1. Environmental Engineering 441
Philadelphia University
Faculty of Engineering
Department of Civil Engineering
First Semester, 2013/2014
Environmental Engineering 441
Lecture Time:
Class 1:
11:15 to 12:45
Monday & Wednesday

2. International System of Units
The International System of Units (abbreviated SI) is the modern form of the metric system. It is the world's most widely used system of units, both in everyday commerce and in science.
The older metric system included several groupings of units. The SI was developed in 1960 from the metre-kilogram-second (mks) system, rather than the centimetre-gram-second (cgs) system which, in turn, had many variants.
The SI introduced several newly named units. The SI is not static; it is a living set of standards where units are created and definitions are modified with international agreement as measurement technology progresses.
With few exceptions, the system is used in every country in the world, and many countries do not maintain official definitions of other units. In the United States, industrial use of SI is increasing, but popular use is still limited. In the United Kingdom, conversion to metric units is official policy but not yet complete. Those countries that still recognize non-SI units (e.g. the U.S. and UK) have redefined their traditional non-SI units in terms of SI units.

3. SI base units Type Name Symbol length metre m mass kilogram kg time
 second  s
 electric current
 ampere  A
 temperature
 kelvin  K
 amount of substance
 mole 
mol
 luminous intensity
 candela  cd

4. SI derived units Type Name Symbol inductance henry H mass flow rate
 kilogram/second 
kg/s
 mole flow rate
 mole/second 
mol/s
 power
 watt  W
 pressure
 pascal  Pa
 speed
 meter/second 
m/s
 surface tension
 newton/meter 
N/m
 torque
 newton meter 
N-m
 voltage
 volt  V
 volume
 cubic meter  m3
 volume flow rate
 cubic meter/second 
m3/s
 amount-of-substance concentration
 mole/cubic meter 
mol/m3
Type
 Name
Symbol 
 acceleration
 meter/square second 
m/s2
 angle
 radian 
rad
 area
 square meter  m2
 capacitance
 farad  F
 density
 kilogram/cubic meter 
kg/m3
 dynamic viscosity
 pascal second 
Pa-s
 electric charge
 coulomb  C
 electric conductance
 siemens  S
 electric resistance
 ohm  Ω
 energy
 joule  J
 force
 newton  N
 frequency
 hertz  Hz

5. SI prefixes Factor Prefix Symbol 1024 1E24 yotta Y 1021 1E21 zetta Z
 1024
1E24
 yotta  Y
 1021
1E21
 zetta  Z
 1018
1E18
 exa  E
 1015
1E15
 peta  P
 1012
1E12
 tera  T
 109
1E9
 giga  G
 106
1E6
 mega  M
 103
1E3
 kilo  k
 102
1E2
 hecto  h
 101
1E1
 deca  da
 deka 
 10-1
1E-1
 deci  d
 10-2
1E-2
 centi  c
 10-3
1E-3
 milli  m
 10-6
1E-6
 micro 
 10-9
1E-9
 nano  n
 10-12
1E-12
 pico  p
 10-15
1E-15
 femto  f
 10-18
1E-18
 atto  a
 10-21
1E-21
 zepto  z
 10-24
1E-24
 yocto  y

6. USCS - United States Customary System Units
USCS - United States Customary System Units: are the measuring units used in the U.S. consisting of the
Mile (eq m)
Foot (equal m)
Inch (eq m)
Gallon ( US eq L) (UK eq L)
second
Pound (eq Kg)

7. Commonly used USCS and SI-units
USCS unit
SI unit
SI symbol
Conversion factor (mutiply USCS unit with factor )
Square foot
Square meter m2
0.0929
Cubic foot
Cubic meter m3
0.2831
Pound per square inch
Kilopascal
kPa
6.894
Pound force
Newton N
4.448
Foot pound torque
Newton meter
N·m
1.356
Kip foot
Kilonewton meter
kN·m
Gallon per minute
Liter per second
L/s
Kip per square inch
Megapascal
MPa
6.89

8. for online conversion you can use the following http://www

9. Example #1: Concentrations and Conversions
Some employees at GE wash the PCB tainted floor with organic solvent (TCE) and the discharge enters a holding tank that is 25 m x 25 m x 5 ft and is full with water. The volume of solvent is 3 L and the concentration of PCBs in the solvent is 10 ppm. What is the final concentration of PCB in mg/l in the holding tank?

10. Material Balances
MB is a key tools in achieving a quantitative understanding of the behavior of environmental systems. Mass Balances provide us with a tool for modeling the production, transport, and fate of pollutants in the environment.

11. Material Balances / Mass Balnce
Conservation of mass Mass is neither created nor destroyed” Mass that comes in either stays, reacts or goes out. “the sum of weights (masses) of substances entering into a reaction is equal to the sum of weights (masses) of the products of the reaction
Feed In
Products out
Inputs - Output = Accumulation

12. Steady State Flow Conservative System:
Σ CinQin = ΣCoutQout
Assumption #1: Steady‐state: no change in conc. throughout control volume
Assumption #2: Conservative system: No reaction

13. Example #1
The Hudson river flows with a flow rate of 300,000 cfs. GE discharges to the Hudson with a flow rate of 10 cfs. The concentration of PCBs in the discharge is 5 g/L. What is the final concentration in the river? downstream from the discharge? Assume perfect mixing. Also assume concentration of PCBs upstream of the discharge is 0 ppm.

14. Strategy of solving MB
Sketch a flow chart or figure defining the boundary of the process
Label the flow of each stream & their composition with symbols
Show all known flows and compositions on the figure. Calculate additional compositions from the data where possible
Select the basis for calculations e.g. 1h, 1 day, 1 kg, etc
Write the MBs which includes the total balance and component balances. There must be x independent equations if there are x unknowns
Solve the equations and check the solutions

15. Example #2
A wastewater treatment plant with an output of m3/day discharges the liquid effluent with a BOD of 20mg/L into a river. If the BOD of the river upstream of the discharge point is 0.2mg/l, at a minimum flow of 20m3/s, compare the BOD of the river downstream of the discharge, assuming complete mixing.
Answer = 0.63mg/L

16. Example #3
A slurry containing 20 percent by weight of limestone (CaCO3) is processes to separate pure dry limestone from water. If feed rate is 2000kg/h, how much CaCO3 is produced per hour?

17. Home Work
Each day 3780 m3 of wastewater is treated at a municipal wastewater treatment plant. The influent contains 220 mg/L of suspended solids. The clarified water has a suspended solids concentration of 5mg/L. Determine the mass of sludge produced daily from the clarifier and write down the mass balance of the clarifier.
As a fuel source 20kg of ethylene (C2H4) is burned with 400 kg of air. Determine the composition of the resulting mixture. What is the percentage of excess air, assuming complete conversation?

18. Analysis performance of reactor type
Effluent
influent
V (m3)
Qin
CAin
Q out
C Aout
Input – output+ generation= accumulation

19. General Material Balance equation for first order reaction rates:
Reactor
influent
Effluent
V (m3)
Qin
CAin
Q out
C Aout
VdC/dt =ΣCinQin − ΣCoutQout ± kCV
C = concentration in the control volume (river/stream/reactor) [=] mg/L
V = volume of control volume [=] L, m3, ft3
Qin = flowrate of inlet streams [=]m3/s, L/s, cfs, MGD
Qout = summation of all outlet streams [=]m3/s, L/s, cfs, MGD
Cin = concentration in each inlet stream [= ] mg/L
Cout = concentration in each inlet stream [= ] mg/L
k = 1st order reaction rate constant (will be given) [=] 1/s
t = time [=] sec, mi