CEE 357 Win 2014 HW#1 Solutions
1. (a) The mass of silver in the oceans is just the product of its concentration and the oceans
volume:
mAg = cAgV
g Ag
g sw 3 kg
L
m3
= 50x1012
1025
10
(1370 x 106 km3 ) 103 m3 109 km3
g sw
L
g
= 7.02x1010 kg
(b) Di
CEE 357 Winter 2014, HW#5
1. Iron species in solution exist in two major forms with different charges: ferrous iron, with a
charge of +2, and ferric iron with a charge of +3. Ferrous iron typically dominates in
anaerobic environments, and ferric in aerobi
CEE 357 Win 2014 HW#4 Solutions
1. Once equilibrium has been attained, all the relevant equilibrium constants will be
satisfied; in this problem, those constants are the KH values for both gases, the Ka1 and
Ka2 values for both H2CO3 and H2SO3, and Kw. In
CEE 357 Winter 2014. HW#6 Assignment
1. The maximum concentration of algal biomass that can be generated using each of the
nutrients is as follows:
N:
1.1 mg N/L 1 mmol N 14 mg N 4.9 103 mmol Alg
P:
0.2 mg P/L 1 mmol P 14 mg P 6.4 103 mmol Alg
S:
0.03 m
CEE 357 Aut 2012, HW#4 Solutions
1. The mass balance for the air inside the bar (treating the system as a CSTR) for any time after
the bar opens is:
V
dc
= Qcin Qcout + Vrgen Vk1c
dt
(1)
where c is the formaldehyde concentration inside the bar, cin and co
CEE 357 Winter 2014. HW#6 Assignment
1. Although it is rarely considered as such, sulfur could potentially be a limiting nutrient in
some aquatic systems.
a)
If a lake contains 1.1 mg/L NH3-N, 0.20 mg/L PO4-P, and 0.03 mg/L SO4-S, and if the
average compo
Class CEE 357
Introduction to Environmental
Engineering
Lecture 1
Introduction. Syllabus and
schedule review.
Processes and units
Instructors
Instructor: Prof. Gregory Korshin
Office:
Office Hours:
e-mail:
Phone:
More Hall 307
MW 1.30-2.30 PM
[email protected]
CEE 357 Aut 2012 Homework #6
1. The leachate from a municipal landfill contains 225 mg/L Fe2+ and 950 mg/L of organic
material with an average composition of C5H14O4N. When the sample is diluted and
incubated in a BOD bottle, all of the Fe2+ is rapidly co
CEE 357 Homework 3
Each problem is credited with 0.40 points.
Problem 1 A river water used as a drinking water source has a bicarbonate concentration of 72 mg/L
and a CO2(aq) of 4 mg/L. What is the pH?
Problem 2 (Textbook Problem 2.27) Suppose the gas abo
CEE 357 Homework 6
Each problem is credited with 0.40 points.
Problem 1 (Textbook Problem 5.40) Consider three monitoring wells, each located at the
vertex of an equilateral triangle. The distance between any pair of wells is 300 m. The head in
each well,
CEE 357 Week 7 Homework
Problem 1 (Textbook 6.4) (a) What is the terminal settling velocity of a particle
with a specific gravity 1.4 and a diameter of 0.010 mm in 20C water?
(b) Would particles of the size in part (a) be completely removed in a settling
The diagram shown below characterizes the relative concentrations of species in the phosphoric
acid/base group. The chemical formula of phosphoric acid is H3PO4, and it is possible for zero,
one, two, or all three H+ ions to be released.
