Dentre as várias técnicas de tratamento e disposição dos resíduos sólidos urbanos a disposição em aterros sanitários é a mais usada, devido ao baixo custo e relativa simplicidade operacional. No entanto, a falta de estudos para áreas adequadas é um dos principais fatores limitantes da aplicação desta técnica. É imprescindível o conhecimento dos atributos do meio-físico para avaliar as suas várias interações com o aterro sanitário. Essas interações e a variedade de atributos, dificultam a seleção do local adequado para a instalação do aterro sanitário. Diante disto, há a necessidade de uma metodologia que considere as interações, juntamente com os atributos, e se mostre eficaz na seleção do melhor local para o aterro. Propões-se aqui uma metodologia que considera 14 atributos do meio físico, referentes ao substrato rochoso, materiais inconsolidados, água e feições de relevo. Em vista da variedade de atributos, múltiplas alternativas possíveis e objetivos muitas vezes conflitantes, a serem considerados, foi aplicada a técnica de tomada de decisão denominada processo hierárquico analítico (PHA). O PHA divide um problema complexo em problemas mais simples na forma de uma hierarquia de decisão e, permitiu a obtenção do índice de adequabilidade (I.A.), que representa o valor numérico da adequabilidade de uma determinada áreas para a instalação de aterros sanitários, além de possibilitar a sua hierarquização em relação às áreas adjacentes. Esta metodologia foi aplicada na região de Araraquara, estado de São Paulo, limitada pelo paralelos 21º45\' e 22º00\' sul e meridianos 48º00\' minutos e 48º15\' minutos oeste Gr. O I.A. possibilitou o zoneamento e a classificação de unidades de combinação em favorável, moderada, severa e restritiva para a implantação de um aterro sanitário. A metodologia mostrou-se eficaz e permitiu comparar os 14 atributos de forma numérica, ao introduzir a ) técnica de tomada de decisão através do processo de hierarquia analítica. Desta forma, apresentou as vantagens de diminuir a subjetividade do processo de seleção e ponderar atributos inter-dependentes, direcionados ao objetivo de selecionar áreas para a implantação de um aterro sanitário. / Among several techniques for disposition and treatment of urban solid waste, sanitary landfill is the most employed, by their low cost and relative operational simplicity. However, the lack of research for suitable areas is one of the main problems to the application of this technique. It is necessary to know the attributes of the environment to assess their numerous interactions with the environment sanitary landfill. This interactions and the variety of the attributes becomes diffilcut the selection of the most suitable area to the installation of the sanitary landfill. A methodology to be effiecient in the selection of the best site to this facility, must consider the interactions and the attributes of the environment. This paper proposes a methodology which consider 14 attributes of the environment related to the rocky substrate, unconsolidated materials, water and relief. Because the variety of attributes, multiple possible alternatives and competing objectives to be consider was applied a decision support system (D.S.S.) technical named analytic hierachy process (AHP) which divides a complex problem in simpler ones in the form of a decision hierarchy. The use of AHP reaches the numerical suitability index (SI), of the areas to the installation of a sanitary landfill and becomes possible to hierarchy these areas. This methodology was applied in an area located in the Araraquara region, São Paulo state, limited by the parallels 21º45\' and 22º15\' south and meridians 48º00\' and 48º15\' West gr. The use of the suitability index (SI) permitted the zoning and ranking of the sub-areas and their classification in favorable, moderate, severe and restrictive to the installation of a sanitary landfill. The methodology to compare the 14 attributes in a numerical way by the use of the making decision technique applied to the AHP. By this way had the advantage of less subjectivity of the process of area selection and to weigh inter-dependents attributes, addressed to the objective of to select sites to the sanitary landfill.

