EWB-MN Kyetume, Uganda Critical Design Review

March 5, 2008

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IntroductionIntroduction

Location – rural village 40 km south of Masaka, Uganda

Community of 2000 where 19% of the children are orphans

Partnership – Uganda Rural Fund All volunteer 501(c)3 non profit

started in 2005 to provide education and support for disadvantaged children, AIDs orphans, and marginalized communities throughout Uganda

The SchoolThe School

Uganda Rural Fund is building the Hope Integrated Academy

This school is designed to provide young people and adults with education and technical skills as a primary school, vocational school, community library, community center; and health clinic

Currently a after school program for 200 children

Future development will provide housing for 300 AIDS orphans and teach 200 children and adults from the community.

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Current and Future LayoutCurrent and Future Layout

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NeedsNeeds

Water supply Currently water is not provided to after school students. Closest water supply is 1 km away from school

Sanitation System Currently using deep pit latreens Need system for up to 300 children

System Rainwater harvesting Ecological sanitation system with dry composting Future work on Well drilling

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Water StorageWater Storage

Capacity for next two years – 250 after school children Usage – 5 L/day

Size estimate

100,000-120,000 L

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Storage TankStorage Tank

Options Ferrocement tanks Polytanks

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Ferrocement ConstructionFerrocement Construction Tank Size

Height 8 ft Diameter 18 ft 57,000 L

Steps Outline tank placement Dig and Level ground with

1o slope Lay mesh rebar for floor Extend Rebar for walls Outline with wire mesh Pour concrete for floor keep

wet for days Bend rebar for roof Plaster walls After week Seal it

Total Time 2 weeks8

Ferrocement TankFerrocement Tank

5/16 rebar (40’ pieces) - > 30 pieces @ 5.71 = $171.30 6x6x10x10 Welded Wire Mesh (7’x200’ rolls) -> 1.5 @ ? = ? ½” Hardwire Cloth (4’x100’ rolls) -> 2 @ ? = ? Tie Wire (big loop bundles) -> 3 @ ? = ? Cement (50 lb bag) - > 80 @ 13.14 = $1051 Sand (yd3) -> 5.5 @ 34.29/truck = $68.58 ? Water (L) -> 3800 @ ? = ? Aggregate (yd3) -> 4.5 @ 40/truck = $80.00 ? Hog ring staples (boxes of 10,000) -> 2 @ ? = ? Supporting poles for ceiling -> 15 @ ? = ? Spacers for floor -> 65 @ ? = ? Labor -> 2 weeks = ?

Total/tank = ~$3000

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24,000 L Tanks -> 4 @ 3,439 = $13,756 PVC Pipe connectors, Hand pump?, drain Steps

Dig and level ground, sight slope for first tank Place tanks Connect with pipes

Poly TanksPoly Tanks

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Sludge Drain

3.4 m – 11 ft

Inflow

Outflow

3.22 m – 10.5 ft

Settling Tank

Comparison of TanksComparison of Tanks

Ferrocement

Advantages

Cheaper

Larger Capacity

Disadvantages

Construction time

Complexity of construction

Could crack

Permanent

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Poly tank

Allows for a settling tank

Can be improved or easily expanded

Can be moved/not permanent

Cost

UV degradation

Tank PlacementTank Placement

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13

11 ft

2 ft

Rainwater FlowRainwater Flow

ElevationsElevations

ElevationsElevations

ElevationsElevations

Collection systemCollection system

Debris collection- leaf screen

Gutter system- facia, gutter attachment

Disinfection- chlorination

Large particle collectionLarge particle collection

• 3 ft sections

• $1

• $6

FasciaFascia

Gutter Price listPVC piping size quantity $cost/ unit $costdownspouts 5" 6 5.88 35.2890 deg elbow 5" 16 6.39 102.2445 deg elbow 5" 6 3 1810 ft of gutter 5" 24.05 12.88 309.764PVC cement 2 4 8downspout adapter 6 0hanger system 5" 22 2.98 65.56epoxy paint 1 gal 1 44 44leaf guard 5" 2.5 63 157.5

total 740.344

disinfectiondisinfection

Boiling Rapid sand filter Slow sand filter SODIS-solar disinfection Filtron- porous clay filter Electrical Ultraviolet Chemical disinfection-chorlination

ChlorinationChlorination• sanitization with 20-ppm chlorine for 30 to 60 minutes. Higher concentrations

or longer soak times will increase effectiveness of sanitization, but we do not recommend using higher than 50-ppm chlorine in any case. Repeated sanitization at higher concentrations can cause corrosion of stainless steel drinking valves, manifolds, and room distribution piping in an automated watering system.

