Effectiveness Of Biogas Production Research Articles

Effect of magneto-active filling on the effectiveness of methane fermentation of dairy wastewaters

ABSTRACT The goal of this study was to determine the effectiveness of methane fermentation in dairy wastewaters in terms of the volume and qualitative composition of biogas produced in an anaerobic reactor with magneto-active filling (MAF) mounted in the zone of hydrolysis and acidogenesis. Experiments were conducted on the fractional-technical scale in a vertical fermentation reactor with a labyrinth flow. Synthetic dairy wastewaters prepared based on milk powder were used as a substrate. The analyzed filling was made of plastic covered with iron and copper powders and was additionally equipped with fluid magnetizers (FM) in the form of neodymium magnets. The study demonstrated that MAF incorporation into the technological system significantly improved the effectiveness of biogas production, increased methane concentration and lowered the content of hydrogen sulfide in gaseous metabolites of fermentative bacteria. A significant increase was also observed in the effectiveness of COD removal from dairy wastewaters. The reported experiments proved a correlation between the effectiveness of methane fermentation and the number of MAF elements introduced into the anaerobic reactor.

MACROALGAE MANAGEMENT IN COASTAL REGIONS IN THE ASPECT OF SUSTAINABLE DEVELOPMENT STRATEGY

The article discusses the problem of excessive growth of one-year filamentous algae, contributing to the disturbance of ecological balance in the Puck Bay. The aim of the study is to estimate the possibility of restoring this balance through the use of macroalgae as a co-substrate for biogas and fertilizer production in the regional biological wastewater treatment plant (WWTP). Effectiveness of biogas production from aquatic plants, including free-floating filamentous algae, was examined. Tests have shown that the biogas potential of seaweed constitutes the level of 162 m3/Mg of organic dry solid substances of algae. It was estimated that using the summer intense algal growth, removing 65,000 Mg of algae, 800,000 m3 of biogas can be obtained from the area covering the inner Puck Bay. After biogas conversion, 2,320 MWh of electricity and 2,100 MWh of heat energy could be produced. Harvesting free-floating algae enables the annual removal of 100-150 Mg of phosphorus and 200-400 Mg of nitrogen from Puck Bay and, thus, reduces the level of its eutrophication. Macroalgae management at a certain stage of growth also prevents the presence of algae on beaches and contributes to the improvement of fishing conditions and boosts the tourism value of the region.

The incidence of biogas feed-in tariffs on farmland rental rates – evidence from northern Germany

This paper investigates the effects of biogas production on farmland rental rates. We clarify the mechanisms by which biogas subsidies can inflate land rents and how regional livestock density may reinforce this effect. We use spatial econometrics to explain arable land rents in northern Germany based on 2010 agricultural census data. The results indicate that increasing biogas density is associated with a significant rise in the rental rates of arable land only in regions with high livestock densities. In biogas-intensive regions, biogas production is estimated to inflate land rents by €61 to €141 per hectare, depending on regional livestock densities.

Possibility of hydrogen production during cheese whey fermentation process by different strains of psychrophilic bacteria

The aim of this study was to determine the possibility of applying psychrophilic bacteria for hydrogen production in whey biofermentation process. Experiments were conducted in 500-mL anaerobic respirometers at a temperature of 20 °C. The initial organic load of fermentation tanks reached 10 g COD/L. Depending on the experimental variant, analyses were carried out for psychrophilic bacteria isolated from underground water and from demersal lake water that represented Gammaproteobacteria class – Rahnella aquatilis (9 strains) and Firmicutes phylum: Carnobacterium maltaromaticum, Trichococcus collinsii and Clostridium algidixylanolyticum. The effectiveness of biogas production was diversified and strain-specific, ranging from 126.48 to 4737.72 mL/g bacterial biomass. The highest concentration of H2 in biogas, ranging from 65.15% to 69.12% and effectiveness of H2 production from 1587.47 to 3087.57 mL/g bacterial biomass, were determined for R. aquatilis strains isolated from the demersal lake water. The lowest H2 concentration in the gaseous metabolites, i.e. 15.46% to 20.70%, was noted for bacteria of the phylum Firmicutes.

Impacts of Biogas Production on the Production Factors Land and Labour – Current Effects, Possible Consequences and Further Research Needs

Among the members of the European Union (EU), Germany has the largest biogas produc-tion from agricultural sources. However, many other EU member states are creating the necessary conditions for rapid growth in this area. The German Renewable Energy Sources Act (EEG), which sets payments over a long time period for electricity supplied from renewa-ble sources, often serves as a benchmark. However, the continuing biogas boom has also led to criticism of the EEG in Germany. Opponents of biogas production point to the rising cost of leasing land, changes in the agricultural structure due to maize monoculture, increased competition with other agricultural branches (e.g., livestock husbandry) and the crowding out of classical food production. This paper examines the validity of these points of criticism. To this end, a written survey (n = 246) of farmers in six selected rural districts in the German state of Lower Saxony was carried out in 2010 and 2011. OLS regressions conducted on the data from these farmers showed that biogas production has led to a substantial increase in land lease prices for cropland. Furthermore, approximately 20% of the respondents report complete crowding out of established agricultural production forms, resulting in a decrease in the resource basis for downstream animal and plant processing industries. The results also indicate that, in extreme cases, such crowding out might even reduce the availability of em-ployment in rural areas. In closing, the paper highlights further research needs in order to provide comprehensive information (for every German state, the entire country of Germany and other EU member states) regarding the effects of biogas production on net employment, infrastructure and added value.