i

Sustainable Water Demonstration

Final Report

Bryan Dripps

Heather Reinhart

Michael Henderson

2010/11

Project Sponsor: First Alternative Coop and the Corvallis Sustainability Coalition

IE 497/498

Project Number: 11

Course Instructor: Kenneth Funk

Faculty Advisor: Nancy Squires

Sponsor Mentor: David Eckert

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DISCLAIMER

This report was prepared by students as part of a college course requirement. While considerable effort has

been put into the project, it is not the work of a licensed engineer and has not undergone the extensive

verification that is common in the profession. The information, data, conclusions, and content of this report

should not be relied on or utilized without thorough, independent testing and verification. University faculty

members may have been associated with this project as advisors, sponsors, or course instructors, but as such

they are not responsible for the accuracy of results or conclusions.

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EXECUTIVE SUMMARY

The primary focus of this project was to research, design and implement a fully functional, interactive, and

entertaining public display system which collects, stores, and distributes rainwater to a vertical garden in order

to demonstrate to the community the practicality of sustainable water practices. The display drives to educate

on the feasibility of rainwater use and demonstrate the work required to move water.

The project includes a collection system of PVC piping, leaf screen filters, first flush diverters, mosquito

screens, and water safe tanks. The piping moves the water from the roof through the filters and into storage

tanks. Leaf screen filters remove large debris from the water before first flush filters remove polluted water

from a new rain, and mosquito screens keep mosquitoes from infesting the water stored in the tanks.

The pumping system includes a peristaltic, or roller pump, attached to a bicycle powered by the user. The rear

wheel of the bicycle was removed and replaced with a stand and hybrid chain-and-v-belt drive system to power

the roller pump and support the user. Standardized hose fittings attached to the pump allow garden hoses to be

connected to the pump and tanks, which permit a range of applications and portability of the pump to any

demonstration site.

The pump is capable of moving water to any height that this demonstration requires, delivering large volumes

of water even at roof height. It has been tested for reliability, and functions well due to its simplicity. The

pump fits well within the site and is fairly lightweight, allowing for easy storage and transport. It is simple to

use and requires little effort, which permits a large demographic to use the system.

Multiple design changes were required to refine the human-powered pump system, but the end result is a clean,

elegant, and efficient device, capable of pumping water with little effort and no electricity.

The result of this project is a completely functional rainwater collection and irrigation system. The tanks are

filling with clean, non-potable water during every rain event, and the bicycle powered pump is ready and

capable of moving water for irrigation and display purposes.

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TABLE OF CONTENTS

1. PROJECT DESCRIPTION ............................................................................................................................. 1

1.1. Background ............................................................................................................................................. 1 1.2. Requirements .......................................................................................................................................... 1

1.2.1. Project Description.......................................................................................................................... 1 1.2.2. Customer Requirements (CRs) ....................................................................................................... 2

1.2.3. Engineering Requirements (ERs) ................................................................................................... 3 1.2.4. Testing Procedures (TPs) ................................................................................................................ 4 1.2.5. Design Links (DLs)......................................................................................................................... 6 1.2.6. House of Quality (HoQ).................................................................................................................. 8

2. EXISTING DESIGNS, DEVICES, AND METHODS .................................................................................. 9

2.1. System Level ........................................................................................................................................... 9 2.1.1. Kelly Engineering Center ............................................................................................................... 9 2.1.2. Montana Residents Home System ................................................................................................. 9 2.1.3. Portland Residential Rainwater Irrigation ...................................................................................... 9

2.2. Component Level .................................................................................................................................. 10 2.2.1. First Flush Management ............................................................................................................... 10 2.2.1.1. Floating Ball.................................................................................................................................. 10

2.2.1.2. Tipping-Gutter System.................................................................................................................. 10 2.2.1.3. Vertical Gravity Filter ................................................................................................................... 10

2.2.2. Filtration ........................................................................................................................................ 11 2.2.2.1. Sand Filter ..................................................................................................................................... 11 2.2.2.2. Screen Filter .................................................................................................................................. 11

2.2.2.3. Carbon Filter ................................................................................................................................. 11 2.2.3. Water Delivery .............................................................................................................................. 12

2.2.3.1. PVC Piping ................................................................................................................................... 12

2.2.3.2. Gutters ........................................................................................................................................... 12

2.2.3.3. Metal Piping .................................................................................................................................. 12 2.2.4. Human Power Interface ................................................................................................................ 12

2.2.4.1. Foot Pedals .................................................................................................................................... 12 2.2.4.2. Merry-Go-Round .......................................................................................................................... 13 2.2.4.3. See-Saw......................................................................................................................................... 13

2.2.5. Pumping Mechanism .................................................................................................................... 13 2.2.5.1. Centrifugal Pump .......................................................................................................................... 14 2.2.5.2. Reciprocating Pump ...................................................................................................................... 14

2.2.5.3. Archimedes Screw ........................................................................................................................ 14 2.2.6. Delivery to Vertical Garden .......................................................................................................... 14 2.2.6.1. Drip Irrigation System .................................................................................................................. 15 2.2.6.2. Misting Irrigation System ............................................................................................................. 15

2.2.6.3. Flooding ........................................................................................................................................ 15 3. DESIGNS CONSIDERED ........................................................................................................................... 16

3.1. Design #1 .............................................................................................................................................. 16

3.2. Design #2 .............................................................................................................................................. 18 3.3. Design #3 .............................................................................................................................................. 19

4. DESIGN SELECTED ................................................................................................................................... 21 4.1. Rationale for Design Selection ............................................................................................................. 21 4.2. Design Description................................................................................................................................ 21

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4.2.1. Collection System ......................................................................................................................... 21

4.2.2. Pump ............................................................................................................................................. 22

4.2.3. Human Interface and Power Generation ....................................................................................... 23

4.2.4. Living Wall Irrigation ................................................................................................................... 24 5. IMPLEMENTATION ................................................................................................................................... 25

5.1. Implementation Plan ............................................................................................................................. 25 5.2. Implementation Overview .................................................................................................................... 26

5.2.1. Centrifugal Pump .......................................................................................................................... 26

5.2.2. Human Interface and Drive System .............................................................................................. 27 5.2.3. Piping Network ............................................................................................................................. 27 5.2.4. Living Wall Irrigation ................................................................................................................... 28 5.2.5. Bike Stand ..................................................................................................................................... 28

6. TESTING ...................................................................................................................................................... 29

6.1. Overflow ............................................................................................................................................... 29 6.2. First Flush Diverters ............................................................................................................................. 29

6.3. Pumping Head ....................................................................................................................................... 29 6.4. Aesthetics .............................................................................................................................................. 30 6.5. Usability ................................................................................................................................................ 30 6.6. Maintenance .......................................................................................................................................... 30

6.7. Weight ................................................................................................................................................... 31 6.8. Draining ................................................................................................................................................ 31

6.9. Sizing .................................................................................................................................................... 31 6.10. Entertaining ........................................................................................................................................... 31 6.11. Delivery................................................................................................................................................. 32

7. BIBLIOGRAPHY ......................................................................................................................................... 33 8. APPENDIX A: ENGINEERING CALCULATIONS .................................................................................. 34

9. APPENDIX B: BILL OF MATERIALS ...................................................................................................... 40

10. APPENDIX C: PART DRAWINGS ........................................................................................................ 42

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ACKNOWLEDGEMENTS

David Eckert

Hazen Parsons

Dr. Nancy Squires

Dr. Kenneth Funk

Dr. John Parmigiani

First Alternative Coop

Robert Culbertson

Joe Richard and JTI Supply, Inc.

Gary Borntrager

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1. PROJECT DESCRIPTION

1.1. Background

This project aimed to build the beginning of a sustainable water demonstration at the First Alternative Coop.

