Purpose: A novel composting process suitable for handling food waste in an island community is developed. Food waste collection exhibits a substantial variation in quantities over the year and is based on separate disposal of food waste from residents and shops at the source.
Methods: The food waste is properly mixed with recycled compost and bulking material, consisting of a mixture of prunings, leaves and sawdust and placed in one of 24 1m3 closed container. After approximately one month, it is transferred to a second 1m3 container and after one more month to a final 1m3 container. Then it is sieved using an automated sieve and separated into two fractions. The net product is bagged and returned to the citizens, while the “reject” fraction is mixed with the feed. Approximately 15 tons of food waste were processed in 44 batches and produced approximately 3.4 tons of compost product. During the composting batches the composting mixture temperature and volume were monitored, the mixture was stirred 2-3 times weekly and water was added as needed to maintain a good level of moisture. For each of the 44 batches, the mean and maximum temperature reached, the mean ambient temperature, the process duration and the amounts of crude and net compost obtained after sieving are presented.
Results: Five machine learning models (Linear Regression, Decision tree regressor, K-Neighbors Regressor, Support Vector Regression, XGBoost Regression) were developed capable of predicting these outputs, using as inputs ambient temperature and the mixture amount and composition with excellent results.
Conclusion: The developed machine learning models are useful for predicting the outcome of composting food waste and could be used for optimal designing compost plant operations.