C. Nwoye^1,, A. O. Agbo², K. C. Nnakwo¹, E. M. Ameh², C. C. Nwogbu³

Assessment evaluation of the reliability level of methane gas production dependence on organic loading rate and hydraulic retention time during biodegradation of fruit wastes was carried out. A two-factorial linear model was derived and validated for the predictive analysis and evaluation. The validity of the model; ζ = - 0.3127 (ln ϑ - ln ɤ) - 0.2014 was rooted on the core model expression ζ + 0.2014 = - 0.3127(ln ϑ - ln ɤ) where both sides of the expression are correspondingly approximately equal. Regression model was used to generate results of methane gas yield, and its trend of distribution was compared with that from derived model as a means of verifying its validity relative to experimental results. The results of this verification show very close dimensions of aligned areas designating methane gas yield, which precisely translated into significantly similar trend of data point’s distribution for experimental (ExD), derived model (MoD) and regression model-predicted (ReG) results. Evaluations from generated results indicated that methane gas yield per unit hydraulic retention time and organic load mass as obtained from experiment, derived model & regression model were 0.0242, 0.0239 & 0.0209 m³ kg ^-1 VS d^-1 and 0.0064, 0.0063 & 0.0055 (m³ kg ^-1)² respectively. Standard errors incurred in predicting the methane gas yield for each value of the hydraulic retention time and organic loading rate considered as obtained from experiment, derived model & regression model were 0.1032, 0.1042, & 0.0011 % and 0.1237, 0.1220 & 2.5x10^-5 % respectively. Deviational analysis indicates that the maximum deviation of model-predicted methane gas yield from the experimental results is less than 22%. This translates into over 78% operational confidence and reliability level for the derived model as well as over 0.78 reliability coefficient for the methane gas production dependence on organic loading rate and hydraulic retention time.

reliability level, methane gas production, hydraulic retention time, organic loading rate, biodegradation, fruit wastes