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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
131

Hydrothermal processing of waste biomass: recovery of nutrients (N, P, soil amendments) and energy valorization

Scrinzi, Donato 18 July 2023 (has links)
Many environmental crises are threatening to collapse human societies, but also life on the Earth as we may know. Climate change due to anthropogenic global emissions is one of the main issues, but also soil degradation, and the management of the enormous amount of organic wastes that are harmfully released into the environment by human activities. On the one hand, direct spreading of biowastes onto the land is often limited due to eutrophication or pollution by toxic compounds. On the other hands, these biomasses may contain nutrients, such as phosphorus (listed as a critical raw material) and nitrogen, which could be recovered to sustain the high demand in expensive soil amendments and fertilizers. Thus, finding new solution to close the loop towards circular economy and sustainable processes is crucial, nowadays, to convert the global trends and restore the delicate equilibrium in the water-food-energy nexus, with soil ‘under special surveillance’. In this framework, many researchers are focusing their attention on hydrothermal carbonization (HTC) as a possible candidate, in particular to treat moist biowastes and obtain useful solid (hydrochar) and liquid (HTC liquor) products. Nutrients contained in biowastes are sensitive to HTC process parameters and initial feedstock properties, thus it is crucial to analyze their distribution and (im)mobilization among the HTC products for their reuse in soil. On the other hand, since some organic compounds are generated during the thermochemical process, which may be responsible for toxicity to plants and other organisms, analysis of their possible toxicity towards the biosphere becomes crucial before implementation at a large scale. This thesis collects our efforts to explore new processes and deepen the knowledge about the possibility to produce amendments suitable for soil application from hydrochar. The core is from a process engineering perspective, focusing on the production phase and the characterization of the products, never forgetting any possible limits or the implications on ecotoxicological issues. In the first part of the thesis, ‘How to make hydrochar a soil amendment?’ is the main question. Based on few pioneer studies about composting of hydrochar, we assessed a complete analysis of hydrochar co-compost, produced from the 25-day aerobic stabilization of digestate of organic fraction of municipal solid waste, together with a fraction of its hydrochar, and green waste. Under the umbrella of C2Land project (funded by The European Institute of Innovation & Technology -EIT), we produced this new amendment in specifically designed bioreactors, then we characterized the products from the point of view of physico-chemical properties, nutrients distribution, toxicity to plants and mammalian cells. We are confident that the crucial result of toxicity removal from hydrochar through composting will attract the interest of many stakeholders, since implementing HTC in anaerobic/aerobic plants is almost ready to be applied at a large scale. Moreover, an experimental campaign performed at the University of Leeds further explored the effect of some other post-treatments on hydrochar composition and phytotoxicity, depending on the initial feedstocks (manure, sewage digestate, water hyacinth, and grass). The second part of the thesis was dedicated to nutrients recovery, necessary when some harmful matrixes - such as the municipal sewage sludge digestate - are not allowed to be reused for agricultural purposes, due to law limitations or pollution issues. In this case, nutrients recovery (N, P) could be achieved chemically, via HTC and struvite precipitation, being struvite recognized as a good fertilizer. Firstly, we performed a techno-economic assessment of the implementation at a district level of HTC-centered sewage sludge management. The mass reduction of waste streams may have some important effects on transportation costs, while the recirculation of HTC liquor back to the anaerobic digestors can imply more biomethane production with increased revenues. A mass balance for the potential of N and P recovery through struvite precipitation in the centralized facility was also assessed. Secondly, a near-zero waste treatment process for municipal sewage sludge via HTC was designed according to the available literature and preliminarily analyzed at lab level. The fractionation of the different types of phosphorus was analyzed through the STM-P protocol before and after HTC, confirming the mineralization of organic phosphorus during the process. Citric acid was validated as a good green solvent for phosphorus extraction and high-quality struvite precipitation, even if the process was not still optimized in terms of yields. Future works may identify the best process parameters for final metal recovery from liquid byproducts in order to internally recirculate them back to water line, and to characterize the leached hydrochar as purified renewable fuel or soil amendment. Thus, the proof-of-concept chain would be confirmed and could be applied to the sustainable HTC-centered biorefineries of the future.
132

