A disposição final dos resíduos, de forma a minimizar a contaminação das águas, é feita, em geral, em aterros sanitários os quais devem apresentar na base camadas de argila compactada (CCL) que também são conhecidas como liners. Esses sistemas de barreiras desempenham funções diversas, dentre as quais se destacam o isolamento do resíduo e a diminuição da infiltração e a minimização da migração de contaminantes (filtragem, sorção e outras reações geoquímicas) em direção à água subterrânea. O objetivo deste trabalho foi avaliar os materiais argilosos relacionados à Formação Corumbataí com o intuito de selecionar os materiais que reúnem as melhores características para serem usados em liners compactados. Os aspectos avaliados foram a retenção de contaminantes por meio dos ensaios de equilíbrio em lote (batch test) e percolação em coluna com solução de CuCl2.2H2O, e avaliação da resistência à compressão simples do solo compactado, para suportar as cargas exercidas em um aterro sanitário. Para os cálculos dos parâmetros de adsorção utilizando o batch test, procedeu-se à construção e linearização das isotermas e, a partir do coeficiente de determinação, foi possível observar que os melhores ajustes foram com os modelos linear e de Freundlich. A isoterma de melhor ajuste para o cátion foi à de Freundlich em todas as amostras, destacando principalmente AM-2 e AM-16 com R² de 0,9983 e 0,9978 respectivamente. Na percolação em coluna os valores do fator de retardamento (Rd) para o Cl- e Cu++ foram determinados utilizando os métodos de Freeze e Cherry (1979) e Shackelford (1994) nas curvas de chegada. Na resistência à compressão simples a amostra mais significativa foi a AM-3 que resistiu uma força média de 992,1 N, chegando a uma tensão média de 477,4 kPa. Após uma análise integrada as amostras com maior desempenho foram AM-2 e AM-3, sendo que a AM-2 não foi apta apenas em um cenário elaborado para analisar a resistência à compressão simples. / The final waste disposal is usually the landfills. In order to minimize water contamination because of the waste, the landfills ought to have layers of clay compacted (CCL). Those layers are also known as liners. The barriers system has many functions, for instance, the isolation of the waste, the reduction of infiltration and also the reduction of contaminants migrations (filtering, sorption and other geochemical reactions) toward groundwater. This paper aims to evaluate the clay materials presents in Corumbataí Formation. The main objective was to select materials that have the best characteristics to be used in compacted liner. The aspects that were analyzed includes: the retentions of contaminants using batch test, and also column percolation with CuCl2.2H2O solution. It was also evaluated the resistance of the compacted soil to stand the loads exerted in a landfill. To calculate the adsorption parameters by using the batch test, the constructions and also the linearization of the isotherms were made, through coefficient of determination as its base. Because of those tests it was possible to identify that the best settings are the linear model and also the Freundlich model. The isotherm that presented the best adjustment for the cation was Freundlich isotherm. It was the best adjustment in all samples, mainly in AM-2 and also in AM-16 with R² of 0,9983 and 0,9978 respectively. In percolation column the values of retardation factor (Rd) for Cl- and also for Cu++, were determined by using Freeze and Cherry (1979) and also Shackelford\'s methods (1994) on breakthrough curves. In the \"compressive strength\", the most significant sample was AM-3 that resisted an average force of 992.1 N, reaching an average stress of 477.4 kPa. After an integrated analysis, the best samples were AM-2 and AM-3. However, the AM-2 was not able to work in a scenario that was created to analyze an unconfined compressive strength.