Rainwater was collected, filtered, and delivered to existing storage tanks. A human powered pump was

built to pump rainwater up to a vertical garden. The demonstration aimed to illustrate the usefulness of

rainwater collection and also demonstrate how much work is required to transport it.

Rainwater collection is of increasing importance around the world. After the implementation of this project,

the sponsor possesses a system for collecting clean rainwater to use for a public demonstration and also for

watering plants. The sponsor has also gained a human powered pump that can be used for a variety of

purposes in the demonstration. The demonstration will not only inform people, but will also attract

customers to the First Alternative Coop, possibly increasing sales.

1.2. Requirements

1.2.1. Project Description

The original project description is as follows.

Students will coordinate with the Corvallis Sustainability Coalition and the First

Alternative Natural Foods Co-op to design and install a series of water delivery

systems to collect rainwater and transport it on-site for approved uses and to collect

gray water (once used, relatively non-polluted water) and transport it on-site for

approved uses. The purpose of the project is to reduce municipal tap water use on-

site and to reduce the discharge of wastewater and storm water into the municipal

piping systems. The City of Corvallis and First Alternative Natural Foods Co-op

have allocated some funding. The student will gain hands-on experience with fluid

transport/storage and management on a government/business/non-profit project.

The students will use existing surveys and develop any necessary additional surveys

to design plans for delivering storm water from two buildings to a variety of storage

tanks and for delivering that stored storm water for later use on the site. Some of the

delivery systems will include electrical or human-powered pumps. One area has

been set-aside as a public storm water demo area. This area will include many

techniques for storm water mitigation, interpretive displays and interactive

components. Human powered pumps, such as hand pumps, treadle pumps and bike

pumps, will be incorporated on this area. A concept design has been approved and

the basic landscaping and tank installation has begun.

The project has been modified significantly and the scope more explicitly defined. Students were to

work with the First Alternative Coop and the Corvallis Sustainability Coalition to develop a system for

delivering and filtering rainwater to storage tanks. A human powered pump was to be designed and

implemented in the watering of a vertical garden, as part of a sustainable water demonstration. As this is

part of a demonstration, the systems needed to be engaging and accessible to a wide range of users. The

area for the demonstration is limited, so students needed to consider spatial limitations. A budget of

$1500 had been supplied. Further funds were available if justified.

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1.2.2. Customer Requirements (CRs)

1. System shall allow for draining of excess water to municipal storm water.

The system as a whole can only handle so much water. Any water overflowing the system must be

rerouted to conventional municipal storm water system. If not properly managed, overflow can

accumulate in unwanted places and cause flooding.

2. System shall remove debris from first flush.

First flush refers to the first rain after a dry period. This first rain carries a significant portion of

sediment, organic matter, oil, debris, and bacteria; the system must be able to remove first flush

contaminants prior to the main filter.

3. System shall allow for pumping of water from tank to an adequate height and pressure.

The pumps performance will be based upon the subsequent engineering requirements derived from this requirement. It will be based on the height of the living wall, and the required pressure for the delivery

system.

4. Pumping mechanism should be aesthetically pleasing.

The pump is to be used in a public demonstration, so the end product should be attractive and not look

jumbled.

5. Shall be easy to use and accessible to a range of users.

This project is an interactive display, so it must accommodate a wide spectrum of customers.

6. Pump shall be low maintenance.

The pump should be durable and not require undue maintenance scheduling. This pump will be unique,

so less maintenance requirements are ideal.

7. Pump shall be human powered.

The basis of this project is the incorporation of human power to see how much work is actually required

to move water, so this is absolutely necessary.

8. Pump should be movable.

If the project area is being modified, or the pump is moved to another display site, it should be portable.

9. Pump should be able to be drained.

If the region freezes, the pump must be able to be drained in order to reduce chance of freeze-based

damage to the pump.

10. Pump connections should use standard hose fittings.

If the pump is delegated to a new task or hoses are damaged, standardization of components is cheaper,

easier to maintain, and easier to fix

11. Pump should be compact.

Space is limited, thus the pump should take up minimal space.

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12. Pump should be entertaining.

An entertaining pump will boost use among the potential customer base, and thus awareness of

sustainable water techniques.

13. Pump shall contain a steel tab to lock it to the building.

Theft is always a valid concern, especially in outdoor public areas.

14. Each tank shall contain a backflow prevention valve.

This is for sanitation reasons. Any water that has left the tanks should not re-enter without being

filtered first.

15. System shall deliver adequate water to plants.

The primary purpose of the pump is to water a living wall. The plants must receive adequate water or

the pumping and watering systems are useless.

1.2.3. Engineering Requirements (ERs)

1. Overflow piping should be able to export water at a rate of 6 GPM.

Tolerance: -0.5 gallons, no upper limit

Rain typically doesnt fall at a rate of more than 0.30 inches per hour. This equates to around 6 GPM for this roof. In order to compensate for a severe storm once the tanks are full, an export rate of 6

GPM adequate to avoid flooding of the area.

2. First flush filter shall remove first 17 gallons from first rain.

Tolerance: -1 gallon, +10 gallons

This ensures that all buildup of debris from the dry season is removed from the water before entering

the tanks. A convention usually followed for first flush systems is that the first 10 gallons per 1000

square feet are removed. The roof is approximately 1650 square feet.

3. Pump should move water to a height of ten feet.

Tolerance: -2 feet, no upper limit

This ensures the water will reach the top of the living wall, watering all levels.

4. Pumping mechanism shall have zero rough edges, visible glue or blemishes.

Tolerance: +2 blemishes

This makes sure the device is safe and professional looking.

5. A range of users shall be able to pump for 10 minutes without tiring.

Tolerance: - 2 minutes, no upper limit

The device must be easy and enjoyable to use for a wide range of age, height, and physical fitness

levels.

6. Pump shall require maintenance no more than once per 10 hours of use.

Tolerance: -2 hours/ no upper limit

10 continuous hours of use would equate to months of use under predicted normal operating

conditions.

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7. Pump shall weigh 40lbs or less.

Tolerance: +5 pounds

40 lbs is a manageable weight for a team of people to move when pump relocation is necessary.

8. Pump shall require no tools for draining.

Tolerance: 0 tools

In order to prevent freeze damage, the pump must be drainable. Requiring no tools makes draining

for storage a much easier task.

9. Pump shall fit inside a 3x4x4 foot box.

Tolerance: +6 inches per dimension, no lower limit

Space is limited at the site, so the pump must be small. There is a picnic bench near the coffee stand

that could be moved for the pump. Also, the pump could be placed between the two larger tanks.

These size constraints would allow for the pump to fit in either of these locations.

10. 80% of users should find the pump entertaining after completing a survey.

Tolerance: -5%, no upper limit

Users should enjoy the device and want to come back or tell others about the project. The project is

aimed at raising awareness and interest, so an adequate number of users should find the system

entertaining.

11. System shall deliver at least 1 inch per hour of water.

Tolerance: 0.5 inches

Too little water would be insufficient to plant growth. Too much water delivered can damage plants

and erode soil base. As the living wall is not built yet, this requirement is subject to change. We don't

currently know what the soil area of the living wall the sponsor will provide will be, so we are unable

to give a specific volume at this time.

1.2.4. Testing Procedures (TPs)

1. A bucket of 6 gallons or greater will be filled to 6 gallons with a garden hose. The overflow pipe for

each tank will be disconnected and the bucket will be slowly poured down the overflow pipe. A stop

watch will be used to time the pour. The water must go down the overflow in less than 1 minute without

backing up in order for this test to be successful.

2. Team members will pour a five gallon bucket filled with water down each downspout. After each

downspout has received approximately five gallons, each first flush filter will be emptied into the empty

bucket. The volume of water from each downspout will be measured by looking at the marks on the

bucket. The volume of water diverted by the downspouts shall total between 16 and 27 gallons in order

for the system to pass this test.

