Predicting the heating value of sewage sludges in Thailand from proximate and ultimate analyses

There have been various methods used for determining a heating value of solid fuel such as coal, biomass and municipal solid waste (MSW) either by experiment using a bomb calorimeter or by modeling based on its compositions. This work proposes another aspect in developing models to predict the heating value of sewage sludge from its proximate and ultimate analyses data. The extensive number of samples was collected from different wastewater treatment plants in Bangkok and in the vicinity and was then analyzed for their heating values, proximate and ultimate analyses. Based upon proximate and ultimate analyses, the models were proposed. The best results show coefficients of determination (R2) of 0.899 and 0.905 for the models based on the proximate and ultimate analyses, respectively. The heating values obtained from the models were in good agreement with that attained by experiment. The application of the selected models was appreciable for the sewage sludge with ash content up to 50% (db).