Agricultural Biogas Production Research Articles

Impact of genotype, harvest time and chemical composition on the methane yield of winter rye for biogas production

Abstract Rye ( Secale cereale L.) is an ideal crop for the agricultural biogas production in regions with less fertile and sandy soils. Maximum methane yield per hectare is the main aim of the farmer. Objectives were to establish differences by the Hohenheim Biogas Test among (1) 25 genotypes (experiment 1) and (2) three harvest dates (early heading, early and late milk ripening) and three plant fractions (ears, leaves and stems, stubbles) for four genotypes including an analysis of their nutrient composition (experiment 2). Significant ( P −1 and 840 m 3 ha -1 respectively, combined with moderate to high heritabilities (0.71–0.98). Both traits were highly correlated ( r = 0.95, P −1 . Accordingly, methane yield was reaching a mean of 4424 m 3 ha -1 and a maximum of 4812 m 3 ha -1 . No correlations between content of crude nutrients or cell-wall fractions and specific gas or methane yield were evident neither for the plant fractions nor for the whole plant. In conclusion, harvesting at late milk ripening was clearly superior in dry matter and methane yields although specific methane yield was higher at early heading. A selection for maximum dry matter yield in rye breeding should indirectly improve also methane yield.

Effect of Drought Stress on Yield and Quality of Maize/Sunflower and Maize/Sorghum Intercrops for Biogas Production

AbstractIntercropping represents an alternative to maize (Zea mays L.) monoculture to provide substrate for agricultural biogas production. Maize was intercropped with either sunflower (Helianthus annuus L.) or forage sorghum [Sorghum bicolor (L.) Moench] to determine the effect of seasonal water supply on yield and quality of the above‐ground biomass as a fermentation substrate. The two intercrop partners were grown in alternating double rows at plant available soil water levels of 60–80 %, 40–50 % and 15–30 % under a foil tunnel during the years 2006 and 2007 at Braunschweig, Germany. Although the intercrop dry matter yields in each year increased with increasing soil moisture, the partner crops responded quite differently. While maize produced significantly greater biomass under high rather than low water supply in each year, forage sorghum exhibited a significant yield response only in 2006, and sunflower in none of the 2 years. Despite greatly different soil moisture contents, the contribution of sorghum to the intercrop dry matter yield was similar, averaging 43 % in 2006 and 40 % in 2007. Under conditions of moderate and no drought stress, sunflower had a dry matter yield proportion of roughly one‐third in both years. In the severe drought treatment, however, sunflower contributed 37 % in 2006 and 54 % in 2007 to the total intercrop dry matter yield. The comparatively good performance of sunflower under conditions of low water supply is attributable to a fast early growth, which allows this crop to exploit the residual winter soil moisture. While the calculated methane‐producing potential of the maize/sorghum intercrop was not affected by the level of water supply, the maize/sunflower intercrop in 2006 had a higher theoretically attainable specific methane yield under low and medium than under high water supply. Nevertheless, the effect of water regime on substrate composition within the intercrops was small in comparison with the large differences between the intercrops.

Możliwości wykorzystania biogazu rolniczego do produkcji paliwa silnikowego

Agricultural biogas production and its applications are some of the most favorable methods of receiving the energy at present. Thanks to using biogas both to the production of electricity and the warmth and as an engine fuel we can limiting consuming nonrenewable energy sources. Using biogas as a fuel contributing also to the reduction of the greenhouse effect mainly thanks to methane reduction.

New mixtures and technologies for biogas production at biogas plants of agricultural type processing livestock slurry

The basis of the biogas production in agriculture is the processing of waste agricultural products (particularly excrements of farm animals but also phytomass). Different but rather similar is the biogas production from biologically degradable municipal waste (BDMW) and biologically degradable industrial waste (BDIW) coming mainly from food industry. The processing of these wastes in agricultural biogas stations could significantly improve their economy. It is necessary to note that all these biogas stations differ from the wastewater cleaning plants where municipal sludge water from public sewers is processed. The municipal sludge water processing to biogas by anaerobic fermentation is a classical technology introduced all over the world. At present, about 100 wastewater cleaning plants operate in the Czech Republic using regular sludge processing into biogas. Electricity produced is utilised mainly for the needs of own operation of waste water treatment plant (WWTP), partly it is sold into public power net. The heat energy is used for heating in the process and its surplus is utilised for operational and administrative facilities. Usually, the heat and electricity quantities produced do not cover the wastewater cleaning plant operation. Agricultural biogas stations and biogas stations for BDMW processing provide considerably higher gas yields because they work with higher dry matter contents in substratum, i.e. 8–12% (compared with waste water treatment plants – 2–6%), and are able to produce high gas surpluses for following applications. Frequently discussed issue are the processing of slaughter waste and grass (or public green areas at biogas stations).

Kinetic study of biogas production from energy crops and animal waste slurry: Effect of organic loading rate and reactor size

Biogas production in agriculture is processed mostly continuously at mesophilic temperatures in completely stirred tank reactors. Therefore, reactor performance data were studied in long‐term semi‐continuous laboratory‐scale experiments with maize silage, whole‐crop rye silage and fodder beet silage as mono‐substrate and cattle slurry at mesophilic temperatures. For calculation of biogas yield as function of the organic loading rate, a hyperbolic equation was developed on the base of a first‐order reaction rate for substrate degradation. The biogas yield depends also on the maximum biogas yield, the concentration of volatile solids of the input, the density of the effluent, the density of the biogas and the reaction rate constant, which are all substrate‐ or process‐specific. Values of the theoretical maximum biogas yield and the reaction rate constant were observed in the range 0.61–0.93 m3 per kg volatile solids and 0.032 – 0.316 d−1, respectively. By means of the hyperbolic equation, the proportion of the biogas yield from the maximum can be calculated for the first and a second reactor which also depends on the volume of each reactor.

Application of hydrolytic enzymes in the agricultural biogas production: Results from practical applications in Germany

Application of hydrolytic enzymes in the agricultural biogas production: Results from practical applications in Germany