Material- och energiåtervinning är två sätt att ta hand om avfall. Materialåtervinning av papper är generellt det sätt som ger upphov till lägst ackumulerade utsläpp av koldioxid. Kuvert är en pappersprodukt som idag saknar producentansvar och branschen för returpapper anser inte att kuvert skall materialåtervinnas i och med att kuvert innehåller substanser som kan ge upphov till stickies. Ett argument som används mot materialåtervinning av kuvert är att problem orsakade av stickies medför ökade kostnader för företagen som tillverkar papper från returpapper. På den svenska marknaden finns det kuvert som, när de processeras i pappersbruken, inte ger upphov till stickies, nämligen svanenmärkta kuvert. Syftet är att ta reda på vilket som är det bästa sättet att ta hand om kuvert och målet är att ta reda på hur stor nettoenergiförbrukning material- och energiåtervinning av kuvert ger upphov till. Fyra scenarier undersöktes; Samtliga kuvert energiåtervinns, samtliga kuvert materialåtervinns, endast svanenmärkta kuvert materialåtervinns, samtliga kuvert ersätts mot svanenmärkta och materialåtervinns. Resultatet är inte samstämmigt. Att ersätta samtliga kuvert mot svanenmärkta är det scenario som ger upphov till lägst nettoenergiförbrukning, förutsatt att materialåtervinning av papper är att föredra framför energiåtervinning av papper. / Recycling and incineration are two ways to deal with waste. Generally, paper recycling has lower carbon dioxide emissions than incineration of paper. Envelope is a paper product that is not included in any producer responsibility and the pulp and paper industry recommends consumers not to sort envelopes in the paper recycling container, since envelopes contain substances that can be a source for stickies. An argument against recycling is that problems caused by stickies increases costs for the companies that produces paper from waste paper. The Swedish market has envelopes that, when they are processed in the paper mill, do not develop stickies, namely envelopes tagged with Svanen. The purpose of this paper is to find the most suitable way to deal with envelopes. The aim of this study is to find the net energy consumption for recycling and incineration of envelopes. Four scenarios were investigated; all envelopes are incinerated, all envelopes are recycled, only envelopes tagged with Svanen are recycled, all envelopes are replaced with envelopes tagged with Svanen and are recycled. The results are not unanimous. Replacing all envelopes with envelopes tagged with Svanen is the scenario with lowest net energy consumption, presupposed paper recycling is to prefer before paper incineration.

Reports from various institutions claim that garbage management in Rwanda has had diverse effects on both the natural environment and human society. Such claims prompted for an exploratory study to find out an optimal system to handle solid waste in Kigali City. The study considered a literature review and primary data from 400 randomly selected citizens. They were surveyed about their opinions on which system they perceived to be the optimal to handle garbage in Kigali City. The computer software Web-Hipre was used to analyze data on the three systems considered to handle solid waste in Rwanda: briquetting, composting, and incineration.The results indicate briquetting as the optimal alternative to handle solid waste from homesteads and workplaces of Kigali City. Briquetting considers production of solid fuels that may reduce destruction of forests for fuel. Other major reasons for briquetting, highlighted by respondents, include improved kitchen hygiene and sanitation and replacement of charcoal for a less dusty fuel. Economic factors governed surveyed participants to prioritise briquetting system to handle solid waste in Kigali. Composting may be considered for transforming organic materials into mulch to support farming activities in rural areas as well as gardening in the towns. However, a centralised incineration system is presently not suitable. The private sector has so far not fully been engaged in the transformation of solid waste into bioenergy in Rwanda.

