Cover Image
close this bookWater and Sanitation Technologies: A Trainer's Manual (Peace Corps, 1985)
close this folderSessions
View the documentSession 1 - Water and sanitation issues in third world countries
View the documentSession 2 - Introduction to the training program
Open this folder and view contentsSession 3 - Facilitation skills
Open this folder and view contentsSession 4 - Community mobilization
Open this folder and view contentsSession 5 - Math review
Open this folder and view contentsSession 6 - Concrete and reinforcement
Open this folder and view contentsSession 7 - Project documentation
View the documentSession 8 - Field demonstration: Formwork and pouring concrete
Open this folder and view contentsSession 9 - Introduction to environmental sanitation
View the documentSession 10 - Non-formal health education
Open this folder and view contentsSession 11 - Community water supply case study
Open this folder and view contentsSession 12 - Project planning and management
View the documentSession 13 - Community needs and resource assessment
Open this folder and view contentsSession 14 - Communicable diseases and control
Open this folder and view contentsSession 15 - Excreta disposal systems
View the documentSession 16 - Health education presentations
View the documentSession 17 - Basic drawing and blueprint reading
View the documentSession 18 - Field demonstration: block laying
View the documentSession 19 - Project planning: Latrine construction
View the documentSession 20 - Latrine construction
Open this folder and view contentsSession 21 - Women and water
Open this folder and view contentsSession 22 - Hydrology
View the documentSession 23 - Water supply improvements
View the documentSession 24 - Pumps: Installation, operation, maintenance
View the documentSession 25 - Field demonstration: Pump assembly and disassembly
Open this folder and view contentsSession 26 - Field demonstration: Pipework and plumbing
Open this folder and view contentsSession 27 - Principles of hand-dug shallow wells
View the documentSession 28 - Well site inspection and feasibility survey
View the documentSession 29 - Project planning: Well rehabilitation
View the documentSession 30 - Shallow well rehabilitation
Open this folder and view contentsSession 31 - Gravity water systems: Part I
Open this folder and view contentsSession 32 - Survey and measurement
View the documentSession 33 - Field demonstration: Surveying
Open this folder and view contentsSession 34 - Gravity water systems: Part II
Open this folder and view contentsSession 35 - Principles of spring development
View the documentSession 36 - Spring site feasibility survey and flow measurement
View the documentSession 37 - Project planning: Spring development
View the documentSession 38 - Spring development construction
View the documentSession 39 - Ferrocement technology and construction
View the documentSession 40 - Project planning: Ferrocement water tank
View the documentSession 41 - Ferrocement water tank construction
View the documentSession 42 - Constructing projects in a community
Open this folder and view contentsSession 43 - Proposal writing
View the documentSession 44 - Training review and assessment

Session 20 - Latrine construction

TOTAL TIME

38 Hours

OBJECTIVES

* Construct a ventilated pit latrine using reinforced concrete, adobe block walls, cement stucco finish, and framed roof


* Formulate a maintenance plan for the latrine

RESOURCES

Small Excreta Disposal; Ross Institute, Chapters 4-5


Sanitation Without Water; Winblad/Kilama, Chapters 4-6


Rural Water and Sanitation Projects; USAID, pp. 199-208, 219-231, 245-259


Rural Sanitation: Planning and Appraisal; Arnold Pacey, Chapters 4-5

PREPARED

Shovels, hammers, crosscut saws, keyhole saws, hacksaws, hoes,

MATERIALS

sledge hammers, trowels, picks, paint brushes, pliers, crow bars, brace and bit, tape measures, T-squares, builders' levels, line levels, string, screwdrivers, woodrasp, buckets, wheelbarrows, wrenches, mattocks, vise grips, wire cutter, water level, bailing wire, reinforcement bar, nails (#8, #12, #16, roofing), lumber (4x2, 1x4, 1x6, 2x6), anchor bolts, roofing material, cement, sand, aggregate, adobe blocks, door hinges and fittings, chicken wire, PVC pipe and fitting, PVC solvent cement, screening, plastic sheeting, burlap sacks, and gloves

FACILITATORS

One or more trainers

Trainer Introduction

During this session, an improved ventilated pit latrine is built. The basic design consists of a pit (two to three meters deep), a foundation collar for the pit (three meters by two meters), a reinforced concrete slab (three meters by two meters), adobe brick walls (two meters high), a framed roof, and a finished cement stucco. It is designed with one squat hole chamber and entry way with door. Refer to the drawings on pages 165 & 166. This basic design may be altered to fit the circumstances of specific training program. However, it should be kept in mind that this design focuses not only on latrine building, but also on teaching construction skills such as masonry and framing.

If the design is changed, time allotments for each step will have to be changed in accordance. Whatever basic design is selected, the exact specifications should be done by the trainees themselves, in conjunction with local community members if the project is done on the community level. The number of trainees in the group should be between eight and 12. Trainers should serve as technical advisors during the design and construction phases of the project. The resource books should serve as reference information for the trainees. The time set aside for each construction step is a close approximation, based on previous training experience. It does not include time spent on logistics, transportation, or digging the pit. It is assumed that the pit is dug before the overall session begins.

