ECOLOGICAL AND ECONOMIC ASPECTS OF MANURE MANAGEMENT - CONCLUSIONS FROM THE MILKEY AND MELS PROJECTS

The main purpose of the publication was to show the differences in revenues, costs and profits when using manure directly as a fertilizer (after storage) or as a substrate for a biogas plant equipped with a cogeneration unit, and then using the digestate for fertilization purposes. The comparison includes cost, revenue and profit streams throughout the year. It also takes into account the introduction of additional co-substrates in order to increase the yield of biogas (biomethane), and thus the profits from the future investment. Forecasts of the profitability of biogas investments were presented, taking into account the reduction of greenhouse gas emissions, i.e. methane and nitrous oxide, which are several dozen or even almost 300 times more harmful to the atmosphere than carbon dioxide. The economic, energy and ecological accounts of manure management can serve as guidelines for pre-investment analysis when considering investments in biogas plants. In addition, the published data indicate that the energy management of cow manure is of great importance when estimating the carbon footprint of the entire dairy production. It should be expected that in the near future such solutions will become more and more popular almost all over the world. Input parameters of substrates, gaseous emissions and biogas (and biomethane) yields were obtained from own research (cow manure samples were taken from a working farm) and from literature sources, e.g. these were international and national IPCC (Intergovermetal Panel on Climate Change) protocols.