abstract: Seeking to address sustainability issues associated with food waste (FW), and fat, oil, and grease (FOG) waste disposal, the City of Mesa commissioned the Biodesign Swette Center for Environmental Biotechnology (BSCEB) at Arizona State University (ASU) to study to the impact of implementing FW/FOG co-digestion at the wastewater treatment plant (WWTP). A key issue for the study was the “souring” of the anaerobic digesters (ADs), which means that the microorganism responsible for organic degradation were deactivated, causing failure of the AD. Several bench-scale reactors soured after the introduction of the FW/FOG feed streams. By comparing measurements from stable with measurements from the souring reactors, I identified two different circumstances responsible for souring events. One set of reactors soured rapidly after the introduction of FW/FOG due to the digester’s hydraulic retention times (HRT) becoming too short for stable operation. A second set of reactors soured after a long period of stability due to steady accumulation of fatty acids (FAs) that depleted bicarbonate alkalinity. FA accumulation was caused by the incomplete hydrolysis/fermentation of feedstock protein, leading to insufficient release of ammonium (NH4+). In contrast, carbohydrates were more rapidly hydrolyzed and fermented to FAs. The most important contribution of my research is that I identified several leading indicators of souring. In all cases of souring, the accumulation of soluble chemical oxygen demand (SCOD) was an early and easily quantified indicator. A shift in effluent FA concentrations from shorter to longer species also portended souring. A reduction in the yield of methane (CH4) per mass of volatile suspended solids removed (VSSR) also identified souring conditions, but its variability prevented the methane yield from providing advanced warning to allow intervention. For the rapidly soured reactors, reduced bicarbonate alkalinity was the most useful warning sign, and an increasing ratio of SCOD to bicarbonate alkalinity was the clearest sign of souring. Because I buffered the slow-souring reactors with calcium carbonate (CaCO3), I could not rely on bicarbonate alkalinity as an indicator, which put a premium on SCOD as the early warning. I implemented two buffering regimes and demonstrated that early and consistent buffering could lead to reactor recovery. / Dissertation/Thesis / Masters Thesis East Asian Languages and Civilizations 2020

Os processos biológicos apresentam o menor custo de todas as técnicas atualmente aplicadas para o tratamento de lixiviados de aterros sanitários. Porém, eles não vêm demonstrando capacidade em degradar a matéria orgânica recalcitrante presente nesse tipo de água residuária. O presente estudo teve por objetivo avaliar a possibilidade da utilização de enzimas, que são largamente empregadas na indústria, como auxílio em tal remoção. Após a caracterização do lixiviado do aterro sanitário da cidade de Paulínia, verificou-se que o mesmo se encontrava em adiantada fase de biodegradação, com pH de 8,40 ± 0,14; baixa concentração de matéria orgânica facilmente biodegradável (DBO de 857 ± 475 mgO2/L) e altas concentrações de N-NH3(2343 ± 399 mg/L) e de Carbono Orgânico Total (2066 ± 746 mg/L). A investigação experimental foi realizada em duas etapas, empregandose um reator de lodo ativado em bateladas sequencial, com biomassa adaptada ao lixiviado. Na primeira etapa, utilizando o planejamento fatorial completo 2³, verificouse que aumentando o pH e diminuindo a concentração inicial de N-NH3 era possível evitar o acúmulo de nitrogênio amoniacal no sistema a partir da remoção total desse composto. Porém, a inibição às bactérias oxidantes da amônia não foi cessada, pois a eficiência de oxidação via biológica chegava no máximo a 49,1%, sendo os 50,9% restantes atribuídos à volatilização de nitrogênio amoniacal, que era intensificada com o aumento do pH. A segunda etapa teve por objetivo a remoção de matéria orgânica recalcitrante, medida como COT, presente no lixiviado de aterro sanitário, com a utilização da enzima lacase. Esta demonstrou uma expressiva capacidade de remoção de nitrito, de 127 mgNO2 -/L para menos que 0,1 mgNO2 -/L em 4 dias, e de COT, passando de 2333 mgC/L para 1400 mgC/L, ao ser utilizada sozinha, e de 1317 mgC/L para 174 mgC/L quando utilizada juntamente com bactérias heterotróficas. Ao final, observou-se remoções superiores a 99,9% de N-NH3 mantendo-se a concentração de OD=2,4 mg/L, pH=8,5 e concentração de N-NH3 inicial em torno de 270 mg/L. Remoções de 92,3% de nitrito e 40% de COT foram obtidas ao se adicionar a enzima ao efluente nitritado, porém foi observado um aumento na