Les boues d’épuration des eaux usées, produites en grandes quantités partout dans le monde, sont riches en matière organique et leur utilisation en tant que conditionneur de sol présente un intérêt potentiel. Cependant, la présence de polluants et notamment de contaminants non biodégradables tels que des métaux (Éléments Traces Métalliques: ETMs) peut limiter leur utilisation en agriculture et constitue un défi pour la protection de l'environnement. Le lombricompostage, processus biologique dans lequel des vers de terre sont utilisés pour accélérer la dégradation des déchets organiques, peut être appliqué aux boues. Des travaux ont montré que les vers peuvent accumuler certains ETMs et modifier leur biodisponibilité dans le compost. L'objectif principal de cette thèse est d'évaluer le lombricompostage en tant que processus de valorisation des boues d'épuration urbaines. Après une analyse bibliographique, des expérimentations en conditions contrôlées ont été réalisées afin d’évaluer l'efficacité du lombricompostage appliqué à différents boues (profils de contamination différents) et en utilisant différentes espèces de vers. Le compostage des boues en présence d’autres déchets a également été analysée. La qualité agronomique du compost a été évaluée de même que les capacités de tolérance de 3 espèces de vers et leur aptitude à accumuler plusieurs ETMs. Le traitement par lombricompostage a permis une réduction considérable de la masse du mélange traité et a considérablement changé les teneurs métalliques dans le compost obtenu. Globalement, le produit final présente des paramètres agronomiques acceptables au regard des normes de qualité en vigueur en France et en Pologne. / Large sewage sludge quantities are produced in wastewater plants, worldwide. Sewage sludge is rich in organic matter and its use as soil conditioner might be of interest. However, pollutants and especially non-biodegradable contaminants such as metallic trace elements (MTEs) are present in sludge. This may prevent the use of sewage sludge in agriculture and constitutes a challenge for environmental protection. Vermicomposting is an eco-friendly process in which earthworms are used to accelerate the degradation of organic wastes. Moreover, earthworms have shown an ability to accumulate MTEs and change the bioavailability of MTEs in compost. The main aim of this thesis was to evaluate the vermicomposting process applied to urban sewage sludge. After a bibliographic synthesis, experiments in controlled conditions have been performed in order to assess the effectiveness of vermicomposting applied to different sewage sludge (exhibiting contrasted contamination levels) and using different earthworm species. The mixing of different sewage sludge with other organic wastes has also been analyzed. The capacity of earthworms to accumulate several metals and their resistance to different contamination levels were also examined. Compost agronomic quality was assessed as well as the tolerance capabilities of three earthworm species and their ability to accumulate several MTEs. Vermicomposting treatment led to a significant reduction of the treated mixture weight and has significantly changed the content of several metals in the final product. Overall, vermicomposts were acceptable according to agronomic parameters and to compost quality norms in France and in Poland.

The landfilling of biodegradable waste is proven to contribute to environmental degradation. Much wood and lumber is discharged as waste from the cleared fields. These woody wastes are subsequently disposed of by burning. However, it would be preferable to dispose of them without combustion to avoid the release of carbon dioxide, one of the critical greenhouse gases. Instead of burning these woody wastes, we should recycle them as future resources. One solution to this problem is to make compost from the waste. Compost use in agriculture is increasing as both an alternative to landfilling for the management of biodegradable waste, as well as means of increasing or preserving soil organic matter. This research aimed to contribute to the identification of a system for managing the production and utilization of wood waste (Quercus rubra and Pinus sylvestris) compost for sustainable agriculture, with particular regards to carbon dioxide produced from both compost and combustion of wood. Compost of wood was implemented in two consecutive trials. The first was carried out in greenhouse experiment in 4 liter pot of Quercus rubra and Pinus sylvestris (QR and PS) moisted by compost and tap water and infected by tiger worm (Eisenia fetida, EF) and European night crawlers (Dendrobaena veneta, DV) at different mixed ratios with lake mud (LM). The second was conducted in greenhouse experiment in 40 liter pot of the successful wood and worm from the first compost trial (QR and EF respectively). The tested wood (QR) was mixed separately by lake mud and horse manure and irrigated by compost and tap water. The final product, successful wood compost (QR) produced from the first trial (4 liter pot) was utilized in different mixed ratios with coal mine tailings (tertiary sand) in greenhouse pot trial to study his effects on improving soil physical and chemical properties and some plant growth parameters