KINETIC MODELLING FOR BIO-METHANE GENERATION DURING ANAEROBIC DIGESTION OF MUNICIPAL SEWAGE SLUDGE UTILIZING ACTI-ZYME (BIO-CATALYST) AS A RESOURCE RECOVERY STRATEGY

This paper focuses on the kinetic modelling for simulation of bio-methane generation from sewage sludge digestion utilizing Acti-zyme as a bio-catalyst. Sewage sludge was digested at 37°C and 55°C for Acti-zyme loadings of 50 g/m3, sewage sludge loadings of 5-7.5 g/L.day and retention time of up to 40 days. Optimal bio-methanation was achieved at 37°C with 78% composition. The bio-methane production experimental data was fitted to the linear, exponential, logistics kinetic, exponential rise to a maximum and the modified Gompertz kinetic models and the coefficients of determination (R2) obtained. A lag phase of 10 days was observed during the bio-methanation process. The exponential rise to a maximum kinetic model fully simulated the bio-methane generation with a R2 value of 0.999 and a rate constant of 0.073 day-1. The logistics kinetic model can therefore be accurately applied for modelling the experimental data for bio-methane production.