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fermer ce livreA Guide to the Development of on-site Sanitation (WHO; 1992; 246 pages)
Afficher le documentPreface
ouvrir ce répertoire et afficher son contenuPart I. Foundations of sanitary practice
ouvrir ce répertoire et afficher son contenuPart II. Detailed design, construction, operation and maintenance
fermer ce répertoirePart III. Planning and development of on-site sanitation projects
ouvrir ce répertoire et afficher son contenuChapter 9. Planning
ouvrir ce répertoire et afficher son contenuChapter 10. Institutional, economic and financial factors
fermer ce répertoireChapter 11. Development
Afficher le documentImplementation
Afficher le documentOperation and maintenance
Afficher le documentEvaluation
Afficher le documentReferences
Afficher le documentSelected further reading
Afficher le documentGlossary of terms used in this book
Afficher le documentAnnex 1. Reuse of excreta
Afficher le documentAnnex 2. Sullage
Afficher le documentAnnex 3. Reviewers
Afficher le documentSelected WHO publications of related interest
Afficher le documentBack Cover


The purposes of the preliminary surveys are to determine the extent to which a sanitation programme might be effective and to begin to determine the most appropriate means of meeting public health needs. If the surveys indicate that there is a possibility of a programme being successful, a demonstration phase is required. This phase has three main objectives:


- to identify the techniques and materials that will be most cost-effective;
- to demonstrate the resulting sanitation systems to the community and the government;
- to begin to stimulate demand for sanitation from individual householders.

Experimental period

An experimental period is normally required for a new sanitation project, during which field staff investigate whether the proposed combination of materials and techniques will work effectively at an affordable level in the particular sociocultural and geographical situation. For example, different systems may need to be compared, and certain elements, such as pit linings, concrete slabs or water seals, may need to be adapted in order to use locally available materials.

Particularly where new techniques or materials are being introduced, the initiators need to carry out a pilot project to work out the technical details to their own satisfaction before promoting the idea to others. Low-income communities cannot afford the risk of installing an unproved system at their own expense.

The period of experimentation also provides an opportunity for informal training of field staff. Those involved in trying out the various alternatives learn the advantages and disadvantages of many different techniques. They can then subsequently explain in convincing detail and from first-hand experience why certain options are being recommended to the prospective users.

If an affordable design is already well recognized and accepted by the prospective users, the experimental phase may be omitted.


As the project staff gain confidence in the technologies they are promoting, the experimentation period will merge into the demonstration phase, when all interested parties can see the proposed facilities and make their own recommendations and decisions. This enables the promoters to ensure that the technology selected is socially and culturally acceptable to the people. In particular, community representatives and leaders should be given the opportunity to see and discuss the proposals. Results of surveys (which respondents may not always have understood) can be checked against the reality of a demonstration unit.

Government officials from both the sponsoring ministry and related departments and ministries should be encouraged to participate in discussions about the demonstrated systems. Particularly where officials believe that the only acceptable form of sanitation is a high-cost waterborne sewerage system, it is necessary to show that low-cost on-site systems are viable alternatives. Where nongovernmental organizations are involved in the provision of sanitation, it is important that the appropriate government departments have the opportunity to comment at this stage.

The experimental trials are most effective when carried out within the target area at a workshop belonging to the agency or a sympathetic institution, and where prospective users can see the alternatives being tried. The subsequent demonstration sanitation system may be a completed experimental unit or a new system at a new location. The demonstration unit is best installed where local people can try it out in something approaching normal conditions. This may reveal further problems or limitations.

Pilot projects or demonstration systems should be located where people who are committed to the programme can regularly monitor and maintain the latrines. Because a demonstration unit, used by different people, can so easily become fouled, locations that may seem suitable, such as health centres, schools or community buildings, are not always effective sites. More usefully, a health worker's home or the compound of a community development officer who is prepared to care for and maintain the system can be used. Alternatively, the home of a motivated member of the community might be suitable. Where there are village development committees, and particularly where there are water and sanitation committees, prominent members may host demonstration units.