concentração de COT e de NKT após a inserção da solução enzimática, devido a uma alta concentração desses compostos na mesma. / The biological process is the one with the lowest cost of all the techniques currently used for the treatment of landfill leachate. However, it has not demonstrated ability to degrade recalcitrant organic matter present in this type of wastewater. This study aimed to evaluate the possibility of using enzymes, which are already used in industry, as an aid in such removal. After characterizing the Paulinia´s landfill leachate, wich was used in this study, it was found that it was in an advanced stage of degradation, with a pH of 8.40 ± 0.14; low concentration of readily biodegradable organic matter (BOD of 857 ± 475 mgO2/L) and high ammonia nitrogen (2343 ± 399 mgN/L) and Total Organic Carbon - TOC (2066 ± 746 mgC/L). The experimental research was conducted in two stages, using a sequential batch reactor with biomass adapted to the leachate. In the first step, using a full factorial design 2³, it was found that by increasing pH and decreasing the initial concentration of NH3-N is possible to avoid the accumulation of ammonia in the system by the total removal of that compound. However, the inhibition of ammonia oxidizing bacteria is not ceased. The biological pathway for oxidation efficiency reaches the maximum at 49.1%, with the remaining 50.9% being attributed to the volatilization of ammonia, which is enhanced with increasing pH. The second stage was aimed at removing recalcitrant organic matter, measured by the COT present in landfill leachate, with the use of laccase enzyme. The enzyme demonstrated a significant nitrite removal capacity, decreasing its concentration of 127 mgNO2 -/L to less than 0.1 mgNO2 -/L, and the TOC, from 2333 mgC/L to 1400 mgC/L in the same period time.

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.

Landfills are potential sources for PFASs and treatment techniques for landfill leachate are urgently needed. Foam fractionation is an aeration technique which utilizes the tendency of PFASs to escape the liquid phase and build foam. The foam is harvested and with it the contamination. Landfill leachate from Hovgården, Uppsala Sweden contained PFASs of higher concentration than desired and investigations into whether foam fractionation could reduce PFASs amounts were initiated. Landfill leachate containing sum PFASs of 5500 ng/L on average were aerated in two different aeration foam collection pilot set-ups for the research. The pilot set-ups were divided into two models: a batch pilot and a continuous pilot. The batch pilot was run for 60 minutes testing parameters such as column volume, air flow rate, dilution and using additives as NaCl, FeCl3 and dish soap. The continuous pilot used contact times of 5, 10 and 20 minutes with constant air flow rate and column volume and no additives. All batch experiments showed reduced concentrations of PFASs, from 62 up to 91%, with an average sum PFASs removal efficiency of 77%. Air flow rates of 4 and 6 L/min were more effective than 2 L/min to reduce the amount of PFASs. Smaller volumes got higher removal efficiency. The dilution experiments showed mixed and somewhat contradictory results, where the nondiluted experiment had removal efficiency of sum PFASs of average 77% while the 50% diluted had an average sum PFASs removal efficiency of 84%. The experiment with the greatest dilution (75%) had the lowest average sum PFASs removal efficiency as suspected, at 68%. Regarding additives, the experiments with added 0.155 and 0.313% NaCl in the leachate were most effective at removing PFASs. The dish soap and FeCl3 additives also contributed to higher PFASs reduction. The experiment with the addition of dish soap had an average sum PFASs removal efficiency of 88% compared to 77% without additives, and the highest concentration of FeCl3 (0,09% of the leachate) had an average sum PFASs removal efficiency of 85%. All continuous experiments showed reduced reduced PFASs concentrations with sum PFASs removal efficiencies ranging from 72 up to 94%, with an average of 86%. The majority of the PFASs were reduced within the first time steps for all experiments, but for the last amount to be removed the contact time needed to be longer. The column contact time of 20 min had the highest average sum PFASs removal efficiency. The conclusion is that PFASs are reduced during the treatment in the pilots and that the reduction is dependent on the chain length and functional groups of the substances, and increased with additives and increased air flow rate. The volume treated and the concentration of raw water also influenced the removal efficiency.