Reports from various institutions claim that garbage management in Rwanda has had diverse effectson both the natural environment and human society. Such claims prompted for an exploratory study to find outan optimal system to handle solid waste in Kigali City.The study considered a literature review and primary data from 400 randomly selected citizens. They weresurveyed about their opinions on which system they perceived to be the optimal to handle garbage in KigaliCity. The computer software Web-Hipre was used to analyze data on the three systems considered to handlesolid waste in Rwanda: briquetting, composting, and incineration.The results indicate briquetting as the optimal alternative to handle solid waste from homesteads and workplacesof Kigali City. Briquetting considers production of solid fuels that may reduce destruction of forests for fuel.Other major reasons for briquetting, highlighted by respondents, include improved kitchen hygiene andsanitation and replacement of charcoal for a less dusty fuel.Economic factors governed surveyed participants to prioritise briquetting system to handle solid waste in Kigali.Composting may be considered for transforming organic materials into mulch to support farming activities inrural areas as well as gardening in the towns. However, a centralised incineration system is presently notsuitable. The private sector has so far not fully been engaged in the transformation of solid waste into bioenergyin Rwanda.

In industrial wastewater, there are usually many kinds of organics and heavy metals and can cause damage on human health and environment without well treatment. Printed Circuit Board (PCB) industrial wastewater is a typical example due to the complicated manufacture processes and the use of specific chemicals. In this study, the PCB industrial wastewater is collected and then treated by the combination of Fenton method and Ferrite Process (or called Fenton-Ferrite Process, FFP). Moreover, the recycling possibility of sludge generated from FFP is also studied. Through this study, the treatment procedure of wastewater containing organics heavy metals is established and the direction of sludge reuse is also provided. To realize the characteristic of PCB industrial wastewater, the wastewater from some PCB factory in southern Taiwan was firstly collected and analyzed to identify the pollution concentrations and then treated by FFP. The experimental results showed that the optimum parameters of Fenton method in FFP were pH = 2, [Fe2+]= 500 mg/L, [H2O2]= 3000 mg/L, reaction time= 60 min and batch dosing, and the residual COD and TOC were 84.9 mg/L and 58.3 mg/L under the COD regulation standard 120 mg/L. Meanwhile, the proper conditions of Ferrite Process in FFP were pH= 10, reaction temperature= 80¢J, reaction time= 40 min, aeration rate= 3 L/min/L wastewater, Fe/Cu molar ratio= 10 and three-stage reaction. Under that circumstance, the residual [Cu2+] in wastewater was 0.18 mg/L and the Toxicity Characteristic Leaching Procedure (TCLP) test of sludge from FFP was 4.58 far below the effluent standard 3 mg/L and TCLP standard 15 mg/L. The properties of sludge were further investigated by X-Ray Diffractometer (XRD), Scanning Electron Microscope (SEM) and Superconducting Quantum Interference Device (SQUID). The pattern of XRD indicated that the major structures were Fe3O4 and CuFe2O4; the figure of SEM showed that the surface of sludge was composed of many round particles and the distribution of particle size was from 50 nm-100 nm; the magnetic property analyzed by SQUID showed that the saturation moment was 62.85 emu/g. In the research of sludge applied in catalytic incineration, the o-xylene conversion was 97 % by sludge but only 31 % by quartz sand at 400 ¢J. Moreover, in the 72 hr-decay test of catalyst, the results clearly indicated that the performance did not obviously decline and there were no any byproducts but CO2. Therefore, the investigation revealed that the sludge had great potential in catalytic reaction. The catalytic performance of various ferrospinels generated from different manufactured conditions was also studied. Through the screening of catalysts, the order of various ferrospinels activity was Cu-ferrite > Mn-ferrite > ferrite ¡Ü Zn-ferrite and the most effective Cu-ferrite was manufactured at pH= 9 and T= 90 ¢J. After 72 hr test, the decay of catalyst was not also found. In the examination of Cu-ferrite physical property, the XRD pattern showed that the structure was CuFe2O4; the figure of SEM illustrated that there was no difference between the surface of fresh and used catalyst; the magnetic property measured by SQUID showed that the saturation moment was 30.89 emu/g.

