Applications of Moringa Oleifera for Wastewater Treatment: Concepts and Approaches

Moringa Oleifera: An Introduction

India is a veritable emporium of numerous restorative and fragrant plants. A notable plant for its characteristics is Moringa oleifera (M. oleifera). Among all the plant species, M. oleifera is described for its astonishing nutritional values and exceptional coagulation properties. An M. oleifera plant is a rapidly growing tree and is also known as a horseradish tree, drumstick tree and benzolive tree (Idris et al., 2016). These plants are found in Bangladesh, Pakistan, Afghanistan and sub-Himalayan tracts of India. Due to its multipurpose uses, it is also known as ‘miracle tree’. Its various parts have different properties, for example its leaves have an ample amount of minerals, vitamins and proteins, while other parts like the roots are used for traditional medicine. In particular, M. oleifera as a natural coagulant has historically been used to treat effluents and it continues to be used today.

According to research, many plants like drumstick (Moringa oleifera), Jatropha curcas, Hibiscus sabdariffa, Pleurotus tuber-regium, neem (Azadirachta indica), tulsi (Ocimum sanctum), amla (Phyllanthus emblica), Guar gum, katakphala (Strychnos potatorum) and wheatgrass (Triticum aestivum) can be used for water/ wastewater treatment. The few studies also reported that some plants have capabilities to work as phytocoagulants and phytodisinfectants in water purification. Among these, M. oleifera has emerged as a green coagulating agent for the treatment of domestic water. So far, most of the studies have been performed on industrial waste- water and its application with domestic wastewater is quite limited. India also has an abundant quantity of such material, which can be used to solve the issue of water scarcity in rural areas. The dry seed suspension of M. oleifera is known as a coagulant aid and natural coagulant (Kumar et al., 2012).

In the family of Moringaceae, M. oleifera is a genus of 14 species, out of which Moringa oleifera is further known as the tree that never dies and the nebeday tree. It is a dry-tolerant plant which can grow up to three meters per year. It can withstand drought conditions and an assortment of precipitation and soil conditions. According to the literature, M. oleifera seeds show 90-99% reduction in the bacterial load and around 90% in turbidity and color compound. At present, the studies related to the use of M. oleifera are increasing.

Until now, no adverse effects were reported in any research study conducted. Furthermore, numerous preparations and treatments regarding M. oleifera are used around the world without ill effects on human health and the environment. From the study, it concludes that for rats a dose consumption around 2000 mg/kg is safe. In a human study, no adverse effects were reported for the use of M. oleifera leaf powder up to 50 g.

Apart from all these benefits there are a few limitations of using M. oleifera, such as the wood of M. oleifera is basically soft and in water-stress conditions it loses its leaves, because of this, it is not used in heavy construction. The pods of M. oleifera taste quite bitter and it is poisonous if consumed in large quantities. The average age of an M. oleifera tree is around 20 years (Mayde, 1986).

Previous literature reported the usefulness of M. oleifera seeds for the purification and treatment of water. When the treatment efficacy of water with this coagulant was compared with other conventional ones, its notable advantages were observed as effectiveness, biodegradable sludge and less sludge volume generated, environment friendly, no byproduct formation, it handled easily, non-corrosive in nature and did not affect the pH values of water. Among all advantages the most important benefits are that M. oleifera seeds were less expensive, ecofriendly, easily available in nature and a good alternative for developing countries (Idris et al., 2016). It can easily replace the synthetic or commercial coagulants which are many times more expensive and lead to diseases such as Alzheimer’s and cancer. Among all the parts of M. oleifera plant it is reported that the powder form of M. Oleifera seeds works as a most effective coagulant compared to alum (chemical coagulant) for the treatment of water. The drastic removal has been noted through M. oleifera as a coagulant. It also acts as an antimicrobial agent against many pathogenic microorganisms (Mangale et ah, 2012). M. oleifera stalk extract had minimum activity against microbes like E. coli and Entrobacter aerogenes (Bichi et ah, 2012). M. oleifera seeds can also be used for cleaning water by coagulation flocculation, irrigation and vegetable oils, raw as well as wastewater, for removing volatile organic compounds, algae and heavy metals present in liquid from the treatment.

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