A laboratory test program was conducted to determine the moisture-suction relationships of geosynthetic clay liners (GCLs). Moisture-suction relationships were determined by combining suction data from pressure plate tests, contact filter paper tests, and relative humidity tests, then fitting water retention curves (WRCs) to the data. WRCs were determined for wetting processes and drying processes in terms of gravimetric moisture content and volumetric moisture content. The effects of GCL type, hydration solution, wet-dry cycles, and temperature on the moisture-suction relationships were analyzed. The three GCLs of the test program consisted of configurations of woven and nonwoven geotextiles reinforced with needlepunched fibers. A geofilm was adhesively bonded to the nonwoven side of one of the GCL products. The hydration solution tests involved hydrating GCLs with deionized water, tap water, 0.1 M CaCl2, or soil water from a landfill cover test plot for a 30-day conditioning period prior to testing. Cyclic wet-dry tests were conducted on the GCL specimens subjected to 20 wet-dry cycles from 50% to 0% gravimetric moisture content prior to testing. Temperature tests were conducted at 2°C, 20°C, and 40°C. GCL type affected moisture-suction relationships. The GCLs with an adhesively-bonded geofilm exhibited lower air-entry suction and higher residual suction than GCLs without a geofilm. The degree of needlepunched fiber pullout during hydration contributed to hysteresis between wetting WRCs and drying WRCs. Hysteresis was high for suction values below air-entry suction and was low for suction values greater than air-entry suction. Cation exchange reduced the water retention capacity for all three GCL types. The saturated gravimetric moisture contents were reduced from approximately 140% to 70% for wetting WRCs and 210% to 90% for drying WRCs for GCLs hydrated in deionized water compared to CaCl2 solution. Hysteresis of the nonwoven product decreased from 71%, to 62%, to 28% with respect to deionized water, tap water, and CaCl2 solution. Hysteresis of the woven product exposed to soil water was 24% and 0%, in terms of saturated gravimetric moisture content and saturated volumetric moisture content, respectively. The swell index, Atterberg Limits, mole fraction of bound sodium, and scanning electron microscopy images that were determined of bentonite from the conditioned GCLs indicated that changes in water retention capacity corresponded with cation exchange. Wet-dry cycles and temperature affected the moisture-suction behavior for GCLs. Wet-dry cycles reduced hysteresis and increased the swelling capacity of GCL specimens. Microscopy images indicated that wet-dry cycles caused weak orientation of the clay particles. Increasing temperature resulted in a small decrease in water retention capacity. Results of the test program provided a means for predicting unsaturated behavior for GCLs.

Continued population growth is placing strain on the waste disposal facilities available in South Africa. However, limited air space suitable for landfilling drives the need for alternative solutions such as piggyback landfills to expand the waste disposal capacity. This method entails building a new, fully lined, landfill on top of existing waste. However, the old underlying waste is prone settlement that can result in the cracking of new landfill clay liner. Geogrid reinforcement have been successfully used in clay liners to mitigate cracking induced by waste settlement. This research focused on investigating of the optimal reinforcement strategy (ORS) of such a liner subject to settlement. The ORS entails the optimal position for geogrid reinforcement in a liner, and the stiffness to be used at that position, given a total reinforcement cost. Firstly, the fracture behaviour of unreinforced clay liners was investigated by means of four point bending tests on clay beams. It was found that the fracture of this clay occurred in three stages: linear behaviour, followed by non-linear behaviour when micro-cracks forms and finally macro-cracks that opened once the peak load was reached. Thereafter, the behaviour of geogrid-reinforced clay liners, subjected to differential settlement, was investigated with finite element analyses in ABAQUS. A number of key factors were varied and the resulting change in behaviour of the liners was observed. These were: the overburden stress applied, clay liner thickness, magnitude of central settlement and the width and shape of the settlement trough developing in the underlying waste body. Based on the numerical results, a series of plane-strain centrifuge tests of reinforced clay liners subject to differential settlement were designed. An unreinforced liner, a liner reinforced at