b) Calculate the concentration of sodium ions for the case that all calcium ions have been replaced by sodium ions during rock-water interactions (in mg/L, mmol/L and meq/L). 3) Water chemistry 3 (15 marks) A solid solution of Ca-MgCO3 contains 5% (by weight) of Mg. a) Calculate the mole fraction of MgCO3 in the solid solution (the mole fraction of a substance c in a solution is the quotient between molar concentration and total molar concentration). 4) Water chemistry 4 (15 marks) A water with a calcium concentration of (Ca 2+ ) = 80 mg/L is in contact with the mineral fluorite (CaF2). Calculate the solubility of fluorite at a temperature T=25°C. pKs of fluorite is 10.96 at 25°C. 5) Water chemistry 5 (40 marks) 5) The density of saline water has a density of 1.2 kg/L a 25°C. The saline water contains 100,000 mg/kg (ppm) of sodium. a) Express this sodium concentration in mg/L. b) Now the saline water is heated to 100°C. At this temperature, 1 kg of the saline water has a volumen of 0.84 L. Calculate the sodium concentration (in mg/L) at this temperature. 6) Degradation rate calculation (15 marks) At intervals of two days the concentration of nitrogenous waste in a bioreactor is 85, 73, 62, 54, 46 and 39 mg/L. What is the reaction rate constant (k d -1 ) ? 7) Streeter-Phelps calculation (70 marks) 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 25m 3 per day 250m 3 per day BOD5 at 20°C 200 mg/L BOD ultimate 5 mg/L DO 0.5 mg/L 9.35 mg/L Temperature 28°C 19°C Deoxygenation rate constant, kd 0.1 d -1 Reaeration rate constant, kr 0.2 d -1 River bed activity coefficient 0.15 Due to a major upgrade project, an industrial plant is seeking permission to discharge partially treated wastewater into a river over a limited period. Estimate the expected impact river using the Streeter- Phelps model. Answer the following: 1) What is the expected critical DO concentration? 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? 8) Packed Tower Design Calculation (35 marks) Determine the required height of a 3 m diameter packed tower required to remove 0.4 mg/L acetone in contaminated water. Assume water flow is 10 m 3 /s, Henry’s Law constant is 5.0 x 10 -4 atm.m 3 /mol, KLa is 10 x 10 -3 s -1 , air flowrate is 15 m 3 /s, liquid flowrate is 0.07 m 3 /s and temperature is 22°C. 9) Gaussian Dispersion Problem (90 marks) Air pollution from factories located in China is now causing a serious health concern for Chinese residents. As atmospheric stability increases, so pollution plume concentrations at ground level can increase. ...

1. b) Calculate the concentration of sodium ions for the case that
all calcium ions have been
replaced by sodium ions during rock-water interactions (in
mg/L, mmol/L and meq/L).
3) Water chemistry 3 (15 marks)
A solid solution of Ca-MgCO3 contains 5% (by weight) of Mg.
a) Calculate the mole fraction of MgCO3 in the solid solution
(the mole fraction of a
substance c in a solution is the quotient between molar
concentration and total molar
concentration).
4) Water chemistry 4 (15 marks)
A water with a calcium concentration of (Ca
2+

2. ) = 80 mg/L is in contact with the mineral
fluorite (CaF2). Calculate the solubility of fluorite at a
temperature T=25°C. pKs of fluorite is
10.96 at 25°C.
5) Water chemistry 5 (40 marks)
5) The density of saline water has a density of 1.2 kg/L a 25°C.
The saline water contains
100,000 mg/kg (ppm) of sodium.
a) Express this sodium concentration in mg/L.
b) Now the saline water is heated to 100°C. At this temperature,
1 kg of the saline water has a
volumen of 0.84 L. Calculate the sodium concentration (in
mg/L) at this temperature.
6) Degradation rate calculation (15 marks)
At intervals of two days the concentration of nitrogenous waste
in a bioreactor is 85, 73, 62,

3. 54, 46 and 39 mg/L. What is the reaction rate constant (k d
-1
) ?
7) Streeter-Phelps calculation (70 marks)
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 25m
3
per day 250m
3
per day
BOD5 at 20°C 200 mg/L
BOD ultimate 5 mg/L
DO 0.5 mg/L 9.35 mg/L
Temperature 28°C 19°C
Deoxygenation rate constant,

4. kd
0.1 d
-1
Reaeration rate constant, kr 0.2 d
-1
River bed activity coefficient 0.15
Due to a major upgrade project, an industrial plant is seeking
permission to discharge partially treated
wastewater into a river over a limited period. Estimate the
expected impact river using the Streeter-
Phelps model. Answer the following:
1) What is the expected critical DO concentration?
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?
8) Packed Tower Design Calculation (35 marks)

