Use of Moringa oleifera in drinking water treatment: study of storage conditions and performance of the coagulant extract

Abstract

[EN] Access to safe drinking water is one of the main human rights. However, today, more than 700 million people live without access to safe drinking water, especially in rural areas. Simple, effective, and low-cost technical solutions are being sought to resolve this situation. Moringa oleifera is an alternative, since their seeds contain a natural coagulant able to effectively reduce the turbidity of the raw water. Use of the seed as coagulant in water treatment is often performed as an aqueous extract but requires daily preparation in order to keep its clarification properties. This work studies the storage of M. oleifera extract so it can be used for water treatment without reducing its turbidity removal capacity. M. oleifera extract has been stored at different temperatures (25, −4, and −18°C), and it has been stored as liquid (crude extract) or as solid precipitate for 78 weeks. The turbidity removal capacity of extracts was studied by Jar test in synthetic turbid water of 100 NTU at 1, 3, 9, 14, 27, 40, and 78 weeks. It has been found that coagulant protein present in extract can be stored at room temperature as a solid precipitated by more than 78 weeks maintaining its maximum turbidity removal capacity comparable to fresh crude extract. Liquid crude extract storage is recommended at −18°C in order to maintain turbidity removal capacity. The results obtained are very useful and would allow extending the application of the Moringa extract, its storage and it would prevent from daily fresh preparation.