the bottom quarter, a liner reinforced at the top quarter and a liner reinforced at both the bottom and top quarters were tested. Laser scanner scans of the surface and strains calculated from digital image velocimetry results were used to compare the behaviour of the liners. Based on these results it is recommended that for optimal performance the available reinforcement should be divided between the top and bottom quarters of the liner to mitigate the effect of settlement. / Volgehoude bevolkingsgroei in Suid-Afrika plaas bestaande rommelstortingsfasiliteite onder druk. ’n Tekort aan grond geskik vir die bou van stortingsterreine moedig die soektog na alternatiewe oplossings soos abba-stortingsterreine aan. Hierdie metode behels ’n splinternuwe stortingsterrein wat bo-op bestaande rommel gebou word. Versakking van die bestaande rommel kan egter veroorsaak dat krake vorm in die nuwe stortingsterrein se kleivoering wat daarop lê. Vorige navorsing het die vorming van krake in die kleivoerings al welgeslaagd verhoed deur van georoosters as versterking gebruik te maak. Die huidige studie het op daardie navorsing gebou deur die optimale versterkings strategie (OVS) te bepaal vir so ’n kleivoering wat vervorm onder versakking van die onderliggende rommel. Die OVS definieer beide die optimale versterkings posisie in ’n kleivoering, en die styfheid van die georooster wat in daardie posisie geplaas moet word, gegewe ’n sekere totale versterkingskoste. Eerstens was daar ondersoek ingestel na die kraakgedrag van onversterkte kleivoerings. Vierpuntbuigtoetse van kleibalkies was hiervoor gebruik. Die krake het oor drie fases gevorm: eerstens was daar lineêre gedrag tot en met mikro-krake gevorm het. Dit is gevolg deur nie-lineêre gedrag wat gelei het tot makro-krake. Sodra die makro-krake gevorm het, is die maksimum las bereik wat die klei kon ondersteun. Na afloop van die balkbuigtoetse was eindige element analises in ABAQUS uitgevoer om die gedrag van versterkte kleivoerings wat bo-op versakkende afval lê te ondersoek. Die spanning toegepas op die oppervlak van die kleivoerings, die dikte van die kleivoerings en die versakkingstrogwydte, -vorm en -diepte was gevarieer om die effek daarvan op die gedrag van die kleivoerings te ondersoek. Na aanleiding van die resultate van die numeriese analise is ’n reeks sentrifuge toetse van kleivoerings wat aan versakking onderwerp word uitgevoer. ’n Onversterkte kleivoering, kleivoerings versterk in die boonste en onderste kwarte, en een versterk in beide die boonste en onderste kwart was getoets. Die gedrag van die verskillende kleivoerings was vergelyk deur die oppervlaktekrake op te meet met ’n laserskandeerder. Verder is die vervorming van die kleivoerings bepaal vanaf die verplasing van die grondpartikels tussen opeenvolgende digitale foto’s. Na aanleiding van hierdie resultate word dit aanbeveel dat die beskikbare georooster versterking opgedeel moet word tussen die boonste en onderste kwart van die kleivoerings ten einde optimale gedrag te verseker indien versakking sou plaasvind. / Dissertation (MEng)--University of Pretoria, 2017. / Deutscher Akademischer Austausch Dienst (DAAD) / Geosynthetics Interest Group of South Africa (GIGSA) / National Research Foundation of South Africa (NRF) / Civil Engineering / MEng / Unrestricted

Orientador: Marcus Cesar Avezum Alves de Castro / Resumo: O presente estudo teve como objetivo principal analisar a incorporação dos critérios do meio físico na seleção de áreas para implantação de aterros sanitários nos processos de licenciamento ambiental no Estado de São Paulo. A investigação foi realizada a partir da análise de estudos ambientais de aterros sanitários (EIA/RIMA e RAP) apresentados para a Companhia Ambiental do Estado de São Paulo (CETESB), em atendimento ao processo de licenciamento ambiental no Estado de São Paulo. A avaliação da incorporação dos critérios na seleção das áreas nos processos de licenciamento baseou-se em aterros sanitários localizados nas áreas de alta, média e baixa vulnerabilidade à contaminação de águas subterrâneas, conforme Mapa de Vulnerabilidade à Contaminação de Águas Subterrâneas do Estado de São Paulo (IG/DAEE/CETESB, 1997). Foram selecionados um (01) aterro na área de alta vulnerabilidade, dois (02) na de média vulnerabilidade e três (03) na área de baixa vulnerabilidade. A análise dos critérios do meio físico dos EIA-RIMA foi pautada nos capítulos de “Alternativas Locacionais” e “Diagnóstico do Meio Físico”. Com base nos resultados da avaliação dos relatórios ambientais verificou-se que, usualmente, o meio físico não foi considerado determinante na seleção da área de implantação do aterro, predominando critérios financeiros na escolha locacional dentre as alternativas apontadas para cada área. Quanto à caracterização do meio físico apresentada nos relatórios, ela atendeu, em linhas g... