Optimisation of the Efficacy of Watermelon (Citrullus lanatus) Seeds as a Natural Coagulant for the Treatment of Surface Water: A Review

Meshach Williams & Medeba Uzzi

Published: October 4, 2021 • Book of Abstracts – Student Research, Volume 2 [Forthcoming]

Meshach Williams ✉️  Medeba Uzzi Department of Chemistry. Faculty of Natural Sciences. University of Guyana – Turkeyen Campus. Greater Georgetown, Guyana.

Treatment of surface water for drinking purposes is a major challenge in developing countries; current trends in green technology demand a shift from the use of synthetic chemicals to more natural materials. The seeds of Citrullus lanatus (watermelon) are waste materials that have shown potential for being effective coagulants in water treatment. This study aimed to better understand the methodology used to identify the optimum dosage and conditions needed for treatment of surface water using watermelon seeds. A meta-analysis was conducted on secondary data extracted from three research papers. The research papers were selected based on satisfaction of the criteria; similar aims, methodologies, and geographical locations. Each study examined the potential of C. lanatus seeds as a natural coagulant for treatment of surface water in Nigeria. Methods involved the use of hexane to remove fats from the seeds, followed by preparation of an aqueous coagulant solution. Coagulant dosage (0.1 g/L to 0.6 g/L); mixing speed and mixing time were varied. Findings revealed that the greatest reductions in turbidity, conductivity, and colour were observed in samples treated with the lowest dose of watermelon seed coagulant (0.1 g/L). Optimum mixing speed and stirring time were 100 rpm and 8 minutes, respectively. One of the water samples treated at these optimal conditions had turbidity of 3.68 NTU – acceptable by the WHO for drinking water. This study lays the foundation for investigation of C. lanatus seeds as a natural coagulant for water treatment in Guyana. Further research in this area may include the use of lower dosages of the coagulant (<0.1 g/L) in treating surface water samples in Guyana, and a comparison of its effectiveness to that of aluminium sulphate.

Keywords: coagulant, watermelon, water treatment

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Published: 2021-10-04