A disposição final dos resíduos, de forma a minimizar a contaminação das águas, é feita, em geral, em aterros sanitários os quais devem apresentar na base camadas de argila compactada (CCL) que também são conhecidas como liners. Esses sistemas de barreiras desempenham funções diversas, dentre as quais se destacam o isolamento do resíduo e a diminuição da infiltração e a minimização da migração de contaminantes (filtragem, sorção e outras reações geoquímicas) em direção à água subterrânea. O objetivo deste trabalho foi avaliar os materiais argilosos relacionados à Formação Corumbataí com o intuito de selecionar os materiais que reúnem as melhores características para serem usados em liners compactados. Os aspectos avaliados foram a retenção de contaminantes por meio dos ensaios de equilíbrio em lote (batch test) e percolação em coluna com solução de CuCl2.2H2O, e avaliação da resistência à compressão simples do solo compactado, para suportar as cargas exercidas em um aterro sanitário. Para os cálculos dos parâmetros de adsorção utilizando o batch test, procedeu-se à construção e linearização das isotermas e, a partir do coeficiente de determinação, foi possível observar que os melhores ajustes foram com os modelos linear e de Freundlich. A isoterma de melhor ajuste para o cátion foi à de Freundlich em todas as amostras, destacando principalmente AM-2 e AM-16 com R² de 0,9983 e 0,9978 respectivamente. Na percolação em coluna os valores do fator de retardamento (Rd) para o Cl- e Cu++ foram determinados utilizando os métodos de Freeze e Cherry (1979) e Shackelford (1994) nas curvas de chegada. Na resistência à compressão simples a amostra mais significativa foi a AM-3 que resistiu uma força média de 992,1 N, chegando a uma tensão média de 477,4 kPa. Após uma análise integrada as amostras com maior desempenho foram AM-2 e AM-3, sendo que a AM-2 não foi apta apenas em um cenário elaborado para analisar a resistência à compressão simples. / The final waste disposal is usually the landfills. In order to minimize water contamination because of the waste, the landfills ought to have layers of clay compacted (CCL). Those layers are also known as liners. The barriers system has many functions, for instance, the isolation of the waste, the reduction of infiltration and also the reduction of contaminants migrations (filtering, sorption and other geochemical reactions) toward groundwater. This paper aims to evaluate the clay materials presents in Corumbataí Formation. The main objective was to select materials that have the best characteristics to be used in compacted liner. The aspects that were analyzed includes: the retentions of contaminants using batch test, and also column percolation with CuCl2.2H2O solution. It was also evaluated the resistance of the compacted soil to stand the loads exerted in a landfill. To calculate the adsorption parameters by using the batch test, the constructions and also the linearization of the isotherms were made, through coefficient of determination as its base. Because of those tests it was possible to identify that the best settings are the linear model and also the Freundlich model. The isotherm that presented the best adjustment for the cation was Freundlich isotherm. It was the best adjustment in all samples, mainly in AM-2 and also in AM-16 with R² of 0,9983 and 0,9978 respectively. In percolation column the values of retardation factor (Rd) for Cl- and also for Cu++, were determined by using Freeze and Cherry (1979) and also Shackelford\'s methods (1994) on breakthrough curves. In the \"compressive strength\", the most significant sample was AM-3 that resisted an average force of 992.1 N, reaching an average stress of 477.4 kPa. After an integrated analysis, the best samples were AM-2 and AM-3. However, the AM-2 was not able to work in a scenario that was created to analyze an unconfined compressive strength.

The aim of this study was to extend knowledge about the influence of permanent grassland fertilization on the yield and the quality of biogas. During the years 2013 and 2014 three levels of fertilization (non fertilized control, N50PK, N200PK) were tested. Samples were taken from the experiment site Černíkovice, Benešov region. For anaerobic digestion, a 40 day mesophilic conditions batch test was chosen. A statistically significant decrease of substrate biogas yield (SBY) and area biogas yield (ABY) with higher doses of fertilizers occurred between non fertilized control (575.4 ml/g; 3332.4 m3/ha) and N200PK variant (460.5 ml/g; 2605.7 m3/ha) in 2013. The only statistically significant differences in the quality of biogas were found during the first day of anaerobic digestion, when the highest doses of fertilizers caused higher concentration of methane (33.2 %) compared to control variant (22.6 %). Application of fertilizers had no significant effect on SBY in 2014. Still, the highest SBY was obtained from the non fertilized control (762.7 ml/g) compared to N50PK (707.6 ml/g) and N200PK variant (732.8 ml/g). Furthermore, significant most of the ABY was obtained from the N50PK (2911.5 m3/ha) compared to the non fertilized control (2296.3 m3/ha). The only significant differences in biogas quality were found during the initial 7 days of the test. Most of the methane was contained in biogas from the non fertilized control (59.1 %), and least amount of the methane was found in the N50PK variant (57.9 %). ABY is highly influenced by the yields of phytomass, which were negatively affected by the late first cut caused by unfavorable site conditions in 2013. Cumulative biogas production showed that the most important part of anaerobic digestion was during the initial 14 days, which produced upwards of 80 % of total biogas yields in both years.

