Viacheslav Bratishko

The disposal of sewage sludge is a pressing issue for municipal utilities, where the implementation of high-cost thermal drying technologies is economically unviable. Previous research by the authors has demonstrated the effectiveness of “sewage sludge - cereal straw” mixtures for aerobic composting (bioconversion). The aim of this work is to provide a theoretical justification for the use of such composite mixtures in the production of solid biofuel (fuel pellets), whilst simultaneously establishing a standardised Life Cycle Inventory (LCI) for subsequent environmental assessment. The input data for the modelling were the results of laboratory studies of the physical and chemical properties of sludge from the Boiarka wastewater treatment plant (average moisture content – 75.41%, carbon and nitrogen content in dry matter – 24.04% and 3.63%) and the characteristics of wheat straw (moisture content 12%, net calorific value of dry matter 17.6 MJ·kg-1). All mass and energy balances were normalised to a single functional unit – 1 kg of the finished composite mixture. Calculations showed that adding up to 60% straw to sludge allows the moisture content of the mixture to be reduced to 31-39% without the use of additional thermal energy. At this moisture content, according to the modelling results, the lower calorific value of 1 kg of the resulting pellets will be 9.78-10.32 MJ·kg-1. Analysis of the chemical composition demonstrates that “diluting” sludge with biomass further reduces the concentration of heavy metals in the ash residue to a safe level. The mass and energy parameters obtained confirm the energy efficiency of the co-pelletisation technology and form the basis for further multi-criteria life cycle assessment (LCA) of alternative utilisation scenarios.

Agricultural production is one of the most energy-intensive sectors of national economy. One of the unsolved problems of modern livestock breeding in Ukraine remains the creation of standardized conditions for keeping animals in livestock buildings. High concentration of livestock per unit area leads to deterioration of air composition, which is polluted with ammonia, hydrogen sulfide, carbon dioxide and dust. As a result, slaughter increases, weight gain and safety of animals decrease. The standardized air exchange of livestock buildings is provided by the system of mechanical forced supply and exhaust ventilation. The main part of energy in animal husbandry, about 50%, is spent on maintaining the required microclimate parameters. During the heating period, which lasts 6-9 months in 80% of Ukraine, it is necessary to heat air blown into livestock buildings. For this purpose, from 60 % to 80 % of total heat energy consumed is used. At the same time, to ensure the required microclimate parameters inside the livestock house, ventilation air is removed to the atmosphere and, along with harmful substances, a significant amount of heat is removed (90% of total heat loss of buildings). For Ukraine, which has a developed agriculture that produces a significant amount of organic waste, biomass could become a priority source of renewable energy resources. Currently, one of the directions of energy utilization of biomass is production of fuel gas obtained by its thermal decomposition. The study of a large number of pyrolysis plants of various designs cited in scientific literature allows us to conclude that many technologies cannot be sufficiently efficient due to a number of drawbacks: improvement of technological modes is not considered in functional connection with heat and mass transfer and hydrodynamic processes in pyrolysis chambers during thermal decomposition of organic raw materials; no measures are provided for prompt response to current changes in physical and mechanical properties in the feedstock flow and correction of pyrolysis process parameters in order to achieve the required optimal results, which does not allow predicting the composition of resulting gas. Therefore, research aimed at the development of technology for effective heating of livestock buildings is relevant.