Methane removal using materials from biofilters at composting plants

Nguyen, Thanh Phong, Cuhls, Carsten 22 February 2019 (has links)
Methane (CH4) source of Greenhouse Gases should be considered; CH4 is formed by composting under anaerobic conditions. Using microbial Methane oxidation is a solution with low cost and effective. In this study, 27 bio-filters and 18 laboratory-scale bioreactors were used to investigate the potential for CH4 removal in biogas. The CH4, Dinitrogen monoxide (N2O) and Carbon dioxide (CO2) concentrations at the inlet and outlet of the air purifier were measured by gas chromatography. The results showed that the CH4 concentration decreased in experiments while the CO2 and N2O content increased in all experiments. An experiment was conducted with 1 kg of biofilter material with the input of 800 ppm CH4 contained in a 5-liter flask for 49 hours containing. The results also showed that the CH4 concentration decreased by 71% after 20 hours and N2O was formed in the reactor. / Mê-tan (CH4) là nguồn khí gây nên hiệu ứng nhà kính cần được quan tâm, khí CH4 được sinh ra trong quá trình ủ vi sinh trong điều kiện kị khí. Một giải pháp với chi phí thấp là sử dụng vi sinh vật oxy hóa khí CH4 cố định trên giá thể là vật liệu sử dụng trong thiết bị lọc sinh học. Trong nghiên cứu này, 27 thiết bị lọc sinh học trên thực tế và 19 bình lọc tại phòng thí nghiệm đã được sử dụng nhằm mục đích khảo sát khả năng loại bỏ CH4 có trong khí sinh học. Nồng độ khí CH4, N2O và CO2 ở đầu vào và đầu ra bể lọc khí được đo đạc bằng phương pháp sắc ký khí. Kết quả cho thấy nồng độ khí CH4 giảm sau khi qua hệ thống lọc sinh học ở một số bình, trong khi nồng độ khí CO2 và N2O lại tăng lên ở tất cả các bình. Khi khảo sát khả năng oxi hóa CH4 ở nồng độ 800 ppm của 1kg vật liệu thiết bị lọc sinh học chứa trong bình phản ứng thể tích 5L với thời gian 49 giờ. Kết quả cho thấy nồng nồng độ CH4 giảm 71% sau 20 giờ. Tuy nhiên, N2O đã được ghi nhận có hình thành trong bình phản ứng đó.
133

A 2012 SURVEY AND ECONOMIC ASSESSMENT OF COMPOSTING AND ANAEROBIC DIGESTION OPTIONS FOR MIAMI UNIVERSITY

Smith, David Brian 16 August 2012 (has links)
No description available.
134

Avfall eller resurs? En prognos över framtida behandling av restavfall och organiskt avfall

Henriksdotter Langer, Lina January 2015 (has links)
Studien gjordes som ett avslutande moment i den miljövetenskapliga utbildningen vid Malmö högskola. Ämnet valdes i samarbete med NSR i Helsingborg och syftade till att utreda restavfallets framtida innehåll av organiskt material i några nordvästskånska kommuner. Avfallet som inkommit till Filborna i Helsingborg kartlades med hjälp av en materialflödesanalys för att synliggöra materialflödena till och från samt inom anläggningen. Målet med studien var att undersöka om det även i fortsättningen kommer att vara bäst att behandla restavfallet biologiskt eller om det i större utsträckning kommer innehålla brännbart material och därmed kommer vara lämpligare att energiåtervinna restavfallet. På grund av det varierande antalet hushåll sin källsorterar organiskt material i de olika kommunerna var det en svårighet att göra en korrekt bedömning och resultaten grundades på antaganden om hur källsorteringsgraden kommer att förbättras framöver. Resultatet baseras på statistik från 2002-2006 och en prognos fram till och med år 2014 visar på att med dagens hastighet dröjer det ytterligare 19 år från 2014 innan restavfallet består enbart av brännbart material. Det sker hela tiden förbättringar på området i regionen vilket innebär att resultatet kan komma att variera mycket vilket också innebär att tidsprognosen kan komma att kortas ner med tiden. / The study was made as a final exam in Environmental Science at Malmö högskola. The subject was chosen in co operation with a few of the work force at NSR in Helsingborg and was aiming to investigate the future substance of organic waste in a northwest region in Skåne, Sweden. The waste which is taken care of at Filborna in Helsingborg was mapped out with a material flow analysis due to reveal the flows of materials to and from the construction. The aim with the study was to investigate whether the biological treatment still will be the most optimal solution in the future or if the solid waste will contain only flammable material and thereby the optimal solution will be energy recycling. Due to the varying amount of households which are sorting their organic wadte there were diffuculties to make correct estimates and thereby the results are founded on assumptions. The results are based on statistic material 2002-2006 and a forecast until 2014. They show that it will take another 19 years before the solid waste compound only flammable material. However recycling keeps improving and the forecast will shorten in time.
135

