Study of Methane Fermentation of Cattle Manure in the Mesophilic Regime with the Addition of Crude Glycerine

Abstract

The urgency of the study is due to the need to increase the productivity of biogas plants by intensifying the process of methane fermentation of cattle manure in mesophilic mode by adding to it the waste from biodiesel production: crude glycerine. To substantiate the rational amount of crude glycerine in the substrate, the following tasks were performed: determination of dry matter, dry organic matter, and moisture of the substrate from cattle manure with the addition of crude glycerine; conducting experimental studies on biogas yield during fermentation of cattle manure with the addition of crude glycerine with periodic loading of the substrate; and development of a biogas yield model and determination of the rational composition of crude glycerine with its gradual loading into biogas plants with cattle manure. The article presents the results of research on fermentation of substrates in a laboratory biogas plant with a useful volume of 30 L, which fermented different proportions of crude glycerine with cattle manure at a temperature of 30 °C, 35 °C, and 40 °C. The scientific novelty of the work is to determine the patterns of intensification of the process of methane fermentation of cattle manure with the addition of different portions of crude glycerine. A rapid increase in biogas yield is observed when the glycerol content is up to 0.75%. With the addition of more glycerine, the growth of biogas yield slows down. The digester of the biogas plant, where experimental studies were conducted on the fermentation of substrates based on cattle manure with the addition of co-substrates, is suitable for periodic loading of the substrate. As a rule, existing biogas plants use a gradual mode of loading the digester. Conducting experimental studies on biogas yield during fermentation of cattle manure with the addition of crude glycerine with periodic loading of the substrate makes it possible to build a mathematical model of biogas yield and determine the rational composition (up to 0.75%) of crude glycerine with its gradual loading in biogas plants. Adding 0.75% of crude glycerine to the substrate at a fermentation temperature of 30 °C allows to increase the biogas yield by 2.5 times and proportionally increase the production of heat and electricity. The practical application of this knowledge allows the design of an appropriate capacity of the biogas storage tank (gasholder).

Loss of Energy and Economic Potential of a Biogas Plant Fed with Cow Manure due to Storage Time

“…Currently, solutions are also being researched that would reduce the failure rate and at the same time increase the profitability of biogas installations in animal farms, including small ones of less than 200 cows. They concern both the stage before manure is created, among others: feed additives [125][126][127][128]; change in composition, or the ratio of roughage to concentrate [129,130]; and to increase the digestibility of organic matter, by mechanical, chemical or biological fragmentation or spreading of particles before introducing it as a substrate to the biogas plant [131,132]. While the results of some studies are quite promising, often their implementation would require stricter dietary supervision or additional devices and procedures.…”

Biotechnological Valorization of Waste Glycerol into Gaseous Biofuels—A Review

“…The presence of biodegradable organic compounds in natural fertilizers used on agricultural soils or on degraded land under remediation can lead to sanitary difficulties, the spread of nuisance odors, or negative environmental impacts (surface runoff, water erosion, wind erosion) [85]. The quality and profile of the digestate, the options for its use as a fertilizer, and the conditions of such fertilization should always be taken into account when designing systems for the AD of glycerol [86].…”

“…Nevertheless, crude glycerol can be an extremely attractive candidate for an AD co-substrate due to its widely reported boosting effect on biogas production and composition [78]. It is recommended that optimization procedures and multivariate biogas tests be conducted to select the best-performing variants and identify potential problems early [86]. This is important both in terms of the process itself and the later utilization of its products.…”

Institutional Analysis and Development (IAD) Approach for Determining the Effects of the Waste Charging Scheme on Household Food Waste Recycling

“…Some known technologies for recycling food waste into biofuel are already available [36,37]; some bio-processors can reduce up to 80% of the mass of waste [37]. Not needing to be the main substrate, certain glycerin-rich food wastes may also be used as an additive to increase the efficiency of biogas formation [38]. There is also a proposal to use food waste disposers to grind food waste into the sewerage pipes and transport it to sewage treatment plants for processing into possible biofuel [39,40].…”

“…Subsidies are continuously being given out, and infrastructure is being built. Financial burden may be offset nonetheless with energy savings from biofuel utilisation [36][37][38]. The shift of the collection services from a public good to a toll good allows the household to feel the cost burden of disposing of waste.…”