The article reviews the energy potential of microalgae as an alternative raw material for anaerobic digestion. Currently, energy security is one of the main topics among researchers. The amount of generated fossil fuels is limited, it is a question of time when fossil fuels will not continue to be accessible at low cost. There is a need to find an alternative carrier of energy which will replace the fossil fuels in the World. Green microalgae can be proposed as a possible bio raw-material, which can be used as an input material in order to produce energy. Lots of alternative technologies of algae cultivation are currently being developed all over the world. There is a necessity to search for a sensible way to produce algal biomass for bioenergy purposes, while maintaining all requirements involved in environmental and economic issues. The research results presented in the science article show that microalgae biomass is the proper alternative material for biogas production with the method of anaerobic fermentation. We believe that these research results can contribute to the future development of all forms of renewable energy in the Slovak Republic.
The prosecutor’s protest is a legal mean by which the prosecutor supervises the observance of law by public authorities. District offices, cadastral departments decide on the deposit of property rights to real estate, as well as on ownership rights to agricultural land, and also decide on the protest of the prosecutor. If the relevant District office, cadastral department, or its superior authority does not remove the non–compliance by issuing a decision or a measure that complies with the law, the prosecutor may bring the case to court. The court may annul the contested decision or measure. The aim of the paper is to collect and analyse data and evaluate the institute of prosecutor’s protest as an effective tool of agricultural land protection in connection with its acquisition or transfer. The paper compares the individual years in the observed period of time and also compares different regions in Slovakia. The result is a comparison and evaluation of the observed time periods.
Algae represent a potential source of energy via anaerobic digestion. The aim of the study was to obtain the possible potential of green microalgae, which could replace the commonly used corn silage for the production of biogas in the future. The intensive construction of new biogas plants stations across Europe and the lack of arable land suitable for the cultivation of biomass for energy purposes are the fundamental reasons behind looking for the alternative raw materials for energy production as a substitute for commonly used input materials. When comparing green microalgae with conventional crops the high productivity potential (high oil content) as well as the possibility of their production during the whole year can be noticed. It is necessary to find the effective way to produce biomass from green microalgae, proper for energy conversion, while ensuring the economic and environmental aspects. The interim research results mentioned in this article indicate that microalgae present appropriate alternative material for the process of anaerobic digestion.
The paper analyses the legal regulation of the cultivation of fast-growing trees on agricultural land in Slovakia and Czechia. The focus is on the differences in the legislation of the two countries, the application of the regulations of cultivation of fast-growing trees in practice, the level of protection of agricultural land, and the support system for the cultivation of fast-growing trees. Comparison of national legislation dealing with the issue of planting fast-growing trees, taking into consideration the protection of agricultural land and the legislation on granting the state support has also been investigated in the context of European legislation. The procedure before the start of planting, the permission conditions for planting of fast-growing trees, the conditions and the process of support provision have been studied. The result of the documents analysis is a comprehensive comparative overview of the above-mentioned areas of legislation on the cultivation of fast-growing trees in Slovakia and Czechia and the identification of differences, benefits and practical impacts on the cultivation of fast-growing trees.
The paper deals with biogas yield production from two co-substrates - sorghum silage mixture of corn silage and crushed potatoes combined with mixture of livestock manure and swine slurry - in a semi-continuous digester under mesophilic conditions. This paper aims to evaluate the suitability of alternative substrates for biogas production under biogas plant operational conditions. In the first experiment, biogas yield was 0.159 Nm3 per hour with methane content of 56.96% vol. In the second experiment, biogas yield was 0.18 Nm3 per hour with methane content of 52.95% vol. Experiments confirmed that both substrates are suitable for biogas production under the given conditions.
Pavol Porvaz, Ján Gaduš, Štefan Tóth and János Jóvér
“Dry fermentation“ technology may be used for energy recovery of phytomass substrate which has dry matter content from 20 to 60%. In agriculture sector, while only rarely used, it is a very perspective technology at such types of biomass – phytomass which is not recommended to be processed within “wet fermentation” (process is energetically and operationally very costly). For detecting the suitability of Miscanthus × giganteus phytomass to biogas for production through dry fermentation process, as well as determining the biogas yield, at the Slovak university of Agriculture (SUA) there has been developed an experimental device enabling the pilot plant trials, which is installed at the biogas station within the area of the VPP SPU Ltd. in Kolíňany. A pilot plant experiment of biogas production based on Miscanthus × giganteus (Miscanthus sinensis Anderss.) phytomass within dry fermentation process was carried out at the period from 25 February to 25 March 2013. The monitored production of biogas was based on the substrate mixture of components formed as follows: the biomass from preceding cycle (farmyard manure) and ensilage from Miscanthus phytomass. In these experiments the amount of produced biogas, analysis of biogas and the input substrate were materialized by standard methodology. On base of the obtained results, we can formulate the conclusion: the tested substrate mainly consists of Miscanthus phytomass and manure was suitable for biogas production technology and anaerobic dry fermentation process. The yield of Miscanthus substrate in our experiments was around 117 litres of biogas per 1 kg of dry matter silage. For assurance of the continuity and uniformity in the production of biogas by dry fermentation process, the multiple-fermentation chamber is needed, which must be saturated gradually with dosing interval. This dosing interval is caused by residence time and the number of chambers. For example, at the residence time of 28 days and 4 chambers, the need of the substrate change will be on weekly base in each chamber.
Vladimír Sitkey, Ján Gaduš, Ľubomír Kliský and Alexander Dudák
Energy variety of amaranth (Amaranthus spp.) was grown in large-scale trials in order to verify the capability of its cultivation and use as a renewable energy source in a biogas plant. The possibility of biogas production using anaerobic co-fermentation of manure and amaranth silage was verified in the experimental horizontal fermentor of 5 m3 volume, working at mesophilic conditions of 38-40 °C. The goal of the work was also to identify the optimum conditions for growth, harvesting and preservation of amaranth biomass, to optimize biogas production process, and to test the residual slurry from digestion process as a high quality organic fertilizer. The average yield of green amaranth biomass was 51.66 t.ha-1 with dry matter content of 37%. Based on the reached results it can be concluded that amaranth silage, solely or together with another organic materials of agricultural origin, is a suitable raw material for biogas production.