<p>Most of the city of Uppsala rests on postglacial clay with a varying content of sulphur. The sulphur occurs naturally in the clay in reduced form as sulphide and the clay is for that reason usually called “sulphide clay”. Excavation during construction activities gives rise to large amounts of excavation material, of which the sulphide clay is a considerable part.</p><p>When the clay is exposed to air and water, an oxidation of the sulphides occurs which may produce an acid leachate and the mobilisation of heavy metals bound in the clay or underlying material. The aim of the work has been to improve our understanding of the behaviour of sulphide clays and produce a basis for risk assessment in the future handling of excavation material with high sulphide content. After sampling had been carried out in two places, batch tests were performed to examine the long-term acidification potential of clays with different calcium carbonate content. The tests were performed with continuous air supply and during the experiment leachate water was analysed with respect to pH, alkalinity, dissolved sulphate and mobilised metals. The results from the laboratory study showed that a clay with a high calcium carbonate content and thus a high net neutralisation potential (NNP) will consume the generated acid and prevent against a lowering of the pH.</p><p>In clay lacking calcium carbonate, the pH dropped significantly and caused a mobilisation of chiefly Cd, Mn, Co, Ni, Ca and As. Regardless of the changes in pH over time, a large production of sulphur was observed as a result of the sulphide oxidation. In a risk assessment, it is suggested that the NNP should be determined by methods agreed upon to facilitate future comparisons and because different methods may give different results. A clay with a NNP<5 kg CaCO3/ton should be further analysed with respect to metal content to establish the leachate generation potential and estimate the future environmental influence of the excavation material.</p> / <p>Uppsala stad vilar till stor del på postglacial lera med varierande svavelhalt. Svavlet finns naturligt i leran i reducerad form som sulfid och leran kallas därför vanligtvis för ”sulfidlera”. Vid schaktningsarbete i samband med byggnation uppkommer stora mängder schaktmassor varav en betydande del är sulfidlera.</p><p>Då leran exponeras för luft och nederbörd sker en oxidation av sulfiderna som kan ge upphov till surt lakvatten och läckage av tungmetaller bundna i leran eller underliggande material. Syftet med arbetet har varit att öka kunskaperna om hur sulfidleror beter sig och ta fram ett underlag för riskbedömning i samband med den framtida hanteringen av sulfidhaltiga schaktmassor i Uppsala. Efter genomförd provtagning på två platser utfördes skaktest för att undersöka den långsiktiga försurningspotentialen hos lera med varierande kalkinnehåll. Testerna utfördes med kontinuerlig tillförsel av luft och löpande under försökets gång togs lakvatten ut för analys avseende pH, alkalinitet, löst sulfat och utlakade metaller.</p><p>Resultaten från den laborativa studien visade att en kalkhaltig lera med hög nettoneutralisationspotential (NNP) kan förbruka den bildade syran och därigenom genereras ingen pH-sänkning. I lera som saknar kalk sjönk pH kraftigt och föranledde läckage av framförallt Cd, Mn, Co, Ni, Ca och As.</p><p>Oavsett utvecklingen av pH observerades en stor utlakning av svavel till följd av oxidationen av sulfider. I en riskbedömning föreslås att lerans NNP bestäms enligt överenskomna metoder för att underlätta framtida jämförelser och för att olika tekniker kan ge olika resultat. En lera med NNP-värde < 5 kg CaCO3/ton bör analyseras vidare avseende metallinnehåll för att fastställa den potentiella utlakningen och bedöma schaktmassans framtida naturpåverkan.</p>

