Report 3 (of 5): Waste Watchers - Senegal

Introduction

Environment and sanitation are real problems in Senegal because rubbish litters the streets and, in the wet season, the sewage overflows and causes a lot of illness.

The collection of rubbish is something that is taken for granted in some countries but in Rufisque, a city about 30 kilometres from Dakar, the capital of Senegal, there is no door to door collection of rubbish. Rufisque is below sea level and it has a high water table. Blue skips are available for people to dispose of their rubbish but these pose a serious health hazard and the rubbish often blows away.

Castor

A group of young women are taking matters into their own hands and are involved in a scheme, called GIE Castor, to clean up their neighbourhood. This community group, led by Mariem Djouff, are volunteers who have been trying to raise awareness about home waste.

The women targeted 15 homes for a pilot scheme and provided them with bins which they collect on a regular basis. They take the bins to their project centre where the rubbish is weighed to assess the average home waste over time in case they decide to expand. The rubbish is then sorted out for recycling into biodegradable and non-biodegradable waste. The women do a tough job which is rarely associated with volunteer status.

Sewage from the town system which has been collected from domestic household waste is pumped directly into purification ponds in the project centre.

Sewage

Sewage is the waste water of a community. Domestic sewage is composed of human body wastes (faeces and urine) and sullage which is the wastewater resulting from personal washing, laundry, food preparation and the cleaning of kitchen utensils. Sullage contributes a wide variety of chemicals, such as detergents, soaps, fats and greases of various kinds and pesticides etc.

Sewage should be treated prior to its ultimate disposal into a receiving watercourse. This is done in order to reduce the spread of diseases caused by the pathogenic organisms in the sewage and to prevent the pollution of surface and ground waters. A polluted body of water is a potential source of infection, particularly in hot climates.

One of the best ways to prevent the pollution of surface waters is to use the treated sewage to produce some beneficial end product. Domestic sewage can, with the correct treatment, be a valuable raw material.

Treatment of Sewage

Raw sewage contains complex organic and inorganic materials, including proteins, cellulose, fats, carbohydrates and soaps. In biological sewage treatment, bacteria, fungi, zooplankton and algae breakdown and then use these complex materials, resulting in an effluent rich in nitrogen, potassium, phosphorus and other elements. These biological processes utilise natural bacteria to clean sewage. Aquatic plants can therefore be used to transform polluted effluent into clean water.

Various types of bacteria can be used to clean sewage. These bacteria are nature’s workers and they digest the organic matter to produce inorganic compounds which is food for the aquatic plants. The inorganic compounds are consumed by the aquatic plants and the purified water can then be used for agricultural purposes.

Aquatic Plants

Some types of aquatic plants are able to create the ideal conditions around their roots for the essential cleaning bacteria to thrive. Others exude special antiseptic substances from their roots which are valuable in controlling potentially harmful bacteria. Some aquatic plants absorb grease and fat while others remove heavy metals, such as cadmium.

There are types of aquatic weed that scavenge inorganic, and some organic, compounds from water. The weeds absorb and incorporate the dissolved materials into their own structure. Effluent renovated by the plants is stripped of its pollutants. The clean water produced is in most instances, suitable for reuse in irrigation and industry.

By cultivating aquatic plants, such as water lettuce which is used at the project centre in Rufisque, the toxins in the waste water are feed upon and broken down during a biological process. In time, the aquatic plants will produce large quantities of purified water for agricultural use. Furthermore, the plants themselves can be harvested and used, thus providing further additional benefit.

Enda Third World

With money given by the European Union, through a local NGO called Enda, drains have been built in Rufisque and the old septic tank system in the town has been replaced. Enda have also been responsible for assisting the women with the setting up of their rubbish collection service.

Unfortunately, the funding for the Castor scheme has now run out and appeals to the municipality go unanswered. The women hope to become self-sufficient but for now they need a truck with a tank to transport the compost and to distribute the recycled water which is currently going to waste.
 

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Further reading available from ITDG Development Bookshop

Don’t Throw It All Away
Friends of the Earth
This new edition of Friends of the Earth’s popular recycling guide examines the throwaway society’ and offers positive solutions to its waste problem. It explains what is thrown away, why so much of it is produced and the environmental problems this causes. And it offers practical suggestions for you and your family produce.
£4.99 46pp pb (Friends of the Earth) ISBN 1857502000

Rubber Waste: Options for small-scale resource recovery
Edited by Rehan Ahmed, Arnold van de Klundert and Inge Lardinois
This book documents rubber waste recovery and recycling activities in cities in developing countries. It describes how the waste is recovered in informal small-scale enterprises and turned into end-products ready for use by other small entrepreneurs and general customers. The editors consider both the various technologies used, and also financial aspects, marketability of products, environmental problems and the effects of government policies.
£11.50 126pp pb (TOOL) ISBN 9070857359

Plastic Waste: Options for small-scale resource recovery
Inge Lardinois
Plastic Waste documents recycling activities in cities in economically less developed countries. The publication describes how plastic waste is reprocessed in informal small-scale enterprises and turned into end-products or semi manufactured products ready for use by formal industries. Attention is paid to the various technologies used in plastic recycling. Financial aspects, marketability of products, environmental problems, occupational heath and government policies are also dealt with.
£11.50 112pp pb (TOOL) ISBN 9070857340

Green Home: How to make your world a better place
Karen Christensen
A comprehensive, accessible and lively introduction to all aspects of green home-making.
£9.99 326pp pb (Piatkus Books) ISBN 0749914602

Reuse, Repair, Recycle: A mine of creative ideas for thrifty living
Jan McHarry
An up-to-date source book on how to reduce and recycle, how to create new from old, and how to help fight the great waste problem of the current age.
£7.99 288pp pb (Gaia Books) ISBN 1856750450
 

TVE/ Practical Action gratefully acknowledge support for the HANDS ON programmes from the UK's Department for International Development (DFID), the European Commission (EC), the UN Foundation and UNDP/The Equator Initiative in collaboration with the Government of Canada, IDRC, IUCN, BrasilConnects and the Nature Conservancy.