5. Determine the required height of a 3 m diameter packed tower
required to remove 0.4 mg/L
acetone in contaminated water. Assume water flow is 10 m
3
/s, Henry’s Law constant is 5.0 x
10
-4
atm.m
3
/mol, KLa is 10 x 10
-3
s
-1
, air flowrate is 15 m
3
/s, liquid flowrate is 0.07 m
3
/s and
temperature is 22°C.
9) Gaussian Dispersion Problem (90 marks)
Air pollution from factories located in China is now causing a
serious health concern for

6. Chinese residents. As atmospheric stability increases, so
pollution plume concentrations at
ground level can increase. As the number of factories continues
to increase, air pollution
levels also increase. As an environmental consultant you are
required to do some modelling
of this problem using Excel spreadsheet and the Gaussian
Dispersion method. You are
expected to summarise your findings in a short 1000 word
report for the Asian Health
Organisation. In your report:
i. Carry out some research on typical air pollution levels
experienced by people living in
in China, and use this as a basis for writing an introduction
explaining the background
to your report
ii. Do some research to find out what the typical air pollutants
are, from a particular
industry of your choice. Do some research on health effects of
the pollutant and its
human TWA No Effect Level (NOEL) via inhalation.
iii. Develop a spreadsheet model/program to predict a typical

7. ground level centreline
concentration of odour (in µg/m
3
) from a single factory with a release stack 20 m
high. Get your model to produce graphs of average centre-line
ground level
concentration, versus distance in kilometres downwind of the
factory. Assume a
windspeed of 2 m/s and E class stability
iv. Do some modelling to explain the effect of adding additional
identical factories,
placed at 1km centres on a grid, upwind, and to either sides of
the mean wind
direction, from the initial factory which you considered in part
iii.
v. In your report, clearly show your assumptions, calculation
method and your main
findings. Rely on your report to do this, as your spreadsheet
will only be looked at
briefly.
vi. Carry out some additional research on the Gaussian method
and other modelling

8. approaches, and include in the conclusion to your report the
strengths and weaknesses
of using the Gaussian approach to solving this kind of problem.
Figure 1 Conceptual diagram to assist with part iv) – hint –
you can use the line source variant of the Gaussian dispersion
equation
en1ENVIRO-9TASKS
DSS_AssnAbdulaziz AlrashidSpring 2014IS 312 - Spring
2014REPRESENTATIONDATABASEIncome StatementBase
YearChangeResultsIncomeGross Sales$2,500,000Gross
Sales$2,500,000$0$2,500,000Return Fraction4%Returns and
Allowances$100,000$0$100,000Labor Cost Fraction14%Net
Sales$2,400,000$0$2,400,000Materials Cost Fraction23%Fixed
Overhead$70,000ExpendituresOverhead
Fraction28%Labor$350,000$0$350,000MMandG
Fraction18%Materials$575,000$0$575,000Federal Tax
Fraction27%Fixed Overhead$70,000$0$70,000State Tax
Fraction8%Variable Overhead$259,000$0$259,000Cost of
Goods$1,254,000$0$1,254,000MODELProfit and TaxesReturns
and Allowances$100,000Gross
Profit$1,146,000$0$1,146,000Cost of Goods$1,254,000(Total)
Overhead$329,000M, M and G$432,000$0$432,000Variable
Overhead$259,000MMandG$432,000Profit Before
Tax$714,000$0$714,000Federal Tax$192,780State
Tax$57,120Federal Tax$192,780$0$192,780Labor

9. Cost$350,000State tax$57,120$0$57,120Materials
Cost$575,000Profit After Tax$464,100$0$464,100Net
Income$464,100$0$464,100Net Sales$2,400,000Gross
Profit$1,146,000Profit Before Tax$714,000Profit After
Tax$464,100
&A
Page &P
Department of Accounting & Information Systems
College of Business & Economics
IS 312, Information Systems for Business
Building a DSS in Excel, Part II
Page 1 of 3
This document created and maintained by David W. Miller.
PhD. ©2005-2014
This page provided for exclusive use by students in IS 312 at
California State University, Northridge
Read all instructions carefully!
The following assignment is a continuation of the initial DSS
Tool Building assignment. It is intended to
be a brief introduction to how Microsoft Excel may be used as a
Decision Support System for future
projections sensitivity analysis ("what if…?" analysis). You
will expand your DSS model to include five
year projections. You are to follow the instructions and
complete and submit the assignment as

10. individuals.
You are to use the DSS tool (database and model) that you
created in the first DSS assignment. Keep all
of the base year (2013) assumptions (i.e. gross sales of $2.5
million, etc.) and their relationships (the
model base).
Your assignment is to do the following:
Though you will be re-creating the Database and Model from
the first DSS assignment, you are to use the
DSS_II.xls spreadsheet file that I am providing to you. While
this requires extra effort to re-create the
Database and Model, the formatting that is contained in the
provided spreadsheet will make the Part II
DSS tool much easier to build in the long run. At this time, you
should also correct any errors identified
in the Database or Model of the first DSS project—repeating
those errors will likely result in points being
lost in the scoring of this, the DSS II, project. The instructions
for the first DSS project are still posted on
the class Web site.
Add projection formulas for each of the Database values. All
projections will be in the form of fixed
percentages of compound growth (or decline) for the projection
period. Note that values entered in
column C, Annual Change %, are used in the projection
formulas to compound that percent rate over the
projection period (i.e., over 5 years, compounded annually).
Therefore, each year’s value will be the
previous year’s value plus the percentage of the previous year’s
value. Note that a negative percent value
entered into the Annual Change % column will result in a
decrease (reduction) in the projections.

