ENVSE 427 Review Practice

Where do halophiles live?

• Dead Sea

• Spring Creek

• Lake Erie

• Stormwater pond

Virus is a living microorganism.

• Yes

• No

Purple non-sulfur bacteria use sunlight as the energy source and organic carbon as the carbon source. What are their trophic level?

• Chemoheterotroph

• Chemolithotroph

• Photoheterotroph

• Photoautotroph

Which element is required for cell growth?

• C

• N

• O

• All of the above

Which macromolecular of the microorganisms carries genetic information?

• Polysaccharides

• Fatty acids

• Nucleic acids

• Lipids

Which temperature can thermophilic microorganisms grow well?

• 10°C

• 35°C

• 55°C

• 80°C

Which of the following is NOT the function of the protein?

• Catalyzing reactions of the cells

• Turn genes on and off

• Cell movement by flagella

• Backbone of DNA and RNA

Benzene is a typical contaminant in refinery wastewater that can be removed by heterotrophic microorganisms in the present of oxygen. Benzene will be converted to CO₂ and removed from the wastewater. What is the electron donor in this process?

• Benzene

• CO₂

• Oxygen

• H₂O

The microorganism has an initial biomass concentration (X₀) of 15 mg VSS/L. The specific growth rate (µ) =0.5 d^-1, b=0.1 d^-1. Determine the biomass concentration at the end of 5 days during the exponential growth phase.

• 212 mg VSS/L

• 111 mg VSS/L

• 133 mg VSS/L

• 315 mg VSS/L

Answer explanation

dX/dt=(μ-b)X

t=0,  X=X₀

 

X=X₀ e^(μ-b)t

t= 5 days, then

X₅=15*e^((0.5-0.1)*5)=111 mg/L

What are the potential electron donors for denitrification process?

• H2

• Sulfur (S)

• CO₂

• Glucose