Municipal solid waste is a very complex and heterogeneous system made of a wide range of materials. Among thesematerials, more than 50% are biodegradable and can be valorized through treatments based on anaerobic biologicalprocesses to produce biogas, a renewable source of energy. The ligno-cellulosic fraction of waste, mainly constituted by paper and cardboard (25%), plays an essential role in the production of biogas and is responsible for almost 80% ofbiogas emission (Eleazer, et al., 1997).
T. Serain - Irstea, France
It is consequently a keystone in the anaerobic biological processes ofdegradation. However, cellulose is a recalcitrant molecule, and is not hydrolyzed easily in bioprocesses, which limits itsanaerobic digestion kinetic (Verstraete, et al., 1996) and efficiency. The rate of biodegradation occurring in animaldigestive systems, such as ruminants’ guts, is significantly higher despite much lower residence times than in digesters(Weimer, et al., 2009). Consequently, to improve the cellulose degradation and methane production in anaerobicdigesters, several studies involving rumen microorganisms in anaerobic digesters have been conducted (Gijzen, et al.,1987, Blasig, et al., 1992, Barnes & Keller, 2003). However, macroscopic observations suggest that ruminal flora maynot settle easily in industrial anaerobic processes (O'Sullivan & Burrell, 2007). The potential of cellulolytic ruminalflora properties expression in an anaerobic digester can therefore be questioned.In this study, cellulose degrading anaerobic batch incubations were set up and run in parallel. They were co-inoculatedwith MSW digester sludge and ruminal content. 13C labeled cellulose degradation and reaction pathways were followedand described over time with GC-C-IRMS. These results were linked to the identification and the monitoring of thedynamic (Automated Ribosomal Intergenic Spacer Analysis method, ARISA (Fisher & Triplett, 1999)) ofmicroorganisms.This experiment highlighted the functional characteristics of cellulose degradation digestion in a digester co-inoculatedwith a natural and an industrial biomass. After 65 days, 50% of the cellulose was converted into biogas, composed of60% of methane. The dominant intermediates were acetate and propionate. Their partial 13C enrichment suggests astrong degradation of endogenous substrates. The dynamics of functional groups followed by ARISA showed a strongcorrelation of the appearance and disappearance of bands with the dynamics of Volatile Fatty Acids. However none ofthe groups found in the reactors were initially present in the rumen. Cellulolytic potentiality of ruminal flora did notexpressed during the experiment despite inoculation in large quantities, in a closed system, with a suitable substrate(cellulose) and favorable physico-chemical conditions such as mesophilic temperature or the presence of rumen fluid.Yet the diversity was more important in the batch reactor than in the initial industrial sludge. The co-inoculationprobably disordered diversity equilibrium within the anaerobic industrial sludge, and several ecological niches weretaken over by species subdominant in the initial inocula. Co-inoculation of an exogenous flora with anaerobic sludgecould thus be an environmental lever to modify diversity in full scale reactors.This study demonstrates that a more precise identification of selection pressures that lead to the stabilization of differenttypes of flora is necessary to use natural flora into industrial systems. Design of processes mimicking animals digestivesystems also seems very promising (Godon, et al., 2010, Bayané & Guiot, 2011).Statement This work was realized in the Framework of the DANAC research project (ANR-Bioénergies 2009)
|Copyright:||© European Compost Network ECN e.V.|
|Quelle:||Orbit 2012 (Juni 2012)|
|Preis inkl. MwSt.:||€ 7,00|
|Autor:||Olivier Chapleur |
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Kompakte Verbrennungsanlage für Klärschlämme
© Springer Vieweg | Springer Fachmedien Wiesbaden GmbH (12/2020)
Die thermische Klärschlammverwertung mit anschließender Phosphor-Rückgewinnung nimmt an Bedeutung zu. Im Folgenden wird ein Verbrennungskonzept mit einfacher Struktur und hohem thermischen Wirkungsgrad für kleine Kläranlagen vorgestellt.
Application of paper sludge for co-fermentation in MBT
© Wasteconsult International (5/2015)
During the production of paper and packaging materials, various paper sludges are producedas waste material. This research project, funded by the DBU, investigates cofermentation in the digesters of mechanical biological treatment plants (MBT) as an ecological and economical solution for the use of these residuals. Three types of paper sludge from different ways of paper production were analyzed. The slurries were checked for possible inhibition effects upon the biogas process in MBT and their Biogas yield. First results have shown that the co-fermentation of paper sludges in digesters of MBT plants could be useful. The results found so far do not show definite inhibition effects.
RecoPhos and Other Thermo-Chemical Processes for the Recovery of Phosphorus from Sewage Sludge
© Lehrstuhl für Abfallverwertungstechnik und Abfallwirtschaft der Montanuniversität Leoben (11/2012)
In modern sewage treatment plants (STP), about 90 % of the influent’s phosphorus can be re-moved via chemical and/or biological processes. This entire amount is found in the sludge and, after thermal treatment, also in the ashes. If sewage sludge is mono-incinerated, the resulting ashes represent the sludge matter with the highest possible P-concentration and the smallest mass to be treated respectively.
Reducing the environmental impact of biogenic PHAs production using an enzymatic recovery strategy
© European Compost Network ECN e.V. (6/2012)
Bioplastics, in particular polyhydroxyalcanoates (PHAs), are widely studied as biodegradable materials for substitution of oil derived polymers. However, their production at an industrial scale is still limited due to high production costs. In addition, industrial PHAs recovery needs the use of large volumes of organic solvent like chloroform, which is not convenient for environmental safety (Byrom, 1994). Bosco and Chiampo (2010) reported four ways to reduce these costs including new cheap substrates, new fermentative strategies, new recovery and purification steps, and new microorganisms for accumulation of high PHA concentrations. Further Authors: C. Rondel C.E. Mercato-Romain V. Dossat-Létisse D. Lefebvre
Entwicklung eines Verwertungsverfahrens für nanoskaligen Kieselsäureschlamm aus der Industrieabwasserbehandlung
© DGAW - Deutsche Gesellschaft für Abfallwirtschaft e.V. (3/2012)
Bei Kieselsäureproduzenten fällt bei der Neutralisation der Produktionsabwässer ein nanoskaliger Kieselsäureschlamm aus, der nach dem Eindicken und Abpressen in einer schollenartigen Konsistenz vorliegt. Jährlich entstehen auf diese Weise ca. 5 bis 10 Tausend Tonnen Kieselsäureschlamm mit einem Wassergehalt von ca. 50 bzw. 85 % je Produktionsstandort. Die Entsorgung dieser Kieselsäureschlämme erfolgt zurzeit kostenpflichtig auf Deponien. Insbesondere im Sinne einer ressourcenschonenden und nachhaltigen Produktion ist es aus wirtschaftlicher und auch aus ökologischer Sicht sinnvoll, den Reststoff einer Verwertung zu zuführen.