Textile Wastewater Treatment Using Sodom Apple (<i>Calotropis procera</i>) - Aided Tamarind Seed as a Coagulant

Abstract

Water contamination seems unavoidable as many human activities involve the use of water in one way or the other. Chemical coagulants, especially aluminium based, which are widely used in treatment of wastewater or contaminated water have been associated with some health issues. Research on the use of plant based coagulants in water treatment now draws a lot of attentions, not only because the natural coagulants are presumed safe but also because of their biodegradable nature. In this present study, efforts have been made to evaluate the effectiveness of locally available tamarind seed powder as natural coagulant and Sodom apple (Calotropis procera) as coagulant aid for the treatment of textile wastewater. The tests were carried out using the conventional jar test apparatus at various pH and coagulant dosage with no aid added. Also, three sets of jar test experiments were performed at constant values of coagulant dosage and pH (which were found to be favourable in the first experiments) by varying the dosage of liquid and solid coagulant aid as well as time. The results obtained show that pH slightly affected the pollutants removal efficiency of the unaided coagulation. The neutral pH was found to be favourable with turbidity and colour removal of 22.25% and 30.36% respectively. The optimum mixing time of turbidity removal efficiency was found to be 2 min with rapid mixing of 30 seconds and 1½ min of slow mixing with turbidity and colour removal of 69.48% and 60.53% respectively. The optimum dosage was found to be 4.0 g of coagulant and 1.0 g of coagulant aid for turbidity, total dissolved solid and colour removal efficiency.