Valorization of Medical Plants Residues through Anaerobic Digestion

Over the last decade, as a response to the negative effects mainly caused by the economic crisis, young Greeks have turned to the primary sector. In contrast to the traditional cultivation schemes, young farmers have invested in the establishment of alternative crops, among which, are included the Lavender (Lavandula sp.) for the production of essential oils, as well as the industrial hemp (Cannabis Sativa L.) for the production of fibre, food, and medicines. These alternative crops have an important role in the regional development with positive environmental, economic and social impacts, i.e. enhancement of biodiversity, job creation and improvement of the quality of human life. Apart from the benefits resulting from the production of the aforementioned high added value products, the utilization of the by products remained after the processing of raw biomass materials could also contribute to the further development of local economies. The collection, recovery and processing of agricultural origin wastes could lead to the creation of a suitable feedstock for alternative uses. This study aims to highlight the characterization of Lavender straw residues and industrial hemp residues and to investigate their biomethane potential yield, as alternative fuel in frame of the post lignite era of the Western Macedonia. Biochemical methane potential (BMP) is a technique to determine the produced methane yield from organic waste under anaerobic conditions. Although, the biochemical methane potential (BMP_th) could be estimated by ultimate analysis, experimental BMP test provides better accuracy for the produced yield and contributes to complete technical and financial studies of an anaerobic digester plant. It is imperative for the biogas unit manager to possess knowledge regarding the chemical composition of the organic residues and their performance under anaerobic conditions, in order to enhance the energy production of the biogas plant, resulting in a higher income.

Statement of Novelty

This study conducted to highlight the use of aromatic and medical plant residues as an alternative fuel in the frame of decarbonisation and sustainable development. Western Macedonia region is the immediate area of the energy transition. Lavandula Sp. and Cannabis S. constitute a significant part of the total biomass production in Western Macedonia. The different streams of the residues were full characterized. BMP tests were carried out for each substrate (lavender, hemp, hemp cake pellets) and a blend of Lavender and Cannabis S. for co-digestion. The results showed that the medical plants valorization through anaerobic digestion could be promising.