of RSM 7.2.1 grass. The wood compost produced from the second compost experiment (40 liter pot) and other artificial component named Arkadolith® were used as soil amelioration in field experiments of different selected sites with extremely unsuitable characteristics (tertiary and quaternary sand in Lusatia lignite region, Germany). The soil in each site was sowed by RSM 7.2.1 and autochthonous grasses. Also, some vermicompost samples were selected to study its thermal stability which compared with a soil sample (Niedermoorgleys) by using thermogravimetric analysis technique. Further investigation was achieved to evaluate the effect of charcoal as a source of carbon on vermicompost stability. Moreover some selected vermicompost samples were used to examine its microstructure under scanning electron microscope which compared also with the same soil used in thermal analysis. The obtained results under all studied experiments can be arranged as follow: First compost trial, Cumulative amount of carbon dioxide produced during composting period was lower than that evolved by combustion of wood. The results showed composting of wood can reduce the emitted CO2 up to 50 % when compared with the amount of CO2 produced from combustion of wood. The effect of different studied factors on different studied parameters show that, QR wood compost have more responsive to decomposition processes and humification rate in comparison with PS wood compost. Under different infection worms, Eisenia fetida (EF) was better than Dendrobaena veneta (DV) in biodegradation rate. Compost water has had a better impact of tap water in all studied decomposition parameters. For example, The compost content of OM and total OC was decreased with the increase of the decomposition period in the treatments of compost water and EF worm, where this decrease was higher at mixed ratio of 1:3 (wood: mud, w/w). The total content of N in the final products takes reversible trend regarding to OM and C content. The high content of N was found in QR wood compost moisted by compost water and infected by EF worm. The content of both macro-and micro-nutrients was clearly positive affected by the studied factors. The content of these nutrients in QR wood compost was higher than that found in the compost of PS wood. Second compost trial, The observed data show that, the amount of CO2 produced by composting was lower than that evolved by combustion of wood. Composting of wood reduced CO2 emission up to 40 % of the combustion wood CO2. Cumulative amount of CO2 produced from wood compost treated by horse manure was higher than that fount in the other treated by LM. The compost of wood treated by horse manure has had a high decomposition rate in comparison with that treated by lake mud. The treatments left without worms during all composting period and moisted by compost water have a responsive effects but it was lower than that infected by worms. Total and available contents of N, P, K, Mg, Zn, and Cu in the compost treated by HM were higher than that found in compost treated by LM. The other nutrients (Ca, Fe, Cu, and Mn) take reversible trend, which it was higher in LM than HM treatments. Thermal and microstructure analysis, The selected vermicompost samples from both first and second compost experiments showed, up to 200° C temperature the mass loss was due to free water and bound water (It was in vermicompost samples higher than soil sample). Mass loss from 200 to 550° C is due to easily oxidizable organic forms and it was higher in vermicompost than soil. In this stage the soil OM seems to be more stable than vermicompost which can be explained by a more intensive bond between the organic and inorganic components. At higher temperatures (T> 550° C) no significant detectable was appeared of soil organic matter. In contrast, the vermicompost treatments showed a high proportion of stable groups, especially aromatic compounds. These statements seem to be importance particularly for the practical application of the wood compost in terms of their long-term effect in the soil. The application of charcoal, showed no additional stabilizing effect of vermicompost. Also, the data show that, vermicompost structure characterized with high homogeneity and ratio of surface area to volume compared to those in soil structure. First plant trials (greenhouse), Different compost mixed ratios had positive impact on different extreme soil physiochemical properties. At the end of experiment (42 days) compost increased soil water holding capacity, decreased soil bulk and particle density and increased total porosity. The used wood compost modified soil buffering capacity and soil acidity. The availability of soil macro and micro nutrients were increased after adding wood compost. The wood compost had a positive effect in some growth parameters like fresh and dry matter yield of the selected grass. High dry matter yield and nutrients uptake was achieved with higher rates of compost application (25.0% > 12.5% > 3.0% > 0.0 %, w/w). Second plant trials (field experiment), Regarding to the effect of wood compost (QR) and Arkadolith® component on tertiary and quaternary sand, at the end of grown season (6 month) most soil and plant characteristics of tertiary sand were improved