The experimental phase may produce several designs that appear to be suitable for a particular project area. Alternatively, one option that can use a range of different materials may be viable. Variety of design should be encouraged if it enables householders of differing income levels to participate. For example, a ventilated pit latrine can work equally well with a concrete slab or a maintained earth and pole slab. The demonstration phase should show how each solution can be used within the community and at the same time draw attention to possible ways of upgrading the system when financial circumstances permit.

Stimulating demand

The selection of an appropriate sanitation system should be the responsibility of the people who will ultimately use it. The demonstration phase may be considered as a shop window where potential consumers can see what is on offer at a particular price and determine the model they require. Although most of the selling will go on during the full implementation phase, it is useful, even at this preliminary stage of the project, to begin to stimulate demand.

In many sanitation projects, the public health professionals take a strong lead in initiating the feasibility and demonstration phases. However, the responsibility for successful construction, operation and maintenance should be transferred to the community at the earliest opportunity, preferably before the full implementation or expansion phase starts. Experience has shown that the most successful sanitation projects involve a partnership between the people who will use the scheme and an assisting agency. The agency may be tempted to take too strong a lead role and to attempt to move the programme along too quickly. Working without adequate community involvement may appear to achieve progress in the short term, but it is often to the detriment of the project in the long term.

Wherever possible, low-cost on-site sanitation should be planned and built by the people, operated by the people and maintained by the people. The aim is for minimal agency participation in a community project. As described above, the agency can significantly assist with experimentation and demonstrations to aid people in the decision-making process. The agency can attempt to ensure that the right people have visited demonstration projects. It can help local organizations and government bodies to be aware of the issues by preparing clearly presented documentation. However, to be certain that the people know that the project belongs to them and is under their control, it is important for the agency to restrict its role and not try to direct the project. The community and particularly the individual householders have to sort out their own priorities and move forward at their own pace. This may appear to delay progress and it may frustrate helpers, but true community decisions take time.

Glennie (1983) commented that programmes in which people have been forced to build latrines or where latrines have been provided free of cost have generally failed. "It is essential that a villager builds a latrine only as a result of a conscious decision that he wants to use one. It is the use, rather than the construction, of the latrine that is crucial. The strategy to be adopted therefore, is to encourage at least some villagers to decide that they want to use latrines, thereby stimulating a genuine demand."

In terms of the project cycle, information derived from the demonstration phase concludes the feasibility stage. At this stage, some governments and donor agencies may require an appraisal of the proposals, in the form of an independent check on the work that has been carried out. This appraisal normally covers technical, social, health, environmental, institutional, financial and economic criteria to determine whether the project is well planned and worthy of further investment. On the basis of the appraisal, the donor or government ministry may subsequently approve the decision to proceed with the project. This enables the consolidation phase to commence.


At the community level the distinction between the demonstration phase and the consolidation phase may appear blurred. However, there comes a point where the basic technology has been proved to be feasible and the project is generally acceptable. Before widespread implementation can begin a period of consolidation is required, primarily to organize the institutional aspects of the project. The demonstration units should continue to be operated and cared for, but the primary thrust at this stage is to determine the support (technical, financial, material and administrative) that the agency will have to provide in order to enable householders to build their own latrines. Training of community personnel and technicians, identification of community leaders, involvement of staff from the health, education and other sectors, confirmation of sanitary codes and regulations, testing of promotional materials, and general administrative support all have to be considered.

Governmental approval

The agency should finalize, as far as possible, the recommended designs for latrines, and seek the widest possible governmental acceptance for the programme. This approval should be sought not only from the institution directly responsible for sanitation but from all interested ministries, councils and committees. However, following on from the demonstration phase and initial contacts with community leaders, the agency and other institutions have to recognize that householders are unlikely to come to a clear-cut decision. Unless the community is unusually homogeneous, it is probable that the people will want a range of options at varying costs. For example, at the simplest level a lined pit could be constructed with a wood and mud slab and only a screen for privacy. At a later date, the household may be able to afford a concrete slab to replace the timber and mud, and then later still a permanent superstructure could be built. On the other hand, some families may be able to afford a concrete slab from the outset.

In certain situations, some latrines may later be upgraded by connection to a main sewerage system, but it is normally impracticable to make specific plans for such improvements in the early stages.

