Modelling and Optimisation of Water Melon Seed Protein Isolate Coag-flocculation of Nworie River Water

International Journal of Research and Scientific Innovation (IJRSI) | Volume VI, Issue X, October 2019 | ISSN 2321–2705

Modelling and Optimisation of Water Melon Seed Protein Isolate Coag-flocculation of Nworie River Water

Anagwu Festus Ifeanyi^1*, Onukwuli Okechukwu Dominic², Menkiti Matthew Chukwudi², Obiora-Okafo Ifeoma Amaoge², Emurigho Tega Anthony³, Ofoluwanyo Rosemary¹

^1*Department of Chemical Engineering Technology, Federal Polytechnic, Nekede, Owerri, Nigeria
²Department of Chemical Engineering, Nnamdi Azikiwe University, Awka, Nigeria
³Department of Food Technology, Federal Polytechnic, Nekede, Owerri, Nigeria
^*1Corresponding Author

Abstract:– Treatment of surface water by coagulation/flocculation was investigated in this research using protein isolate of water melon seed known as Water Melon Coagulant (WMC) with the aim of removing turbidity and colour in the water sample. Bench-scale nephelometric jar tests were performed to remove turbidity and colour from the water sample collected from Nworie River (NR) in Owerri, Imo state, Nigeria. Process factors were initially varied to investigate their effects on the coagulation/flocculation process adopting one-factor-at-a-time approach. Thereafter, the experiment was designed within a narrower region of search for optimality of the process variables. Response Surface Methodology (RSM) was employed in the experimental design, adopting the rotatable Central Composite Design (CCD) option. ANOVA results showed that turbidity and colour removal efficiencies in WMC-in-NR system are well represented by quadratic models. The turbidity removal efficiency model yielded p-value of 0.0001 at 5 % significance level, coefficient of determination,  of 0.9563 and adjusted  of 0.9126. The adequate precision, representing the signal-to-noise ratio was found to be 14.976, sufficiently above the benchmark of 4. This implies that the quadratic model can be used within the range of variables in the design space. The coefficient of variance which indicates the ratio of the standard error of estimate to the mean value of the observed model was reasonably low at 2.79 %. This value is well below the required maximum of 10 %, clearly pointing to the reproducibility of the models. For colour removal efficiency model, the indices used for the judgement were p-value of 0.0001 as obtained,  of 0.9879, adjusted  of 0.9759, signal-to-noise ratio of 35.692 and coefficient of variance of 2.10. Process optimization results gave optimal process parameters values of 250 mg/l dosage, pH of 7.26 and 35 minutes settling time. At this point, the optimal turbidity and colour removal efficiencies were 94.87 % and 84.66 % respectively. It is concluded that while water melon-derived coagulant is very effective in the removal of turbidity and colour from surface water, the process at room temperature is described by a quadratic model.

Read More