Water Clarification using Moringa oleifera
Gate Information Service Dishna Schwarz (June 2000)
Technical Field: Energy / Environment (E) Water / Sanitation (W) Agriculture (A) Foodprocessing (F) Manufacturing (M)
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This Technical Information is available in: English (e) French (f) German (g) Spanish (s) Other:..............................Water born diseases are one of the main problems in developing countries, about 1,6 million people are compelled to use contaminated water. However in many communities of these countries water clarification methods like flocculation, coagulation and sedimentation are often inappropriate because of the high cost and low availabity of chemical coagulants. The use of natural materials of plantorigin to clarify turbid water is not a new idea. Among all the plant materials that have been tested over the years, the seeds from Moringa oleifeira have been shown to be one of the most effective as a primary coagulant for water treatment and can be compared to those as of alum (conventional chemical coagulant) .
General information about the tree Moringa oleifera was originally an ornamentaltree in the Sudan, planted during British rule. That was where Dr. Samia Al azharia Jahn’s (a german scientist) laboratory tests confirmed the presence of a very efficient coagulant in seeds of Moringa oleifera. Moringaceae is a single-genus family with 14 known species thus far, which are indigenous to Africa (9) , Madagascar (2) , Arabia (1), and India (2). Half of them are relativeiy common andalready sporadically cultivated, yet only Moringa oleifeira (horseradish or drummstick tree) because of its many uses, is planted in the whole tropical belt. 1
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Botany The Moringa oleifera Lam.is a small, fastgrowing, drought deciduous tree that ranges in height from 5-12 m with an open, umbrella shaped crown, straight trunk (10-30cm thick) with corky, whitish bark. The evergreen foliage (depending on climate ) has leaflets 1-2 cm in diameter; the flowers are white or craem coloured. The fruits (pods) are initially light green, slim and tender, eventually becpming dark green, firm andupto 120 cm long,
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depending on the variety. Fully mature, dried seeds are round or triangular shaped, the kernel being surrounded by a lightly wooded shell with three papery wings. It tends to be deeply rooted, has a wide open typically-umbrella shaped crown and usually a single stem. Cultivation Moringa oleifera can be easily established by cutting or by seed. Seedscan be sown either directly or in containers and no seed treatment is required. The Plants raised from 1m cutting beat pods from the second year and growth on wards with maximun production at 4 to 5 years. In a favorable environment an individual tree can yield 50 to 70 kg of pods in one year. Originally considered a tree of hot, semiarid regions (annual rainfall 250–1500 mm) it has also beenfound to be well adapted to hot, humid, wet conditions with annual rainfall in excess of 3000 mm. However It does best where temperature ranges from 26 to 40°C and annual total rainfall at least 500 mm. It grows well from sea level to 1000m in elevation. Its big adaptability is also shown in the variety of soil conditions where it grows continuosly under water stress. Coagulation with Moringa seedsGenerally, coagulants are used for (physical and chemical) purification of turbid raw waters. At very high turbidity the water can no longer be adequately treated by using filters. Coagulants have to be applied to transform water constituents into forms that can be seperated out physically. In large scale treatment plants Aluminium Sulphate is used as a conventional chemical coagulant. As an...