The article discusses the methodology for designing a temperature recorder for livestock facilities based on the ADC10 programmable logic controller (PLC). This solution was developed to meet the growing demand for temperature measurement systems suitable for use in the agricultural sector, particularly in livestock facilities. The key requirements for such systems include versatility, reliability, low cost, low energy consumption, and sufficient speed to effectively execute automated climate control algorithms that ensure optimal conditions for animal husbandry. One of the main challenges in the design process is improving the noise immunity of the communication channel, as livestock facilities often experience strong electromagnetic interference that can distort the transmitted data. The article proposes a combined use of software and hardware approaches to achieve high noise immunity. Specifically, the methodology involves using a two-block mode of operation for the communication channel, which provides better signal stability in the presence of electrical interference. Additionally, the use of a low-pass filter at the output is suggested to effectively suppress unnecessary high-frequency signals and reduce noise, thereby improving the accuracy of data transmission. Another important aspect discussed in the article is reducing the cost of the temperature recorder. To achieve this, the ADC10 programmable logic controller with an integrated temperature sensor was selected, which significantly reduces the manufacturing costs of the equipment. To improve the accuracy of temperature measurements, the article suggests implementing automatic calibration algorithms when the device's power supply is turned on. Additionally, original circuit solutions are presented to eliminate parasitic grounding loops that arise from the flow of reverse current through conductors shared with other elements of the circuit. This significantly enhances measurement accuracy by removing sources of errors caused by the influence of external electrical signals on the measurement part of the circuit. These approaches together offer an effective and reliable solution for temperature monitoring and control in livestock facilities, ensuring the precise and cost-efficient management of environmental conditions critical to animal welfare.

The article summarises the world experience of studying the issue of the negative mechanical impact of milking equipment on the health of cows in the process of machine milking. The design, principle of operation and results of experimental studies the special inserts for serial milking cups and teat rubber are presented. Special inserts for liners and milking cups ensure the implementation of physiologically safe principles of machine milking. Compared to a conventional two-chamber teat cup, the teat cup insert ensures pressure equalisation in the teat and interwall spaces during the sucking phase, while the rubber insert reduces the vacuum pressure in the teat space during the compression phase compared to the pressure in the collector chamber. The most common teat liner today has a circular cross-section and is characterised by a sharp transition from the sucking phase to the compression phase, when its cylindrical shell loses stability under the influence of evenly distributed pressure in the intercellular space of the milking cup. In addition, during the compression phase, at the point of closure such a liner has a cross-section in the form of a figure eight, which means that it does not completely disconnect the teat space from the vacuum pressure, which leads to injury to the tip of the teat, especially during dry milking. It was found that when using nipple liners with an insert, the vacuum pressure in the teat spaces of milking cups increases to 17-18 kPa throughout the entire milking period. The pressure in the milk collection chamber of the collector rises to 20-22 kPa. Such indicators largely correspond to the natural suckling of a calf. During production trials over 30 days, the percentage of cows with mastitis decreased by 1.5% and the milk yields increased by 2.2%.

One of the main technological operations in the harvesting of stem fodder is harvesting with simultaneous chopping. Modern round balers, bale balers, and pickup trolleys are equipped with a beater-knife cutting apparatus. They are based on a rotating beater (a pipe with fingers fixed to it) and a number of knives installed in the channel, along which the fingers of the beater move in a rotational motion. In the process of developing the design of such a cutting apparatus, the beater has evolved from an analogue of a scraper-finger conveyor, a rotor with a controlled rake, into a rotor with a tubular shaft and fixed curved fingers radial to its base. The problem with such cutting machines is a significant increase in friction forces on the side surfaces of the knives with an increase in their number. The increase in the number of knives is caused by the need to reduce the length of the raw material to be cut. The research is aimed at determining the design features of the beater-knife cutting units of forage harvesters, the directions of their improvement by replacing the passive knife with an active disc knife and experimentally determining the effect of the circular speed of the knives on fuel consumption. The monographic method was used in the research. This made it possible to systematize the main design parameters of the beater-knife cutting machine, identify the main works carried out in the study of similar designs, and propose a technical solution that can significantly reduce the friction forces that occur on the side surface of the knives. By varying the distance between the knives of the prototype cutting machine, the weighted average cutting length of the resulting raw material was determined. The results obtained made it possible to determine the ratio between the dimensions of the cutting device (which are in the range of: length – 1120-2000 mm, diameter - 415-880 mm, minimum cutting length – 22-25 mm), experimentally confirm the performance of the cutting device with disc knives, establish the dependence of fuel consumption for picking up, cutting and feeding alfalfa on the circular speed of disc knives, and determine the minimum fuel consumption, which is 0.74 kg·h-1.

