Laboratory lysimeters were used to investigate the behaviour, over time, of a humid west coast forest soil under intermittent primary municipal waste water irrigation. Mineral soil packed to a depth of 69 cm and to a uniform density of about 0.9 gm per cm³ was covered with a forest floor 9 cm thick. Sintered glass bead tensiometers were used to gauge the water potential distributions in the soil lysimeters. Irrigation and drainage systems were designed to maintain constant rates of waste water application and facilitate measurement of drainage rates. Two groups of soil lysimeters each with triplicate samples, were loaded with waste water at the rates of 0.23 cm per day ( 37 cm³ per day ) and 0.47 cm per day ( 75 cm³ per day ) for a period of 9 months. The soil lysimeters were incubated at a temperature of about 15.5 degrees Centigrade. The total amounts of nitrogen added to both groups of soil lysimeters were 223.7 gm and 436.9 gm or equivalent to 1.4 % and 2.7 % of the total nitrogen of the original soil, respectively. Renovations of wastewater in terms of nitrogen were 75 % and 43 % with respect to the two groups of soil lysimeters. Renovations in terms of phosphorus were more than 99 % in both groups of soil lysimeters. Retention of nutrients by the soil was increased with time under favourable aerobic conditions. Uptake of nutrients by vegetation in the field would minimize leaching losses. Results from this experiment indicated no significant changes in the physical and chemical behaviour of the soils. Proper design of the waste water irrigation system in terms of loading would maximize the efficiency of renovation without deteriorating the behaviour of the soils. / Land and Food Systems, Faculty of / Graduate

Despite the extensive research carried out on waste of electrical and electronic equipment (WEEE) over the past decades, little is known about the quality of electronic products discarded and the extent to which quality affects the decisions to dispose and reuse these products as well as the impact of the current design of products for reuse and remanufacture. This information is fundamental to understand the reasons for the recent unfettered growth in electronic waste, and to propose solutions to address this problem. In this thesis, using a multi-method approach, face to face semi-structured interviews and product fault find surveys, the author investigates and reports the reasons consumers dispose of microwave ovens and the quality of the products, in particular microwave ovens, that are discarded in the United Kingdom as well as recommended design changes to original equipment manufacturers in order to facilitate reuse and increase the lifespan of such products. By collecting and testing 189 microwave ovens disposed of cosmetic imperfections, as well as electrical and mechanical defects, the results revealed that: (i) a fifth of all microwaves disposed are in perfect working condition and can be reused without any reuse process, (ii) a high percentage of the microwaves discarded have only very minor defects, (iii) almost all microwaves discarded with minor defects can be safely refurbished for re-use, (iv) very few components are responsible for most mechanical and electrical faults, (v) for most microwaves disposed of, the prices of the parts necessary for repair are a very small fraction of the average price of a new microwave. Using face to face interviews with 82 persons disposing electronic microwaves it was also found that: (i) consumers are largely unaware of alternative routes to send their end-of-life/use functional products other than the public recycling facilities, and (ii) a large proportion of the consumers disposing of microwaves intend to buy a similar product, only partially supporting the widely-held belief that e-waste is driven by a desire for the latest technology. Based on these results, the author argues that, for microwave ovens disposed in the United Kingdom via household waste recycling centres, the quality of the products discarded is not a serious impediment for reuse, neither are the prices of spare parts. Furthermore, the major factor preventing reuse is the current design of this product, which makes remanufacturing difficult and onerous, as well as the receptiveness of the market for second hand items. Using this information, the author also proposes small changes in design that can significantly improve reusability and, as a consequence, increases the life span of these products.