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The main objective of this study was to analyze the incorporation of the criteria of the The main objective of this study was to analyze the incorporation of the criteria of the physical environment in the selection of areas for the implementation of sanitary landfills in environmental licensing processes in the State of São Paulo. The investigation was carried out based on the analysis of environmental studies of sanitary landfills (EIA/RIMA and RAP) presented to the Environmental Company of the State of São Paulo (CETESB), in compliance with the environmental licensing process in the State of São Paulo. The evaluation of the incorporation of the criteria in the selection of the areas in the licensing processes was based on sanitary landfills located in areas of high, medium and low vulnerability to groundwater contamination, according to the Map of Vulnerability to Groundwater Contamination of the State of São Paulo (IG/DAEE/CETESB, 1997). One (01) landfill was selected in the area of high vulnerability, two (02) in the area of medium vulnerability and three (03) in the area of low vulnerability. The analysis of the criteria of the physical environment of the EIA-RIMA was based on the chapters "Local Alternatives" and "Diagnosis of the Physical Environment". Based on the results of the evaluation of the environmental reports, it was verified that, usually, the physical environment was not considered determinant in the selection of the area of implementation of the landfill,... (Complete abstract click electronic access below) / Doutor

Sundsvall Energi har ansvaret för den gamla deponin på Blåbergets avfallsanläggning strax västerut från Sundsvall. Mellan slutet av 1960-talet fram till och med 2008 har ca 2 miljoner ton avfall deponerats. Från denna deponi har det under en längre tid producerats stora mängder deponigas. Deponigasen har tidigare använts i en hetvattenpanna vid Nacksta och tillfört värme till fjärrvärmesystemet. På grund av ineffektiv drift och minskande metaninnehåll i deponigasen stoppades transporten av deponigas till Nacksta 2013. Därefter har deponigasen enbart använts för fackling vilket innebär att deponigasen förbränns i en gasfackla. Enligt bestämmelser måste deponigas behandlas och användas för exempelvis energiutvinning eftersom innehållet i deponigasen har en kraftig växthuseffekt då gasen består av ca 40–60 % metan och 30–50 % koldioxid. Metan har en 28 gånger högre potential för global uppvärmning jämfört med koldioxid över en 100-årsperiod. I detta examensarbete har syftet varit att undersöka vilka möjligheter som finns för att ta vara på deponigasens energiinnehåll och därmed föreslå ett tekniskt alternativ gentemot enbart fackling av deponigasen. Dessutom har arbetet som syfte att beskriva den miljömässiga- och ekonomiska nyttan. Arbetet har utförts genom att energiinnehållet har tagits fram genom formler och antaganden samt att värmebehovet och uppskattningen av investeringskostnaden tagits fram. Nuvärdesmetoden och PayOffmetoden använts i samband ekonomiberäkningen i arbetet. Värmebehovet på anläggningen fick styra över hur mycket effekt som värmekällan bör ha för att klara högsta årsbehovet. Examensarbetet resulterade i att det mest lämpliga teknikalternativet, nämligen Stirlingmotorn, användes i detta arbete. På grund av ogynnsamma förutsättningar för att täcka värmebehovet på anläggningen har antagandet gjorts att den producerade värmen i stället gör miljönytta genom att tillföra värme till en av lakvattendammarna. Den producerade elen beräknades ha en täckningsgrad på ca 19 % av totala energiförbrukningen på anläggningen. Lönsamhetskalkylerna visar att lönsamheten för en eventuell investering blir ogynnsam vid låga elpriser samt vid låga metanhalter. Dock blir lönsamheten lämpligare vid höga elpriser och lägre investeringskostnader. Dessutom kunde det konstateras att lönsamheten blir betydligt gynnsammare om värmeproduktionen skulle ha nyttiggjorts samtidigt som elproduktionen. / Sundsvall Energi is responsible for taking care of the old landfill at  Blåberget waste facility west of Sundsvall. Between the end of the 1960s to year 2008, about 2 million tons of waste were deposit at the landfill. Large amounts of landfill gas have been produced at this landfill over the years. The landfill gas has previously been burned in a boiler at Nacksta and therefore added some heat to the district heating system. Due to inefficiency and declining methane content in the landfill gas, the distribution of landfill gas to Nacksta ended in 2013. Since then, the landfill gas has only been torched at the landfill