Overcoming the drawbacks of natural coagulants for drinking water treatment

A number of natural coagulants from plants or animal origin can be effectively used for the treatment of drinking water. Some are used at household levels in traditional systems using crude (non-purified) extract. In the crude extract form, natural coagulants release organic and nutrient loads to the water resulting in poor treated water quality. In such cases it becomes necessary to purify the coagulant component from the crude extract before using it for water treatment. This paper discusses an effective and simple purification of the coagulant from Moringa oleifera seed using an ion exchange method that would overcome the drawbacks of natural coagulants. The impact of the purification process on reducing organic and nutrient release was studied. Adsorption and elution parameters of the ion exchange process were optimised. The study indicated that the purified protein has effective coagulation activity and it did not release organic and nutrient loads to the water. Compared to other purification methods used in previous studies, this is simple and of comparatively lower cost. This purification method can be readily scaled up and applied even in remote parts of developing countries. This work suggests that the concerns of natural coagulants can be overcome by simple purification and this is believed to promote their use in drinking water treatment.