The project was aimed at the following developmental problems:

Activated carbon was produced at the Universities of Edinburgh and Malawi by a simple one-stage process of heating seed husk material or pods from the tree Moringa oleifera in a furnace with concurrent activation from steam. Various temperatures (either 500, 600, 700, 750, 800 or 850oC, all 110oC) and heating times (30, 60 or 120 minutes) were used and the carbons tested for adsorptive properties (CHN analysis, Nitrogen adsorption isotherms, phenol and methylene blue adsorption tests, scanning electron microscopy). Comparison was made with commercial carbons and the Moringa carbon used at a water treatment works in Malawi.

Leicester University undertook studies into water treatment by contact flocculation-filtration (CFF) and by gravel bed flocculation (GBF) using aluminium sulphate or crushed Moringa oleifera seed kernels as coagulant.

A socio-economic study was carried out in Malawi villages by the Forestry Research Institute of Malawi to identify the prevalence of M.oleifera trees, the uses to which the tree products are put and the potential for commercial development of tree plantations.

Activated carbon of quality comparable with commercial carbons was produced by a simple one-stage process from both seed husk material and pods from the tree Moringa oleifera. 800oC for 30 minutes gave the best carbon from husks and 650 oC for 30 minutes for pods

Neither husk nor pod carbons were sufficiently strong to provide granular material. The husk carbon was shown to be effective for the removal of taste and odour and algal toxin from water.

Contact flocculation filtration was shown to be suitable for urban or peri-urban communities particularly for waters with initially low turbidity. M.oleifera is effective over a wide range of operating conditions up to 10 m/h filtration rate. Gravel bed flocculation was effective in reducing turbidity levels with alum coagulant but was less suitable for treatment with M.oleifera than CFF.

Survey results were that the trees were widespread and used primarily as live fencing. Leaves were used as a vegetable although regarded as inferior to other vegetables. Oil produced from crushing seeds could be used for cooking and the residual cake was effective as a coagulant.

The potential exists for inclusion of M.oleifera within existing cultivation systems. The commercial interest in oil from the M.oleifera seeds should encourage plantation development, with the residual press-cake available as a coagulant for water treatment and the waste husk material a viable source of activated carbon.

1. Warhurst, A.M., McConnachie, G.L. and Pollard, S.J.T. (1996) "The production of activated carbon for water treatment in Malawi from the waste seed husks of Moringa oleifera", Water Sci. Technol., Vol.34, No.11, pp177-184.

2. McConnachie, G.L., Warhurst, A.M., Pollard, S.J.T. and Chipofya, V.H. "Activated carbon from Moringa husks", 22nd WEDC conf., "Reaching the unreached - challenges for the 21st Century", New Delhi, India, Sept 1996.

3. Folkard, G.K., Sutherland, J.P and Al-Khalili, R.S, 1996, Natural coagulants - a sustainable approach. In: Pickford et al (eds). Sustainability of Water and Sanitation Systems. Pub.: Intermediate Technology Publications, London. ISBN 1853393398, pp 63-65.

4. Folkard, G.K. and Sutherland, J.P. 1996, Moringa oleifera - a multipurpose tree. Food Chain - Intermediate Technology, No.18, pp3-5. ISSN 0964-5810

5. Folkard, G.K. and Sutherland, J.P. 1996, Moringa oleifera - a tree and a litany of potential. Agroforestry Today, Vol. 8, No.3, pp5-8.

6. Folkard, G.K., Al-Khalili, R.S. and Sutherland, J.P., 1996, Contact Flocculation Filtration using a natural polyelectrolyte for the treatment of low turbidity surface water in developing countries. In: Hahn H.H. et al (eds). Chemical Water and Wastewater Treatment IV; proceedings of the 7th Gothenburg Symposium; Edinburgh, Scotland, 23-25 September 1996. Pub: Springer, Berlin, ISBN3-540-61624-1, pp213-223.

7. Folkard, G.K. and Sutherland, J.P., 1996, Moringa oil. Footsteps, No.28, p16, ISSN 0962-2861.

8. Folkard, G.K., Sutherland, J.P and Al-Khalili, R.S, 1996, A naturally occurring cationic protein for coagulation of raw water. Chemica Oggi, Vol.14, No.11/12, pp. 36-40. ISSN 0392-839X (Biocides Today supplement).