3. A hose will be attached to the inlet and outlet of the pump. There shall be at least 2 feet of water in

the tank to simulate actual operation. One team member shall stand on a step stool and hold the outlet

end of the hose at ten feet above the pump and lowered until water flows from the hose. Another team

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member shall use a tape measure to measure the height of the outlet. The third team member will

operate the pump. For this test to be successful, water must flow from the end of the hose when held at

a minimum of 8 feet.

4. The sponsor and another individual not involved in the project will thoroughly inspect the human

interface and pump and note any blemishes, visible glue, or any sharp or rough edges. For this test to be

successful, the inspection shall expose no more than two blemishes.

5. Five users of different ages and of different fitness levels shall operate the pump to irrigate the living

wall. The users will be told to operate the pump until they are too tired to continue, up to 10 minutes.

The use of the pump will be timed with a stop watch. All users must use the pump for at least 8 minutes

before tiring in order for the test to be successful. This can be done at the same time as testing

procedure 10.

6. Over the course of a week, each team member shall use the pump to circulate water held in a small

plastic storage container. A garden hose shall be attached to the inlet of the pump. The outlet hose will

go back into the tank. Each team member shall operate the pump for 30 minutes per day for 7 days.

During this week, no maintenance shall be done on the pump or bicycle. For this test to be successful,

the pump must operate for the first eight hours without any maintenance. Maintenance can be done,

however, on the hoses and water containment system. Priming of the pump will not be considered

maintenance for this test.

7. One student will hold the entire pump and stand on a bathroom scale indoors on a flat surface. The

weight will be recorded. The student will put the pump on the ground and stand on the scale without the

pump. Their weight will be recorded. The difference between the two weights must be less than 45

pounds.

8. After testing procedure 6 is complete, the last student to use the pump will remove the hoses attached

to the inlet and outlet and attempt to drain the pump into the plastic container. The other team members

must be present to confirm that no tools were used. If the student can drain the water from the pump

without using any tools, the pump will satisfy the requirement.

9. Students will measure the pumps maximum height, length, and width with a tape measure. The

smallest dimension must be less than 3 feet, and the others must be smaller than 4 in order for this test

to be successful.

10. Students will ask ten individuals to operate the pump and irrigate the living wall. After five minutes

of use, students will ask the user yes or no, this system for irrigation was both entertaining and

interactive to use. Seven of the ten users surveyed must answer yes to this question in order for the

system to satisfy this requirement.

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11. Calculate the volume required in gallons by measuring the surface area of the vertical section of the

tank and multiplying that by one inch, then converting to gallons. Then operate the pump with the outlet

hose held at eight feet until the calculated volume, measured by filling five gallon buckets, has been

reached. This must take one hour or less to pass this. This test can be done along with testing procedure

6.

1.2.5. Design Links (DLs)

1. Overflow for all pipes is three inch diameter PVC. This is fairly wide and can handle flow rates much

higher than 6 gallons per minute, usually several hundred.

2. The design utilizes five first flush systems of four inch diameter. Each pipe shall be five and a half

feet in length. This will allow for each first flush pipe to divert 3.6 gallons of water; a total of 18

gallons will be diverted.

3. The speed that the pump operates at is optimized for the pump radius for a pressure head of four

meters, or approximately twelve feet. For a pressure head of four meters, minimal power is required.

Any user will be able to generate the required power.

4. The system is aesthetically pleasing because careful consideration was put into the materials used for

the pump, the human interface, and the non-intrusive layout of the pipes. The system will be

carefully constructed and all machined parts will be deburred to prevent any blemishes or visible

glue. The casing for the pump will be constructed from polycarbonate, and the impeller will be

powder coated to prevent any oxidation. The bicycle utilizes a belt drive system rather than a chain

to minimize rusting.

5. The system meets this requirement by utilizing bicycle power. Most users can generate between 0.5

and 0.7 HP on a bicycle. Pumping water to the required pressure head requires a fraction of this

power. The actual power required depends on the pump efficiency. This pump shall be easy for the

majority of users. It will require much less power than that required for riding a bicycle at a

reasonable pace.

6. The pump is very simple in design. There are very little parts to the actual pump. On the pump

itself, only the bearing and seal will need to be replaced occasionally. The impeller and case will both

be very rust resistant as well. The case will be secured by stainless steel bolts and heli-coils, to

prevent damage to the plastic case. The mechanism for generating power is a bicycle. It will be belt

driven, to minimize rust. The bicycle itself will be painted and sealed; as will the stand that will

support it and hold the pump.

7. The mechanism for generating power will be a bicycle. Without the tires, it will be compact. The

bicycle itself will weight little, and the stand to secure it to the pump is simple and lightweight. The

pump is small and made from lightweight materials as well. Overall, the human-powered pump will

be small and weight little.

8. The pump design is a centrifugal pump. There are no valves to keep water in the pump. To drain it

for storage, it will be as simple as removing the inlet hose and tilting it until the water is drained from

the pump.

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9. By using a bicycle, users will be able to see the living wall as they power the pump. The system will

be interactive. Users will be able to pump competitively, to see how much water they can get to

come from the delivery lines.

10. The pump is relatively large in diameter and depth. It will be able to produce flow rates high enough

to irrigate an inch of water within an hour.

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1.2.6. House of Quality (HoQ)

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Customer Requirements Wt. X strong

System shall allow for draining of excess water to municipal storm water. 25 X o moderate

System must remove debris from first flush. 25 X * - weak

System shall allow for pumping of water from tank to an adequate height. 25 X

Pumping mechanism should be aesthetically pleasing. 15 X

Pump shall be easy to use and accessible to a range of users. 25 * X *

Pump shall be low maintenance 20 o X o

Pump shall be human powered. LTE *

Pump should be movable. 20 * X o

Pump shall be able to be easily drained. 25 o X

Pump connections should use standard hose fittings. LTE

Pump should be compact. 25 o o X

Pump shall be entertaining. 20 * * o X

Pump shall contain a steel tab to lock it to the building. LTE *

Each tank shall contain a backflow prevention valve. LTE

Pump shall deliver adequate water to plants. 25 * X

Target 6 17 10 0 10 10 40 0 4 80 1

Units GPM Gal ft. issue min hours lbs tools ft. % in/hr

Tol -0.5

-

1/+10 -2 +2 -2 -2 +5 +0 +0.5 -10 -0.2

TP 1 2 3 4 5 6 7 8 9 10 11

DL 1 2 3 4 5 6 7 8 7 9 10

Engineering Requirements

Colle

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9

2. EXISTING DESIGNS, DEVICES, AND METHODS

2.1. System Level

The existing systems chosen for discussion are the system used by Kelley Engineering Center at OSU, a

Montana home system, and a rainwater irrigation system in Portland, Oregon. Kelly Engineering Center

was chosen because it is similar to this project, only of a much larger scale. The Montana system was

chosen because of its similarity to the system this project aims to develop. Finally, the Portland system is

also similar to this project in that it is of similar scale, it is local, and is subjected to nearly identical

2.1.1. Kelly Engineering Center

At Kelly Engineering Center of Oregon State University, a similar rainwater catchment and filtration

system was built, only on a much larger scale. The system collects water from the gutters on the building

and runs it into planters to filter out any particles and debris. Water is then filtered by UV radiation and

stored. There are three 16,500 gallon storage tanks in the basement of the building. This water is used in

non-potable applications throughout the building, mainly in toilets. The system cost $90,000 but saves

approximately 372,000 gallons of water annually (Storm Water Solutions).

This system does not meet many requirements that the Corvallis project will. While it exceeds the

requirements in many areas, such as filtration, the project is on a much larger scale. It is an example of a

large-scale application of rainwater collection and use. It is useful to examine because the system

utilizes cutting edge ideas, such as the planter and UV filtration systems.

