Biofiltration Property of Malunggay (Moringa oleifera) Seed: Innovative Way of Purifying Water
Jay Mark Reponte
Romarilyn Grace Maata
Clark Ervin Conturno
Background of the Study
Drinking water is a basic human need, including food, shelter and clothing. The lack of safe drinking water is a leading cause of mortality, especially in local communities where waterborne diseases are persistent due to low quality surface source waters. Appropriate treatment technology can render this poor water resource into safe potable water; however, conventional technology may not be appropriate for those communities in terms of economics, availability, and operational constraints. There are constraints encountered in the use of chemical coagulants, such as scarcity of foreign currency for importation and inadequate supply of chemicals. Although aluminum is the most commonly used coagulant in the developing countries, studies have linked it to the development of neurological diseases (e.g. pre-senile dementia or Alzheimer’s disease) due to the presence of aluminium ions in the drinking water (Jekel, 1991).
As a consequence of the above mentioned drawbacks, there was a need to develop alternative, cost effective and environmentally friendly coagulants. A number of effective coagulants from plant origin have been identified: Nirmali (Tripathi et al., 1976); Okra (Al-Samawi and Shokralla, 1996); red bean, sugar and red maize (Gunaratna et al., 2007), M. oleifera (Jahn, 1988). Of all the plant material investigated, seeds of Moringa oleifera are one of the most effective sources of coagulant for water treatment. Moringa oleifera, known as Malunggay, is native in Philippines throughout the tropics. Malunngay is also known as horseradish tree, drumstick tree and mother’s best friend. It grows fast and reaches up to 12m. The bark is grey and thick and looks like cork, peeling in patches. It loses its leaves from December to January and new growth starts in February to March. Malunggay produces cream coloured flowers when it is 8 months old and the flowering season begins in January and continues through to March. The fruit ripens from April to June and the pods are triangular in cross section, 30 to 50cm long and contain oily, black, winged seeds. The malunggay tree is grown mainly in semiarid, tropical, and subtropical areas. While it grows best in dry, sandy soil, it tolerates poor soil, including coastal areas. It is a fast-growing, drought-resistant tree that is native to all parts of the country. More so, malunggay seeds treat water on two levels, acting both as a coagulant and an antimicrobial agent. It is generally accepted that Malunggay works as a coagulant due to positively charged, water-soluble proteins, which bind with negatively charged particles (silt, clay, bacteria, toxins, etc) allowing the resulting “flocs” to settle to the bottom or be removed by filtration (Crapper, 1973). According to the Industrial Technology Development Institute (2009), the seed kernels of malunggay contain significant amounts of water-soluble protein that carries a positive charge. When added to turbid water, it can attract negatively charged particles like contaminants, resulting in collection of particles that are easily removed through settling. Among all the plant materials that have been tested over the years, powder processed from the seeds from Moringa oleifera has been shown to be one of the most effective as a primary coagulant for water treatment and can be compared to that of alum (conventional chemical coagulant) (Madsen et al., 1987; Oslen, 1987; Postnote, 2002). It was inferred from their reports that the powder has antimicrobial properties. Earlier studies have found Moringa to be non-toxic (Grabow et al., 1985), and recommended it use as a coagulant in developing countries (Barth et al., 1982; Bhole, 1987; Jahn, 1988; Müller, 1980; Ndabigengesere et al. 1995 and Olsen 1987). The...
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