9. Warhurst, A.M., McConnachie, G.L. and Pollard, S.J.T. "The production of activated carbon for water treatment in Malawi from the waste seed husks of Moringa oleifera", International Association on Water Quality (IAWQ), Singapore, June 1996, Vol.5, pp 150-157.

10. McConnachie, G.L., Warhurst, A.M., Pollard, S.J.T. and Chipofya, V.H. "Activated carbon from Moringa husks and pods", 22nd WEDC conf., "Reaching the unreached - challenges for the 21st Century", New Delhi, India, Sept 1996.

11. Warhurst, A.M., McConnachie, G.L., Fowler, G.D. and Pollard, S.J.T. (1997) "Characterisation and applications of activated carbon produced from Moringa oleifera seed husks by single-step steam pyrolysis", Water Research, Vol.31, No.4, pp759-766.

12. Warhurst, A.M., McConnachie, G.L., Fowler, G.D. and Pollard, S.J.T. (1997) "Pore structure and adsorption characteristics of steam pyrolysis carbons from Moringa oleifera", Carbon, Vol.35, No.8, 1039-1045.

13. Warhurst, A.M., Raggett, S.L., McConnachie, G.L., Pollard, S.J.T., Chipofya, V. and Codd, G.A. (1997) "Adsorption of the cyanobacterial hepatotoxin Microcystin-LR by a low-cost activated carbon from the seed husks of the pan-tropical tree, Moringa oleifera", The Science of the Total Environment, 207, 207-211.

14. McConnachie, G.L., Chipofya, V.H., Warhurst, A.M., and Pollard, S.J.T. (1997) "Activated carbon from Moringa husks and pods", World Bank seminar 'The development of M.oleifera in Malawi', 17-18th June, Blantyre, Malawi

15. Sutherland, J.P., Al-Khalili, R.S., and Folkard,G.K. (1997) "Moringa oleifera - an overview of development to date", World Bank seminar 'The development of M.oleifera in Malawi', 17-18th June, Blantyre, Malawi

16. Sutherland, J.P., Al-Khalili, R.S., and Folkard,G.K. (1997) "Moringa oleifera cultivation and selection", World Bank seminar 'The development of M.oleifera in Malawi', 17-18th June, Blantyre, Malawi

17. Sutherland, J.P., Al-Khalili, R.S., and Folkard,G.K. (1997) "Moringa oleifera - application to community water treatment", World Bank seminar 'The development of M.oleifera in Malawi', 17-18th June, Blantyre, Malawi

18. Al-Khalili,R.S., Sutherland, J.P. and Folkard, G.K. "Filtration with a natural coagulant", 23rd WEDC Conference 'Water and sanitation for all: partnerships and innovation', 1-5th September 1997, Durban, South Africa

19. Chipofya, V.H., McConnachie, G.L., Warhurst, A.M., Patey, E. and Ridgeon, H. "Odour testing using Moringa carbon", 23th WEDC Conference 'Water and sanitation for all: partnerships and innovation', 1-5th September 1997, Durban, South Africa.

20. McConnachie, G.L., Folkard, G.K., Mtawali, M.A. and Sutherland, J.P. (1999) "Field trials of appropriate hydraulic flocculation processes", Water Res., Vol.33, No.6, 1425-1434.

Preparation of a technical brief on the use of natural coagulants for household and community water treatment.

Application of the simple one-stage process for the production of activated carbon from other waste materials such as sunflower seed husks, macadamia nut husks, olive oil pressings following interest from concerns in Malawi, Zimbabwe and Turkey.

The work was carried out by three establishments,
< The Department of Civil & Environmental Engineering, The University of Edinburgh,
The Department of Engineering, The University of Leicester, and
The Department of Civil Engineering, The Polytechnic, The University of Malawi.

Tel: +44 (0) 131 650 5723
Fax: +44 (0) 131 677 9238
Email: g.mcc@civ.ed.ac.uk

Tel: +44 (0) 1162 522538
Fax: +44 (0) 1162 522619
Email: gkf@le.ac.uk