engineering strategies and...
TRANSCRIPT
Engineering Strategies and Practice
University of Toronto
Faculty of Applied Science and Engineering
APS112 & APS113
Final Design Specification (FDS)
Project # 129 Date April 1st, 2016
Project Title Solar Recycled / Greywater Gardening Watering System
Client Name Socio-Economic and Environmental Development
Solutions
Client Contact Joanne Hutchinson
Tutorial Section 30
Teaching Assistant Daniel Jacobs
Project Manager Milan Graovac
Communication Instructor Judith Muster
Prepared By (Names and Student
#s of Team Members) Zhihao Zhang Patricia Marukot
Kanghoo Cho Antony Ndugi
Yuexiang Yu Pak Kin Long
Jennee Yuk-Toung Tjew
This Final Design Specification (the "Report") has been prepared by first-year engineering
students at the University of Toronto (the "Students") and does not present a Professional
Engineering design. A Professional Engineer has not reviewed the Report for technical
accuracy or adequacy. The recommendations of the Report, and any other oral or written
communications from the Students, may not be implemented in any way unless reviewed and
approved by a licensed Professional Engineer where such review and approval is required by
professional or legal standards; it being understood that it is the responsibility of the recipient
of the Report to assess whether such a requirement exists.
The Report may not be reproduced, in whole or in part, without this Disclaimer.
Engineering Strategies and Practice
Executive Summary
Socio-Economic and Environmental Development Solutions (SEEDS) required a solar powered
greywater recycling system to water the fields and trees for their SEEDS Resource Center and
Garden in Mongu, Zambia. Through team discussion of the alternative designs proposed and
creating a weighted decision matrix, the design chosen was the hose and ceramic filter design
based on the fulfillment of the FOC’s and the design scoring the highest on the matrix. The team
has extended the work done on the final design by including a detailed breakdown of the
design’s operation, and justification of how the design satisfies the client's needs and the
functions, objectives and constraints.
The main objectives of the design were distribution coverage, ease of operation, theoretical water
output, power efficiency and security, which were reflected in the design’s operation. The design
has six main stages of operation; collection of the greywater, storage of the greywater, filtration,
disinfection, transportation, and distribution. In the completion of these stages, the design is able
to filter the greywater in 1-3 hours/litre, and requires that the ceramic filter is cleaned once a
week.
The design was able to meet the client’s need of a system that is able to recycle greywater in a
way that would not affect the environment, take human factors into account and uphold the
safety standards that are required. By using activated carbon and the ceramic filter, it eliminates
bacteria, protozoa, and microbial cysts from the greywater. Afterwards, the water is sterilized
with Ultraviolet lights to remove smaller pathogens (namely, viruses). In this way, the use of
chemical solutions to treat the greywater before every watering is not required. The hatch has
also been designed in a way to be suitable for human needs, as it is 80” deep to allow for user
movement. The system was also designed for security and safety by including a locked door
above the hatch (storing the pump and storage tanks), preventing theft and children from falling
in.
Upon implementation of the design, tests must be made to examine the effectiveness of the
design, and detailed implementation requirements (including materials, installation and labour)
and economics must be referred to. The total cost of the design is estimated to be around $3000-
$4000, excluding labour costs.
Engineering Strategies and Practice
1
1.0 Project Requirements
Our client, Joanne Hutchinson, is the founder of Socio-Economic and Environmental
Development Solutions (SEEDS), a Canadian charity that sends seeds to Zambia. They are
concerned that overuse of the borehole near their SEEDS Resource Center and Gardens in
Mongu, Zambia for agricultural uses will leave the residents without access to clean water.
1.1 Problem Statement
This need is a result of the current state of Zambia’s broken” infrastructure [1]. Almost 45
percent of water produced by Zambian water utilities “is lost in distribution due to technical and
non-technical factors” and only 29 percent of Zambia’s rural population has access to safe water
[2]. Additionally, existing agricultural watering systems rely on electricity in order to operate
[3][4]. However, only 20 percent of Zambian population have access to electricity and growth is
slow with a growth rate of only 0.5 percent per year [5]. Ultimately, there is a lack of agricultural
watering systems that reduces water consumption in rural Zambia.
The client has asked that the design should recycle greywater - water from household showers,
and sinks [6]. Greywater treatment methods shall not involve significant chemical solutions and
any designs requiring electrical power shall be solar powered, as requested by the client. Finally,
the client has experienced theft in the SEEDS Resource Center and would like the design to
prevent its components from being stolen.
Engineering Strategies and Practice
2
1.2 Identification of Stakeholders
A major stakeholder is Zambia’s Ministry of Energy and Water Development. Others include
non-governmental organisations concerned with greywater recycling and control and the people
around Mongu District.
Table 1: Stakeholders, their interest, and their impact on the FOCs (F(#), O(#), and C(#) denotes
a function, objective, or constraint.)
Stakeholder Interest Impact on FOC’s
Zambia’s Ministry of Energy
and Water Development
- Minimize water and
environmental pollution [7].
- Shall prevent water
pollution to nearby water
streams from greywater.
F(1) C(3)
Zambia’s Ministry of
Agriculture and Livestock
- “Disseminating technical
and other information to the
farming community”[8]
- The design should be
simple to use O(2)
World Health Organization
(WHO), and health related Non-
Governmental Organizations
(e.g., USAid)
- Improve health status of
people in Zambia [9].
- Combat diseases [10].
- Shall prevent the
spread of waterborne
illnesses (malaria,
diarrhea, etc.) C(1)
- Shall implement
WHO’s Health Aspects
of Plumbing C(3)
Solar energy companies (e.g.
SunTech) and solar related
Non-Governmental
Organizations (e.g, SolarAid)
- To spread the use of solar
energy in Zambia
[11][12][13].
- Design will use excess
generated power to
power the home F(9)
Engineering Strategies and Practice
3
1.3 Functions
The SEEDS home currently does not separate greywater from toilet water. Therefore, the team
decomposed the need of ‘recycling greywater’ into four distinct functions that the design must
do: collect, store, clean, transport, and distribute (Details in Appendix A). Additional functions
are denoted in this section.
1.3.1 Functional Basis:
- To transfer mass.
1.3.2 Primary Functions:
1. To collect greywater (bathroom, sinks, and water runoffs).
2. To store greywater.
3. To treat greywater.
4. To transport greywater to surface level.
5. To distribute the greywater to the corn field and/or the tree nursery.
1.3.3 Secondary Functions
6. To separate solid waste from greywater.
7. To convert solar energy into electrical energy.
8. To flush untreated greywater into the septic tank (See Constraint 1).
1.3.4 Unintended Functions
9. To provide electrical power for the house.
10. To provide shade from the sun.
1.4 Objectives
The objectives of the design are traits that the design should have to meet client’s need. The
following objectives are ranked in order of importance. (Details in Appendix D)
1. Distribution coverage: maximize design garden coverage to at least 66 m2, the
approximate area of one garden in the SEEDS Resource Center and Gardens in Mongu
[16] (see Appendix L).
2. Ease of operation: minimize the number of steps to activate the design to three, the
average amount of unrelated items that can be stored in a human mind [14][15].
3. Theoretical water output: maximize theoretical water output to at least 26 L/day,
estimated minimum volume of water required for one garden per day (Details in
Appendix B, C)
4. Power efficiency: minimize electric power use to 200W, an approximation of the power
production of a 1m2 solar panel [17].
5. Security: minimize the number of components that can be seen above ground of the
design to zero, reducing the possibility of theft by limiting the part’s accessibility [18].
Engineering Strategies and Practice
4
1.5 Constraints
This section details the constraints of the design: mainly health regulations involving water and
specific client needs.