(a) (4) Label the
Three Idealized Models for Reactor
Hydraulics
Completely-mixed batch reactor (CMBR*): No
flow in or out; intense mixing and uniform
concentration inside
Completely-mixed flow reactor (CMFR*):
steady, equal inflow and outflow; intense
mixing and uniform
EnergyBalances
Same idea as mass balances: Conservation
Can be either static or dynamic
(Rate of) accumulation equals net input
(rate) minus net loss (rate) (1st law of
thermodynamics)
Units of energy: Joules (J) or Calories (cal); 1
cal = 4.184 J
Units o
A natural water has a dissolved organic carbon (DOC) concentration of
3.5 mg/L. The average composition of the organic molecules is
C30H33O18N. Assuming that all the molecules actually have that
composition, compute the molar concentration and mass concen
Findthecarbonicacid(H2CO3)concentrationinwatersthat
haveequilibratedwiththeatmosphereat20oC.Henryslaw
constantfordissolutionofCO2 at20oCis0.0331,andtheCO2
concentrationintheatmosphereis370ppm.
CO 2 g H 2 O l H 2 CO3 aq
WhatarethepHandTOTCO3 inasolutionof
CEE 357 Winter 2014. HW#7
1. The Darcy velocity is the ratio of the flow rate to the total cross-sectional area, including the
area that is occupied by aquifer solids. The water actually flows only through the pore
spaces, so its average velocity in the d
CEE 357 Winter 2014. HW#7 Assignment
1. Analysis of the movement of a tracer in a contaminated aquifer indicates that the local Darcy
velocity is 1.2 m/d. The aquifer has a hydraulic conductivity of 14.0 m/d, a depth of 11 m,
and a porosity of 0.3. How lo
1. Two well of radius 18 inches are constructed in a confined aquifer 150 ft thick with
hydraulic conductivity K = 170 gpd/ft2. The wells are separated by a distance of
1000 ft. When Well 1 pumps at a rate of 225 gallons per minute (gpm), the steadystate
1. In a BOD test, 6 mL of sewage is mixed with 294 mL of dilution water containing
8.20 mg/L of dissolved oxygen (DO). After 5 days of incubation, the DO content of
the water is 5.40 mg/L. What is BOD5 of the raw sewage? Assume the initial DO of
the sewag
CEE 357 Winter 2014 Midterm Exam #1 Practice Questions
Atomic weights: H = 1, N = 14, O = 16, P = 31, Ca = 40
Ideal Gas Law: PV = nRT , R = 0.0821 L-atm/mol-K
Heat capacity of steam, cP = 2.01 kJ/kg-oC
For a hypothetical acid HA that can release only one
CEE 357 Winter 2014. HW#8 Solutions
1. a) Footnote f of Table 7-7 says: Regardless of windspeed, class D should be assumed for
overcast conditions, day or night.
By using figure 7.52, for class D and a stack height of 50 m, we can determine the distance a
CEE 357 Winter 2014 Midterm Exam #2 Solutions
1. (a) The reaction and equilibrium constant expression can be written as follows:
Cu 2 ( OH )2 CO3 ( s )
2
2 Cu 2+ + 2 OH + CO3
( Cu ) ( OH ) ( CO ) = K
( Cu ( OH ) CO ( s ) )
2+ 2
2
2
2
2
3
sp
= 1022.53
3
T
CEE 357 Winter 2014. HW#8 Assignment
1. Masters and Ela, Problem 7-32 (Note: read Section 7.11 for background)
2. Masters and Ela, Problem 6-7, parts a-c.
3. Masters and Ela, Problem 6-10a,b.
4. Masters and Ela, Problem 6-24, 6-25a, 6-25b (all relate to t
CEE 357
Quiz #1 solution
The molar concentration of urea (NH2)2CO in human urine is about 0.15
mol/L. Assuming that the average daily excretion rate is about 2 L/day,
determine the mass of urea excreted daily. Atomic masses of nitrogen,
hydrogen, carbon a
CEE 357, Win 2014, Quiz #2
Name _
1. (7 pts) A reactor of volume 60 m3 receives an influent flow of 3 m3/min and has been designed
to be a CMFR. A spike-input tracer is conducted, generating the experimental results plotted
below. Does the test suggest th