Resíduos de coco, acerola e caju para produção de carvão ativado

Ricardo Vandré Trótski Oliveira Silva 25 February 2015 (has links)
Com o crescimento das atividades industriais e da população, aumentam também a quantidade de resíduos gerados que ocasiona problemas ambientais. No Brasil, produtor de bens na agroindústria, os problemas causados pelo acúmulo e destinação inadequada dos resíduos sólidos é de grande porte. A partir dessa problemática são criados mecanismos que incentivam a reutilização e reciclagem dos resíduos. É buscando desenvolver tecnologia inédita de matérias-primas alternativas que se produziu carvão ativado a partir de resíduos de coco, acerola e caju. Primeiramente coletou-se a fibra-de-coco seco e bagaços/cascas de acerola e do caju para posterior preparação desse material através da impregnação com ZnCl2, da ativação química e da realização de um teste de avaliação da eficiência do carvão. Foi produzido carvão ativado com todas as amostras, onde a aplicação na amostra de água coletada no rio Capibaribe (perto do túnel Chico Science), Recife, Pernambuco, apresentou redução da turbidez em 97,3 % usando o tratamento com 25 % de fibra-de-coco + 75 % de caju. / With the growth of industrial activities and population, also increases the amount of generated waste which causes environmental problems. In Brazil, a major producer of goods in the agricultural industry, the problems caused by the accumulation and improper disposal of solid waste are large. From this problematic, mechanisms that encourage the reuse and recycling of waste are created. It is seeking to develop new technology of alternative raw materials that are produced activated carbon from coconut waste, barbados cherry and cashew. Primarily, the collection of fiber-to-dry coconut and cake/shells from barbados cherry and cashew for later preparation of this material by impregnation with ZnCl2, chemical activation and conducting an evaluation test coal efficiency. The result, within all samples, was an activated carbon where the application in the water sample collected from the Capibaribe River (near Chico Science tunnel), Recife, presented a decrease in turbidity in 97.3% using treatment with 25% fiber- coconut + 75% cashew.
136

Resíduos de coco, acerola e caju para produção de carvão ativado

Silva, Ricardo Vandré Trótski Oliveira 25 February 2015 (has links)
Made available in DSpace on 2017-06-01T18:20:45Z (GMT). No. of bitstreams: 1 ricardo_vandre_trotski_oliveira_silva.pdf: 610833 bytes, checksum: 744d83d7588313cd4ff2b78eb59399bf (MD5) Previous issue date: 2015-02-25 / With the growth of industrial activities and population, also increases the amount of generated waste which causes environmental problems. In Brazil, a major producer of goods in the agricultural industry, the problems caused by the accumulation and improper disposal of solid waste are large. From this problematic, mechanisms that encourage the reuse and recycling of waste are created. It is seeking to develop new technology of alternative raw materials that are produced activated carbon from coconut waste, barbados cherry and cashew. Primarily, the collection of fiber-to-dry coconut and cake/shells from barbados cherry and cashew for later preparation of this material by impregnation with ZnCl2, chemical activation and conducting an evaluation test coal efficiency. The result, within all samples, was an activated carbon where the application in the water sample collected from the Capibaribe River (near Chico Science tunnel), Recife, presented a decrease in turbidity in 97.3% using treatment with 25% fiber- coconut + 75% cashew. / Com o crescimento das atividades industriais e da população, aumentam também a quantidade de resíduos gerados que ocasiona problemas ambientais. No Brasil, produtor de bens na agroindústria, os problemas causados pelo acúmulo e destinação inadequada dos resíduos sólidos é de grande porte. A partir dessa problemática são criados mecanismos que incentivam a reutilização e reciclagem dos resíduos. É buscando desenvolver tecnologia inédita de matérias-primas alternativas que se produziu carvão ativado a partir de resíduos de coco, acerola e caju. Primeiramente coletou-se a fibra-de-coco seco e bagaços/cascas de acerola e do caju para posterior preparação desse material através da impregnação com ZnCl2, da ativação química e da realização de um teste de avaliação da eficiência do carvão. Foi produzido carvão ativado com todas as amostras, onde a aplicação na amostra de água coletada no rio Capibaribe (perto do túnel Chico Science), Recife, Pernambuco, apresentou redução da turbidez em 97,3 % usando o tratamento com 25 % de fibra-de-coco + 75 % de caju.
137

A techno-socio-economic potential assessment of organic waste-to- energy conversion through biogas technology for rural households in Vhembe District of Limpopo

Rasimphi, Thilivhali Eugene 02 February 2016 (has links)
MENVSC / Department of Ecology and Resource Management

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