1. Untreated greywater shall not be stored for longer than 48 hours to prevent mosquito and
pathogen growth in greywater [19][20].
2. Greywater output shall meet the standards in the Third Schedule of Water Pollution
Control Regulation [7].
3. Designs that require electrical energy shall be powered by solar energy [17].
4. The design shall not rely on chemical treatment to clean greywater.
1.6 Service Environment
This section describes the service environment of Mongu, Zambia. This section is divided into
three subsections: the physical, living, and virtual environment.
1. Physical Environment
- Porous soil, causing low water retention [21][22].
- Dry season from May to September:
- <10 mm monthly rainfall [23][24].
- 180.48 hours of peak sunlight per month [25].
- Absolute min/max. temperature: 9.5˚C/34.3˚C[23]
- Average wind speed: 2.8 m/s - 3 m/s, blowing east 24% of the year and south-east
12% of the year [24].
2. Living Environment
- Mosquitoes carrying malaria parasites are endemic to the region [26].
- Typhoid bacteria and hepatitis A viruses are prevalent in Zambia [27][28].
- Winter squashes such as acorn squashes are grown in the dry season due to
optimal temperature [29].
3. Virtual Environment
- Minimal electrical power due to hydroelectric costs, along with droughts leading
to sporadic electricity supply [30][31][32].
1.7 Client Ethics and Values
The main considerations in terms of client ethics and beliefs for the design are environmental
impacts and health concerns. Our client has a lifelong concern for the environment. Therefore,
the design should have low environmental impact and not distribute pollutants into the soil. Also,
SEEDS’ purpose is to provide hope for the Zambian people [33]. Thus, in no circumstance must
the design harm an individual directly or indirectly.
Engineering Strategies and Practice
5
2.0 Detailed Design
The design uses a ceramic filtering system. Design delivers greywater from shower and sinks to
an underground tank where the ceramic filter is located. An underground pump then transports
the water to the hose [34]. The pump uses solar energy provided by the solar panels.
This section will explain the following:
● How the design works
● How the design meets the FOC’s and the client needs.
● DFXs of the design
2.0.1 Functionality of the Design
The design has six stages as detailed in Figure 1:
Figure 1: Side-view of Complete System with Dimensions
Engineering Strategies and Practice
6
Collection of the greywater
The system will collect greywater by rerouting the shower and kitchen pipes to a separate storage
tank through gravity. The design will use 25mm in diameter Standard Polyethylene pipes. The
polypropylene pipes are resistant to corrosion and can withstand temperatures of up to 95℃ [36].
Figure 2: Schematic of SEEDS Resource Centre and Re-routed Pipes
Engineering Strategies and Practice
7
Figure 3: Process of Collecting Greywater
Storage of greywater
Two tanks will be involved with a capacity to hold the amount of greywater produced [see
Appendix B].
One is a 30 gallon Polyethylene Cylindrical Tank [37] containing the ceramic filter. A hole will
be drilled at the bottom where filtered water will flow by gravity. The thick walls will prevent
possible leakages while the loose fitting cover will ensure easy installation and access of the
ceramic water filter.
The bottom tank is a 30 gallon Steel drum [38]. The tank will have an inlet, the hose outlet, and
an overflow at the top.
The pump and the tanks will be located at the underground hatch made of concrete with
dimensions 70 by 50 by 80 Inches. They will be accessible through the hatch door (Recess-
Mount Access Door) and locked using Laminated Steel Body Padlock.
Engineering Strategies and Practice
8
Figure 4: Dimensions of Easy-Drain Polyethylene Cylindrical Tank and Steel Drum
Engineering Strategies and Practice
9
Figure 5: Dimensions of Underground Hatch
Engineering Strategies and Practice
10
Filtration
In the storage tank, ceramic filtering is used due to its “ low one-time cost” and functions due to
the pores of ceramic material and gravity[39][40]. The team decided on the ceramic water filter
for its low cost and high availability. It is able to filter out bacteria and microorganisms. The
inside of this filter has activated carbon, which absorbs undesired molecular contaminants, such
as chlorine [41][42]. The ceramic layer should be cleaned once a week (rinse with cold water).
The process is shown in Figure 6 below.
Figure 6: Ceramic Filtering and UV Sterilization Processes
Engineering Strategies and Practice
11
Disinfection
After the greywater is filtered, an ultraviolet light water purifier [43] is installed just under the
ceramic filter to kill any microorganisms too small to be filtered out by the ceramic filter, such as
viruses. The team decided on using UV light because there are microorganisms that are too small
to be filtered by the ceramic filter and are chemical-resistant, such as hepatitis A[44]. Also, using
a chemical solution requires a person to add it into the greywater tank each time it is filled,
which allows the risk of forgetting to disinfect the greywater or adding too much/too little
solution. In contrast, the UV light would require no user input and would operate continuously.
The light would need to be replaced annually.
Transportation
In order to transport water from the clean water tank to the hose, a Pump for Water Removal
pump is used [45]. The clean water tank contains a pump which has a maximum flow of 17
gallons per minute at 10 Feet of Head. The single phase motor requires 720W to operate, and has
a working temperature range from 33-120 F, which is suitable for its service environment. The
hose will be connected via the garden hose adapter.
The pump will be connected to a battery [46] which is charged by the 320W CS6X-P-MaxPower
solar panel unit [47] (installed on the roof of the house). To power the pump, the DC current
from the battery must be converted to AC current. This is achieved by DC to AC Voltage
Transformer that changes up the voltage from 12V DC to 120V AC and produces a maximum
power output of 1250 Watts.[48][49].
The power needed to pump all the water out is calculated in Appendix G.
Distribution
At the last stage, the pump is connected to a 75ft long Heavy Rubber Garden Hose that will
cover the whole garden. The hose has a maximum working temperature of 160F and is weather
and chemical resistant [50]. One end of the hose is connected to the pump and the other is
connected to a nozzle. The Insulated Lever -Activated Hose Nozzle has a maximum flow of 6
gallons per minute and the water will be pumped out in approximately 5 minutes.
The user turns on the pump and opens the nozzle. The water coming out is at a high pressure and
the user can walk through the whole garden to water every plant. However, the user will be
required to water the garden within 5 minutes.
Engineering Strategies and Practice
12
2.0.2 How design meets the client needs and FOCs
Table 2 describes how design meets the functions:
Table 2: How the design meets the functions
Function How the design meets the functions
Collect greywater The greywater is rerouted from the shower house through piping.
Store greywater Two tanks, separating pre-filter and post-filter water.
Treat greywater A ceramic filter with activated carbon and UV sterilization.
Transport greywater A submersible pump to move water up and through the hose.
Distribute greywater A hose that allows the user to have full flexibility on what part of
the garden should be watered.
Table 3 details how the design meets the objectives:
Table 3: How the design meets the objectives
Objective How the design meets the objectives
Distribution coverage The 75ft long hose was chosen to cover the entire garden.
Ease of operation Three inputs: Unlock hatch, activate pump, squeeze nozzle.
Design minimizes inputs via use of passive filtration methods.
Theoretical water output Hose has maximum flow of 6 GPM
Energy efficiency Power usage:~734W (See appendix G)
Security Exposed components: One hatch (which guards the hose, pump,
and tank)
Engineering Strategies and Practice
13
Table 4 shows how design meets the constraints:
Table 4: How design meets the constraints
Constraint How the design meets the constraints
Untreated greywater
shall not be stored for
more than 48 hours
Greywater is treated before entering the clean water tank. Clean
water tank has drainage system: excess treated greywater flows out
of tank and out of concrete container through drainage.
Greywater standards The ceramic filter, bleach and activated carbon will remove almost
all microorganisms, dissolved chemicals, and odor.
Solar power Design powered by solar-powered battery.
