Energy rationale for the Use of the Thermophilic Mode of Anaerobic Bioconversion of Liquid Organic Waste in the Climatic Conditions of the Russian Federation

The transition of livestock production to industrial processes and the concentration of animals associated with this process on large farms and complexes has caused a sharp increase in the volume of manure that must be disposed of without pollution. One of the ways of processing organic waste (biomass) is its anaerobic digestion in biogas plants through the vital activity of microorganisms (methanogenesis).Biogas obtained using microbiological processing of biomass can be used as a raw material for heat and electric energy. Annually, 0.17% of the total livestock manure produced at Russian agricultural enterprisesis used for biogas production.The main component of a biogas plant is a manure fermentation reactor, the required volume of which is determined by the daily output of manure from the livestock farm, the temperature and the hydraulic retention time of treatment. This research explored thermal energy consumption of biogas plants, using the example of a biogas plant of a modular design that depended on the average annual outdoor temperature. Based on the calculations, the thermophilic mode was found to be more energy-efficient than the mesophilic one; thus, with the thermophilic mode, the specific energy consumption needed for the plant was lower at the average annual outdoor temperatures of all the constituent entities of the Russian Federation. At the same time, the specific biogas yield in the thermophilic regime was 20-50%higher than in the mesophilic regime. Keywords: anaerobic processing, agricultural waste, thermophilicmode, mesophilicmode, energy costs, energy rationale

Designing a Biogas Plant for an Educational and Scientific Livestock Complex

To design biogas plants, it is necessary to have accurate data about the properties and biogas productivity of the available substrates. Reference data should not be used because the performance of the same substrate can vary significantly. In this research,chicken, horse, sheep and rabbit manure from one of the farms inthe Belgorod region of Russia were analyzed, and the parameters of a biogas station for the processing of this raw material were calculated.The biogas yield of the substrates was determined using the Hohenheim Biogas Yield Test. It was found that the specific biogas yield from the droppings of broilers, laying hens, rabbits, sheep, and horses, and from corn silage were, respectively, 456, 363, 390, 189, 116 and 618 ml/g оDM. The methane content in the biogas was 58.00, 58.50, 57.00, 62.00, 65.00 and 53.60%, respectively. In most cases, the obtained results differed significantly from the data presented in publications of other researchers and reference books.The biogas plant parameter calculations were made according to generally accepted equations, taking into account the characteristics of the studied substrates. Based on the results, it can be concluded that to dispose of the animal excrement of this farm, it is necessary to build a biogas plant with a bioreactor of volume 102.2 m3 and an engine with a power of 12 to 31 kW. The planned output of electric and thermal energy would be 246.19 and 410.27 kWh/day, respectively. Keywords: Hohenheim Biogas Yield Test, rabbit manure, horse dung, sheep manure, chicken droppings, biogas yield of substrates

Long-Term Assessment of Temperature Management in an Industrial Scale Biogas Plant

Temperature management is one of the primary considerations of biogas plant operation, and influences physical and biochemical processes. An increase in the temperature leads to an increase in the hydrolysis rate of the feedstock, while it can inhibit microorganisms taking part in different stages of anaerobic digestion. Because of the complexity of the biochemical processes within the anaerobic digestion process, there is a lack of knowledge about the effects of temperature and temperature change on efficiency. Moreover, the impact of stirring directly affects the temperature distribution in the anaerobic digestion reactors. In this study, the temperature management in an industrial-scale biogas plant was examined, and the effect of small temperature changes (from the operation temperature 42 °C) on the efficiency was studied in a laboratory under two different conditions: with stirring (at 40 and 44 °C) and without stirring (at 40 and 44 °C). The examination results from the biogas plant showed that heat transfer in the reactor was not sufficient at the bottom of the digester. Adaptation of the post-digester samples to the temperature changes was more challenging than that of the digester samples. From digestate samples, higher biomethane generation could be obtained, resulting from sufficient contact between microorganisms, enzymes, and substrates. Overall, differences between these changing conditions (approx. 6 NmL CH4 g VS−1) were not significant and could be adapted by the process.

Energy and Economic Balance between Manure Stored and Used as a Substrate for Biogas Production

The aim of the study is to draw attention to the fact that reducing methane and nitrous oxide emissions as a result of traditional manure storage for several months in a pile is not only a non-ecological solution, but also unprofitable. A solution that combines both aspects—environmental and financial—is the use of manure as a substrate for a biogas plant, but immediately—directly after its removal from the dairy barn. As part of the case study, the energy and economic balance of a model farm with dairy farming for the scenario without biogas plant and with a biogas plant using manure as the main substrate in methane fermentation processes was also performed. Research data on the average emission of ammonia and nitrous oxide from 1 Mg of stored manure as well as the results of laboratory tests on the yield of biogas from dairy cows manure were obtained on the basis of samples taken from the farm being a case study. The use of a biogas installation would allow the emission of carbon dioxide equivalent to be reduced by up to 100 Mg per year. In addition, it has been shown that the estimated payback period for biogas installations is less than 5 years, and with the current trend of increasing energy prices, it may be even shorter—up to 4 years.

Biogas Plant Digital Transformation Using Edge-Computing Batteryless and Free of Maintenance Atex Iot Powered by Heat

Current industries leave a big ecological footprint that needs to be reduced to preserve our resources. For it, big industries are leading new researches to move to more environmental-friendly technologies. In this paper we explain an innovative technology which has the ability to introduce edge-computing in the node in combination with energy harvesting, which allows the device to work without the need of batteries. Also, as all the computations are performed in the node, it allows the use of long-range communication protocols. To demonstrate the behavior of the technology, the paper also presents two cases of use in facilities.

IMPACT OF MEFOSPHONE ON THE EFFICIENCY OF THE PROCESS OF BIOGAS OBTAINING AND UTILIZATION OF CARBON-CONTAINING WASTE

This article discusses a new method of utilizing carbon-containing waste into biogas with the addition of a biological active additive Mefosfon to the substrate in order to accelerate the process of obtaining biogas and preserve nutrients in the final product - organic fertilizer. The experiments were carried out in a small-volume biogas plant (MBU) without air access in a heat-insulated reactor filled to 2/3. The results of numerical studies of the conversion products of cattle manure are presented. The manure was kept in the reactor for 7 days. The use of the drug Mefosfon in ultra-low concentrations (10-4) made it possible to obtain a useful product in the form of high-quality organic biofertilizers and biogas. The conducted microbiological analysis of the experiments showed that in the experiment with the use of the drug Mefosfon, the content of enterococci and bacteria of the Escherichia coli group were lower than in the experiment without the drug Mefosfon. Bioconversion of the organic component of the substrate allows the use of waste in agriculture as organic fertilizers. Such processing can significantly reduce the dry weight of the treated organic waste and reduce the content of pathogenic microorganisms Salmonella spp. and Enterococcus spp., bacteriophage FX174, Ascarissuumova. Mefosfon reduces the time of maturation and neutralization of carbon-containing agricultural waste, which indicates the prospects of its use. After processing waste in a small-volume biogas plant, there are no pathogenic pathogenic microflora, helminth eggs, weed seeds, nitrites and nitrates. The final nitrogen content of the Mephosphon treated substrate is higher than that of the untreated substrate. The acidity values in the substrate pH 6.7 in the untreated and 7.5 in the treated substrate. Studies have shown that when the drug Mefosfon is added to the substrate, the release of biogas begins on 1-2 days and lasts up to 7 days. In this case, the biogas yield increases up to 25% compared to the use of the control substrate without the use of the Mefosfon preparation. The drug has found application in plant growing, animal husbandry, reclamation of contaminated soils