The purpose of this study was to determine the biogas potential of biomass produced by microbiotic communities developed under natural conditions in freshwater systems such as ponds incorporated into ...agricultural landscapes. Natural communities of microalgae were collected from a small eutrophicated pond where dominant species were euglenoids (
Lepocinclis
species). Cyanobacterial communities dominated by
Lyngbya
species were taken from a domestic aquarium and cultivated under makeshift conditions. Experiments were done using dairy cow manure (DCM) for codigestion with natural communities of microalgae (MDM) and cyanobacteria (CDM) and conducted during 42 days in thermophilic regime. The total biogas yields were 421.40 and 383.34 mL/g volatile solids (VS), while the average methane contents were 63.97 and 64.06% for MDM and CDM, respectively. Our results indicate that the natural communities of microalgae and cyanobacteria used in this study possess the potential for biogas production, which is, in comparison with particular algal and cyanobacterial strains cultivated under strictly controlled cultivation conditions, more promising. Therefore, this study aims to motivate further investigations into the diverse natural communities of microalgae and cyanobacteria and pretreatments that are environmentally friendly and cost-effective and will eventually enhance small-scale biogas production on agricultural farms.
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•A novel method of lignocellulose pretreatment by electroporation was developed.•SEM analysis revealed structural changes in harvest residues after pretreatment.•Electroporation ...improved anaerobic co-digestion of harvest residues.•A positive energy balance was achieved.
The aim of this research was to develop a method for pretreatment of lignocellulose (LC) substrates (harvest residues (HR)) via electroporation (EP) for the purpose of improving the biogas production process. In addition, pretreated LC substrates were analyzed by scanning electron microscopy (SEM) and the energy balance of the total process was calculated. After the conducted pretreatment and anaerobic co-digestion with dairy cow manure (DCM), the statistical data analysis showed statistically significant differences in biogas and/or methane yield for all three LC substrates and their fractions. It was concluded that, after the pretreatment of LC substrates via EP, it is possible to improve the anaerobic co-digestion process and to achieve positive energy balance of the total process.
This research was set up in 2013 in agroecological conditions of continental Croatia (3 different locations). The extperiment was set as a split-plot design in four replicates, with three levels of ...the main treatments of soil tillage (CT - plowing; MD - reduced multiple disk harrowing; SD - reduced single disk harrowing) and levels of subtreatment fertilization (F0 - control; F1 - standard KAN fertilization; F2 - fertilization with 5% urea solution; F3 - Profert Mara; F4 - Profert NGT; F5 - Thiofer; F6 - EM Aktiv). The highest camelina grain and biomass yield was achieved in the subtreatment F6 when using microbiological fertilizer EM Aktiv, regardless of the applied agrotechnics. After the harvest experiment, anaerobic batch co-digestion of camelina and cow manure was conducted under thermophilic conditions to determine camelina's potential for biogas production. The biogas potential of camelina was expressed as biogas and methane yields which ranged from 382.00 and 246.04 cm3 g-1 VS, respectively. If compared to maize which is often used as a standard for comparison of methane yields, maize methane yields are higher by 21 to 40%
Istraživanje je postavljeno 2013. godine u agroekološkim uvjetima kontinentalne Hrvatske (3 različite lokacije). Pokus je postavljen po split-plot shemi u četiri ponavljanja, s tri razine glavnih tretmana obrade tla (CT - oranje; MD - reducirano višestruko tanjuranje; SD - reducirano drljanje jednom tanjuračom) i razinama gnojidbe podtretmana (F0 - kontrola; F1 - standardna gnojidba KAN-om; F2 - gnojidba 5% otopinom uree; F3 - Profert Mara; F4 - Profert NGT; F5 - Thiofer; F6 - EM Aktiv). Najveći prinos zrna i biomase kameline ostvaren je u podtretmanu F6 uz korištenje mikrobiološkog gnojiva EM Aktiv, neovisno o primijenjenoj agrotehnici. Nakon eksperimenta žetve, provedena je anaerobna šaržna kodigestija kameline i kravlje gnojovke u termofilnim uvjetima s ciljem određivanja potencijala kameline za proizvodnju bioplina. Bioplinski potencijal kameline izražen je preko prinosa bioplina i metana koji su se kretali od 382.00 odnosno 246.04 cm3 g-1 OT. U usporedbi s kukuruzom koji se često koristi kao standard za usporedbu prinosa metana, prinosi metana proizvedenog iz zrna kukuruza veći su za 21 do 40 %.