No chemical-based
treatments
A ceramic filter and activated carbon will remove microorganisms
and dissolved chemicals through mechanical means. Afterwards,
an additional UV filter sterilizes the water.
2.0.3 DFXs of the design
Design for safety
Since the design involves the use of greywater, parts not easily replaceable in Zambia, and
electricity, the team has made the following in the design:
● The pump and the two tanks are inside the hatch which will be locked when not in use.
This will prevent theft, unauthorised access and injuries.
● The design uses Monolithic ceramic water filter. This filters bacteria and other
components that could lead to water borne diseases [41][42].
● The design uses Large Battery Rigid Solar Panel Charger, which has an in-built
mechanism to prevent overcharging.
Design for Environment
Our client has a particular interest on conservation of environment. The team developed a design
that takes this into account as follows:
● The ceramic filter and activated carbon gets rid of bacteria and other contaminants that
could harm the environment [41][42]
● The design recycles greywater into water usable for irrigation.
● The materials used have minimal impact on the environment (see section 2.4).
Engineering Strategies and Practice
14
2.1 Regulations, Standards, and Intellectual Property
The following regulations apply to the design:
1. Total bacteria count must be less than 1000 per 100 mL of water to be acceptable for
irrigation [51][52].
2. All materials used for piping must contain at most 0.2% of lead in the solder[53] and/or
have a lead water concentration of less than 10µg/L[54][55]. Although the concentration
of lead in water is with regards to drinking water, lead is bio accumulative [56], meaning
this regulation would be applicable to this design.
3. The installation of the pipes must conform to the OHSA with regards to trench digging
[57].
4. Ensure that the storage tank is clean and covered to prevent mosquitos from breeding and
spreading malaria and other diseases [58][59].
From the regulations, the following standards apply to test whether the design meets the
regulations. The standards are listed in the same order as their corresponding regulations:
1. ISO 9308-2:2012 will be used to determine the number of bacteria present [60], as the
method described in this standard will give an accurate approximation of the number of
bacteria present per specified volume of water.
2. ASTM D3559 - 15 (Method C) will be used to test the concentration of lead in the
water[61], since Method C can detect concentrations of lead from 1.0µg/L to 100µg/L,
while the regulation states that the concentration of lead in water should be less than
10µg/L. That means Method C can detect whether the concentration of lead in water
when operating the design exceed the regulated level.
3. To ensure safety when installing pipes underground, the standard is to have a competent
(someone qualified to organise the work from training or knowledge) [62] person to
assess the environment of the installation, as well as having to shore up the sides of the
trenches to prevent the soil from falling back into the trenches and injuring workers [63].
Engineering Strategies and Practice
15
2.2 Testing
The following tests are established to quantify the effectiveness of the design by conducting
standardized test on the top three objectives.
1. Distribution coverage:
● Uses test on ISO 8026:2009 section 6.3.2.1. to obtain the diameter of
coverage[Appendix H]. [64]
● Test shall be performed indoors with no wind [64].
● Sprayer shall be held at constant height.
● Coverage radius is obtained by adding the length of the hose and the radius of
coverage of the sprayer.
● The area calculated shall not be smaller than 66 m2.
2. Ease of operation:
● Test is developed based on ISO Standard ISO/TS 20282-2:2013[65].
● Test the success rate of each step user has to take to activate the system.
● A “step” is defined as where interaction between user and the system occurs [65].
● Use 5 test users to obtain an accurate result [66].
● Expected outcome to be 100% after training.
3. Theoretical water output:
● Use ISO 8224-2:1991 to find burst pressure [67].
● Water pressure is increased at a constant rate until the hose bursts or a 2500 kPa
water pressure is reached [67].
● Calculate the maximum flow rate the hose can endure without bursting [68].
● The design meets the objective if the theoretical water output of 26 L/day is
reached without bursting.
Engineering Strategies and Practice
16
2.3 Implementation Requirements
Purchases:
1. Greywater tank and clean water tank, both with a capacity of 30 gallons [69][38].
2. Adjustable-Flow Garden Hose Nozzle with Guard [70].
3. Heavy duty rubber garden hose 75 ft. long [50].
4. Water pump [45].
5. Battery [46].
6. Ceramic filter [42].
7. Solar panel (Canadian Solar CS6X-305M) [47][71].
8. 40m long Polypropylene plastic pipes [72].
9. A concrete container that is 80 inches tall, 70 inches wide, 50 inches long[73]
[see Appendix M for more details].
10. Laminated steel body padlock [74].
11. DC to AC converter [49].
12. Hatch door [75].
13. Ultraviolet water purifier [43]
Structure Changes:
1. A 80 inches tall, 70 inches wide, 50 inches long hole in between the corn field and the
shower house [see Appendix K].
2. Disconnect the sink pipe to the septic tank and reroute it to the greywater tank.
3. A 3.875 inches hole at the bottom right of the concrete container for draining purpose.
Installation:
1. Workers are required to add bleach inside of the greywater container after everything is
installed (except the ceramic filter) for the purpose of cleaning.
2. The hatch door needs to be installed into the top of the concrete container.
Labour Cost:
1. Cost for digging a 80″ tall, 70″ length and 50″ width hole.
2. Cost for contractors to pour concrete into the holes.
3. Cost for re-routing the pipes.
4. Cost for installing the hatch door.
Engineering Strategies and Practice
17
2.4 Life Cycle and Environmental Impact
Plastic production is a major contributor of burning fossil fuels, consuming “eight percent of the
world’s oil production.” [76] Additionally, concrete production “accounts for 8-10% of
greenhouse emissions” [77]. Since the greywater recycling design uses both plastics and
concrete, these materials were the focus of the life cycle diagram (Figure 8). (See Appendix K
for amount of concrete used).
Figure 7: Life cycle diagram for greywater recycling system. [78][79][80][81][82]
Engineering Strategies and Practice
18
Table 5. Positive Environmental Impacts
Positive Environmental Impact Cause of Impact
● Lower water consumption ● Reusing greywater
● Increase in plant life ● Reusing greywater
● Less use of public power supply ● Use of solar panel
● Absorption of atmospheric CO2 ● Carbonation of concrete [83]
Table 6. Negative Environmental Impacts
Negative Environmental Impact Cause of Impact Mitigation Strategy
● Decreased visual appeal of
the environment
● Concrete
container on the
SEEDS center
● Shed construction to
hide concrete
extrusion
● Toxic emissions [78][81] ● Plastic production
and disposal
● For future projects:
use of bioplastics [84]
Engineering Strategies and Practice
19
2.5 Human Factors
The team analysed the user experience of the proposed design and identified key human factors
addressed by the design such as the levels of human interaction with technology. Table 7 lists
these factors.
Table 7: Levels of Human Interaction with Proposed Design
Level of
Interaction
Relevant Concerns Effect on Design
Physical The user must enter hatch to clean
filter and activate the pump.
Average adult heights:
● Male (South Africa):
169 cm [85]
● Female (Zambia, age 25-49):
158.5 cm [86]
The underground hatch will be 80”
(~203 cm) deep to allow for
movement.
Children aged 2-6 years have average
heights ranging from 80cm - 120cm.
[87][88]
The hatch is covered by a door and
is locked to prevent access and to
prevent children from falling in.
Psychological Adult literacy rate in Zambia: 61.4%
[89].
Secondary school participation is low
for males (38.2%) and females
(35.6%) [89].
Operation of the design is intuitive
to use and does not require
complex inputs.
(i.e. to distribute water, user must
twist nozzle.)
Organizational Rural areas in Africa do not have
access to resources required for
advanced agricultural technologies
[90].
Use of easily obtainable materials
that can be installed in other
gardens.
