CEE 153 F07 PS4

CEE 153 F07 PS4 - UNIVERSITY OF CALIFORNIA, LOS ANGELES...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: UNIVERSITY OF CALIFORNIA, LOS ANGELES Civil and Environmental Engineering Department CEE 153 Introduction to Environmental Engineering Science Fall Term 2007 T-Th 2-4 PM 4000A Math Science Prof. K. D. Stolzenbach 5732J Boelter Hall, 206-7624 [email protected] Problem Set # 4 (due Thursday November 1) _____________________________________________________________________________ 1. The ultimate BOD of a river just below a sewage outfall is 50.0 mg/L and the DO is at the saturation value of 10.0 mg/L. The deoxygenation rate coefficient k d is 0.3/day and the reaeration rate coefficient k r is 0.90/day. The river is flowing at the speed of 48.0 miles/day. The only source of BOD on this river is this single outfall. a) Find the critical distance downstream at which the DO in the river is a minimum. [87.9 miles] b) Find the minimum DO value. [0.38 mg/L] c) If a wastewater treatment plant is to be built, what fraction of the BOD would have to be removed from the sewage to assure a minimum of 5.0 mg/L of DO everywhere downstream? [48%] 2. Wastewater saturated with dissolved oxygen (DO sat = 12 mg/L) is discharged into a river that has zero BOD and is saturated with oxygen (also DO sat = 12 mg/L) upstream from the point of discharge. The minimum DO in the river downstream from the discharge is DO min = 2 mg/L. Calculate the five-day biological oxygen demand (BOD 5 ) of the wastewater being discharged, assuming that k d = 0.2/day, k r = 0.42/day, Q a = 1 m 3 /sec, and Q e = 0.1 m 3 /sec. [286 mg/L] 3. A well-mixed reservoir has a constant volume V = 10 7 m 3 and a horizontal cross-sectional area A = 10 6 m 2 . The steady flows of water into and out of the reservoir are the river inflow Q in , the outflow Q out , the rainfall P, and the evaporation E....
View Full Document

This note was uploaded on 05/19/2011 for the course CEE 153 taught by Professor Stolzenbach during the Fall '08 term at UCLA.

Page1 / 4

CEE 153 F07 PS4 - UNIVERSITY OF CALIFORNIA, LOS ANGELES...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online