Gustavsson L.K.,Karlskoga Environment and Energy Company |
Heger S.,RWTH Aachen |
Ejlertsson J.,Scandinavian Biogas Fuels AB |
Ribe V.,Malardalen University |
And 2 more authors.
Environmental Sciences Europe | Year: 2014
Background: Methane production as biofuels is a fast and strong growing technique for renewable energy. Substrates like waste (e.g. food, sludge fromwaste water treatment plants (WWTP), industrial wastes) can be used as a suitable resource for methane gas production, but in some cases, with elevated toxicity in the digestion residue. Former investigations have shown that co-digesting of contaminated waste such as sludge together with other substrates can produce a less toxic residue. In addition, wetlands and reed beds demonstrated good results in dewatering and detoxifying of sludge. The aim of the present study was to investigate if the toxicity may alter in industrial sludge co-digested with oat and post-treatment in reed beds. In this study, digestion of sludge from Bjorkborn industrial area in Karlskoga (reactor D6) and co-digestion of the same sludge mixed with oat (reactor D5) and post-treatment in reed beds were investigated in parallel. Methane production as well as changes in cytotoxicity (Microtox(R); ISO 11348-3), genotoxicity (Umu-C assay; ISO/13829) and AhR-mediated toxicity (7-ethoxyresorufin-O-deethylase (EROD) assay using RTW cells) were measured. Results: The result showed good methane production of industrial sludge (D6) although the digested residue was more toxic than the ingoing material measured using microtox30min and Umu-C. Co-digestion of toxic industrial sludge and oat (D5) showed higher methane production and significantly less toxic sludge residue than reactor D6. Furthermore, dewatering and treatment in reed beds showed low and non-detectable toxicity in reed bed material and outgoing water as well as reduced nutrients. Conclusions: Co-digestion of sludge and oat followed by dewatering and treatment of sludge residue in reed beds can be a sustainable waste management and energy production. We recommend that future studies should involve co-digestion of decontaminated waste mixed with different non-toxic material to find a substrate mixture that produce the highest biogas yield and lowest toxicity within the sludge residue. Source
Scandinavian Biogas Fuels Ab | Date: 2013-09-09
A disintegrating system for treatment of organic material may include multiple disintegrating units, each having an inlet for receiving material, and an outlet for outputting treated material. A first inlet of a first disintegrating unit may be configured to receive organic material, and a first feedback pipe may be connected between the outlet of the first disintegrating unit and the inlet of a second disintegrating unit. An outflow of the disintegrating system may be connected to the outlet of at least the first disintegrating unit, wherein the sum of the introduced material is available at the outflow.
Scandinavian Biogas Fuels Ab | Date: 2014-08-07
A method for producing biogas by anaerobic digestion of organic matter may involve feeding organic matter suitable for biogas production to a first tank reactor, and in the first tank reactor, contacting the organic matter with biogas producing microorganisms for digestion under anaerobic conditions. The organic matter may be digested in the first tank reactor while producing biogas. The method may further involve providing digested sludge from an anaerobic digestion process in a second tank reactor, which differs from the first tank reactor, the digested sludge containing a desired composition of nutriments. The nutriments may be fed into the first tank reactor.
Moestedt J.,Tekniska verken i Linkoping AB |
Moestedt J.,Linkoping University |
Moestedt J.,Swedish University of Agricultural Sciences |
Nordell E.,Tekniska verken i Linkoping AB |
And 10 more authors.
Waste Management | Year: 2016
This study used semi-continuous laboratory scale biogas reactors to simulate the effects of trace-element addition in different combinations, while degrading the organic fraction of municipal solid waste and slaughterhouse waste. The results show that the combined addition of Fe, Co and Ni was superior to the addition of only Fe, Fe and Co or Fe and Ni. However, the addition of only Fe resulted in a more stable process than the combined addition of Fe and Co, perhaps indicating a too efficient acidogenesis and/or homoacetogenesis in relation to a Ni-deprived methanogenic population. The results were observed in terms of higher biogas production (+9%), biogas production rates (+35%) and reduced VFA concentration for combined addition compared to only Fe and Ni. The higher stability was supported by observations of differences in viscosity, intraday VFA- and biogas kinetics as well as by the 16S rRNA gene and 16S rRNA of the methanogens. © 2015 Elsevier Ltd. Source
Karlsson A.,Linkoping University |
Einarsson P.,Linkoping University |
Einarsson P.,Scandinavian Biogas Fuels AB |
Schnurer A.,Swedish University of Agricultural Sciences |
And 4 more authors.
Journal of Bioscience and Bioengineering | Year: 2012
The effect of trace element addition on anaerobic digestion of food industry- and household waste was studied using two semi-continuous lab-scale reactors, one (R30+) was supplied with Fe, Co and Ni, while the other (R30) acted as a control. Tracer analysis illustrated that methane production from acetate proceeded through syntrophic acetate oxidation (SAO) in both digesters. The effect of the trace elements was also evaluated in batch assays to determine the capacity of the microorganisms of the two digesters to degrade acetate, phenyl acetate, oleic acid or propionate, butyrate and valerate provided as a cocktail. The trace elements addition improved the performance of the process giving higher methane yields during start-up and early operation and lower levels of mainly acetate and propionate in the R30+ reactor. The batch assay showed that material from R30+ gave effects on methane production from all substrates tested. Phenyl acetate was observed to inhibit methane formation in the R30 but not in the R30+ assay. A real-time PCR analysis targeting methanogens on the order level as well as three SAO bacteria showed an increase in Methanosarcinales in the R30+ reactor over time, even though SAO continuously was the dominating pathway for methane production. Possibly, this increase explains the low VFA-levels and higher degradation rates observed in the R30+ batch incubations. These results show that the added trace elements affected the ability of the microflora to degrade VFAs as well as oleic acid and phenyl acetate in a community, where acetate utilization is dominated by SAO. © 2012 The Society for Biotechnology, Japan. Source