• Bacteria- Effective at reasonable CT values for IWPD use. • Viruses -Effective at reasonable CT values for IWPD use. Use EPA SWTR CT

table for recommended CT values (Table 1). Giardia Cysts Effective at reasonable CT values for IWPD use. Use EPA SWTR CT tables for recommended CT values (Appendix B). Cryptosporidium Oocysts Ineffective, even at high CT values. Not practical for IWPD use.

• Effect of pH- Disinfection efficiency increases with decreasing pH. Recommend pH less than 8.0 to ensure presence of hypochlorous acid (HOCl).

• Effect of Turbidity- Higher turbidity generally reduces disinfection capability. Higher dosages may be necessary to ensure the presence of free chlorine after oxidation of organic matter.

• Health Effects- Chlorine, THMs and HAAs have potential health concerns at elevated levels. IWPD manufacturer-recommended dosages are not likely to cause adverse health effects for healthy adults.

Clean Water SupplyClean Water Supply

The Hope Integrated Academy is located in an area of Uganda that lacks significant available groundwater, yet the area experiences two major rainy seasons per year.

Given the annual rainfall data and the large collection area afforded by the academy building, the EWB-UMN design team has chosen to implement a rainwater harvesting system for the Hope Integrated Academy.

Clean Water Supply: System Clean Water Supply: System OverviewOverview

The system consists of:• Rainwater catchment system to collect the water from the

roof with protected gutters. The gutters will attach to the roof frame. Downspouts and piping will convey the collected water to the storage structures.

• First flush system to prevent the solids and contaminants from the roof entering the storage tanks and to clean the gutters.

• Initial filtration to separate additional solids from entering the storage tanks.

• In-line chlorination treatment to ensure potable drinking water

• Water storage structures to hold 120,000 liters of water in two above ground concrete tanks located behind the school. These tanks will gravity feed water to distribution outlets.

AttachmentsAttachments

•Current resources are boards from the frame that extend to the edge of the roof. The type of timber, age, and expected time duration Is unknown.

•The picture shows John Mary looking at the roof frame. The arrows are not real.

Gutter System ExpensesGutter System Expenses

Material Value Units

Gutters 1,200,000 UGXFace Boards 700000 UGX

Brackets 320000 UGX

Nails 60000 UGXPainted Fascia 100000 UGX

Labor 500000 UGXUnexpected 120000 UGX

Total 3000000 UGX

1900 USD

•Numbers supplied by Uganda Rural Fund

First Flush SystemFirst Flush System

As the chamber fills, the ball floats up and seals on the seat, trapping first-flush water and routing the balance of the water to the tank.

Ref: The Texas Manual on Rainwater Harvesting. Texas Water Development Board. 2005

Sizing the First Flush Sizing the First Flush SystemSystem

•The recommended diversion of first flush ranges from one to two gallons offirst-flush diversion for each 100 square feet of collection area.

•If using a roof for a collection area that drains into gutters, calculate the amount of rainfall area that will be drained into every gutter feeding your system.

•There will be 3 downspouts on each side.

•The PVC pipe will be 4 inches diameter, 8 feet long leading into 1 ft cubed holding tank. Sixteen gallons will be collected at each location.

Roof WasherRoof Washer

•The roof washer, placed just ahead of the storage tank, filters small debris forpotable systems and also for systemsusing drip irrigation.

•All roof washers must be cleaned.Without proper maintenance they become clogged and may become breeding grounds for pathogens.

•The box is placed atop aladder-like stand beside the tank, fromwhich the system owner accesses thebox for cleaning via the ladder.

Ref: The Texas Manual on Rainwater Harvesting. Texas Water Development Board. 2005

In-Line ChlorinatorIn-Line Chlorinator

•CTI 8 Chlorinator is an inexpensive, low-maintenance, non-electrical, appropriate-technology apparatus.

