The effect of natural zeolite on methane production from secondary paper and pulp sludge and its modeling
are evaluated. Five tests with zeolite concentrations of 0, 0.2, 0.5, 1 and 20 g/L were evaluated at
30 C. The modified Gompertz equation, the logistic function and the transfer function were evaluated.
The results show that doses between 0.2 and 1 g/L of zeolite produce a statistically significant increase
of accumulated methane, giving values greater than 183 mL for CH4/g of VSadded. On the contrary, the
20 g/L dose of zeolite reduced the methane production. The modified Gompertz and the logistic function
models concur with the experimental data, the former having the best fit.