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Leite A.F.,Helmholtz Center for Environmental Research | Janke L.,Deutsches Biomasseforschungszentrum Gemeinnutzige GmbH | Harms H.,Helmholtz Center for Environmental Research | Richnow H.-H.,Helmholtz Center for Environmental Research | Nikolausz M.,Helmholtz Center for Environmental Research
Biotechnology for Biofuels | Year: 2016

Background: During strategic planning of a biogas plant, the local availability of resources for start-up and operation should be taken into consideration for a cost-efficient process. Because most bioethanol/sugar industries in Brazil are located in remote areas, the use of fresh cattle manure from local farms could be a solution for the inoculation of the biogas process. This study investigated the diversity and dynamics of bacterial and archaeal communities and the performance of biogas reactors inoculated with manure and a mixed inoculum from different biogas reactors as for a controlled start-up until steady state. Results: Laboratory-scale biogas reactors were fed semi-continuously with sugarcane filter cake alone (mono-digestion) or together with bagasse (co-digestion). At the initial start-up, the reactors inoculated with the mixed inoculum displayed a less diverse taxonomic composition, but with higher presence of significant abundances compared to reactors inoculated with manure. However, in the final steady state, the communities of the differently inoculated reactors were very similarly characterized by predominance of the methanogenic genera Methanosarcina and Methanobacterium, the bacterial families Bacteroidaceae, Prevotellaceae and Porphyromonadaceae (phylum Bacteroidetes) and Synergistaceae (phylum Synergistetes). In the mono-digestion reactors, the methanogenic communities varied greater than in the co-digestion reactors independently of the inoculation strategy. Conclusion: The microbial communities involved in the biogas production from waste products of the Brazilian bioethanol/sugar industry were relatively similar and stable at the reactor's steady phase independently of the inoculum source (manure or mixed inoculum). Therefore, the locally available manure can be used as inoculum for start-up of the biogas process, since it also contains the microbial resources needed. The strong fluctuation of methanogenic communities in mono-digestion reactors indicates higher risk of process instability than in co-digestion reactors. © 2016 The Author(s).

Schmidt T.,Deutsches Biomasseforschungszentrum Gemeinnutzige GmbH
Waste Management and Research | Year: 2011

Oil production from Jatropha curcas L. seeds generates large amounts of Jatropha press cake (JPC) which can be utilized as a substrate for biogas production. The objective of this work was to investigate anaerobic mono-digestion of JPC and the effects of an iron additive (IA) on gas quality and process stability during the increase of the organic loading rate (OLR). With the increase of the OLR from 1.3 to 3.2 gVS L -1 day -1, the biogas yield in the reference reactor (RR) without IA decreased from 512 to 194 LN kgVS -1 and the CH4 concentration decreased from 69.3 to 44.4%. In the iron additive reactor (IAR), the biogas yield decreased from 530 to 462 LN kgVS -1 and the CH4 concentration decreased from 69.4 to 61.1%. The H2S concentration in the biogas was reduced by addition of the IA to values below 258 ppm in the IAR while H2S concentration in the RR increased and exceeded the detection limit of 5000 ppm. The acid capacity (AC) in the RR increased to more than 20 g L -1, indicating an accumulation of organic acids caused by process instability. AC values in the IAR remained stable at values below 5 g L -1. The results demonstrate that JPC can be used as sole substrate for anaerobic digestion up to an OLR of 2.4 gVS l -1 day -1. The addition of IA has effectively decreased the H2S content in the biogas and has improved the stability of the anaerobic process and the biogas quality. © 2011 International Solid Waste Association.

Zech K.M.,DBFZ Deutsches Biomasseforschungszentrum Gemeinnutzige GmbH | Meisel K.,Deutsches Biomasseforschungszentrum Gemeinnutzige GmbH | Brosowski A.,Deutsches Biomasseforschungszentrum Gemeinnutzige GmbH | Toft L.V.,DONG Energy | Muller-Langer F.,DBFZ Deutsches Biomasseforschungszentrum Gemeinnutzige GmbH
Applied Energy | Year: 2016

Inbicon's lignocellulose-to-bioethanol technology is assessed in terms of its environmental and economic performance within this article. This is done under various scenarios to identify the influence of locations, raw materials and plant setups on the results. In all scenarios the specific GHG emissions of the bioethanol production are 50% below those of the fossil reference fuel, some scenarios even reach a GHG mitigation of over 60%. In many scenarios specific production costs are reached that are in the range or below those of conventional bioethanol today. But low emissions and low costs remain contradictory targets to a great extent. However, using C5 sugars in co-fermentation to produce bioethanol and the also generated biogas as an internal heat source seems to be a good compromise and leads to both relatively low costs of 27.2 EUR GJ-1 and low emissions of 28.3 kg CO2-eq. GJ-1. © 2016 Published by Elsevier Ltd.

Kroger M.,Deutsches Biomasseforschungszentrum Gemeinnutzige GmbH | Muller-Langer F.,Deutsches Biomasseforschungszentrum Gemeinnutzige GmbH
Biofuels | Year: 2012

One of the future-generation biofuel options that has recently recieved increased attention is the production of biofuels from microalgae. Besides the use of algae oil for physicochemical biodiesel production, biochemical and thermochemical pathways are possible. Although there is still a need to research algae production systems, downstream processing (e.g., biofuel production) needs to be researched in parallel. As there are several methods to produce biofuel from algae, different possible production processes are reviewed. By investigating the different steps of each of the processes and highlighting the challenges and risks that can occur, it is possible to make a decision regarding which pathway might be feasible for algal resources in the future. © 2012 Future Science Ltd.

Reinelt T.,Deutsches Biomasseforschungszentrum Gemeinnutzige GmbH | Liebetrau J.,Deutsches Biomasseforschungszentrum Gemeinnutzige GmbH | Nelles M.,Deutsches Biomasseforschungszentrum Gemeinnutzige GmbH | Nelles M.,University of Rostock
Bioresource Technology | Year: 2016

The study presents the development of a method for the long term monitoring of methane emissions from pressure relief valves (PRV1PRV: pressure relief valve. 1 ) of biogas storages, which has been verified during test series at two PRVs of two agricultural biogas plants located in Germany. The determined methane emission factors are 0.12gCH4 kWhel -1 (0.06% CH4-loss, within 106days, 161 triggering events, winter season) from biogas plant A and 6.80/7.44gCH4 kWhel -1 (3.60/3.88% CH4-loss, within 66days, 452 triggering events, summer season) from biogas plant B. Besides the operational state of the biogas plant (e.g. malfunction of the combined heat and power unit), the mode of operation of the biogas flare, which can be manually or automatically operated as well as the atmospheric conditions (e.g. drop of the atmospheric pressure) can also affect the biogas emission from PRVs. © 2016 Elsevier Ltd.

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