As a result of analytical studies, the main types of lignocellulose raw materials of communal origin were established (using the example of the city of Kyiv). It was found that the most common and promising for use in biofuel technologies are the following types of lignocellulose raw materials in groups: 1) lawn grass; roadside grass; 2) green trimmings of maple, linden, poplar, chestnut, oak, birch; 3) fallen leaves of maple, linden, poplar, chestnut, oak, birch. These types of trees make up 91.6% of the number of all perennial plantations, excluding coniferous trees (based on the analysed data of municipal enterprises of Kyiv). The largest share of fallen leaves (92.9%) is formed by three types of trees - poplar, maple and chestnut. Chemical studies were conducted on the composition of these types of raw materials, as well as three types of miscanthus and sugar sorghum, as plants that can take a promising place in urban landscapes. As a result of chemical studies, it was found that the highest ash content (mineral component) was observed in the dry matter of roadside grass (31.63%), fallen birch leaves (31.17%) and lawn grass (17.53%), the highest content of lignin is in fallen poplar leaves (30.29%), oak trimmings (29.41%) and fallen oak leaves (27.63%), the highest cellulose content is in miscanthus plants of all species (42.23-46.00%), sugar sorghum (34.07%) and fallen birch leaves (31.79%), hemicelluloses – in fallen maple leaves (36.66%), roadside grass (33.97%) and sugar-flowering miscanthus (33.96%), water soluble substances – in plants of sugar sorghum (33.62%), trimmings of linden (22.81%) and poplar (22.57%), pitches and fats – in fallen birch leaves (14.71%), fallen oak leaves (9.82%) and trimmings of birch (8.73%). The obtained results allow us to determine the most promising types of raw materials of communal origin for use in technologies of liquid and gaseous biofuels.

Butanol-producing strains Clostridium sp. UCM B-7570 and C. acetobutylicum UCM B-7407 were used for research from “Collection of strains of microorganisms and plant lines for food and agricultural biotechnology” of the Institute of Food Biotechnology and Genomics of the National Academy of Sciences of Ukraine, glycerol (BASF, Germany) and apple pomace (total moisture 4%) after apple juice production. The aim of this work was to study the possibility of using apple pomace by domestic butanol-producing strains of Clostridium sp. UCM B-7570 and C. acetobutylicum UCM B-7407 as a substrate. Producers were cultured on medium with different concentrations of apple pomace, glycerol was used for the inoculation. The presence of ethanol, acetone, and butanol in the culture liquid was determined using a gas chromatograph. It was determined that a significant part of the macrocomponent composition of the extracts can be used in bioconversion by producing strains of the genus Clostridium. It was determined that the highest concentration of butanol (10 g/dm³) was at a concentration of 120 g/dm³ in the extracts. The obtained data showed the possibility of using apple pomace as a substrate in biobutanol technology.

The rapid development of new molecular methods and approaches, sequencing technologies, has provided new insights into genetic and structural features of bacterial genomes. Information about the genetic organization of metabolic pathways and their regulatory elements has greatly contributed to the increase in the number of studies related to the construction of new bacterial strains with improved characteristics. In this study, the entire genome of the producing strain Clostridium sp. UCM В-7570 from the “Collection of producing strains of microorganisms and plant lines for food and agricultural biotechnology” of Institute of Food Biotechnology and Genomics of the National Academy of Sciences of Ukraine was sequenced and characterized. The genome was assembled into the scaffold with a total size of 4,470,321 bp and a GC content of 29.7%. The total number of genes identified was 4262, of which 4057 encoded proteins, 10 were rRNA operons, and 80 were tRNA genes. The genes of the sequenced genome encoding enzymes involved in butanol fermentation were found and analyzed. They were organized into cluster structures, and their protein sequences were found to be similar to the corresponding strains of C. acetobutylicum, C. beijerinckii, and C. pasteurianum type strains with the highest similarity to the latter. Thus, Clostridium sp. UCM В-7570 producing strain was identified as C. pasteurianum and suggested for metabolic engineering purposes.