11. All of the values in the Model are calculated from the values in
the Database. Therefore, projection
formulas are not needed for any of the projection model (2014 –
2018) columns. Instead, simply copy
and paste the formulas from the 2013 Base Year column to each
of the projection model (2014 – 2018)
columns (columns D, E, F, G, and H, respectively).
The final element to complete is the row showing the effect or
magnitude of the annually compounded
changes on the Profit After Tax for each projected year.
Formulas need to be entered into cells D35
through H35 that will calculate the change in the Profit After
Tax relative to the 2013 Base Year value.
When completed (with no values entered into the Annual
Change % column but the 2013 Base Year
values set) your spreadsheet should resemble the example in
Figure 1. The balance of the spreadsheet
should change whenever a projection variable changes (i.e.
without any other intervention on your part).
Run each of the scenarios listed below to determine the
organization's sensitivity to certain growth
factors. All growth (and decline) factors are assumed to be
compound annual percentages, unless stated
otherwise in the scenario. Each scenario assumes all items not
mentioned in the scenario are the base
http://www.csun.edu/~dwm3265/IS312/DSS_II.xls
http://www.csun.edu/~dwm3265/IS312/IS312_DSS_assn.pdf
IS 312: Building a DSS In Excel, Part II Course Project –
Spring 2014

12. Page 2 of 3
year values. Be sure to return to the base assumptions before
attempting each question. Your
spreadsheet, if built correctly, will return the correct answers to
the below questions.
Figure 1. Completed DSS II Tool with No Annual Change
(NOTE: Where I ask for descriptive answers, give short and to-
the-point answers, not longer than one
sentence.)
1. Assuming no other changes, with a compound annual growth
in gross sales of five percent, what will
be the profit after tax in:
a. year 1 (2014)?
b. year 2 (2015)?
c. year 3 (2016)?
d. year 4 (2017)?
e. year 5 (2018)?
2. Returning to base assumptions, you are considering new plant
and equipment that will reduce variable
overhead 10 percent a year but increase fixed overhead 15
percent a year.
a. What will be the effect of this investment on net income five
years from now (year five – 2018 -
profit after tax)?
b. Should you do the project?
c. Why should you do or not do the project?

13. IS 312: Building a DSS In Excel, Part II Course Project –
Spring 2014
Page 3 of 3
3. Management is currently in collective bargaining
negotiations considering possible annual percentile
wage increases. You are asked to report what the effect of
certain increases will be on net income
five years from now (year 2018) for each of the following
annual compound percentage increases:
(note: I am asking for the effect which means 'how much will
net income go up or down five years
from now compared to base year assumptions,' not 'what will
the net income be five years from now').
a. 5 percent
b. 10 percent
c. 15 percent
4. You have discovered there to be a two to one relationship
between increases in gross sales and
MM&G expenses (for every one percent increase in sales, there
is a two percent increase in MM&G).
If this were true, what would the net income be five years from
now (year 2018) if there were an
annual percentage increase in gross sales of:
a. 2 percent?
b. 5 percent?
c. Is it worthwhile to try to increase sales?
d. Why?

14. 5. You have a scheme to reduce returns and allowances by 6
percent per year; but, implementing the
scheme means that MM&G will increase by one percent per
year.
a. What will be the change (effect) in net income in year five if
you implement the scheme?
b. Is it a good scheme?
c. Why?
You are to turn in the following:
Answer sheet:
• A one-page, word-processed, document on which you have
answered each of the above questions.
• The sheet will have your name (in First then Last format)
along with the class and section in the
upper-right corner and the answers will be double-spaced.
• The hardcopy printout of the answer sheet is to be handed in,
in class, at the beginning of class on
Monday, May 5.
DSS spreadsheet file:
• Rename the file using your last name followed by your first
name as the filename.
o For instance, the filename I would create would be
MillerDavid.xls (note that there is no space,
comma, etc. in the file name).
o Note too, that if you do not have the folder option turned on
to display the file extensions of
known file types (that is the default setting so it is likely that

15. this option is not on for your
computer) then the .xls file extension will not be displayed. Do
not add the .xls if you do not see
it when you look at the file name in Windows Explorer.
• Your completed DSS tool (the completed spreadsheet) with
base assumptions (i.e., no values in the
Annual Change % column) is to be submitted as an attachment
to an e-mail message.
o Be sure to enter the following as the subject with the proper
course number for your class:
11:00am class
12:30pm class
• The file is to be emailed by classtime Monday, May 5.