CEE 370

Name      _________________________________

# Final Exam

December 21, 2006

Closed book, 3 sheets of notes allowed.

If you cannot finish a problem (e.g., due to lack of time, or a missing formula), explain on your exam paper how you would have completed it.

#### ·        one from the last four questions #8 - #11 (15%)________________

total is 100%

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# Answer both of the first two questions #1 & #2

## 1.                  Stoichiometry (20 points)

### Aerobic heterotrophic bacteria can facilitate the following unbalanced biochemical transformation of glucose:

C6H12O6 + O2 ®  CO2 + H2O

And:

# Answer questions #6 and #7

## 6.      Water Quality Modeling (30 points)

### The Intercontinental Paper Co. is discharging its wastewater directly into the Mill River.The discharge flow is 3.8 ft3/s (cfs) the discharge D.O. is 5.5 mg/L and the discharge ultimate BOD (BODult) is 35 mg/L.They obtain half of this water from an intake 0.5 miles upstream of the wastewater outfall, and half from groundwater via a nearby well field.On average, the Mill River water upstream of the IPC outfall has an ultimate BOD (BODult) of 2.5 mg/L and a D.O. of 8.5 mg/L.If the Mill River has a flow of 12 cfs upstream of the IPC intake, and if the state permits a minimum DO of 7.5 mg/L in the Mill River, will the state have to further restrict the BOD in IPC's wastewater (i.e., is the stream out of compliance)?Calculate the minimum stream D.O. expected as a result of the IPC discharge.

Additional assumptions:           BOD deoxygenation rate: k1(or kd) = 0.23 d-1

reaeration rate constant (k2 or kr) of 0.82 d-1

D.O saturation concentration = 9.5 mg/L

River flow velocity = 0.5 ft/s

# Answer one of the following four questions #8 - #11

## Appendix

Some physical constants of Water:

 Temp., oC Density, kg/m3 Viscosity, N-s/m2 Kinematic Viscosity, m2/s 0 999.8 1.781x10-3 1.785x10-6 5 1000.0 1.518 x10-3 1.519x10-6 10 999.7 1.307 x10-3 1.306 x10-6 15 999.1 1.139 x10-3 1.139 x10-6 20 998.2 1.002 x10-3 1.003 x10-6 25 997.0 0.890 x10-3 0.893 x10-6 30 995.7 0.798 x10-3 0.800 x10-6 35 994.0 0.725 x10-3 0.729 x10-6 40 992.2 0.653 x10-3 0.658 x10-6

Selected Chemical Constants

 Element Symbol Atomic # Atomic Wt. Valence Electronegativity Aluminum Al 13 26.98 3 1.47 Boron B 5 10.81 3 2.01 Calcium Ca 20 40.08 2 1.04 Carbon C 6 12.01 2,4 2.50 Cerium Ce 58 140.12 3,4 1.06 Chlorine Cl 17 35.453 1 Holmiuum Ho 67 164.93 3 1.10 Hydrogen H 1 1.01 1 2.20 Iron Fe 26 55.85 2,3 Magnesium Mg 12 24.31 2 1.23 Manganese Mn 25 54.94 2,3,4,6,7 1.60 Nitrogen N 7 14.0067 3 Osmium Os 76 190.2 2,3,4,8 1.52 Oxygen O 8 16.00 2 3.50 Potassium K 19 39.10 1 0.91 Sodium Na 11 22.99 1 1.01 Sulfur S 16 32.06 2,4,6 2.44

Useful conversion factors

1 ft  =  0.305 m