Utilization of Banana, Pineapple and Watermelon Wastes-Substrate: As Consortiums to Remediating Cyanide Polluted Soil
Florence Obiageli Nduka, Samuel Chibuike Ubani, Victor Eshu Okpashi, NE Nwankwo, Sandra Ajiroghene Gometi, Blessing Chika Nwaso and O.F.C. Nwodo
DOI : 10.3844/ajessp.2018.77.85
American Journal of Environmental Sciences
Volume 14, Issue 2
The act of processing cassava for varied food products has come with unguided and wide-spread contamination of cyanide in the environment. The need for effective reduction in cost to enable remediation of cyanide-contaminated sites from cassava mill factories is the purpose of this investigation. This involves bio-stimulation of organic wastes with indigenous microorganisms to degrade cyanide. The application of organic wastes as a substrate for the removal of cyanide was adopted. Banana, pineapple, and watermelon wastes were selected and bio-stimulated in cyanide contaminated soil. Each set-up containing 100 g of Cassava Mill Effluent (CME) contaminated soil was added with varied percent - 1, 5 and 10% of pineapple, banana, and watermelon waste, respectively. The monitoring of cyanide reduction was studied for 28 days. Periodic collection of soil samples from each set-up was done at four days interval to determine total cyanide concentration, total heterotrophic bacteria, and enzymes activities. Results indicated that after 28 days of applying the 10% watermelon, 5% pineapple and 1% banana waste, the 10% watermelon waste gave a better cyanide reduction compared to pineapple and watermelon waste treatment. The one phase-decay equation of 1% - banana, 5% - pineapple and 10% - watermelon waste treatment gave the shortest disintegration rate. The soil physicochemical properties, agro waste, microbial population, soil enzymes activities, soil microbial respirometric index, the bio-parameters sensitivity, carbon, nitrogen, and phosphorus were determined. The first order kinetics model revealed by the nth order algorithm; pineapple waste treated soil had the highest reduction rate - 0.9098/day of CME with half-life - 6.98 days. The 1% banana and 10% watermelon treated soil samples have the cyanide reduction rates - 0.9315/day and 0.8997/day. The cyanide reduction rate was significantly higher than the untreated contaminated CME (control) soil - 0.8975/day. The microbial counts and the three agrowaste treatment samples increase in day 4-16 (2.20×108 to 6.40×108 CFU/g) for 5% - pineapple; 1% - banana increased from 20×108 to 8.90×108 CFU/g (day 20 - 28) and 10% - banana increased -1.20×108 to 8.70×108 CFU/g (day 4-20); 1% - watermelon increased from 8.40×108 to 8.80×108 CFU/g (day 20-24) and 10% watermelon increased from -8.10×108 to 8.70×108 CFU/g (day 24-28), than the control which showed increase from 3.40×108–7.20×108 CFU/g (day 4-12) during the 28 days of remediation study. Soil organic carbon content gave a positive correlation with microbial biomass, carbon, nitrogen, and phosphorus, as well as microbial population, basal soil respiration and soil enzyme - catalase, lipase, dehydrogenase, urease and phosphatase activity. Soil contamination decreased (p<0.05) catalase, urease and dehydrogenase activities in all the waste treated soil compared to the control set-up. Owing to the use of this agro-waste-banana, pineapple and watermelon has proved to be effective in enhancing soil nutrient, improved soil enzymes activity and removed of cyanide from CME contaminated soil.
© 2018 Florence Obiageli Nduka, Samuel Chibuike Ubani, Victor Eshu Okpashi, NE Nwankwo, Sandra Ajiroghene Gometi, Blessing Chika Nwaso and O.F.C. Nwodo. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.