(i.e. standard garden hose, ceramic
filter, solar panel, pump)
*Note: The team concluded that there is no social level of human interaction as the design is
simple enough to operate without further human collaboration.
Engineering Strategies and Practice
20
2.6 Social Impact
The implementation of the greywater gardening system will have social impacts on the Zambian
community and the affected stakeholders. Table 8 expands on these impacts.
Table 8: Design’s impact on major stakeholders
Stakeholders Social Impact
Zambia’s Ministry of Energy and
Water Development
Minimize water and environmental pollution:
● Use of polypropylene pipes minimizes
environmental impact [36].
● Ceramic filter and activated carbon minimize soil
pollution by removing contaminants from the
greywater [41][42].
Zambia’s Ministry of Agriculture
and Livestock
Promote implementation of new farming
techniques/methods in Zambia (i.e. greywater recycling)
World Health Organization
(WHO), health related Non-
Governmental Organizations
(e.g, USAid)
Improve health status of people in Zambia:
● Greywater is treated prior to use to prevent
spread of diseases.
● Allows for more flexibility with freshwater
consumption from local borehole (i.e. for hygiene
and drinking), while maintaining production of
vegetables.
Solar energy companies (e.g
SunTech), solar related Non-
Governmental Organizations
(e.g, SolarAid)
Encourages use of solar panels and other renewable
energy sources.
Engineering Strategies and Practice
21
2.7 Economics
This section details the design’s expenses.
Table 9: Capital (Initial) Costs
Cost Price ($ USD)
Greywater tank (Easy-Drain Polyethylene tank, 30 gallon) [37] 190.77
Filtered water tank (Steel drum, 30 gallon) [38] 90.52
Nozzle [70] 11.56
Hose (Weather resistant, 75ft) [50] 54.29
Pump [45] 104.42
Solar panel battery [46] 38.21
Ceramic filter [42] 34.50
Solar panel unit [47] 222.77
Polypropylene piping [72] 782.4
Concrete [73] 779.4
Lock [74] 2.71
DC to AC converter [46] 378.95
Hatch door [75] 116.20
UV disinfecting light [43] 363.00
Total (nearest $10) 3,170
Total after tax (a maximum of 16% if purchased in Zambia) [101] 3,680
Total after tax and customs duty (a maximum of 25%) [101] 3,960
Engineering Strategies and Practice
22
Table 10: Fixed Operating Costs: Known expenses over time
Cost Price
Ceramic filter replacement $ 34.50 (USD) / year
UV disinfecting light lamp replacement [102] $70 (USD) / year
Labour 5,220 kwacha / hour
Table 11: Variable Operating costs: Unknown expenses and time
Stuff Price ($ USD)
Piping repair/replacement 782.4
Pump repair/replacement 104.42
Table 12: External Costs
Stuff Price ($ USD)
Inconvenience to SEEDS volunteers during installation N/A
3.0 Project Management Plan
The last item that requires client action is the final presentation. This will be held in the Bahen
building, room 1210, on April 28th, 10:15AM.
4.0 Conclusion and Recommendation
The team further worked on the proposed design in the CDS to provide a more detailed layout of
the design. We believe that this is the best design that fulfills our client needs and therefore we
recommend it to our client.
Engineering Strategies and Practice
23
References List
[1] Samfya (March 26, 2009) “Zambia: Water everywhere, but not to drink”
http://www.irinnews.org/report/83664/zambia-water-everywhere-not-drink
[2] Engineering and Consulting Firms Association, Japan (n.d.). D Water Supply and Sanitation
Sector [Online]. Available: http://www.ecfa.or.jp/japanese/act-
pf_jka/H17/renkei/zambia/Zambia-Chapter%204-D.pdf
[3] James, L (1993). Farm Irrigation Systems and System Design Fundamentals [Online].
Available: http://css.wsu.edu/wp-content/uploads/2012/09/L_James_Ch21.pdf
[4] Bagdasarian, V. (March 2013). Complex irrigation applications require customized and
cutting-edge solutions [Online]. Available:
http://www.pumpsandsystems.com/topics/pumps/pump-systems-today-s-agricultural-irrigation
[5] Foster, V. & Dominguez, C. (March 2010). Zambia’s Infrastructure: A Continental
Perspective [Online]. Available:
http://siteresources.worldbank.org/INTAFRICA/Resources/Zambia-
Country_Report_03.2011.pdf
[6] Washington State Department of Health, Greywater Reuse :: Washington State Dept. of
Health, 2016. [Online]. Available:
http://www.doh.wa.gov/CommunityandEnvironment/WastewaterManagement/GreywaterReuse.
[Accessed: 27-Jan-2016]
[7] FAO Legal Office (2006) Water Pollution Control (Effluent and Waste Water) Regulations
(Cap. 204) [Online]. Available: http://faolex.fao.org/cgi-
bin/faolex.exe?database=faolex&search_type=link&table=result&lang=eng&format_name=@E
RALL&rec_id=038855
[8] Ministry of Agriculture and Livestock (n.d.). Department of Agriculture [Online]. Available:
http://www.agriculture.gov.zm/index.php?option=com_content&view=category&layout=blog&i
d=87&Itemid=1551
[9] United Nations Zambia (n.d.). World Health Organisation (WHO) [Online]. Available:
http://www.zm.one.un.org/node/115
[10] USAID (November 23, 2015). Global Health [Online]. Available:
https://www.usaid.gov/zambia/global-health
Engineering Strategies and Practice
24
[11] SunTech,’Appropriate Technology’ [Online].
Available:http://www.suntech-zambia.com/aboutus.php- [Accessed 24-01-2016]
[12] Clean Technica, ‘Zambia Plans To Add 1.2 GW Solar Power Capacity’ [Online]. Available:
http://cleantechnica.com/2015/08/13/zambia-plans-add-1-2-gw-solar-power-capacity/ [Accessed
23-01-2016]
[13] Zambia,’Renewables Readiness Assessment 2013’ [Online] Available:
http://www.irena.org/documentdownloads/publications/rra_zambia.pdf [Accessed 27-01-2016]
[14] Cowan, N. (2000). The magical number 4 in short-term memory: A reconsideration of
mental storage capacity [Online]. Available:
http://journals.cambridge.org/download.php?file=%2FBBS%2FBBS24_01%2FS0140525X0100
3922a.pdf&code=3d0459c02949d18ef111c69b82140018
[15] Jonides, J. et al. (2008). The Mind and Brain of Short-Term Memory [Online]. Available:
http://www-personal.umich.edu/~jjonides/pdf/2008_8.pdf
[16] J. Hutchinson, "President and Founder", 4 Browning Ave, Toronto, 2016.
[17] "How Much Electricity Can I Generate with Solar Panels?", Theecoexperts.co.uk, 2016.
[Online]. Available: http://www.theecoexperts.co.uk/how-much-electricity-can-i-generate-solar-
panels.
[18] Underwriters Laboratories Inc. (December 31, 2009). Antitheft Alarms and Devices
[Online]. Available: https://subscriptions-techstreet-
com.myaccess.library.utoronto.ca/products/10712
[19] American Mosquito Control Association (n.d.). Life Cycle [Online]. Available:
http://www.mosquito.org/life-cycle
[20] B. Imhof and J. Muhlemann (February 2005). Greywater Treatment on Household Level in
Developnig Countries - A State of the Art Review [Online]. Available:
https://www.uvm.edu/~ewb/Documents/Grey%20Water%20in%20Developing%20Countries.pdf
[21] Plant and Soil Sciences (n.d.). Soils - Part 2: Physical Properties of Soil and Soil Water
[Online]. Available:
http://passel.unl.edu/pages/informationmodule.php?idinformationmodule=1130447039&topicord
er=10&maxto=10&minto=1
Engineering Strategies and Practice
25
[22] USDA Natural Resources Conservation Service (June 2008). Soil Quality Indicators
[Online]. Available: http://web.extension.illinois.edu/bdo/downloads/24253.pdf
[23] Climate-Data (n.d.). Climate: Mongu [Online]. Available: http://en.climate-
data.org/location/47409/
[24] Weathespark (n.d.). Average Weather for Lusaka, Zambia [Online]. Available:
https://weatherspark.com/averages/29089/Lusaka-Zambia
[25] NASA (January 2008). NASA Surface Meteorology and Solar Energy (SSE) Release 6.0
Data Set (Jan 2008) [Online]. Available:
https://eosweb.larc.nasa.gov/sse/global/text/22yr_swv_dwn
[26] CDC (July 31, 2015). Health Information for Travelers to Zambia Traveler View [Online].
