This study is a multi-proxy analysis of a 30-m section of a Barremian-Aptian succession of interbedded, grayish black (N2) and black (N1) limestones from a quarry of the Sierra de Prada. Index taxa include planktic foraminifera Globigerinelloides blowi and Hedbergella sigali, which combined with δ13C data from Cresmina and Gorgo a Cerbara sections indicate a late Barremian to early Aptian age. The rocks are organic-rich with 0.67 - 3.10 wt% total organic carbon (TOC). A marlstone interval (~1m) at 2.24 m has a low bioturbation index (1), TOC ~6.66 wt%, framboidal pyrite, and enrichment spikes of major, biolimiting, and redox-sensitive trace elements (Al, Si, Ti, P, Fe, and Mo, Cr, Cu, V, Th), indicating an anoxic episode. Biomarker analyses show a predominance of n-alkanes (≤nC20) at this level, suggesting an in situ origin of organic matter from phytoplankton. Pr/Phy ratios below 2 imply that organic matter did not reach overmaturity.

Le recyclage des résidus organiques sur les sols cultivés d'un territoire pourrait-il rendre possible la substitution au moins partielle des engrais azotés dans la conduite des cultures ? Cette question a été traitée dans le cas de la conduite des grandes cultures dans une zone périurbaine caractérisée par une forte diversité de résidus organiques. Le territoire étudié est la "Plaine de Versailles et le Plateau des Alluets" (PVPA), situé en Ile de France, à l'ouest de Versailles. Il représente 178km2 dont 9900ha cultivés par 82 agriculteurs dont 60 en grande culture. Il y a peu d'élevage dans la région d'étude et les sols les plus fréquents sont les luvisols et cambisols. Dans ce territoire on a mis au point une démarche d'analyse des substitutions possibles des fertilisants chimiques par des PRO (produits résiduaires organiques) qui comprend plusieurs étapes. Tout d'abord un inventaire de tous les PRO disponibles ou potentiellement disponibles sur le territoire a été réalisé et tous les PRO ont été échantillonnés et caractérisés sur un plan physicochimique : en particulier, la disponibilité du N a été évaluée via la minéralisation potentielle de l'azote organique dans des conditions contrôlées au laboratoire (norme française XPU 44-163). Les résidus organiques du territoire ont été classés en (i) PRO « amendants » (26320 tonnes de matière sèche et 442 tonnes de Ntot) caractérisés par une matière organique stabilisée, ayant un potentiel important d'entretien et d'augmentation des teneurs en matière organique des sols et (ii) les PRO « fertilisants » ayant une forte disponibilité de N (5686 tonnes de matières sèches et 361 tonnes de Ntot). Parmi les PRO recensés, les boues de stations d'épuration (séchées et chaulées), un produit commercial correspondant à un lisier de porc en provenance de Bretagne et les fientes de volailles sont les PRO ayant les valeurs fertilisantes les plus intéressantes. Des PRO à forte valeur amendante ont aussi été recensés, dont des fumiers de chevaux compostés ou non et des composts de déchets verts.[...] Suite et fin du résumé dans la thèse. / Did the recyling of organic residues of a territory on cultivated soils could make possible, at least, partial substitution of nitrogen fertilizers in crop management? This issue was treated in the case of cereal crops in a suburban area characterized by a high diversity of organic residues. The study area is the “Plaine de Versailles and the Plateau Alluets”, located in Ile de France, west of Versailles. The total surface is about 178km2 including 9900ha cultivated by 82 farmers from which 60 cultivate cereals. The animal breeding is scarce in the study area and the most common soils are Cambisols and Luvisols. We tried to develop an approach for analyzing possible substitutions of chemical fertilizers by OWP (organic waste products) use. This approach involves several steps. First an inventory of the entire OWP available or potentially available in the territory has been achieved and all OWP were sampled and characterized: in particular, the availability of N was evaluated using the potential mineralization of the organic nitrogen under controlled conditions in the laboratory (French standard XPU 44-163). Organic residues territory were classified into (i) "organic amendments" (26320 tons of dry matter and 442 tons of total N) characterized by a stabilized organic matter, with significant potential maintenance and increasing levels of soil organic matter and (ii) "organic fertilizers" with a high availability of N (5686 tons of dry matter and 361 tons of total N) . Among the identified OWP, sludge from sewage treatment (dried and limed), and a commercial product corresponding to dried pig slurry from Britain and poultry manure are OWP with the most interesting fertilizing values. Organic amendments with high stabilized organic matter value were also identified, including composted or not horse manure, and green waste compost. Last and final summary in the thesis.