2.1.2. Montana Residents Home System

The system developed in Montana (Rupp) follows a simple design utilizing readily available materials to

catch, filter, and store water. The system uses traditional gutter downspouts to collect water from the

roof of a house and gravity feeds it into a filter that is essentially a metal mesh screen on top of a pipe of

large diameter (1-2 feet) that includes a conventional vertical first flush filter to divert sediment out of

the pipe. This filter sits atop (or moderately close to, and above) the cistern. The cistern is completely

buried in the ground to avoid freezing without the need for an external electric heater or extensive,

expensive insulation. Water is pumped from the deep cistern by means of an electric pump for ease of

use and incorporation into an otherwise standard house layout.

The Montana system meets some of the requirements for this project on the component level. First, the

system filters out particles with a screen filter. Next, the first flush is diverted using a common first flush

filter. This setup may require more maintenance than having the screen filter after the first flush system,

as the filter is more likely to get clogged. Second, the system takes care to avoid freezing the water, and

finally the water is used for irrigation and in home purposes which may be of interest for future projects.

2.1.3. Portland Residential Rainwater Irrigation

The system in Portland, Oregon (Ersson) utilizes an above ground storage tank fed via traditional roof

gutters with leaf screens to protect the system from initial large contaminants. The gutter downspouts

feed a closed system piping unit that flows into a first flush filter. This first flush filter uses a floating

ball that allows the first few dirty gallons to fill up the filter, which allows the ball to seal a valve,

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whereby allowing all remaining water to pass over the first flush filter and into the collection tank. The

tank, being above ground, requires no pump to irrigate the garden, but uses a small electric pump to

pressurize the water supply feeding the houses main water input.

Using the Portland system as a precedent is useful because it uses features that could offer solutions to

component choices for this project. The storage tank is located above ground, leaf screens and a first

flush filter are utilized, and the water collected is used to irrigate a garden. Overall, this system comes

closest to fulfilling the requirements for this project.

2.2. Component Level

This project can be broken down into six general sub-functions: first flush management, filtration, water

delivery, human power interface, pumping mechanism, and delivery to the vertical garden.

2.2.1. First Flush Management

The first flush refers to the first rain after a dry spell. During this time, excess debris shocks the system

and will clog the main filter. Also, build up during the dry period can lead to bacterial contamination and

acidic water. A system is required to filter out this excess debris separately. Three main designs for first

flush systems include the floating ball system, tipping gutter system, and vertical gravity filter.

2.2.1.1. Floating Ball

A floating ball system uses a vertical piece of pipe connected to the main horizontal pipe. This

vertical section fills first, collecting all of the debris and contaminants. There is a ball in this section

that floats to the top and plugs the opening when it is full. The bottom of a floating ball system can

be unscrewed, allowing the draining of the first flush water and debris.

Several retail first flush systems are available. An inexpensive floating ball system available through

Rain Harvest Systems would work well for our project. It contains a ball and a screw cap that has a

drip valve for an automatic reset.

2.2.1.2. Tipping-Gutter System

A tipping gutter system uses a gutter initially tilted away from the tank. The water is directed to a

bucket suspended by a rope that goes through a pulley and is attached to the end of the gutter. As

this bucket fills with water, the increasing weight of the bucket tilts the gutter toward the tank. This

ensures that the first bucket load of water and debris does not reach the tank. A small hole is put in

the bucket, allowing it to drain slowly and reset (REUK). This system fulfills the requirements of the

first flush function, although it is a complex solution. Another issue with this system is the

considerable amount of space it requires over some of the other options.

2.2.1.3. Vertical Gravity Filter

The most basic type of first flush filter involves a large diameter (~6 inch) pipe of variable length to

hold a volume based upon roof area of rain collection. The pipe is outfitted as a vertical unit, sealed

off at the bottom with a screw-in plug and a spigot near the bottom that is constantly left slightly

11

open. As the system is exposed to rain, the pipe fills up with the initial flood of water, and all of the

sediment with the first flush settles at the bottom of the pipe. The cleaner water following the initial

surge will flow straight over the filter and into the water catchment cistern. The spigot allows the

filter to drain standing water. After a set amount of use, the filter can be cleaned out by simply

removing the plug at the bottom of the pipe, which would allow the sediment and other accrued

debris to fall out.

One issue with the vertical gravity filters is that there is turbulent area at the top of the filter where

the clean water flows over the water trapped in the filter. This allows oil and other low density

debris to be swept into subsequent component of the system.

2.2.2. Filtration

Filters offer an in-line solution to reducing or eliminating sediment and debris from entering subsequent

components of the delivery system. Ideally, the filter would be placed immediately after the collection

unit (in this case, the roof) in order to eliminate debris from as much of the system as possible.

2.2.2.1. Sand Filter

Sand filters are a natural way to filter relatively fine contaminants from a water supply. They are

used not only in applications of similar scale, but also for large industrial applications. A sand filter

method to clean the water would meet all of the filtering requirements of this project. Sand filters are

also natural and have little or no negative impact on the environment, making them ideal for this

sustainable water demonstration. Required maintenance of sand filters is minimal, and cost is low.

2.2.2.2. Screen Filter

Screen filters present a simple method to filter large sediment out of the system at an early stage of

the collection process. Utilizing a screen filter offers an inexpensive and easy way to filter the water

at a basic level, while also allowing ease of maintenance. If the filter is installed at an angle, then

debris caught in the filter would be sloughed off as water kept flowing over the filter. Screen filters

are also available in a range of filter mesh sizes to cater toward any diameter of particulate matter to

be removed. The downside of these filters is that they still allow some biological matter, leaves and

bugs, into the system.

2.2.2.3. Carbon Filter

Carbon filters consist of a mass of activated carbon powder, positively charged, that can attract most

of the negatively charged tiny particulates and impurities of a water source. Carbon filtering is a

relatively new method of filtration, and can filter particulate matter as small as 0.5 microns. These

filters are usually used for systems in which the water collected must be drinkable before it is

integrated into the primary water main for a house. Carbon filters are widely available, but are also

costlier than the sand filtration and screen methods. A carbon filter design would fulfill many of the

customer requirements, but may be excessive, as sanitation is not a primary concern.

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2.2.3. Water Delivery

The water delivery function transports water from the collection site to the tanks. Three existing

delivery designs discussed here are PVC piping, typical residential gutters, and metal piping.

2.2.3.1. PVC Piping

PVC piping is a cheap existing method for transporting fluids. It is inexpensive, easy to locate, and

there are many existing joints and attachments. The piping also requires little maintenance and lasts

a long time. This method would work well for this project. One drawback is the purpose for the

system is a sustainable water demonstration, and the manufacturing of PVC is more harmful to the

environment than alternatives, so another method may suffice better, as budget is not a very large

issue. Another issue for consideration is freezing. Because any piping is closed, damage can occur

from water freezing inside the pipe.

2.2.3.2. Gutters

Gutters are used mainly on buildings to direct rainwater to downspouts. Residential gutters are

designed to transport rainwater. They would work very well for this function, as they are designed

specifically for this purpose. While slightly more expensive than PVC, they are less prone to damage

from freezing, as they are open. While they are more prone to clogging from debris, they are also

much easier to clean than piping. If gutters are used, multiple filters must be used intermittently to

ensure that the water is cleared of free-falling debris along the length of the delivery system.

2.2.3.3. Metal Piping

Metal piping is frequently used in buildings to transport fluids. Metal piping doesn't typically contain

the harsh chemicals that PVC does and it serves a similar function. There are several drawbacks to

metal pipes in this application though. For one, it is very expensive. It also transfers heat more

easily, accelerating any freezing, can corrode causing unwanted elements in the water and it is

significantly heavier than PVC.

