Wastewater Treatment Using Alum, the Combinations of Alum-Ferric Chloride, Alum-Chitosan, Alum-Zeolite and Alum-Moringa Oleifera as Adsorbent and Coagulant

摘要

Aluminium sulphate (alum), an inorganic salt, is the most widely used coagulant in wastewater treatment, due to its proven performance, cost-effectiveness and availability. However, the use of aluminium-based coagulant has become under scrutiny. Besides the large amount of sludge produced, high level of aluminium remaining in the treated water has raised concern on public health. Previous research has pointed out that the intake of large amount of aluminium salt may contribute to the development of neurodegenerative diseases. To reduce the large intake of aluminium salt in the treatment of palm oil mill effluent (POME), this research examined the comparative suitability of alum and combinations of alum as the primary coagulant with other coagulants (ferric chloride, zeolite, chitosan and moringa oleifera) for the treatment of (POME) at optimum conditions of both coagulants. It also ascertain which combined coagulants with alum and an anionic polymer has the potential for higher pollutants removal. Results obtained revealed that, addition of 1 g/L of ferric chloride, 0.4 g/L chitosan and 1 g/L zeolite each to different dose of alum, were able to reduce alum dose from 4 g/L to 2 g/L, 3 g/L and 2 g/L. However, 2 g/L moringa oleifera addition could not reduce alum dose as high removal efficiencies for most parameters were obtained at 4 g/L alum + 2 g/L moringa oleifera.