ENE 280 – Principles of Environmental Engineering and Science, Fall Semester, 2023
HOMEWORK ASSIGNMENT 1
INSTRUCTIONS
1. FULLY COMPLETE the homework questions before you enter your responses to D2L.
2. Enter your responses into D2L, as described below.
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Log into D2L
Go to Assessments
Go to Quizzes
Click on Homework Week 1
Select your answers from the multiple choice questions
3. No paper submissions will be accepted
4. You have until 5PM Friday, 1st September to enter your responses into D2L.
********After this, the site will BE CLOSED *******
5. The solutions will be posted shortly after this.
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HOMEWORK 1: ENE 280: Principles of Environmental Engineering & Science, Fall 2023 20 points
All questions are worth 2 points
1. A river water sample contains 0.25 ppm of 2,4-D. Express this concentration as µg/L and ng/L.
2. A lake sample contains 17.5 ng/L of perchloroethene, convert this to ppb.
3. Water in a drainage tile from an agricultural field contains 75 μg/L of atrazine with a flow rate of 1.5
gallons/minute. Calculate the mass in g released per day (three decimal places). Useful conversion: 1
gallon = 3.78541 L.
4. A stream receives effluent containing catechol at a concentration of 50 μg/m3 from an industrial plant at a
rate of 0.5 gallons per second. Calculate the mass in g added to the stream in one year (two decimal
places).
5. Effluent from an industrial plant, containing 30 ng/L of phenol has a flow rate of 125 in3/min. If the
effluent flows into a pond, calculate the mass of phenol in g that the pond will receive in one year (three
decimal places). Useful conversion: 1 in³ = 16.387064 mL
6. A dried soil sample from an agricultural field contains 0.0012% by weight of triclosan. Express this in
mg/Kg and µg/Kg.
7. Every hour, an industry generates 20 g of solid waste that contains 0.000125% by weight of chlorophenol.
Calculate the mass in mg of chlorophenol generated by this industry in one year (no decimal places).
8. An exhaust gas pipe contains 0.000005% of meta-xylene, convert this to ppmv.
9. The carbon monooxide (CO) concentration beside a bonfire was 0.000012%, convert this concentration to
units of µg/m3 (one decimal place) (assume atmospheric pressure = 1 atm, temperature = 21 oC).
10. An industry releases nitric oxide (NO) at the concentration of 150 μg/m 3 (assume atmospheric pressure =
1 atm, temperature = 22 oC), convert this into ppmv to three decimal places (hint: rearrange the mg/m3
equation to solve for ppmv).
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