Available:
http://wwwnc.cdc.gov/travel/destinations/traveler/none/zambia
[27] MDTravelHealth (2014). Zambia [Online]. Available:
http://www.mdtravelhealth.com/destinations/africa/zambia.php
[28] Malaria Altas Project (2015). Malaria in Africa [Online]. Available:
http://www.map.ox.ac.uk/
[29] Alabama Cooperative Extension System (n.d.). Guide to Commercial Pumpkin and Winter
Squash Production [Online]. Available: http://www.aces.edu/pubs/docs/A/ANR-1041/ANR-
1041.pdf\
[30] New Zimbabwe (January 19, 2016). More power cuts feared as Kariba Dam levels down to
12 percent [Online]. Available:
http://www.newzimbabwe.com/news-27230-
Kariba+Dam+levels+down+to+12+percent/news.aspx
[31] Lusakatimes (December 2, 2015). Electricity tariffs increased with effect from midnight,
residential customers unaffected [Online]. Available:
https://www.lusakatimes.com/2015/12/02/electricity-tariffs-increased/
[32] Republic of Zambia (n.d.). Expression of interest to participate in scaling up renewable
energy Programme [Online]. Available:
https://www-cif.climateinvestmentfunds.org/sites/default/files/meeting-
documents/zambia_eoi_0.pdf
Engineering Strategies and Practice
26
[33] Socio-Economic And Environmental Development Solutions (SEEDS), "What We do",
2013. [Online]. Available: http://sendseedstoafrica.org/about-us/.
[34] ARDENA Classic Petrol-driven Motor Pump 9000/3, ‘Mobile and flexible – cable-free
pump operation‘ [Online] Available:
http://www.gardena.com/ca/en/water-management/irrigation-pump/classic-9000-3/
[35] PROGEF® Standard PP Piping System, 1st ed. George Fisher Piping Systems, 2013.
http://www.gfps.com/content/dam/gfps_country_MX/doc/pricelists/S2-
1_EPS_PROGEFStd_010113.pdf
[36] "PP-R Pipes", Narmadapipes.co.in. [Online]. Available: http://www.narmadapipes.co.in/pp-
r-pipes.htm. [Accessed: 31- Mar- 2016].
[37] "Easy-Drain Polyethylene Cylindrical Tank", Mcmaster.com. [Online]. Available:
http://www.mcmaster.com/#3687k103/=11q2wum. [Accessed: 31- Mar- 2016].
[38] "Steel Drum", Mcmaster.com. [Online]. Available:
http://www.mcmaster.com/#4115t45/=11q3z74 . [Accessed: 31- Mar- 2016].
[39] Centers for Disease Control and Prevention,‘The Safe Water System’ [Online] Available:
http://www.cdc.gov/safewater/ceramic-filtration.html
[40] Improving Household Drinking Water Quality, ‘Use of Ceramic Water Filters in Cambodia’
[Online] Available: http://www.unicef.org/eapro/WSP_UNICEF_FN_CWP_Final.pdf
[41] "Water Filter Specifications - Made in the USA", Monolithicmarketplace.com, 2016.
[Online]. Available: http://www.monolithicmarketplace.com/pages/water-filter-specifications-
for-filters-made-in-the-usa. [Accessed: 31- Mar- 2016].
[42] C. LEAD, "Ceramic Water Filter", Monolithicmarketplace.com, 2016. [Online]. Available:
http://www.monolithicmarketplace.com/products/just-water-ceramic-drip-filter. [Accessed: 31-
Mar- 2016].
[43] Atlantic Ultraviolet Corporation (n.d.). BIO-1.5: 1.5 GPM 120V 50/60Hz 316 SST 3/8" NPT
[Online]. Available: http://buyultraviolet.com/ProductDetails.aspx?item_no=25-
9125A1&CatId=f1df6f35-50dc-4143-add1-46dfcee15bab
[44] Wen Li, J. et al. (October 2002). Mechanisms of inactivation of Hepatitis A Virus in
Chlorine [Online]. Available: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC126388/
Engineering Strategies and Practice
27
[45] "Pump for Water Removal", Mcmaster.com. [Online]. Available:
http://www.mcmaster.com/#3023k41/=11pip7q. [Accessed: 31- Mar- 2016].
[46] McMaster-Carr (n.d.). Long-Life Recharge No Maintenance Large Cell Battery [Online].
Available: http://www.mcmaster.com/#2920k2/=11q4ge0
[47] CanadianSolar (n.d.). CSX-6 MAXPOWER [Online]. Available:
http://www.canadiansolar.com/solar-panels/cs6x-p.html
[48] "How is Electrical Energy Measured", Nmsea.org. [Online]. Available:
http://www.nmsea.org/Curriculum/Primer/How_is_electrical_energy_measured.htm. [Accessed:
31- Mar- 2016].
[49] "DC to AC Voltage Transformer", Mcmaster.com. [Online]. Available:
http://www.mcmaster.com/#6987k91/=11r2doe. [Accessed: 31- Mar- 2016].
[50] "Heavy Duty Rubber Garden Hose", Mcmaster.com. [Online]. Available:
http://www.mcmaster.com/#7453t19/=11q875w. [Accessed: 31- Mar- 2016].
[51] Ministry of Agriculture, Food and Rural Affairs (2016). Good Agricultural Practices
[Online]. Available: http://www.omafra.gov.on.ca/english/food/foodsafety/producers/gap-gf-wa-
quality.htm
[52] A. Havelaar, U. Blumenthal, M. Strauss, D. Kay and J. Bartram (2001). Guidelines: the
current position [Online]. Available:
http://www.who.int/water_sanitation_health/dwq/iwachap2.pdf
[53] Office of Water (December 2013). Summary of The Reduction of Lead in Drinking Water
Act And Frequently Asked Questions [Online]. Available:
http://nepis.epa.gov/Exe/ZyPDF.cgi/P100M5DB.PDF?Dockey=P100M5DB.PDF
[54] Government of Alberta (2013). Lead and Drinking Water from Lead Service Lines [Online].
Available: http://www.health.alberta.ca/documents/CMOH-Drinking-Water-Lead-Services-
2013.pdf
[55] Scientific Committee on Health and Environmental Risks (SCHER) (2011-01-11). Lead
Standard in Drinking Water [Online]. Available:
http://ec.europa.eu/health/scientific_committees/environmental_risks/docs/scher_o_128.pdf
Engineering Strategies and Practice
28
[56] Agency for Toxic Substances and Diseases Registry (ATSDR) (August 2008).
Toxicological Profile for Lead [Online]. Available:
http://www.atsdr.cdc.gov/toxprofiles/tp13.pdf
[57] Ministry of Labour (July 2015). Excavation Hazards [Online]. Available:
http://www.labour.gov.on.ca/english/hs/sawo/pubs/fs_trenches.php.