A lab-scale study of anoxic-aerobic digestion of waste activated sludge was performed, using 6 litre digesters, and operated in a semi - continuous (fed-once-a-day) manner with solids retention times (SRTs) of 20, 15 and 10 days and mixed-liquor temperatures of 20 °C and 10 °C. Raw sludge was obtained from a pilot-scale biological phosphorus removal facility operating at U.B.C. Fresh sludge was obtained daily and digested by three different digestion modes: anoxic-aerobic, aerobic with lime addition and aerobic. Two aerobic control digesters were run in parallel with the anoxic-aerobic digesters. One of the aerobic digesters received a daily dose of lime slurry. All three digesters were operated under identical conditions (except for the cycling of air supply to the anoxic-aerobic digesters) so that direct comparison could be made between the three digestion modes. Comparisons were made on the basis of five main parameters related to: (1) digestion kinetics, (2) digested sludge characteristics, (3) supernatant quality, (4) ORP monitoring, and (5) an overall rating system. Percent volatile suspended solids (VSS) reduction was used as one performance variable. Despite using only 42 percent of the air required by the two controls, anoxic-aerobic digestion showed comparable percent VSS reductions. All three digestion modes showed increased solids reduction with increasing SRT and temperature. There was a linear relationship between percent TVSS and the product of SRT and temperature. All three digestion modes had a propensity to retain their percent nitrogen and phosphorus within their solids. However, with respect to retaining phosphorus, the aerobic controls were the least effective. Anoxic-aerobic digestion maintained neutral mixed-liquor pH (MLpH) throughout. Lime controls were maintained at MLpH close to neutral. Aerobic digestion, in general, resulted in MLpH levels below 5.0, however, there were periods when the MLpH of the aerobic digesters varied widely between 4.2 and 6.8. Supernatant quality was superior for the anoxic-aerobic digesters. Due to the incorporation of non-aerated periods, there was almost 100 percent denitrification of nitrates produced during the aerated time. This nitrification-denitrification resulted in very low soluble nitrogen levels in the effluent, as well as considerable removal of nitrogen gas. Neither of the controls showed this ability. The lime and aerobic controls produced high levels of effluent nitrates, as well as occasional measurements of ammonia and nitrite. Phosphorus levels were lowest for the lime control and anoxic-aerobic digesters. Presumably, due to reduced pH levels, the soluble phosphorus levels from the aerobic digesters were 2 to 3 times those in the lime or anoxic-aerobic digesters. Alkalinity was conserved in the anoxic-aerobic digesters as well as the lime control. However, the purely aerobic digesters consumed alkalinity until very little buffering capacity remained. Oxidation-reduction potential (ORP) was used as a means of monitoring the anoxic-aerobic digesters on a real time basis. ORP was particularly useful during the non-aerated periods, due to the fact that, at those times, dissolved oxygen was undetectable. Characteristic real time ORP profiles were revealed. Slope changes correlated well with events of theoretical and engineering interest; the' disappearance of ammonia and nitrates, as well as the (dis)appearance of detectable dissolved oxygen, could be predicted by these slope changes. As a result of the findings, ORP may prove to be an ideal parameter for the control of the anoxic-aerobic digestion process. Finally, an overall rating system was developed. The results of this study suggest that, for the digestion of waste activated sludge, anoxic-aerobic digestion out-performed both lime-control and conventional digestion modes. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

The objective of the research program was to demonstrate the technical feasibility of removing phosphorus, by the enhanced biological phosphorus removal mechanism, from domestic wastewater using a laboratory scale Sequencing Batch Rotating Biological Contactor (SBRBC). The rotating discs of the RBC were subjected to alternating anaerobic/aerobic conditions by varying the water level in the reaction vessel. At the start of the treatment cycle, the RBC reactor would be filled submerging the rotating discs and ensuring anaerobic conditions in the RBC biofilm. Acetate would be added to the reaction vessel at this time. Following the batch anaerobic react period part of the reactor contents were decanted to either the sewage feed tank or a separate holding vessel to later become part of the influent for the next treatment cycle. With the rotating: discs of the-RBC partially submerged oxygen was available to the bacteria, in the RBC biofilm. Three operating schedules were tried with the above process. Each operating schedule differed in the way the decanted wastewater from the anaerobic phase was handled. Batch tests were conducted weekly to determine the nature of the biological reactions taking place in each of the batch anaerobic and aerobic phases. The SBRBC process showed promise for enhanced biological phosphorus removal from domestic wastewater. Carbon removal and nitrification of the wastewater were secondary benefits to this process. The success of the process was found to be dependent on the attainment of proper anaerobic conditions at the start of each treatment cycle. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