Most of the city of Uppsala rests on postglacial clay with a varying content of sulphur. The sulphur occurs naturally in the clay in reduced form as sulphide and the clay is for that reason usually called “sulphide clay”. Excavation during construction activities gives rise to large amounts of excavation material, of which the sulphide clay is a considerable part. When the clay is exposed to air and water, an oxidation of the sulphides occurs which may produce an acid leachate and the mobilisation of heavy metals bound in the clay or underlying material. The aim of the work has been to improve our understanding of the behaviour of sulphide clays and produce a basis for risk assessment in the future handling of excavation material with high sulphide content. After sampling had been carried out in two places, batch tests were performed to examine the long-term acidification potential of clays with different calcium carbonate content. The tests were performed with continuous air supply and during the experiment leachate water was analysed with respect to pH, alkalinity, dissolved sulphate and mobilised metals. The results from the laboratory study showed that a clay with a high calcium carbonate content and thus a high net neutralisation potential (NNP) will consume the generated acid and prevent against a lowering of the pH. In clay lacking calcium carbonate, the pH dropped significantly and caused a mobilisation of chiefly Cd, Mn, Co, Ni, Ca and As. Regardless of the changes in pH over time, a large production of sulphur was observed as a result of the sulphide oxidation. In a risk assessment, it is suggested that the NNP should be determined by methods agreed upon to facilitate future comparisons and because different methods may give different results. A clay with a NNP&lt;5 kg CaCO3/ton should be further analysed with respect to metal content to establish the leachate generation potential and estimate the future environmental influence of the excavation material. / Uppsala stad vilar till stor del på postglacial lera med varierande svavelhalt. Svavlet finns naturligt i leran i reducerad form som sulfid och leran kallas därför vanligtvis för ”sulfidlera”. Vid schaktningsarbete i samband med byggnation uppkommer stora mängder schaktmassor varav en betydande del är sulfidlera. Då leran exponeras för luft och nederbörd sker en oxidation av sulfiderna som kan ge upphov till surt lakvatten och läckage av tungmetaller bundna i leran eller underliggande material. Syftet med arbetet har varit att öka kunskaperna om hur sulfidleror beter sig och ta fram ett underlag för riskbedömning i samband med den framtida hanteringen av sulfidhaltiga schaktmassor i Uppsala. Efter genomförd provtagning på två platser utfördes skaktest för att undersöka den långsiktiga försurningspotentialen hos lera med varierande kalkinnehåll. Testerna utfördes med kontinuerlig tillförsel av luft och löpande under försökets gång togs lakvatten ut för analys avseende pH, alkalinitet, löst sulfat och utlakade metaller. Resultaten från den laborativa studien visade att en kalkhaltig lera med hög nettoneutralisationspotential (NNP) kan förbruka den bildade syran och därigenom genereras ingen pH-sänkning. I lera som saknar kalk sjönk pH kraftigt och föranledde läckage av framförallt Cd, Mn, Co, Ni, Ca och As. Oavsett utvecklingen av pH observerades en stor utlakning av svavel till följd av oxidationen av sulfider. I en riskbedömning föreslås att lerans NNP bestäms enligt överenskomna metoder för att underlätta framtida jämförelser och för att olika tekniker kan ge olika resultat. En lera med NNP-värde &lt; 5 kg CaCO3/ton bör analyseras vidare avseende metallinnehåll för att fastställa den potentiella utlakningen och bedöma schaktmassans framtida naturpåverkan.

