbulent flow)

Which of the following is true of heterotrophs

All (They require preexisting organic compounds (reduced carbon), They obtain energy from thermodynamically favorable redox reactions, They contribute to oxygen depletion in waters with high BOD)

A conservative (unreactive) compound is briefly injected into the influent of an ideally-performing plug flow reactor which of the plots shows the concentration-time profile that will be observed in the reactor effluent

Which of the following is a first-order rate expression for a chemical degradation reaction

dC/dt = -kC

Consider a lake with high alkalinity that begins to be contaminated by acid rain which of the following will happen

The pH will decrease only slightly at first

Biological treatment of wastewater using aeration/aerobic conditions followed by anaerobic conditions is a common way to remove what

Nitrogen Compounds

What is the defining quality of an autotroph

They obtain carbon for synthesis from CO2

Which is a water disinfectant that inactivates microorganisms by directly causing DNA mutations

Ultraviolet radiation