This study aims to undertake a comprehensive analysis of different waste management systems for the wastes produced in Östersund municipality of Sweden with an impact assessment limited to greenhouse gas emissions and their total environmental effects in terms of global warming potential, acidification potential, and eutrophication potential. A life cycle assessment methodology is used by integrating knowledge from waste collection, transportation, waste management processes and the product utilization. The analytical framework included the definition of functional unit, system boundaries, complimentary system design, waste management, and partial use of the energy. Three different municipal solid waste management scenarios, incineration, composting, and digestion were considered for the study. All wastes from Östersund municipality were classified into biodegradable and combustible and thereafter treated for energy and compost production. Greenhouse gas emissions and total environmental impacts were quantified and evaluated their corresponding benefits compared to three different types of marginal energy production system. The results showed that the major greenhouse gas carbon dioxide and nitrous oxide emissions are greater in composting scenario, whereas methane emission is greater in digestion scenario. Composting scenario that uses additional coal fuel has greater global warming potential and acidification potential compared to other scenarios. Composting scenario using wood fuel additional energy has greater eutrophication potential. The highest reduction in global warming potential is achieved when digestion scenario replace coal energy. The greater reduction in acidification and eutrophication potential achieved when digestion scenario replaced coal energy, and wood fuel respectively. Based on the assumptions made, digestion scenario appears to be the best option to manage solid waste of Östersund municipality if the municipality goal is to reduce total environmental impact. Although there may have plentiful of uncertainties, digestion and incineration scenario results are competitive in reducing environmental effects, and based on the assumptions and factors used for the analysis, the results and conclusions from this study appear to be strong. Key words: Solid waste, incineration, composting, digestion, total environmental effect, wood fuel, biogas.

No description available.

No description available.

De-inking sludge generated from pulp and paper industry is considered hazardous since it may contain heavy metals such as Cd, Cr, and Pb. Hence, the de-inking sludge needs to be treated before being disposed of. Sludge combustion is a proven disposal technology, which generates fly ash containing a portion of the heavy metals that may leach out under uncontrolled conditions. The aim of this thesis is to implement a new multi-zone temperature combustion technique (Low-High-Low temperature combustion, LHL) to help contain and immobilize the heavy metals within fly ash particles. During the LHL, the waste will be initially fed into a low-temperature zone (<1100 K) and then subjected to the high-temperature treatment (~1480 K) that will be followed by another low-temperature zone (~1100 K). / This dissertation describes the detailed design and construction of a novel pilot-scale combustion facility, called the Multi-Mode Combustion Facility (MCF), used as a multidisciplinary research tool for investigating the thermal remediation of contaminated solid residues. The MCF is capable of operating in two different modes: Fluidized-Bed combustion mode (FBC) and Single burner furnace mode (SBF). However, this project focuses on the FBC mode (minimum fluidization velocity of 0.42 m/s and bed temperature of 1073 K). / This research compares the combustion characteristics of de-inking sludge obtained in the LHL and in the conventional combustion techniques. The following properties of particulates were studied: morphological evolution of solid particles, structural porosity, metals interactions with fly ash particles, and leachability. / The LHL's final supermicron spherical fly ash went through a molten phase with submicron particles attached to the fly ash particles surfaces. Thus, reducing its porosity to 19%. However, the amorphous final fly ash obtained in the conventional technique reveals 32% porosity. It was found that the physical characteristics of the final LHL's fly ash are the main cause for the reduced heavy metals leachability rates of 0.18, 0.046, and 0.92% for Cd, Cr, and Pb, respectively. The conventional technique had 53.28, 16.79, and 5.20% of Cd, Cr, and Pb respectively, leaching out due to the high porosity percentages. In conclusion, the LHL technique allows for controlling the heavy metals emission from FBCs, while using a waste to energy approach and maintaining environmentally acceptable gas emission levels.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniversitet, 2009. / Härtill 5 uppsatser. "Based on joint research training between SLU and Makerere University"

The subject of this essay is waste and waste management in Sweden during the years1975-2005. The purpose of this investigation is to identify which factors that have affectedthe development of waste management from a political angle in order to identifycharacteristic features of the period in terms of waste management regime. The investigationorigins from Ylva Sjöstrand’s thesis about resource recovery, incineration and tippingof waste in Stockholm 1900-1975 and the theoretical framework in this essay is based onher thesis.By analysing three propositions from the years 1975, 1993 and 2003 concerning wasteand waste management I will argue that the new waste management regime that dominatedSweden during 1975-2005 is called sustainability regime. The name sustainabilityregime is therefore the result which this essay leads to.