Human excreta always contain large numbers of germs, some of which may cause diarrhoea. When people become infected with diseases such as cholera, typhoid and hepatitis A, their excreta will contain large amounts of the germs which cause the disease. Fact Sheet 3.1 discusses excreta disposal options.
When people defecate in the open, flies will feed on the excreta and can carry small amounts of the excreta away on their bodies and feet. When they touch food, the excreta and the germs in the excreta are passed onto the food, which may later be eaten by another person. Some germs can grow on food and in a few hours their numbers can increase very quickly. Where there are germs there is always a risk of disease.
During the rainy season, excreta may be washed away by rain-water and can run into wells and streams. The germs in the excreta will then contaminate the water which may be used for drinking.
Many common diseases that can give diarrhoea can spread from one person to another when people defecate in the open air. Disposing of excreta safely, isolating excreta from flies and other insects, and preventing faecal contamination of water supplies would greatly reduce the spread of diseases. Fact Sheet 3.2 deals with open-air defecation, while Fact Sheet 3.3 covers cartage.
In many cultures it is believed that children's faeces are harmless and do not cause disease. This is not true. A child's faeces contain as many germs as an adult's, and it is very important to collect and dispose of children's faeces quickly and safely.
Fact Sheets 3.4 to 3.8 describe the construction of different types of latrines, and Fact Sheet 3.9 provides information on septic tanks.
The disposal of excreta alone is, however, not enough to control the spread of cholera and other diarrhoeal diseases. Personal hygiene is very important, particularly washing hands after defecation and before eating and cooking.
Wastewater disposal and reuse
Wherever crops are grown, they always need nutrients and water. Wastewater is often used in agriculture as it contains water, minerals, nutrients and its disposal is often expensive. Where effluent is used for irrigation, good quality water can be reserved exclusively for drinking water. Wastewater can also be used as a fertilizer, thus minimizing the need for chemical fertilizers. This reduces costs, energy, expenditure and industrial pollution. Wastewater is also commonly used in aquaculture, or fish farming.
Fact Sheet 3.10 deals with disposal of sullage and drainage, while Fact Sheet 3.1 1 covers sewerage and sewage treatment. The reuse of sewage in agriculture and aquaculture is addressed in Fact Sheet 3.13.
Solid waste disposal
The disposal of refuse can have a significant effect on the health of communities. Where refuse is not disposed of properly, it can lead to pollution of surface water, as rain washes refuse into rivers and streams. There may also be a significant risk of groundwater contamination. Refuse disposed of in storm drains may cause blockages and encourage fly and mosquito breeding. It is therefore very important that household waste is disposed of properly.
Fact Sheet 3.12 deals with solid waste disposal but does not cover industrial solid waste disposal, as this is complex and requires specialist techniques. It is, however, important that industrial waste is disposed of safely, as it is sometimes toxic and highly dangerous to human health.
Sanitation in public places
Where a large number of people are using one area, such as a bus station or school, especially when they are eating food from the same source, there is a greater risk of the spread of diseases such as cholera, hepatitis A, typhoid and other diarrhoeal diseases.
These places vary in the number of people using them, the amount of time that people spend there and the type of activity that occurs in the area, but all public places need to have adequate sanitation and hygiene facilities. Fact Sheet 3.14 covers sanitation in public places.
Responsibility for the provision of sanitation facilities in public places is not always obvious, especially where these are informal gathering places. It is vital, however, that an agency monitors the sanitation facilities in public places on behalf of the users. Ideally, this should be part of the role of the ministry of health, or its equivalent. Special attention should be paid to the adequacy of facilities, their availability to the public, and the conditions of their operation.
There are several basic rules for sanitation in public places:
• There should be sufficient toilet facilities for the maximum number of people using the area during the day. This normally means one toilet compartment for every 25 users. The toilet facilities should be arranged in separate blocks for men and women. The men's toilet block should have urinals and toilet compartments; the women's block, toilet compartments only. The total number of urinals plus compartments in the men's block should equal the total number of compartments in the women's block.
• Toilet facilities should not be connected directly to kitchens. This is in order to reduce the number of flies entering the kitchen and to reduce odours reaching the kitchen. It is important that people using the toilet facilities cannot pass directly through the kitchen.
• There must be a handwashing basin with clean water and soap close to the toilet facilities. There should be separate, similar facilities near to kitchens or where food is handled.
• There must be a clean and reliable water supply for handwashing, personal hygiene and flushing of toilet facilities. The water supply should meet quality standards and be regularly tested to ensure that any contamination is discovered quickly and that appropriate remedial action is taken.
• Refuse must be disposed of properly and not allowed to build up, as it will attract flies and vermin.
Responsibilities for cleaning sanitation facilities should be very clearly defined. Dirty facilities make it more likely that people will continue to use the facilities badly or not at all. Clean facilities set a good example to users.
It is important to make sure that information about health is available in public places. Such information should be displayed in an eye-catching, simple and accurate way. Where appropriate, large posters with bright colours and well chosen messages, put up in obvious places, are effective.
Health and hygiene messages may be passed on to the public using such posters in public places. These messages should include the promotion of:
• Use of refuse bins.
• Care of toilet facilities.
• Protection of water supplies.
Local school children and college students can be involved in preparing educational posters and notices for public places. Hygiene education is covered in Fact Sheets 4.1 to 4.12.