[58] Centre for Disease Control and Prevention (CDC) (n.d.). How Prevent the Spread of
Mosquito that Causes Dengue [Online]. Available:
http://www.unicef.org/pacificislands/preventMosquitoCauseofDengue.pdf
[59] World Health Organization (WHO) Chapter 5: Vector Surveillance and Control [Online].
http://www.who.int/csr/resources/publications/dengue/048-59.pdf
[60] International Organisation for Standardisation (2012). Water quality — Enumeration of
Escherichia coli and coliform bacteria — Part 2: Most probable number method [Online].
Available: https://www.iso.org/obp/ui/#iso:std:iso:9308:-2:ed-2:v1:en
[61] ATSM International (2015). Standard Test Methods for Lead in Water [Online]. Available:
http://compass.astm.org.myaccess.library.utoronto.ca/download/D3559.21586.pdf
[62]: Government of Ontario (2016). Occupational Health and Safety Act, R.S.O. 1990, c. O.1
[Online]. Available: https://www.ontario.ca/laws/statute/90o01/v19
[63] Occupational Safety and Health Administration (2015). Trenching and Excavation Safety
[Online]. Available: https://www.osha.gov/Publications/osha2226.pdf
[64] ISO (2009). Agricultural irrigation equipment — Sprayers — General requirements and test
methods [Online]. Available: https://www.iso.org/obp/ui/#iso:std:iso:8026:ed-3:v1:en
[65] ISO (2013). Usability of consumer products and products for public use -- Part 2:
Summative test method [Online]. Available:
http://www.iso.org/iso/home/store/catalogue_tc/catalogue_detail.htm?csnumber=62733
[66] Jakob Nielsen (June 4, 2012), Nielsen Norman Group. How Many Test Users in a Usability
Study? [Online]. Available: https://www.nngroup.com/articles/how-many-test-users/
[67] ISO (1991). Traveller irrigation machines - Part 2: Softwall hose and couplings - Test
methods [Online]. Available: https://www.iso.org/obp/ui/#iso:std:iso:8224:-2:ed-1:v1:en
[68] The Engineering Toolbox (n.d.). System Curve and Pump Performance Curve [Online].
Available: http://www.engineeringtoolbox.com/pump-system-curves-d_635.html
Engineering Strategies and Practice
29
[69] McMaster-Carr (n.d.). Easy-Drain Polyethylene Cylindrical Tank [Online]. Available:
http://www.mcmaster.com/#3687K111
[70] McMaster-Carr (n.d.). Adjustable-Flow Garden Hose Nozzle with Guard [Online].
Available: http://www.mcmaster.com/#7641t34/=11r2mjh
[71] Peek, S. (2014-03-26). Kyocera KD315GX-LPB Review [Online]. Available: http://solar-
panels-review.toptenreviews.com/kyocera-solar-panels-review.html
[72] McMaster-Carr (n.d.). 25mm Pipe, Polypropylene Pipe, 8' Length [Online]. Available:
http://www.mcmaster.com/#45435k92/=11rxn2d
[73] McMaster-Carr (n.d.). Concrete Mix, 40 lb. Bag [Online]. Available:
http://www.mcmaster.com/#76805t83/=11rsmfw
[74] McMaster-Carr (n.d.). Laminated Steel Body Padlock [Online]. Available:
http://www.mcmaster.com/#1189a41/=11rnjwj
[75] McMaster-Carr (n.d.). Recess-Mount Access Door [Online]. Available:
http://www.mcmaster.com/#8143a33/=11rni51
[76] J. Knoblauch (2009). The environmental toll of plastics [Online]. Available:
http://www.environmentalhealthnews.org/ehs/news/dangers-of-plastic
[77] A. Willis (1998). Concrete and not so concrete impacts [Online]. Available:
http://www.changedesign.org/Resources/EDFPublications/Articles/Papers/Concrete.pdf
[78] Franklin Associates (August 2011). CRADLE-TO-GATE LIFE CYCLE INVENTORY OF
NINE PLASTIC RESINS AND FOUR POLYURETHANE PRECURSORS [Online]. Available:
https://plastics.americanchemistry.com/LifeCycle-Inventory-of-9-Plastics-Resins-and-4-
Polyurethane-Precursors-APPS-Only
[79] J. Sjunnesson (2005). Life Cycle Assessment of Concrete [Online]. Available:
http://lup.lub.lu.se/luur/download?func=downloadFile&recordOId=4468239&fileOId=4469176
[80] G. Thomas (2012). Recycling of High-Density Polyethylene (HDPE or PEHD) [Online].
Available: http://www.azocleantech.com/article.aspx?ArticleID=255
[81] G. Thomas (2012). Recycling of Polypropylene (PP) [Online]. Available:
http://www.azocleantech.com/article.aspx?ArticleID=240
Engineering Strategies and Practice
30
[82] Concrete Network (n.d.). Recycling Concrete [Online]. Available:
http://www.concretenetwork.com/concrete/demolition/recycling_concrete.htm
[83] B. Lagerblad (2005). Carbon dioxide uptake during concrete life cycle [Online]. Available:
http://www.dti.dk/reports-on-co2-uptake-from-the-carbonation-of-concrete/state-of-the-
art/18487,2
[84] Bioplastic Magazines (2016-02-03). DYKA premieres world’s first plastic pipe system from
renewably-sourced plant-based material [Online]. Available:
http://www.bioplasticsmagazine.com/en/news/meldungen/2016-02-03-DYKA-lauches-
bioplastic-pipe-system.php
[85] AverageHeight.co (n.d.). Male Average Height By Country [Online]. Available:
http://www.averageheight.co/average-male-height-by-country
[86] S. Subramanian, E. Özaltin and J. Finlay (2011-04-02). Height of Nations: A Socioeconomic
Analysis of Cohort Differences and Patterns among Women in 54 Low- to Middle-Income
Countries [Online]. Available:
http://journals.plos.org/plosone/article?id=10.1371%2Fjournal.pone.0018962#s3
[87] CDC (2000-11-21). 2 to 20 years: Girls Stature Weight-for-age percentiles [Online].
Available: http://www.cdc.gov/growthcharts/data/set1clinical/cj41l022.pdf
[88] CDC (2000-11-21). 2 to 20 years: Boys Stature Weight-for-age percentiles [Online].
Available: http://www.cdc.gov/growthcharts/data/set1clinical/cj41l021.pdf
[89] UNICEF (2013). Statistics: Zambia [Online]. Available:
http://www.unicef.org/infobycountry/zambia_statistics.html#124
[90] Lado, C. (1998). The transfer of agricultural technology and the development of small-scale
farming in rural Africa: Case studies from Ghana, Sudan, Uganda, Zambia and South Africa
[Online]. Available: http://www.jstor.org/stable/41147236?seq=1#page_scan_tab_contents
[92] ChartsBin, "Total Water Use per capita by Country", 2011. [Online]. Available:
http://chartsbin.com/view/1455.
[93] Urban and Peri-Urban Water Supply and Sanitation Sector Report 2014, National Water
Supply and Sanitation Council, 2014, p. 41.
[94]Water Wise, "Water Wise - Frequently Asked Questions". [Online]. Available:
http://www.waterwise.co.za/site/water/faq/use.html.
Engineering Strategies and Practice
31
[95] Old Farmer's Almanac, "The 2016 Old Farmer's Almanac - Collector's Edition", 2016.
[Online]. Available: http://www.almanac.com/content/when-water-vegetables.
[96] Bonnie Plants, "Growing Cucumbers", 2013. [Online]. Available:
https://bonnieplants.com/growing/growing-cucumbers/.