Two oceanographic cruises were conducted during September 2003 and March 2004 in the eastern half of the Cariaco Basin. Specific objectives were to examine the hydrography of the seasonal upwelling plume characteristic of this region, the spatial distribution of particles in the area, and to help determine the source and relative importance of in situ particle production vs. terrigenous particles delivered laterally from the coast. During September 2003, average surface salinities within the basin were higher (36.6) relative to Caribbean Sea waters outside the basin (35.6). Salinity patterns indicated that the Orinoco and Amazon River plumes did not enter or influenced the basin directly. The upwelling plume in March 2004 stimulated primary productivity. Beam attenuation and CDOM fluorescence profiles showed marked vertical structure in biomass of microbial populations, particularly near the oxic-anoxic interface typically located between about 250 and 300 m. There is an increasing difference in temperature and salinity between the Cariaco Basin and the adjacent Caribbean Sea below 200 m. Inside the Basin temperatures and salinities were higher by 4oC and 0.5. The influence of local rivers on the Cariaco Basin was evident during September 2003. Low salinity plumes with high beam attenuation (1m-1) lined the southern margin of the Basin. The primary rivers that affected the basin were the Unare and Neverí Their sediment input affected the shelf near the river mouths, and a surrounding radius of up to 40 Km. Their low salinity plumes were carried northwestward toward the CARIACO time series station. In March 2004, there was minimal or no terrigenous input from local rivers. Near the Manzanares River, off the city of Cumaná and near Cubagua Island, located south of Margarita Island, attenuation due to suspended particles (0.09 m-1) was observed at depth (70-150 m) during both cruises (0.09-0.15 m-1). Therefore, sediment transport from the shelf into the basin seems to occur year-round. More observations are necessary to determine the nature and origin of these particles. In March 2004, there was minimal or no terrigenous input

The phenomenon called soil aggregate coalescence occurs at contact-points between aggregates and causes soil strength to increase to values that can inhibit plant root exploration and thus potential yield. During natural wetting and drying, soil aggregates appear to ‘weld’ together with little or no increase in dry bulk density. The precise reasons for this phenomenon are not understood, but it has been found to occur even in soils comprised entirely of water stable aggregates. Soil aggregate coalescence has not been widely observed and reported in soil science and yet may pose a significant risk for crops preventing them from achieving their genetic and environmental yield potentials. This project used soil penetrometer resistance and an indirect tensile-strength test to measure the early stages of aggregate coalescence and to evaluate their effects on the early growth of tomato plants. The early stages of aggregate coalescence were thought to be affected by a number of factors including: the matric suction of water during application and subsequent drainage, the overburden pressure on moist soil in the root zone, the initial size of soil aggregates prior to wetting, and the degree of sodicity of the soil aggregates. Seven mainexperiments were conducted to evaluate these factors. The matric suction during wetting of a seedbed affects the degree of aggregate slaking that occurs, and the strength of the wetted aggregates. The matric suction during draining affects the magnitude of ‘effective stresses’ that operate to retain soil structural integrity as the soil drains and dries out. An experiment was conducted to evaluate the influence of matric suction (within a range of suctions experienced in the field) on aggregate coalescence using soils of two different textures. Sieved aggregates (0.5 to 2 mm diameter) from a coarse-textured and two fine-textured (swelling) soils were packed into cylindrical rings (4.77 cm i.d., 5 cm high) and subjected to different suctions on wetting (near-saturation, and 1 kPa), and on draining (10 kPa on sintered-glass funnels, and 100 kPa on ceramic pressure plates). After one-week of drainage, penetrometer resistance was measured as a function of depth to approximately 45 mm (penetrometer had a recessedshaft, cone diameter = 2 mm, advanced at a rate of 0.3 mm/min). Tensile strength of other core-samples was measured after air-drying using an indirect “Brazilian” crushing test. For the coarse-textured soil, penetrometer resistance was significantly greater for samples wet to near-saturation, despite there being no significant increase in dry bulk density; this was not the case for the finer-textured soils, and it was difficult to distinguish the effects of variable bulk density upon drying from those of the imposed wetting treatments. In both coarse- and fine-textured soils, the tensile strength was