There are a variety of activities during this session. Make sure all trainees participate in all activities by having the project manager rotate trainees through the various tasks. Finally, proper construction safety practices should be followed at all times. Trainers should take the time to explain such practices and make sure that they are followed throughout the exercise.

PROCEDURES

Step 1

4 hours


Form and pour a reinforced concrete foundation collar, 12-14cm in width and depth (depending on soil conditions), around the edge of the pit.

Trainer Note

The foundation collar serves as the footing for the slab and superstructure. Rough lumber can be used for the formwork and should be squared and leveled. However, the surface of the concrete should be left rough to provide a good bond with the slab. Reinforcement should be properly placed. The collar should be cured properly and allowed to set up at least overnight before Step 2 begins.

Step 2

6 hours


Form and pour in place a reinforced concrete slab with squat hole and vent pipe hole.

Trainer Note

Pouring the slab in place is done for two reasons. First of all, it will not be necessary to move the slab after it has been poured, which is difficult for a slab of this size. Secondly, the process teaches valuable concrete and formwork skills.

To pour the slab in place, a table must be constructed over the pit (rough lumber works well). It should be well supported both across horizontally and vertically down in the pit, and sit flush with the top of the foundation collar. A form of 2x4 lumber should be set around the outside edge of the collar and leveled, which will serve as the finished dimensions of the slab. Reinforcement should be properly placed, as should the holes for the squat and vent pipe. A PVC pipe fitting may be cast in the slab to allow easy installation of the vent pipe. The slab should be cured properly and allowed to sit two to three days before Step 3.

Step 3

8 Hours


Erect at least three-fourths of the adobe walls. Construct door frame.

Trainer Note

At least three quarters of the wall should be laid; if time allows finish the wall. Starting with the first course, make sure the bricks are laid properly and plumb. Inspect how the corners are being laid and the overall brick laying patterns. Insert wooden blocks, the exact size of a brick, into the walls every two or three courses (gringo blocks) to serve as nailers for the door frame. The dimensions for the door frame must be exact or it will not fit when put in place. The door frame should be set no later than after two or three courses of bricks have been laid. Step Four may begin the following day.

Step 4

8 Hours


Finish the adobe walls. Form and pour a concrete bond beam. Construct door. Apply cement stucco scratch coat.

Trainer Note

The final courses should also be laid properly and plumb. The bond beam should be 12-14 cm thick. It can be formed by fitting lengths of rough lumber to the top of the walls, inside and outside, held together by lengths of wire at the top and bottom. The forms should be leveled, reinforcement placed, concrete poured, and anchor bolts set for the roof plate. Make sure the bolts are properly placed, and the beam is cured.

To apply the stucco, the walls must first be wrapped tightly with chicken wire. Use nails to anchor the wire, nailing into bricks rather than joints. Next, wet the walls down with water and then plaster the cement stucco. The plaster used for stucco is usually a cement to sand ratio of 1:4, with lime added to the mix, if available, in a lime/cement ratio of 1:3. This coat should cover the walls completely, with little or no wire exposed. It should be scratched rough to provide for a good bond with the finish coat. Make sure that the walls are protected from direct sunlight and cured properly.

Step Five may begin the following day, or allow the bond beam to set one full day if time allows.

Step 5

8 Hours


Place a roof plate on the bond beam, secured with anchor bolts.


Build the roof frame. Lay the roofing material. Place the door(s).


Apply finish coat of cement stucco to the walls.

Trainer Note

If the bond beam is level, anchor bolts placed correctly, and the walls built plumb, the roof construction should go smoothly. Begin framing by securing the roof plate on the bond beam. Then, frame out the roof structure with rough lumber. The roof header should be square, securely nailed in place, and provide a 1:3, or 1:4 pitch. The rafters should be notched, placed on centers, and nailed in place. For roofing material, use rough lumber covered by roofing paper, or use corrugated iron or tin sheeting. A hole should be cut in the roof for the vent pipe, if necessary. The plaster used for the stucco is again a 1:4 mix, with lime if available. Wet down the walls before applying the plaster. This will be the finish coat and should be worked smooth with no exposed wire when completed. Make sure the stucco walls are cured properly and protected from direct sunlight. Start Step Six the following day.

Step 6

4 hours


Install and secure the vent pipe. Complete any remaining work on the latrine, such as painting, stuccoing, and cleaning. Formulate a maintenance plan, and explain it to local community members.

Trainer Note

This time is set aside to finish all remaining work and clean up the site. If the latrine will be used by members of the community, make sure they understand the maintenance plan.

Lastly, the entire group should review the construction procedures and processes that went into the project. Discuss positive and negative aspects. Ask what could have been done differently to improve the construction. Ask about the group dynamics of the exercise. What improvements could have been made? What worked particularly well? Point out the importance of hard work, flexibility, and cooperation throughout such an activity.


Latrine Design Drawing - Plan View


Latrine Design Drawing - Side View