Institutional support

The flexibility required to meet the differing expectations of householders makes the agency's work more difficult. The assistance proffered has to take into account the various income levels and preparedness of the different groups to invest. The agency therefore needs to focus on the aspects of the programme that are crucial to its success. These may be technical, financial, institutional, social or promotional, but the agency would do well not to be diverted into trying to enforce one set solution. In many projects this means that the superstructure, design and construction are left to individual householders, while the agency concentrates on general promotional work and helping with slabs and linings along with the water seal (and connecting pipe) or vent pipe, where required.

The approach adopted by the agency must be worked out in advance of widespread promotion within the community so as to minimize any confusion. Whichever approach is taken, standardized procedures should be fixed during the consolidation period. Agency staff can then be trained in these procedures to enable them to give clear and coherent advice to householders.

Any necessary administration required to support the field staff should also be determined on the understanding that it will be there to assist rather than to restrict or limit.


Sanitarians and technical staff who were not involved in the demonstration phase should be told about the results and techniques developed earlier. Related staff, such as health workers and sociologists, should also be given an introduction to the programme. The extent of training needed will depend on their proposed role within the programme, but at the least they should be fully informed as to what is expected of the householders.

Similarly, teachers in local educational establishments should be introduced to the programme and ideally provided with suitable educational material to use with their students. Artisans not directly responsible to the agency but who may become involved as small contractors should be trained in any specialized techniques that may have been developed during the experimentation. Training programmes for householders should be prepared and tested for later use.

Pre-testing of promotional materials

Any leaflets, plans, posters or other explanatory or promotional material should be pre-tested during the consolidation phase to ensure that the message being received by the readers is the one intended by the promoters. Similarly any teaching materials for schools should also be tested.

Sanitary codes and regulations

Basic legislation is necessary to enable a public health agency to initiate and develop activities in the field of public health and sanitation. Enabling legislation is normally confined to statements of broad principles, responsibilities and penalties. On the basis of such legislation, the public health agency concerned is in a position to formulate more detailed rules, regulations and standards.

Any existing sanitary code may exert a strong influence on the nature and content of an excreta disposal programme. If the sanitary regulations are outdated, or too elaborate or exacting, they may restrict both the technical and the administrative aspects of the project. Such regulations may defeat their own purpose and are often ignored by the population. When suitably drafted, regulations are useful in helping to ensure a basic minimum of sanitary safeguards and the elimination of potential health hazards, especially in densely populated communities. They usually deal with and prescribe standards for such matters as: the prevention of soil and water pollution, the disposal of human and animal wastes; the hygiene aspects of housing; the protection of food supplies; the control of arthropod, rodent and mollusc hosts of disease; and the use of surface water.

When elaborating sanitary regulations it is important to keep in mind the following principles:


• No regulation should be made that cannot be enforced.
• No law can be enforced without the cooperation of most of the people concerned.

Rules and regulations applying to excreta disposal in low-income areas should be reasonable and no stricter than necessary; above all they should be in accordance with the basic principles of sanitation. It is important to consider every contigency that may occur within the foreseeable future, and the best way to do so is to consult the people for whose benefit the regulations are formulated. While the experience of others may be useful in drafting new regulations, it is always a mistake to adopt the regulations of another country without making necessary modifications.

On the need for the cooperation of the people in the enforcement of legislation, Lethem (1956) wrote, "No form of control can be effective without the support of most of the people concerned, backed by an enlightened public opinion. Hence, education must precede legislation; in fact it might be described as the father of legislation. The lower the standard of education, the greater the need for careful preparation before new regulations can be introduced and enforced. It is better to start in a small way and work up, than to introduce a multiplicity of rules and raise a wall of opposition, which makes enforcement difficult. Legislation alone cannot improve hygiene. To launch regulations without first preparing the way, is like sowing seed without first ploughing the ground. Old traditions die hard, and bad habits are not easy to change."

This statement is particularly applicable to excreta disposal programmes, which are designed to bring about changes in people's attitudes and practices. In this field, public health instruction is more important than compulsion, and sanitary inspection should not have as its primary aim the enforcement of regulations by means of sanctions.