significantly greater for samples wet to near-saturation. Thus wetting- and draining-suctions were both found to influence the degree of soil aggregate coalescence as measured by penetrometer resistance and tensile strength. Aggregate coalescence in irrigated crops is known to develop as the growing season progresses. It was therefore thought to be linked to the repeated occurrence of matric suctions that enhance the phenomenon during cycles of wetting and draining. An experiment was conducted to determine the extent of aggregate coalescence in a coarsetextured and two fine-textured (swelling clay) soils during 8 successive cycles of wetting and draining. Sieved aggregates (0.5 to 2 mm diameter) from each soil were packed into cylindrical rings (4.77 cm i.d., 5 cm high) and wetted to near saturation for 24 h. They were then drained on ceramic pressure plates to a suction of 100 kPa for one week, after which penetrometer resistance and tensile strength were measured as described above. The degree of expression of aggregate coalescence depended on soil type. For the coarse-textured soil, repeated wetting and draining significantly increased bulk density, penetrometer resistance and tensile strength. For the fine-textured soil, penetrometer resistance and bulk density did not vary significantly with repeated wetting and draining; on the contrary, there was evidence in these swelling clay soils to suggest bulk density and penetrometer resistance decreased. However, there was a progressive increase in tensile strength as cycles of wetting and draining progressed. The expansive nature of the fine-textured soil appears to have masked the development of aggregate coalescence as measured by penetrometer resistance, but its expression was very clear in measurements of tensile strength despite the reduction in bulk density with successive wetting and draining. Field observations have indicated that aggregate coalescence is first expressed at the bottom of the seedbed and that it develops progressively upward to the soil surface during the growing season. This suggests that overburden pressures may enhance the onset of the phenomenon by increasing the degree of inter-aggregate contact. Soils containing large quantities of particulate organic matter were known to resist the onset of aggregate coalescence to some extent. An experiment was conducted to evaluate the effects of soil organic matter and overburden pressures, by placing brass cylinders of various weights (equivalent to static load pressures of 0, 0.49, 1.47 and 2.47 kPa) on the top of dry soil aggregates (0.5 – 2 mm diameter) having widely different soil organic carbon contents placed in steel rings 5 cm high and 5 cm i.d. With the weights in place, the aggregates were wetted to near-saturation for 24 h and then drained on ceramic pressure plates to a suction of 100 kPa for one week. Bulk density, penetrometer resistance and tensile strength were measured when the samples were removed from the pressure plates and they all increased significantly with increasing overburden pressure in the soil with low organic matter content, but not in the soil with high organic matter content. The amount of tillage used to prepare seedbeds influences the size distribution of soil aggregates produced – that is, more tillage produces finer seedbeds. The size distribution of soil aggregates affects the number of inter-aggregate contact points and this was thought to influence the degree of aggregate coalescence that develops in a seedbed. Previous work has shown that soil organic matter reduces aggregate coalescence and so an experiment was conducted to evaluate the effects of aggregate size and organic matter on the phenomenon. For soils with high and low organic matter contents, aggregate size fractions of < 0.5, 0.5 – 2, 2 – 4, and < 4 mm were packed into soil cores (as above) and wetted to near-saturation then drained to 100 kPa suction as described above. Penetrometer resistance and tensile strength were measured and found to increase directly with the amount of fine material present in the soil cores – being greater in the < 0.5 mm and < 4 mm fractions, and being less in the 0.5 – 2 mm and 2 – 4 mm fractions. In all cases, penetrometer resistance and tensile strength were lower in the samples containing more organic matter. The rate at which soil aggregates are wetted in a seedbed affects the degree of slaking and densification that occurs, and the extent to which aggregates are wetted influences the overall strength of a seedbed. Both wetting rate and the extent of wetting were believed to influence the onset of aggregate coalescence and were thought to be affected by soil organic matter and irrigation technique. An experiment was therefore designed to separate these effects so that improvements to management could be evaluated for their greatest efficacy – that is, to determine whether management should focus on improving irrigation technique or increasing soil organic matter content, or both. The rate of wetting was