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The objective of this work was to determine the potential of chicken manure as a substrate for biogas production after pretreatment. The effects of removing excess nitrogen from chicken manure by water extraction in a temperature range from 20 °C to 60 °C to increase methane production were investigated. The dynamics of the process and efficiency of biogas production were also analyzed. As a result of manure fermentation after pretreatment, 16 to 45% more biogas and 18 to 39% more methane were obtained compared to manure without pretreatment. The effect of extraction was to increase the ratio of carbon to nitrogen by 2–2.7 times, which contributed to increasing biogas efficiency. The proposed method seems to be a promising enhancing of biogas and methane production in comparison with raw chicken manure. Biomass in the form of chicken manure is a promising substrate for biogas production, due to the constantly growing poultry meat production as well as environmental aspects such as reducing gas emissions from manure into the atmosphere. [ABSTRACT FROM AUTHOR]

In this study, alternative uses for lignocellulosic waste by considering them a source of eco-friendly and renewable energy generation with the application of the anaerobic digestion of treated and untreated waste for biogas and biohydrogen generation were investigated. The diluted sulfuric acid method was used for both the substrates and inoculum. Hydrogen production was absent when untreated spent coffee grounds (SCG) and alcohol waste (AW) were both used with the inoculum at pH 5.5 and pH 7.5. Meanwhile, the highest biogas yield of 320 dm3 kg V.S−1 was obtained when using AW at pH 7.5, with a 190 dm3 kg V.S−1 yield of methane. Instead, hydrogen production was observed when initially 4% (w/v) and 6% (w/v) SCG-containing hydrolysates were used as the substrates at pH 5.5, yielding 2.9 ± 0.09 dm3 kg V.S−1 and 3.85 ± 0.12 dm3 kg V.S−1, respectively. The further optimization of pretreatment technologies and pH control could lead to increased and prolonged hydrogen production. [ABSTRACT FROM AUTHOR]

Municipal landfills generate a significant amount of high-energy biogas, which can be used as a renewable gaseous fuel. However, it is necessary to improve the quality of this biogas due to the presence of various chemical compounds. The most common pollutants in landfill biogas include volatile compounds of silicon, sulphur, phosphorus and chlorine. The aforementioned elements, as well as other metals, were found both in the deposits and in the engine oil. The paper presents detailed characteristics of the solid residues formed in selected parts of gas engines powered by landfill biogas. Its elemental composition and morphology were investigated in order to determine the structure and influence of these deposits. In order to better understand the observed features, selected analyses were also conducted for biogas, engine oil and the condensate generated during biogas dewatering. It was found that the content of individual elements in samples collected from the same part of the gas engine but sourced from various landfills vary. The occurrence of elements in deposits, e.g., Mg, Zn, P and Cr, depends on the location of sampling sites and the type of engine. It was also observed that the deposits formed in parts that come into contact with both biogas and engine oil contain Ca or Zn, which can be related to biogas pollutants as well as different oil additives. The presence of Al, Fe, Cu, Cr, Sn or Pb in selected motor oil samples can be explained by the penetration of metallic abrasives, which confirms the abrasive properties of the formed deposits. The analysis of the characteristic deposits may contribute to the selection of an appropriate landfill biogas purification technology, thus reducing the operating costs of energy cogeneration systems. Finally, we highlight challenges for biogas purification processes and anticipate the direction of future work. [ABSTRACT FROM AUTHOR]

Hydrogen sulphide is corrosive to most metallic equipment such as pipelines, compressors, gas storage tanks, engines, turbines and other units. It acts as a strong poison for fuel cells and its combustion leads to SO2 emissions. Due to the problems associated with hydrogen sulphide, it is critical to remove it from biogas before further processing. The removal of hydrogen sulphide from biogas using MnO2, which acts as a sorbent and catalyst, was investigated. The research was conducted in a full-scale agriculture biogas plant using chicken manure and maize silage as substrate. The manganese dioxide (manganese (IV) oxide) was derived from the waste products of a water conditioning system, after manganese removal from drinking water. The obtained results showed significantly better adsorption of hydrogen sulphide and faster regeneration of the bed compared to the bed filled with hydrated iron oxides. The H2S concentration in the treated biogas dropped from about 1,650 to 0-5 ppm. [ABSTRACT FROM AUTHOR]

The biogas produced in municipal wastewater-treatment plants (WWTP) should be cleaned before it can be used as a fuel in internal combustion engines. Efficient running of such engines is possible only subject to using high quality biogas and lubricating oil. Otherwise, biogas impurities in course of complex chemical reactions may form deposits on various engine parts as well as seriously contaminate the lubricating oil. In this paper, mineral deposits containing high concentration of bismuth, silicon, sulphur, calcium and zinc are studied. Silicon deposits demonstrating strong friction properties are formed during combustion of volatile silica compounds. As these deposits build up, abrasion problems, ignition failure and even engine failure result. The bismuth containing deposits comes from bearings degradation, zinc and calcium were derived from the additives present in commercially available lubricating oil, while lead, aluminium, copper, nickel, iron and chromium were introduced by engine wear phenomena. The highest bismuth content was located at the engine cylinder heads and the lowest at the exhaust elements, whereas highest calcium content was registered on the pistons. Silicon containing deposits are highest in the exhaust and lowest at the engine head. Zinc deposits are highest at the piston. [ABSTRACT FROM AUTHOR]