The effect of temperature, storage time and collection method on biomethane potential of source separated household food waste.

The aim of this study was to mimic real conditions for storage and transport and to evaluate how much of the biomethane potential is lost before the organic fraction of municipal solid waste (OFMSW) from households in Sweden reaches the biogas plant. The laboratory biomethane potential (BMP) experiments was carried out with respect to the storage time, collection method (paper or plastic bag) and storage temperature (22°C and 6°C) in order to evaluate the effect of these factors on the biomethane potential. A recipe representative for OFMSW from households in Sweden was designed with the help of literature and modification of recipes from technical reports and scientific literature. Laboratory experiments showed that the difference in the BMP of OFMSW stored in plastic- compared to paper bags were obvious at 22°C with a lower biomethane potential for paper bags, but there was no difference at 6°C. Provided that the loss of organic matter during pre-treatment is equivalent for both paper and plastic bags it is possible to get more biomethane from OFMSW collected in plastic bags during the warmest part of the year, since they have a more preservative effect on OFMSW than paper bags. This could be explained by the plastic bags being denser than paper and therefore maintain the volatile organic compounds inside the bag and promote a pre-hydrolysis of the material rather than aerobic degradation.