The influence of physico-chemical parameters, substrate concentration, and species variations on the biochemical methane production rates of ten tropical/subtropical grasses

There are several problems faced by small island developing states (SIDS), especially when it comes to waste management and energy production. There is little land space available for dumping and fuel has to be imported in order to meet energy demands. These problems can be mitigated by using grass cuttings from landscaping, which are often dumped, to produced biogas, which can be used as a fuel. In this study the rates of methane production of 10 different tropical and subtropical species of grasses were determined. Based on the results for 20 g/kg samples, the specific rates of gas production ranged from 2.40 +/- 0.21 NmL/gFM/day (Zoysia matrella) to 6.52 +/- 0.36 NmL/gFM/day (lemon grass). It was also observed that organic dry matter (oDM) loads did not correlate with methane production, suggesting that the oDM content is not necessarily an accurate indicator of a substrate's methane potential, and highlighting areas for further study. The results in this paper provide a database on the rates of methane production of grasses which are common to the tropical and subtropical regions and can be found in several SIDS. (c) 2018 Society of Chemical Industry and John Wiley & Sons, Ltd.