Settling properties of activated sludge or mixed liquor suspended solids (MLSS) have been studied for more than 75 years at wastewater treatment plants. Temperature, together with MLSS concentration, has been acknowledged as important contributors to MLSS settling variations. Batch MLSS settling tests are performed on a regular basis at most of the plants. The majority of these MLSS settling test reports reflect the complete absence of any form of temperature compensation or even MLSS sample temperature (Ts) recordings. The objective of this study is to evaluate the effects of short-term temperature variations on MLSS settling parameters. This is done by means of simplified theoretical calculations, followed by operational reactor temperature (Tr) observations, and batch MLSS settling tests. The experimental work concludes with the implementation of an on-line MLSS settling test procedure at a full-scale plant reactor to develop settling models based on diurnal Tr fluctuations. These settling models illustrate that parameter correlations improve when Tr is included in on-line MLSS concentration-based settling models. The unhindered settling velocity of a single solid biofloc in water is considered in a simplified calculation to estimate the effect of temperature variations on MLSS settling. Over a Ts increase of 20°C, water density and viscosity reductions result in a calculated biofloc settling velocity increase of less than 0.5 m/hr. Similarly, biofloc density, shape, and size changes result in calculated biofloc settling velocity increases of about 11, 10, and 2 m/hr respectively over the 20°C Ts range. Plant temperature recordings show significant short- to long-term variations. Ambient temperature (Ta) and Tr fluctuate about 20°C and 1.8°C respectively per day, and Tr changes by about 4°C within a week, as measured on-line at local plants during the test period in winter. The aeration method can have a significant impact on Tr. Differences in Tr in adjacent surface and bubble aeration reactors in the same plant were about 5°C. Large enough Tr and Ta variations exist at these local plants to affect MLSS settling test results. The MLSS settling test cylinder environment and meteorological conditions have a direct influence on Ts during batch settling tests. Direct solar radiation increases the average Ts by 4.3°C, or by 0.15°C per minute, during a 30-minute MLSS settling test duration. This Ts change leads to a sludge volume index (SVI) change of 63 mℓ/g, at an average SVI decrease of 14.8 mℓ/g per 1°C Ts increase. Changes to other parameters include an initial settling velocity (ISV) increase of about 0.12 m/hr for every 1°C Ts increase, together with a clarified supernatant turbidity increase of about 1.4 formazine nephelometric unit (FNU) for every 1°C Ts increase. Ts adjusts towards Ta before and during a batch MLSS settling test, thereby influencing MLSS settling results. Compensation for Ts variations during routine MLSS settling tests is nevertheless not reported as a common practice. To some extent, this is due to a lack of temperature-controlled MLSS settling test equipment. An automated MLSS settling meter demonstrates a semi-continuous on-line method to determine settling parameters in situ at the operational Tr of a full-scale plant. A basic polynomial fits 11 MLSS settling parameters that indicate in most instances improved MLSS settling at increased Tr. The average SVI decreases by 14.8 mℓ/g for every 1°C Tr increase. Similarly, for every 1°C Tr increase, the maximum settling velocity (u_max) increase is 0.1 m/hr, and the time to reach maximum settling velocity (t_umax) decreases by 2.4 minutes. The incremental 5-minute duration average settling velocities increase over the first 15 minutes of a MLSS settling test, as the MLSS concentration decreases and the Tr increases. This direct incremental settling velocity trend with Tr is reversed between 15 and 30 minutes, as the average 5-minute MLSS settling velocity increases at a reduced Tr. The inclusion of Tr in MLSS concentration-based settling best-fit correlations with SVI, u_max, and t_umax improves the coefficient of multiple determinations (R2) by an average of 0.32. Best-fit SVI models with u_max and t_umax have R2-values of 0.90 and 0.95 respectively. The developed models are only valid for the individual reactor MLSS conditions within the experimental parameter ranges. The main contribution of this study is to present temperature-based MLSS settling models. These models illustrate that an automated on-line MLSS settling meter is suitable to identify and model temperature related MLSS settling data with minimal experimental effort. A suitable approach is provided to improve the reliability of MLSS settling data, as effects of short-term temperature variations can be practically eliminated from settling test. / Thesis (PhD)--University of Pretoria, 2008. / Chemical Engineering / unrestricted

Univerzita Karlova v Praze Lucie Ramešová Přírodovědecká fakulta Květen 2014 Ústav pro životní prostředí a VÚV T.G.M. v.v.i. OPTIMIZATION OF CONDITIONS FOR DETERMINATION OF BOTTOM SEDIMENT SORPTION CHARACTERISTICS ABSTRACT An option of this study was to optimize conditions of distribution coefficients determination in the water-sediment system. The study results will be applied in the task A research on influence of Temelín Nuclear Power Plant accident on the Vltava and Labe water environment contamination to the border profile Labe - Hřensko. After finding optimal conditions for sorption experiments, these will be applied on the experiments using real sediment samples and corresponding surface water extracted from different localities of Vltava River, Labe River respectively. A goal of the whole project is to contribute to creation of a crisis scenario of potential accident of Temelin Nuclear Power Plant and its impact on Vltava and Labe water environments. Above all, the aim is to answer the question which processes would take place in dams and basins during the contamination by fission and activation products, whether and which products would be preferably adsorbed and would consequently settle down and which would supposedly be transported to the lower parts of the watershed. The practical part of the...

