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During the last 40 years, there has been a growing awareness of the environmental issues associated with current energy technologies and natural resource utilization. An unsustainable use of fossil energy reserves has led to a deterioration of urban and rural environments, as well as a depletion of natural assets. A growing global population demands increasing amounts of energy and goods, requiring efficient resource utilization and the development and improvement of renewable energy technologies. Decision Support Systems have been developed as a basis for scientific decision-making in environmental impact assessments, while legal frameworks and policy initiatives, for example, carbon taxes and payment for ecosystem services programs, may function as support and drivers for climate change mitigation, environmental protection, and resource management.

Incineration of municipal solid waste (MSW) is a waste treatment method which can be sustainable in terms of waste volume reduction as well as a source of renewable energy. In the process fly and bottom ash is generated as a waste material. The ash residue may vary greatly in composition depending on the type of waste incinerated and it can contain elevated levels of harmful contaminants such as heavy metals. In this study, the ecotoxicity of a weathered, untreated incineration bottom ash was characterized as defined by the H14 criterion of the EU Waste Framework Directive by means of an elemental analysis, leaching tests followed by a chemical analysis and a combination of aquatic and solid-phase bioassays. The experiments were conducted to assess the mobility and bioavailability of ash contaminants. A combination of aquatic and terrestrial bioassays was used to determine potentially adverse acute effects of exposure to the solid ash and aqueous ash leachates. The results from the study showed that the bottom ash from a municipal waste incineration plant in mid-Sweden contained levels of metals such as Cu, Pb and Zn, which exceeded the Swedish EPA limit values for inert wastes. The chemical analysis of the ash leachates showed high concentrations of particularly Cr. The leachate concentration of Cr exceeded the limit value for L/S 10 leaching for inert wastes. Filtration of leachates prior to analysis may have underestimated the leachability of complex-forming metals such as Cu and Pb. The germination test of solid ash and ash leachates using T. repens showed a higher inhibition of seedling emergence of seeds exposed to the solid ash than the seeds exposed to ash leachates. This indicated a relatively low mobility of toxicants from the solid ash into the leachates, although some metals exceeded the L/S 10 leaching limit values for inert wastes. The Microtox (R) toxicity test showed only a very low toxic response to the ash leachate exposure, while the D. magna immobility test showed a moderately high toxic effect of the ash leachates. Overall, the results from this study showed an ecotoxic effect of the solid MSW bottom ash and the corresponding ash leachates. The material may therefore pose an environmental risk if used in construction applications. However, as the testing of the solid ash was rather limited and the ash leachate showed an unusually high leaching of Cr, further assessments are required in order to conclusively characterize the bottom ash studied herein as hazardous according to the H14 criterion.

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.

During the last 40 years, there has been a growing awareness of the environmental issues associated with current energy technologies and natural resource utilization. An unsustainable use of fossil energy reserves has led to a deterioration of urban and rural environments, as well as a depletion of natural assets. A growing global population demands increasing amounts of energy and goods, requiring efficient resource utilization and the development and improvement of renewable energy technologies. Decision Support Systems have been developed as a basis for scientific decision-making in environmental impact assessments, while legal frameworks and policy initiatives, for example, carbon taxes and payment for ecosystem services programs, may function as support and drivers for climate change mitigation, environmental protection, and resource management.

Four bioassays were used in this study for the hazard assessment of sediments from sediment traps and several ponds in a treatment wetland for landfill leachate at Atleverket, Sweden. In the 6-day solid phase microbiotest with the sediment-dwelling crustacean Heterocypris incongruens both acute and chronic effects were observed with a gradual decrease and loss of toxicity with treatment in the wetland system. Some samples showed a low toxicity in porewater and only one sample was weakly toxic in the whole sediment test when assessed with Aliivibrio fischeri (Vibro fischeri). No genotoxicity was detected in the umu test. The toxicity response in the H4IIE- luc test evaluating the presence of dioxin-like compounds was considerably higher in the samples from the sediment traps. The hazard of the sediment therefore appears to be highest in the sediment traps and pond 1 with the methods employed. The result indicates that the wetland system has a design supporting the concentration and sequestration of toxic substances in the first part of the wetland. Based upon the results we suggest that hazard assessment of sediments from other treatment wetlands for landfill leachate should be conducted.

With a greater focus on soil protection in the EU, the need for ecological risk assessment tools for cost-effective characterization of site contamination is increasing. One of the challenges in assessing the risk of soil contaminants is to accurately account for changes in mobility of contaminants over time, as a result of ageing. Improved tools for measuring the bioavailable and mobile fraction of contaminants is therefore highly desirable. In this study the Triad method was used to perform a risk characterization of a former surface treatment and metal industry in Eskilstuna, Sweden. The risk assessment confirmed the environmental risk of the most heavily contaminated sample and showed that the toxic effect was most likely caused by high metal concentrations. The assessment of the two soil samples with low to moderate metal contamination levels was more complex, as there was a higher deviation between the results from the three lines of evidence; chemistry, (eco)toxicology and ecology. For the slightly less contaminated sample of the two, a weighting of the results from the ecotoxicological LoE would be recommended in order to accurately determine the risk of the metal contamination at the sampling site as the toxic effect detected in the Microtox^® test and Ostracodtoxkit™ test was more likely to be due to oil contamination. The soil sample with higher total metal concentrations requires further ecotoxicological testing, as the integrated risk value indicated an environmental risk from metal contamination. The applied methodology, the Triad method, is considered appropriate for conducting improved environmental risk assessments in order to achieve sustainable remediation processes.