site. Since the landfill gas has a strong greenhouse effect and due to regulations, the landfill gas must be treated and used for, as an example, energy utilization. Methane has a 28 times higher contribution risk to global warming compared to carbon dioxide over a 100-year period. In this project, the purpose has been to investigate what opportunities there are to utilize the energy content in the landfill gas and by that suggest an alternative instead of just torching the landfill gas. Additionally, the further purpose with the project is to describe the  environmental and economic benefits of the solution. The work has been done by determine the energy content by using formulas and assumptions. In addition, the heat demand for the landfill site as well as the estimation of investment cost was determined. The NPV and the Pay-Off was used in the economic calculations. The heat demand of the landfill site was the deciding factor of how much power the technical alternative should have to meet the highest annual heat demand. The project resulted in the fact that the most suitable technical alternative, namely the Stirling engine, became the technical choice in this work. Due to unfavorable conditions for the heat production from the Stirling engines at the plant, the assumption was made that the produced heat instead got  to supply heat to one of the leachate ponds. The electricity produced was calculated to meet around 19% of the total energy consumption at the landfill site. The economical estimates showed that the profitability of an eventual investment becomes unfavorable at low electricity prices and at low methane contents. However, the investment becomes far more profitable at high electricity prices and at lower investment costs. In addition, the results showed that profitability would be far more favorable if the produced heat had been utilized for property heating simultaneously as the electricity got produced.

Modern landfills produce landfill gas, LFG, on a smaller scale and with limited content of degradable organic materials in the waste. The waste deposit in the Sofielund landfill began in 2005 and the final coverage is not yet commenced. The landfill waste must contain up to 10% decomposable organic materials at most. In a previous experiment on Sofielund landfill in summer 2011, the measurements from four sample wells showed the landfill gas consisted of up to 45% Methane and about 17000 ppm of Hydrogen sulfide, and the rest was only carbon dioxide. During the earlier experiment in 2011 and during 2012 the smell of H2S got offensive periodically and apart from that, concentrations above 1000 ppm are toxic. Previous research, Bottom ash for biogas upgrading, BABIU, shows that bottom ash from municipal solid waste incinerator (MSWI) can effectively reduce CO­­2 and H2S contents of landfill gas. Bottom ash from MSWI can be utilized in upgrading landfill gas and reduce odor problems of landfills with high H2S production. In this study, an area of 15m x 12m was covered with weathered slag from bottom ash with thickness of about 30cm, to examine how this layer can reduce the concentrations of H2S and CO2. Gas samples were taken from depths of 10cm and 15cm below the surface of bottom ash. There were also samples taken from around the slag-covered area. The surface was laid out 5 days before the first measurement was performed. The experiment was carried out for 20 days, 5, 7, 11, 13, 18 and 20 days after establishment of the surface with bottom ash. The intensity of emissions in different parts of the landfill varied from time to time, due to compacting and changing the permeability of the surface, and it shows that LFG flow in the Sofielund is near the lowest limit of it. Considering the results from the tests in 2011 in deep wells, the recent measurements done in this study showed low contents of LFGs. The highest contents of LFGs in the measurements belong to a pipe, which was found in the waste area of the landfill. Those highest contents of LFG were 15.1% methane, 12.1% carbon dioxide, 0.4% oxygen and the hydrogen sulfide did not exceed 2 ppm. This shows that in deeper depths concentrations of LFG is higher than that of the surface and 10cm below the surface. In the slag covered area CO2 content increased day by day from the first day of the measurement to the last day due to carbonation of the slag and its role in CO2 sequestration.  According to the recent measurement, it can be suggested to cover the landfill with a layer of slag as a construction material, to minimize the LFG emissions and the bad smell from H2S. Therefore it can eliminate direct emissions of LFG to the atmosphere by diffusion through the slag layer. This diffusion allows adsorption of CO2 and oxidation of H2S.