POTENTIAL APPLICATION OF NATURAL COAGULANTS IN SMALL SCALE SEWAGE TREATMENT

Coagulation and flocculation provide a rather straightforward method towards water clarification. However, ongoing debates over worrying health issues linked to chemical coagulants have paved the way to develop plant based natural coagulants. Typically, the synthetic chemicals Alum (Al2 (SO4).12H2O), Ferric chloride (FeCl3), or poly aluminium chloride (PAC) are used for coagulation processes. There are however, numerous drawbacks to using these synthetic chemicals, including inefficiency at low temperatures, associated health problems, high costs, production of large volumes of sludge and the significant effect on pH that these chemicals cause. This has caused a push for “greener” alternatives, especially for use in low- and middle-income countries. While coagulants are typically thought of for use in drinking water treatment, they are also often used for wastewater treatment. The objective of this study is to assess the possibility of using natural coagulants as an alternative to the current commercial synthetic coagulant and to optimize the coagulation process. Here in this study, the effectiveness of five indigenous plants-based coagulants were used for small scale sewage treatment. The turbidity removal efficiency for the natural coagulants Cucurbita pepo seeds, Citrullus lanatus seeds, Leucaena leucocephala seeds, Chrysopogon zizanioides powder, Azadirachta indica powder respectively were 69.7%, 40.7%, 45.72%, 78.4%, 66.8% against 64% obtained for alum.