Performance of Natural Coagulants in the Treatment of Vegetable Oil Industrial Effluent

Abstract

The potentials of natural coagulants (egg shell and fish scale) in the treatment of vegetable oil industrial wastewater were investigated. The coagulants were characterized to determine their chemical compositions, functional groups and morphology using proximate analysis method, Fourier Infra-red spectroscope (FTIR) and Scanning Electron Microscope (SEM) respectively. The industrial wastewater was equally characterized to determine its heavy metal composition and physico-chemical properties. The effects of various process parameters such as pH, coagulants dosage, time and temperature were examined during the treatment of the waste water using the natural coagulants. The proximate analysis shows that Fish Scale Coagulant (FSC) contains more carbohydrate, 42.30% while Egg Shell Coagulant (ESC) has protein content of 39.65%. It was discovered that the coagulating properties of both FSC and ESC improve after extraction due to presence of isocyanates, isothiocyadilimides, azides, ketenes, aldehydes and ketone. The turbidity of the wastewater was very high (365NTU) above the WHO recommended value. The process variables have significant effects on the coagulation with best removal efficiency of 88.54% for ESC and 74.12% for FSC at pH of 4.0 (ESC) and pH of 7.0(FSC); 0.5 g/L (ESC) and 0.04 g/L (FSC) coagulant dosage and temperature of 40°C. Therefore, both coagulants are effective in treating vegetable oil effluent but egg shell coagulant was found to be a better coagulant. Further research on optimization, kinetics and thermodynamics of the coagulation process using ESC and FSC should be carried out.