2.2.4. Human Power Interface

One of the most important areas of this project is the pumping mechanism. Because this project is

intended to be used as an interactive demonstration, the human interface must be interesting and easy to

use. The purpose of this function is to generate mechanical power, which will be used by the pump.

Three powering mechanisms discussed here are foot pedals, merry-go-rounds, and see-saws. All three

of these methods have been employed for pumping water in other systems.

2.2.4.1. Foot Pedals

Foot pedaling power is one of the most efficient ways to utilize human power. The efficiency of

foot pedaling, the power it generates, and its ease of use are reasons foot power is used extensively

for human powered transportation. Bicycles and unicycles are also readily available and could

13

easily be fitted to the pump by means of a chain. One disadvantage is that there are several moving

parts that require maintenance, but bicycle maintenance knowledge is fairly easy to find.

Jon Leary, a mechanical engineering student from University of Sheffield, designed and built a

portable human powered pump. It was designed for Guatemalan farmers to help irrigate fields. The

pumping mechanism can be flipped upward and the bicycle can be ridden (Coxworth). This design

would serve the pumping function well. It is not extremely compact, but it would fulfill most of the

customer requirements. This example shows what human power can accomplish with pumping.

Biking is an effective and especially ergonomic way to deliver power to a pump.

2.2.4.2. Merry-Go-Round

A merry-go-round is not only a fun playground toy, but also a useful means of powering a water

pump. The merry-go-round powers an underground pump that moves the water from an aquifer to an

above ground tank. The bottom of the tank stands several meters above ground so when the water is

called upon, gravity does all the work. These fun and hard working pumps have mainly been

installed in Africa to help provide safe clean drinking water. These play-pumps, as they have

become aptly named, are showing up in the U.S. as well (Torrone).

The merry-go-rounds are very effective human powered pumping tools that are also accessible to a

range of users, entertaining, very low maintenance, and can provide adequate power to the water

pump. The size of the merry-go-round may render the option impractical for this project.

2.2.4.3. See-Saw

Another way to harness human power is the see-saw or teeter-totter, a common playground

attraction. A community in Columbia was rebuilding their water pumps when the children noticed

the pumping handle was very similar to half of a see-saw. The community developed a see-saw that

could be attached to their water pump and have since introduced this method to over 600

neighboring villages.

The see-saws are a great way to power a water pump while also being entertaining. They are low

maintenance and accessible to most everyone. The force input on every stroke of the cycle of this

particular design can provide a large torque value and be used as the input for a fairly high-output

pump. This design may be too large for our size requirements.

2.2.5. Pumping Mechanism

Pumping the water will be accomplished with the use of human power, and presents the most difficult

component level design of the system. The pump must be able to force water to an adequate pumping

height without requiring excessive user energy input. The pump must allow for a wide range of physical

fitness levels while still delivering sufficient water. The pump designs discussed here are the centrifugal

pump, reciprocating pump, and the Archimedes's screw.

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2.2.5.1. Centrifugal Pump

A centrifugal pump is commonly used in small-scale and large-scale industrial fluid applications. A

centrifugal pump makes use of an impeller that forces the water outward from a central water intake.

The pump casing directs this outward flow through a single outlet. The water moving outward is

replaced with water that is at the inlet. The main advantage of a centrifugal pump is that it provides

constant, steady pressure and flow. The only disadvantage to this method is that it requires priming,

but this could be resolved if the water intake were to be drawn from the bottom of the tanks near the

pump. A centrifugal pump would provide adequate pumping height and pressure, require relatively

little maintenance with few moving parts, and could be easily drained.

2.2.5.2. Reciprocating Pump

A reciprocating pump often uses a plunger or piston to move the liquid and is generally used for

small-scale operations. The pump operates by effectively expanding a volume via a moving piston,

creating a vacuum that draws fluid into the cylinder via a one-way valve. The fluid is then forced out

of another, opposing one-way valve as the piston descends and decreases the effective cylinder

volume.

Piston pumps are difficult to design and would more than likely require a lot of maintenance. The

pump would not need to be drained and are usually small and portable. Siphoning and back flow

would not be a problem when using this pump and the pump is capable of providing an adequate

amount of water to the vertical garden.

2.2.5.3. Archimedes Screw

The Archimedes's screw is one of the oldest pump designs, dating back thousands of years, when it

was powered by a hand crank, and is still used extensively in industrial applications. It is essentially

a large screw inside of a casing. When turned, it forces the fluid up the casing. This design would

fulfill most of the customer requirements, but it is rather complex design. The Archimedes's screw,

while effective, doesnt provide much pressure; it simply lifts fluids. One advantage is that it is very

resistant to damage, which would lower maintenance requirements. This design can operate as an

open system, thus increasing visibility of the water being moved around.

2.2.6. Delivery to Vertical Garden

The final sub-function within this system is the delivery of water to the plants in a vertical garden. This

serves as the final outcome of the system and gives a purpose to the public demonstration. The three

existing watering designs discussed herein are drip irrigation systems, misting irrigation systems, and

flooding.

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2.2.6.1. Drip Irrigation System

A drip irrigation system is a common method for watering gardens. It would require little to no

pressure from the pump, effectively water the vertical garden, and offers a relatively inexpensive

option. A drip system would fulfill almost all of the customer requirements, as it is low impact and

is an effective way to water gardens, but it would not be very visible or exciting. This problem

could be corrected by making the delivery visible by another means.

2.2.6.2. Misting Irrigation System

Misting systems are a commonly employed method for watering small gardens and for keeping

produce fresh. There are retail misting designs available, ranging from full systems to in-line PVC

nozzles. Misting systems are gentle on the plants, deliver a reasonable volume of water, and are

visible. The only disadvantage this method has is that it requires greater pressure than alternatives,

such as a drip system.

2.2.6.3. Flooding

Another existing method for watering plants is simply to flood the area with water. This is

commonly done with potted and hanging plants. The soil is flooded with water until it drips through

the bottom of the pot. This watering method could be employed to water the vertical garden. The

downfall is that the delivery of this system is only minimally visible, and minerals and tiny

particulates would leech out with the water as it seeped through the soil to the next layer in the

vertical garden.

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3. DESIGNS CONSIDERED

This chapter discusses possible system designs for the project as viewed from the individual component

designs. These designs came from research of current designs and devices that are used for water transportation,

storage, and delivery in modern systems. Those designs and devices that are most applicable to this project are

stated in chapter two, and they are considered the most cutting-edge for their particular purpose.

3.1. Design #1

System Outline

First Flush Management: Floating Ball First Flush System

Filtration: Slanted Box Leaf Screen and an Angled Screen Filter

Transportation to Tanks: PVC Piping

Human Interface: Unicycle with Arm Supports

Misc. Water Transport: Garden Hoses

Pumping Mechanism: Centrifugal pump

Delivery Method: Holding Tank with Watering Troughs

System Description

In this system the water runs from the roof into a slanted box leaf filter. This removes large debris and

keeps the first flush system from getting clogged. The water flows out of the slanted box leaf filter and

straight into a floating ball first flush system. There are several kits online that include the ball, the joint,

and the cap with a drip valve. This first flush system replaces the buildings normal drain pipes. The water

then leaves the first flush by means of PVC piping that runs along both sides of the building.

The PVC piping on the south side of the building leads to the east-most 3000 gallon holding tank. The

piping can be supported by the pole between the building and the tank. Water enters a 35 mesh slanted

screen filter, to lower cleaning requirements. The two 3000 gallon tanks are connected by a pipe that will

allow them to fill simultaneously. The tanks have an overflow pipe at a height directly beneath the filter

height. This ensures that the water cannot ever flow back up through the filter, as the water level could

never reach the height at which the water enters. These overflow pipes run down the sides of the tanks into

municipal pipes underground.

On the north side of the building, the collection pipe first enters the 500 gallon tank through the same type

of angled screen filter. The overflow from this tank leads to the 1650 gallon tank, which overflows into the

municipal drainage system. This allows for the 500 gallon tank to remain full most of the time, making the

watering of the vertical garden more dependable.