controlled by spraying (or not spraying) soil aggregates (0.5 – 2 mm diameter) with polyvinyl alcohol (PVA). Samples of coarse- and fine-textured soils were packed into steel rings (as above) and subjected to different application rates of water (1, 10 and 100 mm/h) using a dripper system controlled by a peristaltic pump. Samples were brought to either a near-saturated state or to a suction of 10 kPa for 24 h, and then drained on a pressure plate at a suction of 100 kPa for one week. Measurements of penetrometer resistance and tensile strength were then made as described above. As expected, penetrometer resistance was lower in samples treated with PVA before wetting (slower wetting rates) and in samples held at a greater suction (10 kPa) after initial wetting (greater inter-aggregate strength). The effects were more pronounced in the coarse-textured soil. In both coarse- and fine-textured soils, tensile strengths increased with increasing wetting rate (greatest for 100 mm/h) and extent of wetting (greater when held at near-saturated conditions). The rate of wetting was found to be somewhat more important for promoting aggregate coalescence than the extent of wetting. Because aggregate coalescence often occurs with little or no increase in bulk density, an explanation for the increase in penetrometer resistance and tensile strength is unlikely to be explained by a large increase in the number of inter-aggregate contacts. An increase in the strength of existing points of inter-aggregate contact was therefore considered in this work. For inter-aggregate bond strengths to increase, it was hypothesized that small increases in the amount of mechanically (or spontaneously) dispersed clay particles, and subsequent deposition at inter-aggregate contact points could increase aggregate coalescence as measured by penetrometer resistance and tensile strength. An experiment was devised to manipulate the amount of spontaneously dispersed clay in coarse- and fine-textured soils of high and low organic matter content. The degree of sodicity of each soil was manipulated by varying the exchangeable sodium percentage (ESP) of soil aggregates (0.5 – 2mm) above and below a nominal threshold value of 6. Dry aggregates were then packed into steel rings (as above) and subjected to wetting near saturation, then draining to a suction of 100 kPa for one week as described above. Measurements were then taken of penetrometer resistance and tensile strength, both of which were affected by ESP in different ways. In the coarse-textured soil, sodicity enhanced aggregate slaking and dispersion, which increased bulk density. While penetrometer resistance also increased, its effect on aggregate coalescence could not be separated from a simple effect of increased bulk density. Similarly, the effect of sodicity on aggregate coalescence in the fine-textured soil was confounded by the higher water contents produced by greater swelling, which produced lower-than-expected penetrometer resistance. Measurements of tensile strength were conducted on air-dry samples, and so the confounding effects of bulk density and water content were eliminated and it was found that tensile strength increased with sodicity in both coarse- and fine-textured soils. The presence of dispersed clay was therefore implicated in the development of aggregate coalescence in this work. Finally, a preliminary evaluation of how the early stages of aggregate coalescence might affect plant growth was attempted using tomatoes (Gross lisse) as a test plant. Seeds were planted in aggregates (0.5 – 4 mm) of a coarse- or fine-textured soil packed in steel rings. These were wetted at a rate of 1 mm/h to either near-saturation (for maximum coalescence) or to a suction of 10 kPa (for minimum coalescence) and held under these conditions for 24 h. All samples were then transferred to a ceramic pressure plate for drainage to 100 kPa suction for one week. Samples were then placed in a growth-cabinet held at 20C with controlled exposure to 14 h light/day. Germination of the seeds, plant height, and number and length of roots were observed. Germination of the seeds held at near-saturation in both coarse- and fine-textured soils was delayed by 24 h compared with seeds held at 10 kPa suction. Neither the number nor the length of tomato roots differed significantly between the different treatments and soils. In the coarse-textured soil, however, the total root length over a period of 14 days was somewhat greater in the uncoalesced samples than in the coalesced samples, but this difference was not statistically significant. These results suggest that aside from delaying germination, aggregate coalescence may not have a large effect on early growth of tomato plants. However, this is not to say that detrimental effects may not be manifest at later stages of plant growth, and this certainly needs to be evaluated, particularly because aggregate coalescence increase with repeated cycles of wetting and draining. In conclusion, the primary findings of the work