TITLE:
Value Addition to Waste Material Supported by Removal of Available Phosphate from Simulated Brackish Water—A Low Cost Approach
AUTHORS:
S. Malavipathirana, S. Wimalasiri, N. Priyantha, S. Wickramasooriya, A. Welagedara, G. Renman
KEYWORDS:
Aquaculture; Adsorption; Distribution Coefficient; Nutrient Loading; Phosphate Fertilizer; Pollution; Potentially Toxic Elements
JOURNAL NAME:
Journal of Geoscience and Environment Protection,
Vol.1 No.2,
November
7,
2013
ABSTRACT: Phosphorus is one of the major nutrients that
have been identified as a limited resource that would
end up earlier than predicted at the rate of current consumption. Therefore, attempts
to recover phosphorus from waste and its subsequent use are a concern of current
researchers. Nevertheless, recovery of nutrients from wastewater is cumbersome because
nutrients such as phosphates () and nitrates
() prefer to remain
in aqueous phase rather than being adsorbed on solid matrixes. Investigation of
adsorption of available - P from simulated brackish water, on granulated
solid waste material, prepared by crushed autoclaved aerated concrete (CAAC), and
subsequent use of the material as phosphate fertilizer would be the focus of this
research. Treatment of nutrient-rich brackish water is important because such water
is discharged in huge volume at the time of harvesting of shrimp aquaculture ponds.
Experiments conducted in simulated brackish water confirmed non-linear adsorption
association with changing distribution coefficient (KD) which attributed the maximum removal of about 98% - P from 100 mgdm-3solution at its
value of 40. The non-linear adsorption supported by both the Langumuir and the Freundlich
isotherm models simultaneously satisfied monolayer adsorption and multilayer adsorption
depicted by the regression coefficients of greater than .99 by the linearized forms
of the isotherm models. Moreover, promising phosphate uptakes characteristics are
exhibited by the adsorbent at the process of repetitive adsorption which resulted
in 12 g/kg uptake of phosphate at 81% efficiency. The adsorbent seems to be used
as a slow-released phosphorus fertilizer at the end of its life as an adsorbent.