Utilization of natural carbon sources in bioflocculation using plastic-bioreactors: A trial experiment

Abstract

A three-week trial on the efficacy of local carbon sources in the production of biofloc, and their resulting proximate and mineral compositions were evaluated. Five experimental treatments (labelled A, B, C, D, and E) in triplicates were prepared and maintained with equal volume of inoculum (500ml inoculum and 2.5L tap water) in 5L plastic bioreactors with constant aeration. Groups A, B, C, D, and E received different local carbon sources: white yam, cocoyam, water yam, Elephant ear yam, and glucose respectively. During the biofloc development period, C: N ratio was maintained at 10. The flocs were collected weekly using an improvised Imhoff cone for 10minutes. High floc volume was observed in water yam and cocoyam groups. Floc yield was significantly different between the setups on week 1 (p< 0.0001), week 2 (p<0.0001), and week 3 (p=0.018). The local carbon sources produced floccules that yielded quality nutrients and minerals. The fats, fiber, and carbohydrate compositions were similar between the different species of yam. The total heterotrophic counts (x105cfu/ml) controlled the nitrogenous wastes with total suspended solids level of 111.33 to 311.50mg/L and contributed to better water quality while water yam and cocoyam produced the best biofloc yields.