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This paper has been peer-reviewed but does not include the final publisher proof-corrections or journal pagination. Citation for the published paper: Permanent link to this version: However, to be commercially competitive with other types of fuels, efficiency improvements of the biogas production process are needed.
In this paper, results of improvements studies done on a full scale co-digestion plant are presented In the plant organic wastes from households and restaurants are mixed and digested with crops from graze land.
The areas for improvements of the plant addressed are treatment of the feed material to enhance the digestion rate, limitation of the ballast of organics in the water stream recirculated in the process, and use of the biogas plant residues at farms.
Results from previous studies on pre-treatment and membrane filtration of recirculated process water are combined for estimation of the total improvement potential.
Further, the possibility to use neural networks to predict biogas production using historical data from the full-scale biogas plant was investigated.
Results from investigation of using the process residues as fertilizer are also presented. Neural networks have the potential to be used for prediction of biogas production.
Further, it is shown that the residues from biogas production can be used as fertilizers but that the emission of N2O from the fertilised soil is dependent on the soil type and spreading technology. Keywords biogas, optimization, waste, household, fertilizer, N2O emissions Corresponding author: However, the interest to produce biogas from any kind of organic residue as well as from different crops, farm land residues or ley crop has increased.
Today the technology for biogas production is not optimized and to be fully commercially competitive with other types of fuels improvements have to be done. This plant was taken into operation in ; its main parts can be seen in Figure 1.
The materials used for biogas production are organic wastes from households and restaurants also called biowaste and ley crops silage. The incoming biowaste is mixed with recirculated process water to produce slurry that can be pumped throughout the plant.
The solid and liquid wastes are co-digested in a m3 digestion tank. The biogas produced is subsequently cleaned and purified and used by buses, refuse collection vehicles or cars.
The residues from the plant are sent to local farmers as fertilizer [1, 2]. In this paper possible performance improvements of the full-scale biogas plant and surrounding system are studied.
The areas for optimizing the performance of a biogas plant addressed are: Results from previous studies on pre-treatment and membrane filtration of recirculated process water are combined for estimation of the total improvement Figure 1: Concerning how the residues can best be used on farmland, laboratory and field studies on the emission of N2O have been done.
Further, the possibility to use neural networks to predict biogas production using historical data from the full-scale biogas plant has been investigated. The biogas production can be increased by enhancing the digestion rate with a pre-treatment step.
The idea is to make the material more accessible to the micro organisms involved in the process. Therefore pre-treatment of the ley crop silage to increase the digestion rate is of interest to improve the performance of the plant. Mechanical pre-treatment and pre-treatment by electroporation of ley crop silage has previously been studied by the authors [5, 6].
The pre-treatment tests on ley crop silage were made in a 0. The performance of the pre-treatment methods has been evaluated with biochemical methane potential BMP tests, based on the method described by Hansen et al , in both studies. Also the energy efficiency, measured as the energy input needed for the pre-treatment in relation to the increase in energy output in the form of increased biogas yield of the treatments, has been calculated in both studies.
Some of the results of the studies are summarised in Table 1. The possible increase in biogas yield by pre-treatment is dependent on both the material to be treated and the pre-treatment method used.
Several studies can be found that show that reduction in particle size by physical or mechanical pre-treatment give an increased methane yield, for example .
However, Hartmann et al  state that the fibre size cannot be directly correlated to an increased biogas yield and that there can also be a shearing effect from the treatment that cannot be measured from fibre size alone.
Pre- treatment with electroporation has not yet been extensively studied but there are some reports on its positive effect on the biogas production from sewage sludge and source-sorted municipal organic solid waste .waste Essays | See the List of Sample Papers For Free - Bla Bla Writing.
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Save time and order Biowaste Grinding Machine essay editing . Asbestos became a central part of commercial product manufacturing in America in the early s. Its first popular use was the lining in steam engines in Tensile tests were performed at room temperature with an Instron (USA) universal testing machine with cross-head maximum strength capacity of N.
A fixed cross-head rate of 5 mm/min was utilized in all cases, and results were taken as average of three tests (± standard deviation). Abstract. Treatment of biowaste, the predominant waste fraction in low- and middle-income settings, offers public health, environmental and economic benefits by converting waste into a hygienic product, diverting it from disposal sites, and providing a source of income.
Two types of grinding machines In materials processing a grinder is a machine for producing fine particle size reduction through attrition and compressive forces at the grain size level.
See also crusher for mechanisms producing larger particles. In general, grinding processes require a relatively large amount of energy; for this reason, an .