<p>Mine waste from Ljusnarsbergsfältet in Kopparberg, Sweden, is considered to constitute a great risk for human health and the surrounding environment. Some of the waste rock consists of sulphide minerals. When sulphide minerals come into contact with dissolved oxygen and precipitation, oxidation may occur resulting in acid mine drainage (AMD) and the release of heavy metals. The purpose of this study has been to characterise the waste material and try to chemically stabilize the waste rock with a mixture of sewage sludge and calcium carbonate. The drawback of using organic matter is the risk that dissolved organic matter can act as a complexing agent for heavy metals and in this way increase their mobility. An additional study to examine this risk has therefore also been performed.</p><p>The project started with a pilot study in order to identify the material fraction that was suitable for the experiment. When suitable material had been chosen, a column test was carried out for the purpose of studying the slurry’s influence on the mobility of metals along with the production of acidity. To clarify the organic material’s potential for complexation a pH-stat batch test was used. Drainage water samples, from the columns, were regularly taken during the experiment. These samples were analysed for pH, electrical conductivity, alkalinity, redox potential, dissolved organic carbon (DOC), sulphate and leaching metals. The effluent from the pH-stat-test were only analysed on a few occasions and only for metal content and change in DOC concentration.</p><p>The results from the laboratory experiments showed that the waste rock from Ljusnarsberg easily leached large amounts of metals. The stabilization of the waste rock succeeded in maintaining a near neutral pH in the rock waste leachate, compared to a pH 3 leachate from untreated rock waste The average concentration of copper and zinc in the leachate from untreated waste rock exceeded 100 and 1000 mg/l respectively, while these metals were detected at concentrations around 0.1 and 1 mg/l, respectively, in the leachate from the treated wastes. Examined metals had concentrations between 40 to 4000 times lower in the leachate from treated waste rock, which implies that the stabilisation with reactive amendments succeeded. The long term effects are, however, not determined. The added sludge contributed to immobilise metals at neutral pH despite a small increase in DOC concentration. The problem with adding sludge is that if pH decreases with time there is a risk of increased metal leaching.</p> / <p>Gruvavfallet från Ljusnarsbergsfältet i Kopparberg anses utgöra en stor risk för människors hälsa och den omgivande miljön. En del av varpmaterialet, ofyndigt berg som blir över vid malmbrytning, utgörs av sulfidhaltigt mineral. Då varpen exponeras för luft och nederbörd sker en oxidation av sulfiderna, vilket kan ge upphov till surt lakvatten och läckage av tungmetaller. Syftet med arbetet har varit att karaktärisera varpen och försöka stabilisera den med en blandning bestående av mesakalk och avloppsslam, samt att undersöka risken med det lösta organiska materialets förmåga att komplexbinda metaller och på så vis öka deras rörlighet.</p><p>Efter insamling av varpmaterial utfördes först en förstudie för att avgöra vilken fraktion av varpen som var lämplig för försöket. När lämpligt material valts ut utfördes kolonntest för att studera slam/kalk-blandningens inverkan på lakning av metaller, samt pH-statiskt skaktest för att bedöma komplexbildningspotentialen hos det organiska materialet vid olika pH värden. Från kolonnerna togs lakvattenprover kontinuerligt ut under försökets gång för analys med avseende på pH, konduktivitet, alkalinitet, redoxpotential, löst organiskt kol (DOC), sulfat och utlakade metaller. Lakvattnet från pH-stat-testet provtogs vid ett fåtal tillfällen och analyserades endast med avseende på metallhalter och förändring i DOC-halt.