Each of the tanks are fitted with a standard hose spigot towards the bottom of the tank. This ensures that the

hose is always pressurized, so long as there is water in the tank. This way, the centrifugal pump, when

lower than the water level at the top, is always be primed. A vacuum breaker is fitted to the end of the

17

spigot and prevents back flow into the tank. To prevent free flow of water, the valve on the spigot can

simply be turned off when watering is complete.

The centrifugal pump is powered by means of foot pedaling. A frame is to be made from aluminum tubing

and a bicycle seat and crank is fitted to the system. Arm supports are included so that the user can be

stabilized while pedaling. The system has three gears, so that users of different strengths are able to power

the pump. The centrifugal pump consists of a two part casing sealed with a liquid gasket and bolted

together, a simple impeller, a water proof bearing, and a shaft fitted with a bicycle gear. It is chain driven.

A garden hose is fitted to the outlet of the pump and run up to a Plexiglas tank on top of the vertical garden.

This tank is fitted with a toilet flush valve. This will be opened by a buoy that is chained to the valve.

When released, the water inside the tank runs into troughs containing many small holes above the vertical

garden planters. The water drips out of the trough and water the plants.

System Advantages and Disadvantages

Advantages:

1. Compact and powerful power mechanism.

2. Simultaneous tank filling allows for a greater variety of uses for the water.

3. Steady flow from centrifugal pump.

4. Constant resistance to drive.

5. Two-step filtration with angled screens requires little maintenance.

6. Floating ball contains contaminated water.

7. Holding tank gives control over total volume delivered to plants.

8. Holding tank with troughs gives visible and entertaining water delivery.

Disadvantages:

1. Tilted box leaf filter takes up a lot of vertical space, making it difficult to fully fill the 3000 gallon

tanks.

2. Simultaneous tank filling gives less available pressure for a given volume.

3. Floating ball first flush system is more complex than alternatives.

4. Bicycle components are vulnerable to rust and wear.

5. Bicycle components require more maintenance than alternative human interfaces.

6. Centrifugal pump requires priming. Limits available uses for pump.

7. Water delivery system to the vertical garden is more complex than alternatives.

8. Plexiglas holding tank requires cleaning to look appealing and sanitary.

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3.2. Design #2

System Outline

First Flush Management: Vertical Pipe Filter

Filtration: Cartridge Filter and Box Leaf Screen

Water Delivery: Open Gutters

Human Interface: See-Saw

Pumping Mechanism: Diaphragm Pump

Misc. Water Transport: Garden Hoses

Delivery Method: Garden Drip System

System Description

The second design considered starts with water from the roof flowing into a box leaf screen filter to remove

large leaves and debris. The water enters an open gutter attached to the outside footprint of the building.

From there, the water heads to the vertical pipe first flush filter which filterd the first 17 gallons of the first

rain. Next, the water flows into PVC piping to a cartridge filter in order to remove any small particles left in

the water to prevent debris in the tank.

The pipe layout is be similar to that of design #1, with the south pipe delivering water to the two 3000

gallon tanks and the north pipe supplying the 500 gallon and 1650 gallon tanks. The one difference with the

delivery to the tanks is that the first 3000 gallon tank fills first and the overflow fills the second large tank.

This allows for higher available pressure for a lower volume of collected rainwater. The overflow from the

second tank drains into the municipal storm drain pipe. This overflow pipe is be located at a lower height

than the entrance in the first tank. The 500 gallon tank fills first and overflow into the 1650 gallon tank in

order to keep adequate water in the 500 gallon tank.

The water is drawn from the bottom of the tank and has a spigot and vacuum breaker. This gives the most

pressure to begin with and lowers pumping requirements for the diaphragm pumps. The pumps are powered

by a see-saw. This human interface is both entertaining and effective. Two small diaphragm pumps are

located at each side of the see-saw. When one is on its intake cycle, the other will be exhausting. Water for

both pumps is drawn from the same line for the intake and water is outputted to the same line as well. Each

pump consists of a diaphragm, a casing, and two one way valves, one for intake and one for exhaust. The

diaphragm would not need to move much, so the pumps can be near the fulcrum. This allows for good

leverage from the users.

The vertical garden will be watered with a standard garden drip system. Before entering the drip system,

water will be run through a trough and will turn a pinwheel. This will give a visible delivery and make the

system more entertaining.

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System Advantages and Disadvantages

Advantages:

1. Individual filling of the large tanks gives higher available pressure for a smaller volume of water.

2. Flat box leaf filter takes up less vertical space.

3. Vertical pipe first flush system is a simple design.

4. Cartridge filter removes very small particles.

5. Open gutters are easier to maintain than piping alternatives.

6. Human interface is exciting and allows for competitive pumping.

7. Diaphragm pumps are simple.

8. Drip systems are inexpensive and extensively used.

Disadvantages:

1. Individual tank filling restricts uses for water when there is a small volume.

2. Flat box leaf filters require more maintenance than tilted box filters.

3. Cartridge filters require frequent replacement.

4. PVC pipe is already available on site, making gutters a much more expensive option.

5. See-saw is not compact enough to fit within space restrictions.

6. Diaphragm pumps do not supply consistent flow.

7. Drip systems are not visible.

3.3. Design #3

System Outline

First Flush Management: Floating Ball Filter

Filtration: Screen Filter and Cone Leaf Screen

Water Delivery: Metal Piping

Human Interface: Merry Go Round

Pumping Mechanism: Centrifugal pump

Misc. Water Transport: Garden Hoses

Delivery Method: Mist system

System Description

Water starts by collecting on the collection roof. From the roof, the water enters the metal piping. The

entrance to the metal piping contains a conical, wide mesh screen. This ensures that no large leaves or

debris enter the collection pipes. Following the screen filter, water is then routed into the first flush filter,

where the dirty water with sediment and contaminants are contained within a floating ball filter.

After filling the first flush systems, the water continues through the metal pipes into a screen filter assembly

and into the tanks. The pipes on the south side feed the 3000 gallon tanks and the pipes on the north side fill

the 500 gallon tank and the 1650 gallon tank. The 3000 gallon tanks are filled simultaneously and an

20

overflow pipe is near the top of the west-most tank. The overflow from the 500 gallon tank is used to fill

the 1650 gallon tank, which overflows into the storm drain system.

Water would be drawn from bottom of the tanks with a typical garden spigot and a vacuum breaker. The

water then flows into a centrifugal pump which is powered by a merry-go-round. A merry-go-round is an

effective and entertaining human pumping interface. With enough users, the pump would get an adequate

amount of power. This method is able to power a larger pump than the other methods, as many users are

able to power the pump simultaneously.

The vertical garden is watered by a misting system. Misting systems are widely available and come in

several forms. The type used in this design is in line PVC mister nozzles. These nozzles are inexpensive

and provide adequate water. A centrifugal pump can provide both plentiful and constant pressure, making a

misting system ideal.

System Advantages and Disadvantages

Advantages:

1. Cone leaf filter is compact.

2. Simultaneous filling of tanks allows for more uses for a lower volume of water.

3. Floating ball system seals contaminated water from system water.

4. Metal piping is more durable than PVC piping.

5. Merry-go-round is an interactive and fun human interface.

6. Merry-go-round can allow many users to power pump.

7. Centrifugal pump delivers constant flow of water.

8. Mist system is gentle and visible.

Disadvantages:

1. Cone leaf filter requires more maintenance than alternatives.

2. Simultaneous filling of tanks yields lower available pressure for a small volume of water.

3. Floating ball system is more complex than alternatives.

4. Metal piping is more susceptible to freezing.

5. Merry go round is not very compact. It would be difficult to fit in a 3x4x4 foot box.

6. Misting system requires higher pressure to function properly.

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4. DESIGN SELECTED

4.1. Rationale for Design Selection

The most reasonable design for this system is design number one in section 3.1. This section discusses why

the system and components chosen for this project prevail over other options.