Anaerobic co-digestion of dairy cow manure (DCM) and separated tomato greenhouse waste (tomato stalks and leaves (TSL) and rotten and damaged tomato fruits – TF) was conducted under batch ...thermophilic conditions (
= 55 °C) for period of 45 days. Concentrations of substrates (tomato waste) were 5 and 10% (w/v). Each substrate, as well as experimental mixtures, was analysed in order to specify the content of pH, total solids (TS), volatile solids (VS), total extractable nitrogen (TN) and total organic carbon (TOC). Biogas yield and composition, as well as cumulative biogas curves, were reported. In comparison to DCM monodigestion (329.5 cm
·g
VS), biogas yield was significantly improved in experiment C (365.1 cm
·g
VS) (with 5% (w/v) TF added), whereas methane yield did not show any significant difference. Experiment D (with 10% (w/v) TSL added) resulted in significantly lower biogas and methane yields in contrast to the rest of experiments performed. Average methane content in all analysed experimental samples ranged from 65 to 69%. It is evident from the results that biogas production can be improved by addition of separated tomato greenhouse waste to DCM process and issue of organic waste disposal could be effectively solved.
Duckweed is a widespread type of tiny free-floating plants of the flowering class. A typical representative of the family of the cowhide (Lemnaceae) is a large duckweed (Spirodela polyrhiza) and it ...is very common on Croatian inland waters. Like all other species of duckweeds, it is characterized by the possibility of vegetative and sexual reproduction and very rapid growth. It has the ability to remove nitrogen, phosphorus and some heavy metals from the substrate and is considered a very desirable raw material for biogas production for several reasons. The necessity of reducing environmental pollution of nitrates from agricultural production and the ability to grow water lenses under eutrophic conditions have sparked this research. The primary objective of the study is to determine the possibilities of continuously growing large duckweed at different concentrations of digestates for the purpose of biogas production. The secondary goal is to determine the dependence between the different digestate concentrations used for the duckweed green mass production and the quantity and quality of the biogas obtained through the anaerobic digestion process at thermophilic conditions.
Vodena leća je široko rasprostranjena vrsta sitnih slobodno plivajućih biljaka iz razreda cvjetnica. Tipičan predstavnik porodice kozlačevki (Lemnaceae) je velika vodena leća (Spirodela polyrhiza) i vrlo je česta na vodenim površinama kontinentalne Hrvatske. Kao i sve ostale vrste vodenih leća, karakterizira ju mogućnost vegetativnoga i spolnog razmnožavanja te vrlo brz rast. Smatra se vrlo poželjnom sirovinom za proizvodnju bioplina iz nekoliko razloga. Nužnost smanjenja zagađenja okoliša nitratima iz poljoprivredne proizvodnje te sposobnost rasta vodenih leća u eutrofnim uvjetima potaknuli su ovo istraživanje. Primarni cilj istraživanja jest utvrditi mogućnosti kontinuiranoga uzgoja velike vodene leće na različitim koncentracijama digestata, sa ciljem proizvodnje bioplina. Sekundarni je cilj utvrditi zavisnost između različitih koncentracija digestata korištenih za proizvodnju zelene mase vodene leće te kvantitete i kvalitete bioplina dobivenog postupkom anaerobne digestije pri termofilnim uvjetima.
•PEF is predominantly used in medicine and in food industry.•Up to now PEF is efficiently applied to sludge pretreatment for biogas production.•Application of PEF in lignocellulose pretreatment ...demonstrated its high potential.•Transfer of PEF from batch to continuous industrial-scale is in its R&D phase.
This review focuses on current status of pulsed electric field (PEF) technology and its implementation in biogas production. First, basic principles of PEF and a schematic overview of typical PEF processing system were provided. Thereafter, lab- and pilot-scale PEF pretreatments of sludge with subsequent anaerobic digestion (AD) were provided. Furthermore, PEF technology, as an emerging technology for the lignocellulose (LC) pretreatment in biogas production which is still predominantly used at lab-scale, was outlined. Eventually, conclusion together with future perspectives and challenges were outlined.