and it was better than that in quaternary sand. This trend reveals to, physical and chemical properties of tertiary sand was better than that in quaternary sand, like organic matter content, CEC, WHC, TOC, available nutrients. In the both sites, the effects of different type of soil conditioners arranged as follow: the treatments treated with wood compost is the better followed by the other treated with both wood compost and Arkadolith. Wood compost increased soil pH, CEC, soil buffering capacity, OM content, and soil WHC in comparison with Arkadolith which make a small improvement of these properties in both sites. Finally, Different growth parameters (height, covering, fresh and dry matter yield) of the used grasses were clearly positive affected by wood compost, with the highest production inherent to the treatments treated by the high amount of wood compost. / Entsprechend der Zielstellung wurden zunächst verschiedene Varianten der Kompostierung von Holzsubstanz getestet, um eine optimale Technologie, die auch für Entwicklungsländer realisierbar ist, herauszufinden. Hierzu sind in Pflanztöpfe Holzspäne (Woodchips) von zwei verschieden Holzarten (Laub- und Nadelholz) gefüllt und mit verschiedenen natürlichen Stickstoffquellen gemischt worden. Diese Ansätze wurden regelmäßig mit Kompostwasser appliziert. Nach vier Wochen sind zwei verschiedene Wurmarten (Dendrobaena veneta und Eisenia fetida) hinzugegeben worden. Die Feuchthaltung erfolgte ab diesem Zeitpunkt durch Frischwasser. Die qualitativ beste Versuchsvariante ist im nächsten Schritt mit weiteren natürlichen Stickstoffquellen, die in Entwicklungsländern zur Verfügung gestellt werden könnten, getestet worden. Von allen Kompostvarianten sind im Labor eine Vielzahl von bodenphysikalischen (z.B. Dichte, Wasserhaltekapazität) und bodenchemischen Zustandsgrößen (z.B. Elektrische Leitfähigkeit, Totalgehalte biophiler Elemente, Bodenreaktion, organische Substanzgehalte, Kationenaustauschkapazität) bestimmt worden. Die Wiederum qualitativ beste Mischung ist in einer weiteren Versuchsreihe in verschiedenen Mengenverhältnissen mit tertiärerem Abraumsand des Braunkohlebergbaus gemischt worden. In diese Versuchsmischungen wurde die Grasmischung RSM 7.2.1 eingesät und regelmäßig bewässert sowie die Wuchshöhe gemessen. Nach 42 Tagen wurden das Gras geerntet und die biometrischen Parameter, die Nährstoffgehalte (pflanzenverfügbare Fraktionen), die Bodenreaktion, die effektive bzw. potentielle Kationenaustauschkapazität sowie die Pufferkapazitäten der Mischsubstrate bestimmt. Die nächsten Versuchsvarianten sind als Feldversuche in der Niederlausitz durchgeführt worden. Für ihre Realisierung wurde als weiterer Zuschlagsstoff Arkadolith® zugemischt. Die Plotflächen sind sowohl auf Abraumsanden des Tertiärs als auch Quartärs angelegt worden. In jeweils eine Subvariante ist RSM 7.2.1, in die andere eine autochthone Grasmischung eingesät worden. Diese Experimente wurden nach 6 Monaten beendet, die Bestimmung aller Parameter erfolgte in gleicher Weise wie bei den Gewächshausversuchen. Auf Basis aller Versuchsreihen konnten die besten Kompostqualitäten und ihre optimalen Herstellungsvarianten ermittelt werden. Eine weitere Aufgabe war es zu untersuchen, wie im Vergleich zur Verbrennung von Holzmasse die CO2-Emission in die Atmosphäre durch Holzkompostierung verringert werden kann. Hierzu wurde während der verschiedenen Kompostierungsvarianten die CO2-Freisetzung gemessen. Im Vergleich dazu ist jeweils die gleiche Masse an Holzsubstanz verbrannt worden. Die Ergebnisse zeigten, dass im Vergleich zu der thermischen Verwertung von Holsubstanz die CO2-Emission bis zu 50 % verringert werden kann. Dem Boden kann darüber hinaus energiereiche organische Substanz zugeführt werden, die eine Entwicklung der Bodenorganismen ermöglicht. Ein weiteres Experiment zielte darauf ab, die Stabilität der Holzkomposte zu bestimmen. Darüber hinaus sollte untersucht werden, ob durch die Zufuhr von pyrogenem Kohlenstoff eine Vergrößerung der Stabilität zu erreichen ist. Diese Untersuchungen wurden mit Hilfe der Thermogravimetrie vorgenommen. Alle wichtigen Kompostierungsvarianten sind sowohl mit verschiedenen Zusatzmengen als auch ohne Zusatz von pyrogenem Kohlenstoff vermessen worden. Als Vergleichssubstanz diente der Oberboden eines Niedermoorgleys, der naturgemäß einen relativ hohen Anteil an organischer Substanz aufweist. Die Ergebnisse zeigten, dass im Bereich niedriger Temperaturen die Wasserbindung im Naturboden fester ist. In der Fraktion der oxidierbaren organischen Substanz, im mittleren Temperaturbereich gemessen, ist die natürliche Bodensubstanz ebenfalls stabiler, was auf eine intensivere Bindung zwischen den organischen und anorganischen Bestandteilen, also auf stabilere organisch-mineralische Komplexe, schlussfolgern lässt. Im Bereich höherer Temperaturen (T> 550° C) waren im Naturboden keine nennenswerten organischen Bestandteile mehr nachweisbar. Hingegen wiesen die Kompostvarianten einen hohen Anteil stabiler Fraktionen, vor allem aromatische Verbindungen, auf. Diese Aussagen erscheinen vor allem für die praktische Anwendung der Holzkomposte in Hinblick auf ihre Langzeitwirkung bedeutsam. Der Zusatz von pyrogenem Kohlenstoff zeigte keine zusätzliche Stabilisierungswirkung.