The system is most appealing for many reasons. The first being the first flush system is very low

maintenance and better at keeping the debris out of the system than the alternatives. When the floating ball

system is compared to the vertical pipe system, it has one clear advantage. Both systems can handle the 17

gallon capacity, but the floating ball system keeps any debris that has entered the filter in the filter, where

the vertical pipe system does not get closed off once filled up.

Next the angled screen filter allows any debris to slide off the filter to avoid clogging and is inexpensive to

install and replace. The cartridge filter would filter the smallest debris and is easily replaceable, but the

cartridge filter is expensive and requires more frequent maintenance.

The slanted box leaf screen when compared to the box screen and the cone leaf filter comes out on top

because the angle allows the leaves to slide off of the filter on their own where as the box leaf filter and

cone leaf filter would need to have the leaves removed on occasion to avoid clogging and flooding. While

the slanted box leaf screen filter takes up more vertical space than the other alternatives, its lower

maintenance requirement overshadows the lower water height in the 3000 gallon tanks, which are at nearly

the same height as the building.

PVC piping excels against the metal piping system and the open gutters for water delivery. The PVC piping

is closed to the environment to keep any extra debris from entering the system. The PVC is offered in larger

diameters to prevent clogging and the PVC has a larger resistance to heat transfer, which will protect against

freezing to a certain degree. Another distinct advantage to the PVC is that much PVC piping has already

been purchased by the sponsor, lowering the financial requirement for the water delivery.

The unicycle human interface design is ideal over the see-saw and merry-go-round, the main reason being

its size. Human pedaling is a very space efficient method for generating power. That is, it can generate the

most power per area that it takes up. Since the entire pump must fit into a 3x4x4 foot volume, this design is

much more practical. Bicycle components are also readily available and relatively easy to install. The

centrifugal pump is advantageous in this application because a constant flow and constant resistance are

generated. This makes use of the pedaling system much easier.

The main advantage with the holding tank and trough design is that it is visible. The filling of the holding

tank makes pedaling more interactive and engaging. It also allows for some control over how much total

water is delivered to the vertical garden.

4.2. Design Description

4.2.1. Collection System

The collection system includes the transport, drainage and collection of rainwater. It begins at the

downspouts of the building, including first flush systems and screen filters, and then ends with the tanks.

The system also includes overflow and drainage of the tanks. All drawings for the collection system

22

can be found in appendix C in drawings L1 through L6.

The water collected on the buildings roof passes through the existing screens above the downspouts. Water first enters the first flush systems, which are at each of the five downspouts. Standard practice

for rainwater collection dictates that approximately 10 gallons per 1000 square feet of roof area are

diverted. Per this calculation, the first flush system must divert 17 gallons. To achieve this, the filters

will divide this load between the five downspouts; each first flush system should divert 3.4 gallons of

water. The first flush systems are floating ball systems, which can be purchased as kits. These include a

screw cap for cleaning, a drip valve for reset, and a floating ball. Each first flush system is 5 feet 6

inches long and is made with 4 inch PVC pipe. The system on the downspout on the outcropping will

be slightly shorter, 4 feet 10 inches, to accommodate the overflow from the 500 gallon tank. Using

simple geometry, the volume of a cylinder that is 66 inches tall and 4 inches in diameter is 829 cubic

inches. This is equivalent to 3.6 gallons. The smaller filter is 58 inches tall, and thus divert 3.15 gallons.

The total volume diverted by the five first flush systems is 17.6 gallons.

After the first flush diverters are full, water begins to bypass the filter and collect in the storage tanks.

The water flows through 3 schedule 40 PVC pipe to fill the tanks. The two downspouts on the north side of the building, as well as the downspout on the buildings outcropping feed the 500 gallon tank, which overflows to fill the 1650 gallon tank. The downspout on the outcropping contains a leaf beater

angled screen for demonstration purposes. Filling the 500 gallon tank first ensures the tank, which is

used for irrigating the living wall, is always be full. The water enters the tanks through a large opening

on the top. This opening contains a large 35 mesh screen to keep out mosquitoes and other fine debris.

The delivery to these tanks is illustrated in detail in drawings L2 through L4 in appendix C.

The two downspouts on the southern side of the building feed the two 3000 gallon tanks. The 3 PVC pipes leave the main building at the southwest corner of the building. Two 45 degree joints direct the

pipes along a power pole, which is used to support the pipes leaving the building. The water enters the

east-most 3000 gallon tank as high as possible (approximately eight feet). It is directed into a pipe

reducer that is open to the air. Inside the reducer is a size 35 mesh screen to filter out small debris and

block mosquitoes and their eggs. This is illustrated in appendix C in drawing L5. The two 3000 gallon

tanks are connected underground to allow them to fill simultaneously. A T-joint is located along this

pipe, where a valve is attached to allow for draining. The tanks overflow connects to this pipe, which feeds into the fountain. The fountain will overflow into a raingarden. The overflow from the 1650

gallon tank will also flow into this raingarden. The fountain and raingarden are out of the scope of this

design, and are being handled by the sponsor. This project simply sets up a drainage and overflow pipe

to be used for the fountain. Detailed drawings of the northern delivery and overflow can be found in

appendix C in drawings L5 and L6.

4.2.2. Pump

The pumping apparatus allows for the sustainable water demonstration to be interactive. The pump

consists of two sub-assemblies: the shaft assembly, and the centrifugal assembly. The shaft housing

consists of a casing, a ball bearing, a bearing cover plate, two thrush washers, a shaft seal, a pulley, and

a shaft. This sub-assembly is attached to the centrifugal assembly by four bolts and the shaft. The

centrifugal assembly consists of a hose inlet and outlet, two case halves, and an impeller.

23

Shaft housing assembly serves to provide support for the drive shaft and to apply pressure to a shaft seal,

to seal the interface between the shaft and the centrifugal casing. The bearing is a x 1 inch x 5/16

inch SR8-2RS rubber sealed stainless steel bearing. Although not directly exposed to rain or water

within the pump, this bearing is able to withstand much moisture and any outdoor operation. The shaft

case is an aluminum rod machined on a lathe to hold the bearings and provide pressure on the shaft seal.

It is anodized to protect it from oxidation. The case contains a flange for mounting to the centrifugal

assembly. A drawing can be found in appendix C, drawing P6. The shaft seal is used to prevent any

leakage through the interface between the shaft and the centrifugal case. It is designed to operate at a

height of 0.831 inches. The seal slides onto the shaft and is pressed against the case by the shaft casing.

The inch shaft is constructed from a inch stainless steel rod. It is threaded at the end, to allow for

bolting onto the impeller. Set screws are drilled through the impeller and the shaft to secure the

impeller. The pulley is machined from the same aluminum stock as the shaft housing. It is one inch in

diameter, to give the proper gear ratio of 10:1. It is secured with a Woodruff key and an e-clip. The

drawings for all parts in the shaft housing assembly are located in appendix C, drawings P5 through P8.

The centrifugal assembly is the part of the pump that is actually moving the water. The casing for the

pump is made of translucent polycarbonate. One half provides the location to bolt the shaft housing to

the assembly. The holes do not penetrate through, they are tapped and have helicoils inserted, to

improve longevity and prevent damage during maintenance. The second half contains a conical cutout

to fit the impeller. This half contains the inlet. The outlet is on a feature created by both case halves.

The casing is tapped to attach the hose fittings. Four bolts hold the case halves together. The bolt holes

contain a metal insert to prevent wear on the plastic. The case halves contain RVT liquid gasket to

prevent leakage. Drawings for the case halves can be found in appendix C in drawings P1 through P3.