undertaken in this thesis were: • Rapid wetting of soil aggregates to near-saturation enhanced the onset of soil aggregate coalescence as measured by (in some cases) penetrometer resistance at a soil water suction of 100 kPa, and (in most cases) tensile strength of soil cores in the air-dry state. The rate of wetting appeared to be more important in bringing on aggregate coalescence than how wet the soil eventually became during wetting. This means reducing the rate at which irrigation water is applied to soils may reduce the onset of aggregate coalescence more effectively than controlling the total amount of water applied – though both are important. The literature reports that aggregate coalescence occurs in the field over periods of up to several months, involving multiple wetting and draining cycles, but the work here demonstrated that this can occur over much shorter time periods depending on conditions imposed. • Aggregate coalescence occurred in coarse-textured soils regardless of whether the bulk density increased during wetting and draining. In finer-textured soils, the response to wetting conditions varied and was complicated by changes in bulk density and water content due to swelling. • Small overburden pressures enhanced the onset of aggregate coalescence, but these effects were diminished in the presence of high soil organic matter contents. • Finer aggregate size distributions (which are often produced in the field by excessive tillage during seedbed preparation) invariably led to greater aggregate coalescence than coarser aggregate size distributions. The effects of aggregate size were mitigated to some extent by higher contents of soil organic matter. • Sodicity enhanced aggregate coalescence as measured by tensile strength, but when penetrometer resistance was measured in the moist state, the effects were masked to some extent by higher water contents generated by swelling and dispersion. This work suggests that tensile strength (in the air dry state) may be a more effective measure of aggregate coalescence than penetrometer resistance. • Early plant response to aggregate coalescence was not large, but the response may become magnified during later stages of growth. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1297583 / Thesis (Ph.D.) -- School of Earth and Environmental Sciences, 2007

<p>Microbial decomposition of organic matter in aquatic environments plays an important role in natural fluxes of methane and carbon dioxide because the gases are end-products in microbial energy metabolism of organic matter. Microbial metabolism depends on the use of electron donors and electron acceptors in redox reactions that generate energy for growth and maintenance. Energy yields can be used to envisage specific patterns of microbial redox reactions and these predictions depend on the hypothesis that, in a specified environment, the metabolic reaction that yields most energy will dominate over any competing reactions. The energy yield hypothesis indicates a sequential order in electron acceptor use by microbes and also make it tempting to conclude that degradation rate of organic matter is different depending on available electron acceptors. The main purpose of this thesis was to study how the presences of different electron acceptors in freshwater sediments influence organic matter decomposition. Mineralization rates of organic matter under six different conditions regarding the electron acceptor availability were investigated in a river sediment sample from Stångån, Sweden, by measuring carbon dioxide and methane production using gas chromatography. This was done during a fixed time period, in vials containing a mixture of water, sediment, buffer solution and a dominating electron acceptor. Six different metabolic processes; aerobic respiration, denitrification, manganese reduction, iron reduction, sulphate reduction and methanogenesis were included. The overall result indicates similar mineralization rates in both oxic and anoxic treatments. The result also indicates that methane formation was present in the iron reduction and methanogenesis treatments and not evident in the oxic treatments. Sulphate reduction, denitrification and manganese reduction seems to inhibit methanogenesis, but the result also indicates that no significant total mineralization was apparent when NO3- and Mn(IV) were the dominating electron acceptors. The similarities between oxic and anoxic mineralization rates indicates that organic matter degradation rates are not dependent on available electron acceptors and that degradation rates of organic matter are independent of the thermodynamically based energy yield.</p>