There may be particular areas of concern in existing by-laws which may limit the freedom to introduce low-cost sanitation programmes. For instance, regulations may specify that only water closets connected to a sewer or septic tank are acceptable in urban areas. Other rules may specify a minimum depth for pit latrines which would be unrealistic in particular ground conditions. It is important that these points are amended after full consultation. The most suitable time to make changes is during the consolidation phase, after the various technologies have been tested but before the expansion phase.

Other points to be considered for legislation include the following:


• Defecation in streets and public places should be illegal once sanitary facilities have been made available. Households should be required to install sanitation systems within a specified time of the sanitation programme commencing.

• No new housing developments should be allowed to proceed without suitable sanitation provision.

• The letting of any house or part of a house or household plot for residential purposes without sanitation facilities should be illegal.

• Where a landlord fails to provide sanitation within a specified time, tenants should be empowered to construct facilities and deduct the expense, as agreed with the agency's officers, from the rent payable to the landlord.

• In certain circumstances, local authorities may be empowered to recover loans for construction of latrines from the beneficiaries through local taxation (Roy et al., 1984).

Mobilization or expansion

The mobilization or expansion phase aims to encourage and enable every householder and institution in the target area to acquire satisfactory sanitation facilities within a certain period of time. This period of expansion may be considered in terms of promotion and construction. Promotion consists of convincing individual householders that they need to improve their sanitation and have the capability to do so. Once the householders make their decision, the individual construction phase begins with particular requirements for support.


The mobilization phase is a time of mass communication. It is an opportunity to share information and lessons learnt from the preceding stages with the target group for the programme. Health education to explain the need for sanitation usually has to be stressed as strongly as the proposed solutions. Until people understand the objectives of the project and why sanitation is so important to them, they are unlikely to be fully committed to it. However, in considering the methods of health education and promotion listed below, it is helpful to remember that the primary motivation for sanitation is often the desire for privacy and convenience. Ultimately it has been found that most people choose to improve their sanitation when they see that their neighbour has a clean affordable system which is pleasant to use.

Sanitation may therefore be seen in certain circumstances as a consumer product. The technology that is successful in terms of user take-up has to have some of the attractiveness of any consumer product in addition to being effective and of good value (Franceys, 1987). A valid approach to the promotion of latrines is to consider them as products to be marketed to individual households using all the skills of the advertising and marketing industry.

This approach has been taken in programmes where the experimentation or demonstration workshops have been turned into sanitation centres. These are effectively shops where prospective customers can come to inspect the options available in the various price ranges. They can then discuss with a "salesman" the possibilities of purchasing a system and hear of the special offers open to them regarding technical assistance and financial help. This approach is particularly appropriate for on-site sanitation where each system stands on its own, unconnected to any sewer lines or communal facilities.

A more conventional approach is to consider initial promotion as part of a health education programme which has the following purposes:


• to demonstrate the possibility of improving the health status of the individual and the household;

• to demonstrate the link between well-being, health and sanitation practices;

• to create a desire for improvement in sanitary habits;

• to help determine what changes are needed and desirable for improving sanitation and how they can be implemented;

• to encourage people to put into practice good habits of personal hygiene, and measures to improve personal, home and community sanitary conditions;

• to secure sustained interest and participation in a community programme of environmental health improvement.

There are many methods of promoting health and improved sanitation as a means to health. The ideas listed below should be used in a mixture that suits the culture and aspirations of the people at the time of the programme. It is important to note that the extent of promotional activities should be linked to the agency's capacity to assist with construction of sanitation systems. Otherwise considerable frustration may build up which could be counterproductive.

Meetings and visits

Various types of meetings can be used, for example, individual discussions with community leaders, house-to-house visits by community development officers or sanitarians, visits by women health workers to the women in the community, and general public meetings where the wider issues can be discussed by the whole community.

Role of schools and teachers

Schoolteachers, especially at primary level, should be trained to prepare the children to use sanitation facilities correctly at school and to understand the need for hygiene and latrines at home. Special lessons should be given to help children understand that a clean water supply with effective sanitation can lead to improved health. This will not only be of benefit to the children but will also serve to reinforce the health message to the community as the children report back to their parents.

Demonstrations and mass treatment

Demonstrations may be held using microscopes to show what can be seen in apparently clean water. This is most effective when what is seen can be shown to result from inadequate sanitation. Where such demonstrations can be linked with special clinics to treat people who are ill from excreta-related diseases, a powerful lesson can be provided.