The impeller is CNC machined from an aluminum disc. The part contains 6 curved vanes to channel the

water outward and a left-hand threaded tapped hole in the center allowing for the impeller to be attached

to the shaft. The impeller is anodized to prevent oxidation and for aesthetic appeal. The impeller is 4.5

inches in diameter which is the optimum diameter for the operating conditions (3 feet of water in the

tank, and a pumping height of 12 feet), calculated in appendix A. The part is designed to operate at

1000 - 1200 RPM which allows for adequate flow and delivers a pumping head of approximately 9 feet.

4.2.3. Human Interface and Power Generation

The human power interface includes a bicycle, a belt and pulley system, and a stand. The bicycle is of

medium size to accommodate men, women and age appropriate children. The rear tire of the bicycle is

removed and the wheels shaft is salvaged to attach the back of the bicycle to the rear stand. The rear

stand is manufactured from structural steel pipe, available at Home Depot for $8.2 for 10, bent in the

formation shown in drawing P10, as well as 3/16x1.5 flat steel bar, also available from Home Depot

for $6.52/4, welded to the piping in two ways. The first is on the bottom of the stand for structural

support and to attach the pump, and secondly, plating is welded to the top and holes drilled in which to

attach the shaft recovered from the rear wheel. This creates a stable stand for the bicycle and allows for

pump attachment. A floor stand to stabilize the front tire may also be used if needed. This stand is

available from Gearup for $19.95.

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The usual gear and sprocket system is replaced with a belt and pulley system, a 1 pulley attached to the

pump and a 10 pulley to the bicycle and pedals. This gives the 10:1 gear ratio, low maintenance, and

durability required. The belt size is not yet known, as the bicycle had not been purchased during the

design phase; however a V-belt is available from all local auto stores.

4.2.4. Living Wall Irrigation

Specific plans for the living wall had not been provided during the design phase, so the design for the

vertical garden irrigation system had been designed to be adaptable to the vertical gardens geometry.

The set up was to be made from inch PEX hose, which is strong and flexible to some degree. The

PEX hose would be fitted with a hose attachment at one end as an inlet, and would contain a plug at the

other end. The hose was to have a 1/16th inch hole every one inch along the pipe. The hose would wrap

around the living wall and water will drip onto the plants as the user pumps water into the hose inlet.

This system was to be retrofitted after the living wall had been constructed by a third party.

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5. IMPLEMENTATION

5.1. Implementation Plan

Over winter break, the collection system was to be completed. Construction began December 13, 2010.

The collection system was to be completed by the beginning of January. All parts for the collection system

that were not currently in possession would be purchased at home depot, or ordered online between

December 6 and December 10. The sponsor for this project had already purchased much of the necessary

supplies for the collection system. These parts were not to be taken from the budget.

At least one team member would be in Corvallis working on construction with Hazen Parsons over the

break. Over the week of December 6, the city would mark all underground electrical wires. This is required

before pipes can be placed underground for filling the 3000 gallon tanks, and for draining. After all pipes

are placed underground and on the building, an inspector must first examine the system to make sure it is up

to code. After the system passes inspection, the system would be connected to the downspouts, and the first

flush systems put in place.

All parts for the pump would be ordered over winter break. The bearing (PMP003-5), thrust washers

(PMP003-4), shaft seal (PMP003-3), Woodruff key (PMP003-12), and all raw materials for the

manufactured parts are purchased locally. Almost all of the parts and materials are available for order

online or through a local vendor. The turnaround time for the parts and materials would be a maximum of a

few weeks. If ordered over the break, they would be available before the start of winter term.

Edgecam code for the impeller (PMP002-3) and case halves (PMP002-1 and PMP002-2) was to be written

and a jig would be constructed before winter term begins. Writing the NC code and manufacturing the jig

before the beginning of the term would allow for more time to machine parts, and to troubleshoot any

design or manufacturing errors. Dean Codo, a local machine shop owner who volunteered some space and

equipment for this project, would be contacted at the beginning of the break to discuss the use of his shop.

When winter term begins, the impeller, and two case halves NC code should be tested on the Bridgeport

mill using machinable wax. While this does add to the cost of the pump, it decreases the likelihood of

making an expensive mistake on the polycarbonate stock. This was to occur during the first week of winter

term. If the code contained any errors, these had to be fixed before the following week so that the impeller

can be machined. The casing for the pump would be machined from polycarbonate. The top and bottom of

the casing would be machined separately from 6 inch square stock of heights three inches for the bottom and

2 inches for the top case. The shaft housing assembly and shaft would be constructed during week two of

winter term also. The shaft casing (PMP003-2) would be fabricated on a lathe in the MIME shop, or in

Dean Codos shop. The bearing plate (PMP003-6) would be machined from a slice from the same stock

used on the shaft casing. The shaft (PMP003-1) would be made from inch diameter stainless steel rod. It

would be machined on a lathe to precisely inch. The more precise this diameter, the better the seal will be

at the interface between the shaft seal and the shaft. Once all parts have been machined, each of the pump

sub-assemblies (PMP002 and PMP003) would be assembled and joined to form the finished pump. The

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pump was to be completed by the end of week 3 of winter term.

After the pump was to be completed, the assembly of the human interface (HPWASSEM) would be done.

The location of the pump on the stand depends on the bicycle (HPW001) that is purchased. The pump must

be constructed first so the drive pulleys can be aligned. The bicycle would be attached to a stand

(HPW0003) that allows the bicycle to remain upright with a stable base for ease of mounting and egress

from the riding position. The bike stand would be bolted directly to the frame.

The living wall is intended to be finished during winter break by a third party. Once the wall is built and

installed, the basic piping layout can be installed with it. This layout includes a vertical PVC pipe of

internal diameter to be laid flush against the wall. It would be filled from the top by the output from the

pump. The bottom of the pipe should be sealed off and one hose fitting would be made horizontally from the

elevation of each of the tiers of the wall. As discussed above, the hose will have pre-drilled holes to allow

for the water to drip out at multiple points along the length of the hose.

The team was given a total budget of $1,500; $960.30 was allocated per the original Bill of Materials

(Appendix B). This included the piping that the sponsor already purchased, so the total cost would be far

under budget. The remaining $540 would be used for finishing of aluminum parts, testing, and a buffer for

troubleshooting any design issues.

5.2. Implementation Overview

5.2.1. Centrifugal Pump

Materials for the proposed team manufactured pump were purchased towards the end of winter break

and the beginning of winter term. Finding the materials was relatively strait forward, as most of the

materials were common. The one exception was the polycarbonate, which was difficult to locate. It was

purchased within the first few weeks of the term.

The initial pump, fabricated by the team, was made of 4 main body parts: top and bottom case halves

(PMP002-1 and PMP002-2), an impeller (PMP002-3) and a shaft (PMP003-1).

The shaft casing (PMP003-2) was the first to be manufactured. This was done on a lathe, and there were

no complications in the fabrication. The shaft (PMP003-1) was then manufactured from stainless steel.

This part was more complex, and after its completion, it was evident that the shaft needed to be longer in

order to properly attach to the pump and stand. The shaft was redesigned an inch longer, to allow for the

shaft collar that resided on a large support bearing. A pulley (PMP003-9) was made on a lathe from

aluminum, and was very easy to manufacture.

The top case half (PMP002-1) was fabricated from polycarbonate plastic to allow for viewing into the

pump, to keep the pump interesting by allowing visibility of how a centrifugal pump functions. The part

was drawn in SolidWorks and exported into Edgecam software to generate CNC machining code. The

code was run on a Bridgeport CNC machine, which is a computer controlled 3-axis milling machine.

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The bottom case half (PMP002-2) and the impeller (PMP002-3) were machined in a similar fashion, but

were machined on a Fadal CNC, which has coolant capabilities to expedite the machining process and

allowed fa