[97] The Engineering Toolbox (n.d.). Densities of some Common Materials [Online]. Available:
http://www.engineeringtoolbox.com/density-materials-d_1652.html
[98] The Engineering Toolbox (n.d.). Concrete - Properties [Online]. Available:
http://www.engineeringtoolbox.com/concrete-properties-d_1223.html
[99] The Engineering Toolbox (n.d.). Euler’s Column Formula [Online]. Available:
http://www.engineeringtoolbox.com/euler-column-formula-d_1813.html
[100] Concrete Network (n.d.). Concrete Stairs [Online]. Available:
http://www.concretenetwork.com/stairsandsteps/stepdesignbasics.html
[101] "Tax Systems", Ministry of Finance and National Planning, 2016. [Online]. Available:
http://www.zambia.or.jp/docs/Tax%20System.pdf.
[102] Atlantic Ultraviolet Corporation (n.d.). GPH287T5L/4 4 Pin Replacement [Online].
Available: http://buyultraviolet.com/ProductDetails.aspx?item_no=05-1366-R&CatId=
Engineering Strategies and Practice
32
Appendix A: Functions Generation
The design team first used functional decomposition to find the primary functions of the design.
(See Figure 9) Afterwards, the design team used the Black Box method to discover secondary
and unintended functions (See Table 13).
Figure 8. Function decomposition chart.
Table 13. Black Box method chart.
Inputs Output
Mass
- greywater
- solid waste
Mass
- greywater to surface
- solid waste to septic tank
Energy
- solar energy
- mechanical
- human labour
DESIGN
Energy
- excess electrical energy
- kinetic energy
Information
- amount of water needed
per plant nursery per day
- when to water plant
Information
- plant growth and
germination of seeds
Engineering Strategies and Practice
33
Appendix B: Greywater Production Estimation
Table 14. Calculation of approximate greywater production. *Note, an assumption that the
SEEDS Mongu home’s water usage distribution is similar to a low income home in South Africa
was made based on South Africa’s water consumption being almost double of Zambian water
consumption per capita. [92]
Step Value
Avg. residential water consumed in Zambia (2014) 74 L/capita/day [93]
Number of people in residence [interview] 2 - 25 people
Avg water consumed by residence (taking lowest number of
people)
2*74 = 148 L/day
Water used in baths, showers, cooking, washing dishes, laundry * 27 % [94]
Approximate greywater produced by residence 148*.27 = 40 L/day
Engineering Strategies and Practice
34
Appendix C: Water Usage Estimation
Table 15 Calculation of approximate volume of water needed for a single unit garden in the
SEEDS Mongu home. Note the unit cell terminology; a unit cell is the area associated with the
recommended seed spacing multiplied by 5 feet because the recommended watering
measurement is in per 5 feet. [95]
Step Value
Area of 1 garden (20/3m)(10m) = 66.7 m2
Minimum area of cucumber unit cell (3ft) [96] (5ft) [95] = (1.524m)(.9144m) =
1.39m2
Number of unit cells (66.7m2) / (139.35m2) = 47.9 unit cells
Amount of water per week (47.9 unit cells)(3.7854L/unit cell/week) [95]
= 181.19 liters per week
Amount of water per day (181.19 L / week)/(7 days) = 25.9 liters per day
Engineering Strategies and Practice
35
Appendix D: Objective Ranking
The team used pairwise comparison to approximate the relative importance of each objective.
Objectives List:
1. Energy efficiency
2. Theoretical water output
3. Ease of operation
4. Distribution coverage
5. Security
Table 16. Pairwise comparison chart
1 2 3 4 5 Total
1 null 0 0 0 1 1
2 1 null 0 0 0 2
3 1 1 null 0 0 3
4 1 1 1 null 0 4
5 0 0 0 0 null 0
Objectives List in Order of Importance:
1. Distribution coverage
2. Ease of operation
3. Theoretical water output
4. Energy efficiency
5. Security
Engineering Strategies and Practice
36
Appendix E: Idea Generation:
This appendix shows the idea generation techniques used by the design team; namely, structured
brainstorming, SCAMPER, and the morph chart.
Figure 9. Idea Generation using the word “Filter/Clean”
Engineering Strategies and Practice
37
Figure 10. Idea Generation using the word “Distribute”
Engineering Strategies and Practice
38
Figure 11. Idea Generation using the word “Transport”
Engineering Strategies and Practice
39
Figure 12. Scamper Method using the irrigation system currently in place at SEED’s [67]
Engineering Strategies and Practice
40
Table 17. Morph chart used during the solution generation phase. Note that only feasible ideas
were transferred from the idea generation process to the morph chart. This chart represents the
alternative selection process.
Collect Store Treat Transport Distribute
rewire pipes tank boil pipes hose
containers flask sand filter vacuum mister
condense
vapour
leaf cup chlorination electric pump sprinkler
distill balloons activated carbon buckets capillary
action
kitchen strainer phase change buckets
bleach trenches phase change
ceramic hand pump rain
charred animal bones archimedes's wheel manual
pouring
Engineering Strategies and Practice
41
Appendix F: Objective Weighting and Rubric
Table 18. Weight Decision Matrix. Through team discussion, the following objective weights
were decided based on the objective rankings (See Appendix D).
Objective Rank (from pairwise comparison) Weighted Objective
Distribution coverage 1. 35%
Ease of operation 2. 30%
Theoretical water output 3. 15%
Energy efficiency 4. 10%
Security 5. 10%
Total 100%
The team also made a rubric to determine the rankings of the alternative designs out of 5:
Distribution coverage
For this objective, the minimum pass was defined to have a score of two, and the design would
cover the area of one garden with no choice. The Area of one garden is found in Appendix C.
5. No limitation on coverage
4. Is able to cover the area of all gardens in the Resource Center
3. Is able to cover the area of one field with freedom of choice.
2. Is able to cover only one field.
1. Cannot cover the area of one field
Ease of operation
Although the objective goal was three inputs or less, the team decided that this goal should be the
median to allow distinction between meeting and exceeding the goal. The rankings following this
increased by one input each time, with a failure being five inputs or more.
5. 1 input or less
4. 2 inputs
3. 3 inputs, the objective
2. 4 inputs
1. 5 inputs or more
Theoretical Water Output
Engineering Strategies and Practice
42
The rankings were created by taking the estimated amount of greywater produced, subtracting it
by the lowest amount and dividing it between the four remaining rankings (Rankings 2-5). The
lowest ranking indicate a failure in meeting the objective goal.
5. 40 L/day, the estimated amount of greywater produced by the home (Appendix B)
4. 35 L/day
3. 30 L/day
2. 25 L/day, the lowest estimated amount of greywater required for a garden (Appendix
C)
1. Water output lower than 25 L/day
Power efficiency
To gauge energy efficiency, score five was given to any system that does not require electrical
energy. Score subsequent scores represent the number of solar panels described in 1.3 of this
document required to power the design in terms of wattages.
5. No electrical power needed
4. 0W - 200W (the objective goal of 1 solar panel with m2 area)
3. 200W - 400W (two panels)
2. 400W - 600W (three panels)
1. 600W - 800W (four panels)
Security
Security was measured based on the number of exposed components. The minimum number of
exposed components is zero and is therefore the highest rank.
5. No exposed components
4. One exposed component
3. Two exposed components
2. Three exposed components
1. Four or more exposed components
Engineering Strategies and Practice
43
Appendix G: Power Required
This section calculates the power required to use the greywater recycling system. The pump
requires 6 amps from a 120V source. [45]
Power=Voltage * Current
= (120 V) * (6 amps)
= 720W
The UV light system draws 14W [43]. Hence, total power draw is 734W.
Engineering Strategies and Practice
44
Appendix H: Diameter of coverage test
“The collectors shall be placed on a level surface along 8 radii which are determined by lines
extending from the sprayer at 45° angles. In the radii, the collectors shall be spaced at 0.25 m for
sprayers with a diameter of coverage of up to 6 m, or 0,5 m for sprayers with a diameter of
coverage greater than 6 m. The end of each line shall extend beyond the surface sprayed.