Community groups

Selected target groups within the community may be invited to participate in drama or role-playing related to health education and the need for sanitation. Stories and songs can also be effective ways of communicating ideas.


Simple technical information leaflets are required, containing illustrations and drawings that have been pre-tested. The leaflets should describe the different parts of the system, and explain how they work together and how they can be constructed. Written information may also be supplied detailing the help that each household can obtain from the agency. Even if householders are illiterate they are likely to be able to call upon others to explain. It is important that everybody has equal access to details of assistance. Vague promises given at public meetings are not sufficient.

The information given should stress that any solution can eventually be upgraded. Even if householders find that they do not have the required piped water or that they cannot immediately afford the type of sanitation they desire, they should be able to see that there are ways to upgrade their facilities in stages while enjoying the benefits of improved sanitation.


Ideally, the skills that may be required by local artisans or technicians should be transferred during the consolidation stage. However, where training is also required during the expansion phase, simple practical sessions or demonstrations, where participants construct components and complete systems in selected households in the target area, are effective as a form of promotion as well as training.

Use of the mass media

There are many forms of the mass media that can be used for promoting specific sanitation options as well as for health education. Their use and the balance between them will depend on the size of the target group, the relative wealth of the people and the availability of funding. Posters, billboards, newspapers, radio, loudspeaker trucks, slides, flip-charts, film, video, and broadcast television have all been used successfully in differing mixes. Careful planning is necessary, as too much information and health education coming too soon may lead to a build-up of resistance against the ideas. Karlin & Isely (1984) considered in detail the use of audiovisual materials for use in sanitation programmes.

Care should be taken to ensure that all the agencies, institutions and health-related bodies have prepared their staff to give the same message. Any conflict between them will lead to mistrust on the part of prospective users.


Selection of system by householders

In the majority of cases individual householders will be responsible for organizing the building of sanitation systems at their own houses. Having chosen the system they feel best fits their needs, they will benefit from continued assistance and support during the construction period.

Technical assistance

Technical advice regarding the choice of system, the best site for a unit, the depth to which any pit should be dug, and requirements for lining, ventilating, sealing and covering the pit should be available from technicians who can visit the household for detailed discussions. This information should also be available in the form of a written leaflet.

Where required, an auger kit for drilling trial holes may be used by the technical staff to determine the best place to dig the pit.

Training for householders

Short training sessions may be held at the demonstration workshop to teach householders how to dig and line pits and how to make slabs, vent pipes or seals. Alternatively, householders may be helped to make their own components at the demonstration site.

Identification of contractors and artisans

Although the skills required for latrine construction are relatively simple, many householders may prefer to pay others to carry out the work. A project can assist by identifying pit excavators, masons or contractors who are trained and able to carry out the work to a satisfactory standard. Agreements and pricing levels may also be negotiated by the agency on behalf of the householders.

Tools and moulds

Special tools, such as iron bars, pickaxes, spirit levels, or plumb-bobs, that are not normally available in the community, may be provided, for loan, hire or sale. Similarly, reusable moulds for concrete lining rings, slabs or water seals may also be made available by the agency.


Where the cost or a shortage of materials necessary for construction causes difficulties, the agency may help with procurement. There is, however, a danger that such materials will be misused, either by incorporation in nonsanitary household building work or through resale to traders. Because of this, materials support is often limited to the provision of precast components of a sanitation system, such as slabs, seals and vent pipes. These may be sold at commercial rates to encourage their production by local businesses, thus fostering industrial development (International Development Research Centre, 1983). Another alternative is to sell at cost price to ensure that people are paying the real cost of their sanitation and to enable a revolving fund to be set up to help others.

Where ventilated pits are recommended, PVC-coated glass fibre or stainless steel fly screens should be readily available from the agency. It is unlikely that householders will be able to purchase such material from local merchants. The alternative mild steel fly screens corrode quickly, giving rise to a significant problem with flies.

Finance and subsidies

As discussed in Chapter 10, the financial costs to be paid by the householder usually reflect the economic costs (that is, the overall cost to the nation) as closely as possible. However, where it is considered necessary for reasons of social welfare, subsidies may be employed.