In order to better predict the aggregation state of nanomaterials, the factors that influence aggregation must be understood. The combined effects of natural and engineered coatings have been shown to factor into nanoparticle aggregation behavior in preliminary research. In this study, aggregation behaviors of gold nanoparticles with two different engineered coatings were investigated in the presence of the monovalent electrolyte KCl and the divalent electrolyte CaCl���. Aggregation studies were conducted using dynamic light scattering to determine the relative stability of the NMs in environments of varying ionic strength in the absence and presence of Suwannee River Natural Organic Matter (SRNOM). Coatings which provided primarily electrostatic stabilization were found to adhere closely to DLVO theory, while coatings which provided steric stability inhibited aggregation over a wide range of ionic strengths for both electrolytes. The presence of SRNOM was found to provide some electrostatic stability in the presence of KCl, but appeared to form agglomerates with calcium ions, especially at higher SRNOM concentrations. / Graduation date: 2013

In Sweden, utilisation of incinerator residues outside disposal areas is restricted by environmental concerns, as such residues commonly contain greater amounts of potentially toxic trace elements than the natural materials they replace. On the other hand, utilisation can also provide environmental benefits by decreasing the need for landfill and reducing raw material extraction. This thesis provides increased knowledge and proposes better approaches for environmental assessment of incinerator residue utilisation, particularly bottom ash from municipal solid waste incineration (MSWI).A life cycle assessment (LCA) based approach was outlined for environmental assessment of incinerator residue utilisation, in which leaching of trace elements as well as other emissions to air and water and the use of resources were regarded as constituting the potential environmental impact from the system studied. Case studies were performed for i) road construction with or without MSWI bottom ash, ii) three management scenarios for MSWI bottom ash and iii) three management scenarios for wood ash. Different types of potential environmental impact predominated in the activities of the system and the scenarios differed in use of resources and energy. Utilising MSWI bottom ash in road construction and recycling of wood ash on forest land saved more natural resources and energy than when these materials were managed according to the other scenarios investigated, including dumping in landfill. There is a potential for trace element leaching regardless of how the ash is managed.Trace element leaching, particularly of copper (Cu), was identified as being relatively important for environmental assessment of MSWI bottom ash utilisation. CuO is suggested as the most important type of Cu-containing mineral in weathered MSWI bottom ash, whereas in the leachate Cu is mainly present in complexes with dissolved organic matter (DOM). The hydrophilic components of the DOM were more important for Cu binding than previously understood. Differences were also observed between MSWI bottom ash DOM and the natural DOM for which the geochemical speciation models SHM and NICA-Donnan are calibrated. Revised parameter values for speciation modelling are therefore suggested. Additions of salt or natural DOM in the influent did not change the leachate concentration of Cu. Thus, although Cl and natural DOM might be present in the influent in the field due to road salting or infiltration of soil water, this is of minor importance for the potential environmental impact from MSWI bottom ash.This thesis allows estimates of long-term leaching and toxicity to be improved and demonstrates the need for broadening the system boundaries in order to highlight the trade-offs between different types of impact. For decisions on whether incinerator residues should be utilised or landfilled, the use of a life cycle perspective in combination with more detailed assessments is recommended. / QC 20100914

Conventional end-of-pipe solutions for wastewater treatment have been criticized from a sustainable view-point, in particular regarding recycling of nutrients. The integration of hydroponic cultivation into a wastewater treatment system has been proposed as an ecological alternative, where nutrients can be removed from the wastewater through plant uptake; however, cultivation of plants in a temperate climate, such as Sweden, implies that additional energy is needed during the colder and darker period. Thus, treatment capacity, additional energy usage and potential value of products are important aspects considering the applicability of hydroponic wastewater treatment in Sweden. To enable the investigation of hydroponic wastewater treatment, a pilot plant was constructed in a greenhouse located at Överjärva gård, Solna, Sweden. The pilot plant consisted of several steps, including conventional biological processes, hydroponics, algal treatment and sand filters. The system treated around 0.56-0.85 m3 domestic wastewater from the Överjärva gård area per day. The experimental protocol, performed in an average of twice per week over a period of three years, included analysis and measurements of water quality and physical parameters. In