Environmental/Health Impact Reduction by Composting Horse Manure, Mauritius

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Project ID

Project Title

Environmental/Health Impact Reduction by Composting Horse Manure, Mauritius


Focus Areas

Geographic Scope

Lead Organization(s)

Project Partners

  • Ministry of Agriculture
  • University of Mauritius


Total: $25,000;

Sources of Financing: GEF SGP, National Environment Fund, Ministry of Co-operatives,


2008 - 2009


Preparatory phase

Project website(s)




This project looks into safely treating the 2000 to 3000 tons of horse manure produced annually by preventing nutrients and bacteria present to pollute watercourses. The overall objective is to ensure safe disposal of horse manure through composting and promote application of composts to growing crops. Secondary objectives will include recycling of organic wastes, produce a safe compost of good quality, train people in compost making, construct large-scale facilities to compost large amounts of waste and apply compost produced on vegetables in view of reducing usage of chemical fertilisers.

Raw horse manure poses a direct threat to the environment because of the presence of excessive nutrients, larvae, odours, strong leachate generation and risks of direct contamination of ground water. Around 2000 to 3000 tons of horse manure are collected by the Les Mariannes Agricultural and Mechanical Co-operatives on an annual basis. Since 1985, the NGO collects horse manure and bedding materials from around 329 horses every week from Champ de Mars and Domaine Les Pailles. The horse manure is disposed at the Roche Bois dumping site. Part of it is used by the NGO as fertiliser for growing vegetables. It is to be noted that in the vicinity of the Roche-Bois station, there are 2 localities, Roche-bois and Tombeau Bay, as well as the Terre-rouge estuary and the bird sanctuary (a potential Ramsar site)

Because of improper disposal of horse manure, both land degradation and contamination of waterbodies leading to an unhealthy environment can occur. Unfortunately, because of lack of data on the subject, one cannot measure the environmental and health impact caused these last 16 years by unsafe disposal of horse manure in Mauritius. It is known however that horse manure is very high in salts, contains parasite larvae and eggs and provides as well an excellent fly breeding environment. It contains nitrogen, phosphorus and potassium, which contribute to pollution of water bodies. It is also a threat to human and livestock health as it may contain bacteria and disease causing micro-organisms. Excessive manure application rates on vegetable crops can result in high nitrate levels in shallow ground water. Nitrate levels above 10 milligrams per litre is unsafe for human consumption.

A preliminary study was conducted by the consultant with the NGO to identify key issues pertaining to formulation of and complete project proposal. These consisted in assessing characteristics of horse manure, determining the technical feasibility of the composting process and the quantity of the final compost. This was made possible by using the planning grant scheme under the UNDP/GEF Small Grant Program. Under this study, successful composting was carried out and the final compost produced was of high quality. (full report in annex 2). A large amount of flies was noticed during the composting process. Mitigating measures will have to be taken to minimize the generation of flies. No leachate was produced during the composting process.

The NGO is a cooperative society (Les Mariannes Agricultural and Mechanical Cooperative) regrouping 12 members and 6 Committee members. It is specialised in the cultivation of cane, vegetables and fruits mainly. It employs about 8 casual workers as labourers and one secretary on a part time basis. The NGO is also responsible for the collection and disposal of horse manure produced from 329 horses from Champ de Mars and Domaine les Pailles.

This project will specifically address community initiatives to eliminate the causes of land and water based sources of pollution, particularly nutrients present in horse manure as well as decrease the likelihood of disease transmission. It also aims at reducing the use of chemical fertilizers thus reducing the impact of leaching of nutrients during agricultural runoff. It is thus in line with the operational program 10 of the GEF, under the focal area of the international waters. It falls under the GEF/SGP category of demonstration and capacity building.

The project is thematically linked with other UNDP GEF/SGP projects for the safe treatment of animal wastes using the composting technology. At least two other UNDP GEF/SGP projects of composting of chicken waste, cattle manure and agricultural wastes have been completed successfully in the past using different types of composting technologies with community of planters at Belle Mare in Mauritius and Riviere Banane in Rodrigues.

The project is also in accordance with the Country Programme Strategy of the UNDP GEF/SGP (1999-2001) which promotes activities to eliminate land and sea based sources of pollution. It is also in line with Government Policy as one of the main projects covered under the 'National Environmental Strategies for the next decade' is the setting up of a large scale composting plant in the North of the island.

Expected Outcomes

Achievements: Results and Impact

Lessons for Replication



See also

  1. Water and wastewater management contract
  2. Remedial Works at the Waste Treatment Plant, St. Martin Pig Farm, Mauritius
  3. Minimisation and Safe Disposal of Pesticides Waste, Mauritius
  4. Integrated Farming- An Animal Waste Treatment plant, Mauritius
  5. Decrease Pesticide Use in Crop Production for a Better Health and Environment, Mauritius
  6. Agulhas and Somali Current Large Marine Ecosystem (ASCLME) Project

External Resources


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