Remediation of Boating and Jetty Pollutants from the Okavango Delta Surface Water Employing Valorized Tilapia ruweti Waste Material

Abstract

Aims: To employ valorized waste materials from Tilapia ruweti scales for removal of heavy metals from areas with major boating activities and high numbers of jetties at the Okavango delta, Botswana.
 Study Design: Biowaste materials were Identified, valorized and then optimized for adsorption and removal of boating and jetty pollutants from profiled Okavango Delta surface water samples.
 Place and Duration of Study: Okavango Delta, Maun and Botswana International University of Science and Technology, Palapye, Botswana between March 2017 and September 2018.
 Methodology: Tilapia ruweti scales were collected from Sehithwa, Maun while water samples were collected from areas with jetties and major boating activities at Shakawe, Mboma Island and Xakanaxa. The concentration of Zn, Cu, Ni, Co, Pb and Cd at all the sampling sites were accurately determined using micro-plasma atomic emission spectroscopy (MPAES). The fish scales were pulverized and valorized by subjecting them to 12.7% vinegar. Minitab 14 software was used as a modeling tool to provide multivariate optimized parameters that affect sorption studies that included initial ion concentration, sorbent dose, contact time and solution pH. The valorized waste materials were then utilized for removal of the selected heavy metals.
 Results: The optimized adsorption parameters that included contact time, solution pH, sorbent dose and initial ion concentration were ≤ 88.63 min, ≤ 8.75, ≤ 84.29 mg and ≤ 28.44 mg/L respectively. The valorized Tilapia ruweti waste displayed high removal efficiencies toward removing the selected ions from the Okavango Delta surface water samples up to 94.21% with %RSD < 2 for n = 3 (triplicate).
 Conclusion: The valorized Tilapia ruweti scales were recommended as a cheap, simple and an effective method for remediation of boating pollution at the Okavango delta and other recreational areas.