Subsidies may be used where the poorest people in the community would not otherwise be able to afford a sanitation system, though care must be taken to ensure this is not simply an excuse to promote inappropriate technology (e.g., to use a more expensive alternative). Subsidies may also be employed where people are unwilling to invest in sanitation because they remain unconvinced as to the benefits to be gained, or where householders are reluctant to invest in what is perceived to be a temporary form of sanitation which does not confer the desired benefits of status and convenience. Finally, subsidies may be used where the agency desires to speed up the development process, to encourage more people to install systems at a faster rate than would otherwise be possible.

The methods used have included subsidized (low-interest) loans for construction of the complete system or loans for the purchase of specific materials or components. These loans usually form part of a revolving fund, set up by a donor, a proportion of which is made available for further projects in other areas. Loans may be totally free of interest or may include a nominal rate of interest to pay overhead charges. Where loans are charged at full commercial rates of interest there is no direct subsidy involved.

A subsidy may also be in the form of a grant for materials or components or as materials or components provided at reduced cost. One approach has been for grants to be made to householders on completion of an acceptable latrine, as an added incentive. Indirect grants may be given in the form of technical assistance or general project assistance which is not charged to the householder. Similarly, some projects may establish shops to sell building materials at cost price, avoiding normal trader profits. There is, however, a subsidy in the form of the overhead costs of the materials store.

The aim of subsidies is to enable householders to construct an acceptable sanitation system at the earliest opportunity. The resultant system has to be at a level where the householder can afford the recurrent costs of operation and maintenance. The level of the subsidy is gauged as the level that enables a sustainable system to be built which is still perceived by the householders as being under their ownership and control.

In India, experience suggests that if a programme is designed to serve the poorest of the poor, a subsidy has to be provided (Roy et al., 1984). But even for the poorest households, a small loan component requiring repayment is recognized as being vital to ensure effective participation and use of the latrines.

Site supervision

Information leaflets and training courses alone are not sufficient to ensure that latrines will be built correctly. Technical helpers need to pay visits to households where latrines are being constructed to advise and check on the technical details. Such personnel should provide constructive suggestions and encouragement, rather than negative comments and criticism.

Institutional support

The lead agency which is promoting sanitation has the major role. However, other government departments, councils, health and educational establishments can also support the project. They should ensure that their own sanitation facilities are adequate for the use of their staff, students and visitors. Such institutions can also assist by providing space for temporary storage of materials.

There are various other forms of institutional support. Government employees have been given time off from work to construct their own sanitation systems as a model for their neighbours to copy. Similarly, it has been known for a government to declare a public holiday for all employees, both private and public, to spend time building latrines. However, there is a strong likelihood that the results of such special events will be less than hoped for unless the correct preparation (surveys and demonstrations) has been done.

Loan repayments

Monthly instalments to pay back loans should be fixed at levels that are affordable rather than at rates designed to ensure quick repayment. However, this has to be balanced by the need to ensure that repayment periods are not excessive, since householders may be reluctant to continue paying over a long period for a facility such as sanitation.

Where the people have been fully involved in the construction of their latrines, it is usual to find that small loans for latrine construction are repaid. If a programme is forced through by an agency without full community involvement, it is likely that there will be a low return rate on loans.

Completion of the programme

Within most programmes, the rate of completion of individual sanitation units tends to follow an "S" curve (Fig. 11.1). In the initial demonstration and consolidation phases there is little progress in terms of numbers of systems completed. During the expansion phase the majority of the population are expected to install latrines. However, the rate of installation normally falls as the 80% completion level is neared. During the completion stage additional positive inducements should not be used, since this would be unfair to those who have already constructed their facilities on their own. Unless the failure to complete is due to particular social disadvantage, in urban and periurban areas legal action may have to be taken to ensure completion by all households. As the health benefits cannot be fully realized unless all members of the community use improved sanitation (particularly in areas of high population density), it is reasonable to expect substantial compliance.

Fig. 11.1. Pattern of installation of latrines in a sanitation programme


WHO 91500

There are many different approaches to assisting householders to construct their own sanitation facilities. For each project the right mix of assistance, motivation and legislation has to be determined in order to produce the desired results.

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