The sprayer shall be placed at the centre of these radii (see Figure 14).
Figure 13: Setup of coverage test
Operate the sprayer for a minimum period of 1 h at the test pressure as measured at the inlet of
the sprayer.
Measure the quantity of water in the collectors along eight radii from the sprayer to the most
remote point at which the sprayer deposited water at one of the following minimum rates:
a) 0,26 mm/h for a sprayer with a flow rate that exceeds 75 l/h;
b) 0,13 mm/h for a sprayer with a flow rate equal to or less than 75 l/h.
Calculate the diameter of coverage as the average of the eight distances multiplied by two. ” [61]
Engineering Strategies and Practice
45
Appendix I: Thickness of the concrete walls
Dimensions of the container: 50″ width, 70″ length, 50″ depth
Density of sand (using maximum value): 1602 kg / m3 [97]
Pressure exerted by sand at 50″ depth:
Psand = 1602 kg / m3 × g × (50″)(2.54 cm/inch)(0.01 m/cm)
Psand = 19,959Pa
Finding the load intensity (Wsand) for 50″ width:
Wsand = (50″)(2.54 cm/inch)(0.01 m/cm) × Psand
Wsand = 25,347.7 N/m
Force exerted by sand:
Fnet (width) = 0.5 × Wsand × (50″)(2.54 cm/inch)(0.01 m/cm)
Fnet (width) = 16,096N
Calculating the required thickness of the wall to sustain the force exerted by the sand, with a
safety factor of 1.5:
Let L = depth of the hole, b = width of the hole, and d = thickness of the wall
σfs = (3 × 1.5 × Fnet (width) × L) ÷ (2 × b × d2)
Using the minimum value for flexural strength, which is 3 MPa [98]:
3MPa = 91,989 Nm ÷ (2.54m × d2)
2.54m × d2 = 0.031m3
d2 = 0.012m2
d = 0.110m
Hence, the thickness of the wall at 50″ width needs to be 0.110m (4.33 inches) to sustain the
force exerted by the sand with a safety factor of 1.5.
Engineering Strategies and Practice
46
Finding the load intensity (Wsand) for 70″ length (Psand is the same since the depth is still the
same):
Wsand = (70″ - 10″)(2.54 cm/inch)(0.01 m/cm) × Psand
Wsand = 30,417.5 N/m
Force exerted by sand:
Fnet (width) = 0.5 × Wsand × (50″)(2.54 cm/inch)(0.01 m/cm)
Fnet (width) = 19,315N
Calculating the required thickness of the wall to sustain the force exerted by the sand, with a
safety factor of 2:
Let L = depth of the hole, b = length of the hole, and d = thickness of the wall
σfs = (3 × 1.5 × Fnet (width) × L) ÷ (2 × b × d2)
3MPa = 110,385 Nm ÷ (3.56m × d2)
3.56m × d2 = 0.037m3
d2 = 0.010m2
d = 0.102m
Hence, the thickness of the wall at 70″ length needs to be 0.102m (4.02 inches) to sustain the
force exerted by the sand with a safety factor of 1.5. However, as the difference of the thickness
between the two types of walls is 0.08m, we decided to have all the walls be 0.110m thick, in
order to allow quicker installation of the design while still keeping a safety factor of 1.5 for all
walls.
Engineering Strategies and Practice
47
Appendix J: Specifications of the concrete cover (before hatch doors are installed)
As the concrete cover will be on top of the concrete walls, the force that would cause the walls to
buckle will be calculated:
Walls with 4.33″ width, 50″ length and 50″ depth:
Assume the origin of the bending moment axis is the centre of gravity of the concrete wall. Then,
the centre of gravity of the concrete wall using its cross section (5″ width and 50″ depth) is the
centre of the concrete wall. Then, the moment of inertia of the concrete wall is:
Ix = (1/12) × (4.33″)(2.54 cm/inch)(0.01 m/cm) × ((50″)(2.54 cm/inch)(0.01 m/cm))3
Ix = 0.0188m4
F = nπ2EIx ÷ L2, E = modulus of elasticity, F = maximum force before the wall buckles.
Modulus of elasticity of concrete (using minimum value): 14000MPa [98]
Assume that the bottom end of the concrete wall is fixed, and the top end is free. Hence, n = 0.25
[99]:
F = 0.25π2 × 14000MPa × 0.0188m4 ÷ ((50″)(2.54 cm/inch)(0.01 m/cm))2
F = 4.03 × 108N
Using a safety factor of 2, the maximum force that the concrete wall can sustain would be
2.01 × 108N.
As the walls with 70″ length have the same dimensions for both width and depth as the walls
with 50″ length, the maximum force will be the same.
Engineering Strategies and Practice
48
Since the container has dimensions of 50″ width and 70″ length, the concrete cover would also
have 50″ width and 70″ length in order to fully cover the container. As the density of concrete is
2400 kg/m3 [98], the maximum depth of the concrete cover would be:
F = mg
2.05 × 107 kg = m
m = volume × density
m = ((50″)(2.54 cm/inch)(0.01 m/cm) × (70″)(2.54 cm/inch)(0.01 m/cm) × depth) × 2400 kg/m3
8,537 m3 = ((50″)(2.54 cm/inch)(0.01 m/cm) × (70″)(2.54 cm/inch)(0.01 m/cm) × depth)
depth = 3,781m
As the maximum value obtained would render the design unfeasible, the depth of the concrete
cover would be at most 7″, the maximum height of a single concrete step [100].
Engineering Strategies and Practice
49
Appendix K: Total Volume and Price for the Concrete Container
In this section, the amount of concrete that will be used in this project is calculated. The team
calculated the overall volume and subtracted the empty space and the volume of the hatch door.
Total interior volume of the container:
50'' × 70'' × 50'' = 175,000in3
Empty space inside of the container
(50'' - 8.66'') × (70'' - 8.66'') × 50'' = 126,790in3
The total amount of concrete that the team needs for the container walls is:
175,000in3 - 126,790in3 = 48,210in3
Volume of concrete cover (with hatch door installed):
(50'' - 36.375'') × (70'' - 36.375'') × 7'' = 3,207in3
Total concrete needed: 51,417in3
Density of concrete [98] = 2400kg/m3 = 0.087 lb/inch3
Mass of concrete:
51,417in3 × 0.087 lb/inch3 = 4,473lb
Price of concrete per bag [71] = $6.97/40lb bag
Price of concrete:
4,473lb × (0.174 $/lb) = $779.4
Engineering Strategies and Practice
50
Appendix L: Map of SEEDS Resource Center, Zambia
Figure 14: Map of SEEDS Resource Center
Vegetable Garden 2
Corn Garden
Tree Nursery
Vegetable Garden 1
~
~
Sho
Septic
Resource Center
~
Concrete Container
Engineering Strategies and Practice
51
Appendix M: Size of the Concrete Container
Size of the Greywater tank:
Length: 21.75''
Width: 21.75''
Height: 33.25''
Size of the clean water tank:
Length: 19.25''
Width: 19.25''
Height: 29''
Total Height:
The team decided that the height of the container should be 80'' since the hole needs to be able to
fit a average height person. In addition 80'' is higher than the highest tank that is required in this
project.
Total Width:
Since two tanks are placed parallel to each other, the one with the longest width is being
considered. The team also added an extra 20% of margin of error and a 40'' working space for the
workers.
21.75'' + 21.75'' x 20% + 40'' ≅ 70''
Total length:
Sum of the length of two water tanks with a 20% margin of error.
(19.25'' + 21.75'') + 20%(19.25'' + 21.75'') = 50''