THE USE OF MANGO (MANGIFERA INDICA) SEEDS AND DATES (PHOENIX DACTYLIFERA) SEEDS AS COAGULANTS IN WASTEWATER TREATMENT

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Department of Engineering

ABSTRACT
The use of chemicals in water treatment comes with some challenges including cost and environmental concerns. This has necessitated the need for alternative means of treatment that is relatively cheap and environmentally friendly. This research was aimed at studying the possibility of combining Mangifera indica and Phoenix dactylifera seeds powder as coagulants in wastewater treatment. The seeds were characterized for their composition, active compounds and proximate constituents using Atomic Adsorption Spectroscopy (AAS), Scanning Electron Microscopy (SEM) analysis, and X-ray Diffraction (XRD) analysis. Jar test was carried out using the seeds extracts separately and in combination at varying dosages and the Electrical Conductivity EC, Total Dissolved Solids TDS, Chemical Oxygen Demand COD, Biochemical Oxygen Demand BOD, Turbidity, temperature, pH, and total coliform were measured with every varying dosage. Isothermal studies using Langmuir and Freundlich isotherm models were carried out, and kinetic behavior for the removal of BOD using the seed powders over certain concentration ranges was studied using the Pseudo-first and second order kinetic models. The sludge from the Jar test experiment was analyzed for its total nitrogen, organic carbon, organic matter, total volatile solids, and carbon nitrogen ratio. The Mangifera indica removed 89 % turbidity, 96 % BOD, 84 % COD and 99 % total coliform of the wastewater, while Phoenix dactylifera removed 75 % turbidity, 85 % BOD, 78 % COD and 88 % total coliform of the wastewater. Their combination removed 96 % turbidity, 96 % BOD, 87 % COD and 98 % total coliform of the wastewater. The experiment was observed to fit the Freundlich isotherm model based on the Freundlich constants and the coefficient of determination, R2. The experiment was observed to have followed the pseudo-second order kinetic model as indicated by the K2, R2, and Error analyses carried out on the experimental data. The study has shown that Mangifera indica seed and Phoenix dactylifera seed powders can be used as viable coagulants for water and wastewater treatment using adsorption and charge neutralization