The access to clean water is one of the prerequisites for a modern, industrialized society. The amount of water withdrawn for human activities has risen exponentially during the last 100 years. This rise in water use is accompanied by the production of vast quantities of contaminated water. These wastewaters may be contaminated by substances ranging from heavy metals and organic compounds to nutrients like nitrogen and phosphorous. The aggregate effect of combinations of water contaminants can be difficult to predict as different contaminant substances may interact, leading to additive, synergistic or antagonistic toxic effects in a receiving aquatic ecosystem. With increasing water quality legislation, the pressure to characterize and potentially treat contaminated waters increases. Suitable effect-based assessment methods may greatly reduce the costs of both the wastewater characterization process and the water treatment evaluation. The overall aim of this thesis was to show how a combination of ecotoxicity bioassays may be employed in water treatment method development for initial characterization, assessment of treatment requirements and finally treatment evaluation. The wastewaters characterized originated from different activities such as waste management, metal surfacing and explosives destruction. To fully assess the hazard of the waters sampled, a holistic approach using a combination of chemical tests and bioassays was taken. A combination of acute and chronic assays was used to determine mode-of-action effects and apical endpoints in the aquatic environment. The basic battery consisted of the acute Vibrio fischeri test, the chronic algae test using Pseudokirchneriella subcapitata and either the planktonic crustacean Daphnia magna (for aqueous samples) or the meiobenthic crustacean Heterocypris incongruens (for whole-sediment/soil samples).  In addition to the basic test battery, the mode-of-action Salmonella typhimurium test was used to assess genotoxic effects. Results from the water hazard characterization show that ecotoxicological tests contribute to the evaluation of treatment methods for complex wastewaters by assessing the aggregate biological effect of water treatment. The tests may be used as a screening method to indicate where further treatment may be required, even when chemical measurements show a satisfactory reduction of known contaminants. The toxic effect exerted by the assessed waters did not always correlate with measured levels of contaminants or the chemical measures of bioavailability, e.g. leached fraction. The water treatment evaluation showed that the industrial by-product pine bark is an effective adsorbent for capturing metal contaminants from landfill leachates and stormwater. The pine bark column filter had higher zinc removal efficiency than the polonite filter and the combination filter column with pine bark/polonite. In conclusion, a pine bark filter is a suitable alternative to activated carbon for small-scale, decentralized treatment of wastewaters. Furthermore, the ecotoxicity tests were able to detect effects of unknown contaminants and provided unique characterization data, which complemented the information provided by the chemical analyses.

When selecting a landfill leachate treatment method the contaminant composition of theleachate should be considered in order to obtain the most cost-effective treatment option. In this studythe filter material pine bark was evaluated as a treatment for five landfill leachates originating fromdifferent cells of the same landfill in Sweden. The objective of the study was to determine the uptake,or release, of metals and dissolved organic carbon (DOC) during a leaching test using the pine barkfilter material with the five different landfill leachates. Furthermore the change of toxicity aftertreatment was studied using a battery of aquatic bioassays assessing luminescent bacteria (Vibriofischeri) acute toxicity (30-min Microtox®), immobility of the crustacean Daphnia magna, growthinhibition of the algae Pseudokirchneriella subcapitata and the aquatic plant Lemna minor; andgenotoxicity with the bacterial Umu-C assay. The results from the toxicity tests and the chemicalanalysis were analyzed in a Principal Component Analysis and the toxicity of the samples before andafter treatment was evaluated in a toxicity classification. The pine bark filter material reduced theconcentrations of metal contaminants from the landfill leachates in the study, with some exceptions forCu and Cd. The Zn uptake of the filter was high for heavily contaminated leachates (≥73%), althoughsome desorption of zinc occurred in less contaminated waters. Some of the leachates may requirefurther treatment due to discharge into a natural recipient in order to reduce the risk of possiblebiological effects. The difference in pH changes between the different leachates was probably due tovariations in buffering capacity, affected by physicochemical properties of the leachate. The greatestdesorption of phenol during filtration occurred in leachates with high conductivity or elevated levels ofmetals or salts. Generally, the toxicity classification of the leachates implies that although filtertreatment with pine bark removes metal contaminants from the leachates effectively, it does not alterleachate toxicity noticeably. The leachates with the highest conductivity, pH and metal concentrationsare most strongly correlated with an increased toxic response in the score plots of both untreated andtreated leachates. This is in line with the toxicity classification of the leachate samples. The results fromthis study highlight the importance of evaluating treatment efficiency from the perspective of potentialrecipient effects, rather than in terms of residual concentrations of individual contaminants whentreating waters with a complex contamination matrix, such as landfill leachates.

Two commercially available aerobic bioremediation methods (DaramendA (R) and BioSan) were utilized to study the aerobic biodegradation of polycyclic aromatic hydrocarbons (PAH) and the effect of the simultaneously present arsenic. The soil was collected at an old wood preservation site, and the initial PAH(16)-concentration was 46 mg/kg, with mainly high molecular weight congeners. The As concentration was 105 mg/kg with low availability as assessed with sequential extraction. To enhance the availability of PAH, the effect of a nonionic surfactant was evaluated. Degradation of both low and high molecular weight PAH was observed; however, after 30 weeks, the degradation was generally low and no treatment was significantly better than the others. The treatments had, on the other hand, an effect on As remobilization, with increased As concentration in the available fraction after treatment. This may be due to both the microbial activity and the presence of anoxic microsites in the soil. The overall efficiency of the biological treatment was further evaluated using the standardized ecotoxicity test utilizing Vibrio fischeri (MicrotoxA (R)). The toxicity test demonstrated that the bioremediation led to an increase in toxicity, especially in treatments receiving surfactant. The surfactant implied an increase in contaminant availability but also a decrease in surface tension, which might have contributed to the overall toxicity increase.