Environmental Engineering

Test 1

100

What is the material balance equation for CSTR steady state conservative, outside of water?

0=Σ C_inQ_in-Σ C_outQ_out

200

What is risk (as a formula)?

CDI*Potency

300

What are the three types of ideal reactors?

CSTR, PFR and Batch

Test 2

100

What is Henry's Law 

Henry's constant * Pressure

200

What does BOD and DO stand for?

Biochemical Oxygen Demand and Oxygen Demand

300

What is the BOD₅ with the following numbers 

DO_i= 10 mg/L

DO_f=2 mg/L

using 12mL wastewater and 290 for dilution 

BOD₅= 201mg/L

500

Integrate the following equation 

dDO= (K_r(DO_s-DO) -K_dL₀e^-tKd)dt

DO= DO_s- e^-Kt(DO_s-DO₀+KL₀t)

Test 3

100

What is the pH of distilled water using the following equation 

H⁺= OH-

Hint

K_w=10^-14

OH^-= k_w/H

pH = 7

200

What are the steps for a systematic drinking water treatment 

1. Screen and grit chamber

2. Primary Sedimentation

3. Coagulation and Flocculation

4. Secondary Sedimentation

5. Filtration

6. Disinfectant contact

7. Distribution

300

A perfect emitter at all wavelength, what is this 

Blackbody 

400

Jupiter is 7.8*10⁸ km from the Sun. Its albedo is 0.73. Calculate the effective temperature of Jupiter assuming that the Sun is the only energy source.

Hint S= 51.5 W/m²

σ= 5.67*10^-8 W/m²K^-4

S(1-α)/4σ= T_V⁴

T_v= 88.5K

Laboratory

100

Alkalinity and Hardness are expressed in what units?

mg/L-CaCO₃

200

What is the name of the solid fraction that is not dissolved and would be retained by a very small filter

Total Suspended Solids (TSS)

300

Is a lower or higher BOD/COD ratio value more suitable for water that needs to be chemically treated? Also, is chemical treatment or biological treatment more expensive? 

(Both answers must be correct.)

A low BOD/COD ratio value represents water that has to be treated chemically. Biological treatment is cheaper to perform but will do nothing for water that has to be chemically treated.