addition, two studies were performed when daily samples were analysed during a period of two-three weeks. Furthermore, the removal of pathogens in the system, and the microbial composition in the first hydroponic tank were investigated. Inflow concentrations were in an average of around 475 mg COD/L, 100 mg Tot-N/L and 12 mg Tot-P/L. The results show that 85-90% of COD was removed in the system. Complete nitrification was achieved in the hydroponic tanks. Denitrification, by means of pre-denitrification, occurred in the first anoxic tank. With a recycle ratio of 2.26, the achieved nitrogen removal in the system was around 72%. Approximately 4% of the removed amount of nitrogen was credited to plant uptake during the active growth period. Phosphorus was removed by adsorption in the anoxic tank and sand filters, natural chemical precipitation in the algal step induced by the high pH, and assimilation in plants, bacteria and algae. The main removal occurred in the algal step. In total, 47% of the amount of phosphorus was removed. Significant recycling of nitrogen and phosphorus through harvested biomass has not been shown. The indicators analysed for pathogen removal showed an achieved effluent quality comparable to, or better than, for conventional secondary treatment. The microbial composition was comparable to other nitrifying biological systems. The most abundant phyla were Betaproteobacteria and Planctomycetes. In Sweden, a hydroponic system is restricted to greenhouse applications, and the necessary amount of additional energy is related to geographic location. In conclusion, hydroponic systems are not recommended too far north, unless products are identified that will justify the increased energy usage. The potential for hydroponic treatment systems in Sweden lies in small decentralized systems where the greenness of the system and the possible products are considered as advantages for the users. / QC 20101014

The Mackenzie Delta region of the Northwest Territories, Canada, has experienced rapid climate warming in the past century resulting in rapidly thawing permafrost in this region. This thesis examines spatial and temporal changes to sediment organic carbon and mercury flux in lakes from thermokarst regions by comparing sediment cores from lakes with and without retrogressive thaw slumps on their shorelines. We show that sediments from lakes with permafrost thaw slump development on their shorelines (slump lakes) had higher sedimentation rates as well as lower total Hg, methyl mercury (MeHg), and labile OC fractions when compared to lakes where thaw slumps were absent. Total Hg and MeHg concentrations in sediments were correlated with total organic carbon (TOC), S2 (labile algal-derived OC), and inferred chlorophyll a content, indicating an association between autochthonous organic carbon and Hg in these sediments. Correlations between mercury and S2 in these study lakes generally support the hypothesis that algal-derived materials correlate with Hg concentration in sediments. We observed higher S2 concentrations in reference lakes than in slump lakes, likely due to uninterrupted algal production, lower dilution by flux of inorganic matter, and possibly better anoxic preservation in reference lakes compared to slump lakes. It is evident that thaw slump development in this thermokarst region increases inorganic sedimentation in lakes, while decreasing concentrations of organic carbon and associated Hg and MeHg in sediments.

The Mackenzie Delta region of the Northwest Territories, Canada, has experienced rapid climate warming in the past century resulting in rapidly thawing permafrost in this region. This thesis examines spatial and temporal changes to sediment organic carbon and mercury flux in lakes from thermokarst regions by comparing sediment cores from lakes with and without retrogressive thaw slumps on their shorelines. We show that sediments from lakes with permafrost thaw slump development on their shorelines (slump lakes) had higher sedimentation rates as well as lower total Hg, methyl mercury (MeHg), and labile OC fractions when compared to lakes where thaw slumps were absent. Total Hg and MeHg concentrations in sediments were correlated with total organic carbon (TOC), S2 (labile algal-derived OC), and inferred chlorophyll a content, indicating an association between autochthonous organic carbon and Hg in these sediments. Correlations between mercury and S2 in these study lakes generally support the hypothesis that algal-derived materials correlate with Hg concentration in sediments. We observed higher S2 concentrations in reference lakes than in slump lakes, likely due to uninterrupted algal production, lower dilution by flux of inorganic matter, and possibly better anoxic preservation in reference lakes compared to slump lakes. It is evident that thaw slump development in this thermokarst region increases inorganic sedimentation in lakes, while decreasing concentrations of organic carbon and associated Hg and MeHg in sediments.