• It is capable of delivering a controlled dosage of chlorine sufficient to inactivate most pathogens

•The CTI 8 accomplishes disinfection by directing water flow over solid chlorine tablets in a simple configuration of PVC tubing.

Compatible Technology International (CTI)

In-Line ChlorinatorIn-Line Chlorinator

Costs•A CTI 8 chlorinator can be built and installed for around $100.00 US per unit.

•For a typical community of 200 people, monthly operational costs including chlorine can be expected to be between $5 and $10 US, depending on various factors such as temperature, level of contamination and quantity of water flow.

Materials•The chlorinator is constructed of 3-inch and 4-inch PVC pipe and fittings, and ¼-inch PVC plate.

•The CTI 8 can be built in a matter of hours using basic hand tools.

•It uses chlorine in the form of calcium hypochlorite tablets approximately 2 ½ inches / 6.35 cm in diameter.

In-Line ChlorinatorIn-Line Chlorinator

Criteria Requires pretreatment

Settling tank and filtration

Requires zero water pressure

Chlorine concentration measurements at outlet with color coded chlorine detection kit

In-Line ChlorinatorIn-Line Chlorinator

•Training program on construction, installation and maintenance of the equipment

•Include training programs on alternative treatments such as UV light and sand filters

SANITATIONSANITATION

Ecological Sanitation – Dry Composting

Design ObjectivesDesign Objectives

(1) Prevent disease (2) Protect environment (3) Return nutrients to earth via composting and

agricultural application (4) Provide culturally accepted sanitation (5) Maintainable (6) Convenient to use (7) Affordable (8) Sufficient for capacity (250 people, ~80% Children) (9) Constructible (10) Prevent Odor (anaerobic processes)

System ComponentsSystem Components

Elevated masonry sanitation structure Low-cost urine diverting toilets with separate collection systems

Temporary storage space directly underneath toilets Movable collection containers (>.25 m3) Long-term storage area adjacent to sanitation structure Composting education, hygiene education

Design: System UseDesign: System Use

250 daily users within 1 year School to house 300 orphans within 2 years

20% adults (50) 80% children (200) Density of faeces: 1000kg/m3

Design: System UseDesign: System Use

Solid waste volume Adult Saturated vol: 1.37x10-4 m3/day x 50 adults = .00685

m3/day (conservative as saturated)– 50kg/adult/yr (saturated); 11kg/adult/yr (dry)

Child Saturated vol: 9.60x10-5 m3/day x 200 children = .0192 m3/day (conservative as saturated)– 35kg/child/yr (saturated); 7.5 kg/child/yr (dry)– Based on conservative weight ratio of 30 yr to 10 yr old (M 170lb:85lb = .5;

F 135lb:88lb=.65)

TOTAL DAILY VOLUME = 0.02605 m3/day TOTAL MONTHLY VOLUME = .7815 m3/month TOTAL 6 MONTH VOLUME = 4. 7 m3/6 month

Resource: World Health Organization

Design: System UseDesign: System Use

Liquid waste volume Adult Vol: 400L/yr (.4 m3)= 1.10 L/day (.001 m3/day)

(conservative as saturated) Child Vol: 322L/yr (.322 m3)= 0.77 L/day (7.7x10-4 m3/day)

(conservative as saturated) TOTAL DAILY VOLUME = 467.5 L/day (.4675 m3/day)

Design: StorageDesign: Storage

Solid: 4.75 m3/6 month .25-.5L ash per use

As solids dry, volume reduces 80%, so ash addition is countered by reduction

Design assumes solid waste is always saturated, so assumptions remain conservative

Design: StorageDesign: Storage

Containers: To store 4.75 m3 for

40 gal (80% of 50 gal cans) = .189 m3 33 containers

2’ x 2’ x 3’(garbage can) = .34 m3 14 containers

2’ x 2’ x 4’ (large garbage can) = .45 m3 11 containers

Storage Area required = 6.5 m x 2.5 m

Budget Rainwater collection $1900 Water Treatment $500 Water Storage $15000 Sanitation $5000 Hydrogeology $700 Total $23,100

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Implementation PlanImplementation Plan

Future phases Well Water tower Expansion as school grows