Prepare an excel spreadsheet and short written report (7-10 pages), clearly demonstrating your approach (use diagrams, and properly present and explain any formulae used). In your report, clearly show your main findings in the form of charts, produced from your spreadsheet and no other source. Be sure to present all relevant graphs and charts within your report, and limit large tables of numbers which are undesirable.
1) Carry out some research on the Streeter-Phelps dissolved oxygen model. Use this to form the introduction and background sections to your report.
2) Set up an excel spreadsheet to calculate DO critical concentration and distance. Produce a plot of the Streeter-Phelps DP sag curve. Use the following parameters:-
|
Parameter
|
Wastewater
|
Creek at discharge location
|
|
Flowrate
|
18m3 perday
|
200m3 per day
|
|
BOD5 at 20°C
|
180 mg/L
|
|
|
BOD ultimate
|
|
4.5 mg/L
|
|
DO
|
0.46 mg/L
|
8.75 mg/L
|
|
Temperature
|
28°C
|
19°C
|
|
Deoxygenation rate constant, ka
|
0.16 d-1
|
|
|
Reaeration rate constant, kr
|
|
0.28 d-1
|
|
River bed activity coefficient
|
|
0.10
|
Note: Please do reasonable assumptions if needed
3) Calculate the possible impact into river using the Streeter-Phelps model. Answer the following
1. What is the expected critical DO concentration and critical time?
2. What is the expected distance of the critical location?
3. What is the discharge rate of the wastewater to maintain at least 5 mg/L critical DO concentration in the river?