Several batch experiments were conducted on the anaerobic co-digestion of dairy cow manure (DCM) with three harvest residues (HR) (soybean straw, sunflower stalks, and corn stover). The influence of ...thermal pretreatment of HR on biogas production was investigated, where the HR were thermally pretreated at two different temperatures:
T
= 121 °C and
T
= 175 °C, during
t
= 30 and
t
= 90 min, respectively. All anaerobic co-digestion batch experiments were performed simultaneously under thermophilic regime, at
T
= 55 °C. Biogas and methane yields were significantly improved in experiments performed with corn stover thermally pretreated at 175 °C for 30 min (491.37 cm
3
/g VS and 306.96 cm
3
/g VS, respectively), if compared to experiments performed with untreated corn stover. The highest VS and COD removal rates were also observed in the same group of experiments and were 34.5 and 50.1%, respectively. The highest biogas and methane yields with soybean straw (418.93 cm
3
/g VS and 261.44 cm
3
/g VS, respectively) were obtained when soybean straw pretreated at 121 °C during 90 min. The highest biogas and methane yields with sunflower stalk (393.28 cm
3
/g VS and 245.02 cm
3
/g VS, respectively) were obtained when sunflower stalk was pretreated at 121 °C during 90 min.
Cilj istraživanja je utvrditi prinos bioplina i metana iz gnojovke s dodatkom tri vrste vodenih biljaka (Spirodela polyrhiza, Azolla caroliniana i Lemna minor). Uzgoj tradicionalno korištenih biljaka ...(npr. kukuruz, uljana repica) za dobivanje biogoriva zahtijeva obradive površine, dok se vodene biljke, kao alternativa, mogu prikupiti iz prirode, a zbog jednostavne građe, brzine rasta i povoljnog kemijskog sastava mogu se bez pred-tretmana koristiti kao osnovna ili dopunska sirovina u bioplinskim postrojenjima. Četiri uzorka (kontrola i tri vrste vodenih biljaka) u tri ponavljanja povrgnuta su anaerobnoj digestiji. Različite vrste proizvode različite količine bioplina u odnosu na kontrolu (od 504,83 do 881,62 mL g-1 S.T.). Udio dobivenog metana iznosi od 57,96 do 60,63 % u zavisnosti od biljne vrste. Ovo ukazuje na izuzetan potencijal korištenja ovih vrsta za dobivanje bioplina i metana.
The aim of the study is to determine the yield of biogas and methane from slurry with the addition of three species of aquatic plants (Spirodela polyrhiza,Azolla caroliniana and Lemna ninor). Cultivation of
traditionally used plants (eg.corn, oilseed rape) to produce biofuels requires arable land, while aquatic plants,as an alternative, can be collected from nature, and due to simple structure, growth rate and favorable chemical composition, they can be used as a primary or supplementary raw material in biogas plants without any pre-treatment. Four samples (control and three aquatic plant species) in three replicates were subjected to anaerobic digestion. Different species produce different amounts of biogas compared to the control (from 504.83
to 881.62 mL g-1 DM). The methane content is from 57.96 to 60.63% depending on the plant species. This indicates the tremendous potential of using these species of aquatic plants to produce biogas and methane.
Istraživanje je postavljeno 2013. godine u agroekološkim uvjetima kontinentalne Hrvatske (3 različite lokacije). Pokus je postavljen po split-plot shemi u četiri ponavljanja, s tri razine glavnih ...tretmana obrade tla (CT - oranje; MD - reducirano višestruko tanjuranje; SD - reducirano drljanje jednom tanjuračom) i razinama gnojidbe podtretmana (F0 - kontrola; F1 - standardna gnojidba KAN-om; F2 - gnojidba 5% otopinom uree; F3 - Profert Mara; F4 - Profert NGT; F5 - Thiofer; F6 - EM Aktiv). Najveći prinos zrna i biomase kameline ostvaren je u podtretmanu F6 uz korištenje mikrobiološkog gnojiva EM Aktiv, neovisno o primijenjenoj agrotehnici. Nakon eksperimenta žetve, provedena je anaerobna šaržna kodigestija kameline i kravlje gnojovke u termofilnim uvjetima s ciljem određivanja potencijala kameline za proizvodnju bioplina. Bioplinski potencijal kameline izražen je preko prinosa bioplina i metana koji su se kretali od 382.00 odnosno 246.04 cm3 g-1 OT. U usporedbi s kukuruzom koji se često koristi kao standard za usporedbu prinosa metana, prinosi metana proizvedenog iz zrna kukuruza veći su za 21 do 40 %.
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