</p><p>Resultatet från den laborativa studien visade att varpmaterialet från Ljusnarsberg lätt lakades på stora mängder metaller. Den reaktiva tillsatsen lyckades uppbringa ett neutralt pH i lakvattnet från avfallet, vilket kan jämföras med lakvattnet från den obehandlade kolonnen som låg på ett pH kring 3. Medelhalten av koppar och zink översteg under försöksperioden 100 respektive 1000 mg/l i lakvattnet från det obehandlade avfallet, medan halterna i det behandlade materialets lakvatten låg kring 0,1 respektive 1 mg/l. Av de studerade metallerna låg halterna 40-4000 gånger lägre i lakvattnet från den behandlade kolonnen, vilket innebär att slam/kalk-blandningen har haft verkan. Stabiliseringens långtidseffekt är dock okänd. Det tillsatta slammet resulterade inte i någon större ökning av DOC-halten i det pH-intervall som åstadkoms med mesakalken. Utifrån pH-stat-försöket kunde det konstateras att det tillsatta slammet bidrog till metallernas immobilisering vid neutralt pH, trots en liten ökning av DOC-halten. Om en sänkning av pH skulle ske med tidens gång föreligger dock risk för ökat metalläckage.</p>

Kate Valley is a municipal waste landfill situated in Waipara, Northern Canterbury. It is a joint venture between the 6 local regional councils and Transwaste Canterbury Ltd to help dispose of waste quantities generated in the wider Canterbury region. Landfill waste disposal also generates waste streams. Major waste streams can include methane gas production and liquid leachate. One practice which can turn liquid leachate waste streams into a nutrient source for plants is land irrigation. It is important to have a thorough understanding of the interactions involved with leachate, soil structure, soil microbiology, flora. This thesis investigates the sorption mechanisms between Kate Valley soil and leachates, through batch and column experiments. Sorption mechanisms between leachate and soil were investigated through batch and column tests. Ex-situ soil samples were extracted from Kate Valley, along with raw leachate samples for batch tests at a soil to liquid ratio of 30 g vs. 70 ml respectively. Tested dilution leachate strengths ranged from raw to 50x raw leachate dilution; meanwhile soil samples were categorized into 3 groups based on soil depth: 0-20 cm, 20-40 cm, and 40-60 cm. Column tests were conducted on 3 extracted in-situ soil column monoliths. Column test irrigation conditions included: control case, 2x and 10x raw leachate dilution, and 200 mg/L KBr (bromide column), where the same soil column was used for bromine testing after control testing had ceased. Batch results suggest deeper soils are less effective at sorption of ammonia, where partitioning coefficient ranged from 9.5x*10-7 to 6.4*10-7 L/mg for 0-20 cm soil to 40-60 cm soil respectively. Column results generally showed lower partitioning capacity than batch results, at 4*10-8 and 5*10-8 L/mg for 10x and 2x dilution leachate irrigation respectively. Discrepancies in experimental data have been attributed to: different dilution leachates tested between batch and column tests, making it difficult for direct comparison; extreme soil to liquid ratios employed in experiments; direct data comparison between the “full-contact” experimental data (between leachate and soil), obtained from batch tests with column results, where not all soil may have been fully exposed for shrinkage of boundary layers of soil particles; and oxygen exposure of samples during testing and sampling, possibly encouraging nitrification.

Mine waste from Ljusnarsbergsfältet in Kopparberg, Sweden, is considered to constitute a great risk for human health and the surrounding environment. Some of the waste rock consists of sulphide minerals. When sulphide minerals come into contact with dissolved oxygen and precipitation, oxidation may occur resulting in acid mine drainage (AMD) and the release of heavy metals. The purpose of this study has been to characterise the waste material and try to chemically stabilize the waste rock with a mixture of sewage sludge and calcium carbonate. The drawback of using organic matter is the risk that dissolved organic matter can act as a complexing agent for heavy metals and in this way increase their mobility. An additional study to examine this risk has therefore also been performed. The project started with a pilot study in order to identify the material fraction that was suitable for the experiment. When suitable material had been chosen, a column test was carried out for the purpose of studying the slurry’s influence on the mobility of metals along with the production of acidity. To clarify the organic material’s potential for complexation a pH-stat batch test was used. Drainage water samples, from the columns, were regularly taken during the experiment. These samples were analysed for pH, electrical conductivity, alkalinity, redox potential, dissolved organic carbon (DOC), sulphate and leaching metals. The effluent from the pH-stat-test were only analysed on a few occasions and only for metal content and change in DOC concentration. The results from the laboratory experiments showed that the waste rock from Ljusnarsberg easily leached large amounts of metals. The stabilization of the waste rock succeeded in maintaining a near neutral pH in the rock waste leachate, compared to a pH 3 leachate from untreated rock waste The average concentration of copper and zinc in the leachate from untreated waste rock exceeded 100 and 1000 mg/l respectively, while these metals were detected at concentrations around 0.1 and 1 mg/l, respectively, in the leachate from the treated wastes. Examined metals had concentrations between 40 to 4000 times lower in the leachate from treated waste rock, which implies that the stabilisation with reactive amendments succeeded. The long term effects are, however, not determined. The added sludge contributed to immobilise metals at neutral pH despite a small increase in DOC concentration. The problem with adding sludge is that if pH decreases with time there is a risk of increased metal leaching. / Gruvavfallet från Ljusnarsbergsfältet i Kopparberg anses utgöra en stor risk för människors hälsa och den omgivande miljön. En del av varpmaterialet, ofyndigt berg som blir över vid malmbrytning, utgörs av sulfidhaltigt mineral. Då varpen exponeras för luft och nederbörd sker en oxidation av sulfiderna, vilket kan ge upphov till surt lakvatten och läckage av tungmetaller. Syftet med arbetet har varit att karaktärisera varpen och försöka stabilisera den med en blandning bestående av mesakalk och avloppsslam, samt att undersöka risken med det lösta organiska materialets förmåga att komplexbinda metaller och på så vis öka deras rörlighet. Efter insamling av varpmaterial utfördes först en förstudie för att avgöra vilken fraktion av varpen som var lämplig för försöket. När lämpligt material valts ut utfördes kolonntest för att studera slam/kalk-blandningens inverkan på lakning av metaller, samt pH-statiskt skaktest för att bedöma komplexbildningspotentialen hos det organiska materialet vid olika pH värden. Från kolonnerna togs lakvattenprover kontinuerligt ut under försökets gång för analys med avseende på pH, konduktivitet, alkalinitet, redoxpotential, löst organiskt kol (DOC), sulfat och utlakade metaller. Lakvattnet från pH-stat-testet provtogs vid ett fåtal tillfällen och analyserades endast med avseende på metallhalter och förändring i DOC-halt. Resultatet från den laborativa studien visade att varpmaterialet från Ljusnarsberg lätt lakades på stora mängder metaller. Den reaktiva tillsatsen lyckades uppbringa ett neutralt pH i lakvattnet från avfallet, vilket kan jämföras med lakvattnet från den obehandlade kolonnen som låg på ett pH kring 3. Medelhalten av koppar och zink översteg under försöksperioden 100 respektive 1000 mg/l i lakvattnet från det obehandlade avfallet, medan halterna i det behandlade materialets lakvatten låg kring 0,1 respektive 1 mg/l. Av de studerade metallerna låg halterna 40-4000 gånger lägre i lakvattnet från den behandlade kolonnen, vilket innebär att slam/kalk-blandningen har haft verkan. Stabiliseringens långtidseffekt är dock okänd. Det tillsatta slammet resulterade inte i någon större ökning av DOC-halten i det pH-intervall som åstadkoms med mesakalken. Utifrån pH-stat-försöket kunde det konstateras att det tillsatta slammet bidrog till metallernas immobilisering vid neutralt pH, trots en liten ökning av DOC-halten. Om en sänkning av pH skulle ske med tidens gång föreligger dock risk för ökat metalläckage.