The way in which we approach building design is constantly being influenced by evolving economic, environmental and social parameters. These factors have implications on both pragmatic and aesthetic facets of design. The built environment is not autonomous from its immediate site or the ecologies of the region in which it is located, rather, the former must be designed to symbiotically exist within and enhance the latter. The term ecology is defined as “a branch of science that deals with the relations of organisms to one another and to their physical surroundings.” Although this typically relates to biology, the term can be expanded to include economic or social ecology. It has been proposed that architectural design can be informed through and should evolve in relation to; environmental, economic and social ecologies. This thesis will examine the relationships between these “ecologies” and how they can inform the adaptive reuse of a vacant industrial site. It will include an examination of the paradigm shift from large-scale industrial manufacturing to Small and Medium-sized Enterprises (SMEs) at the economic and social level. It will further discuss the evolution of environmental awareness within this shift and how these values can drive architectural design while allowing for long term flexibility in adaptive reuse.

0 / SPK / archives@tulane.edu

Ett hållbart tänkande blir allt viktigare i dagens samhälle. EU-kommissionen har beslutat att resurser ska användas på ett mer effektivt sätt för att främja en hållbar utveckling. Inom byggbranschen kan detta handla om Design for Deconstruction (DfD), vilket kan översättas till projektering för demontering. En tidigare undersökning för DfD har genomförts av SBUF tillsammans med NCC för att kartlägga demonterbarhet för stomelement. Osäkerheten finns däremot kring hur enkelt det är att demontera och detta kräver ytterligare utredning. Denna undersökning syftar därför till att göra en kvalitativ studie av hur det ser ut i praktiken i Sverige samt vilka tankar som finns hos främst projektörer och leverantörer. Arbetets mål är att bidra till en ökad kunskap och medvetenhet inom byggbranschen kring hur byggelement kan projekteras med hänsyn till DfD. Den huvudsakliga frågan som behandlas i denna undersökning är hur demontering och återanvändning kan tas hänsyn till redan i projekteringen.En litteraturstudie genomfördes för att skapa en överblick av kunskapsläget och tillämpningen av DfD som sedan verifierades och kompletterades med en intervjuundersökning.Projektering för demontering har stor betydelse för att öka byggbranschens resurseffektivitet och förbättra avfallshanteringsprocessen. Byggandet idag ser främst till funktion och estetik framför värdet i att demontera och återanvända komponenter, material eller byggelement. För att möjliggöra demontering och återanvändning bör elementen standardiseras och tillämpas för byggnader där verksamheten kan komma att ändras eller flyttas. Håldäcks- och massivelement är mest lämpade för detta, tack vare sin flexibilitet.Vanliga kopplingar som används idag är kramlor, bult, dubb, svetsplåt, expanderbult och skruvfäste. Vid projektering för demontering är en allmän regel att kopplingar ska vara reversibla. Mekaniska kopplingar är därför mest lämpliga för demontering och återanvändning. Många kopplingar och lyftsystem för byggelement är idag inte helt lämpade för demontering och återanvändning. Både kopplingar och lyftsystem behöver därför utvecklas vidare.För att kunna etablera en cirkulär princip behövs även dokumentation och spårbarhet, för byggelementen. Dokumentation om spårbarhet och demontering är idag näst intill obefintlig. Anvisningar för demontering måste finnas tillgängliga, som separata dokument eller monteringsanvisningar vilka kan användas vid demontering. En ny metod som kallas materialpass tillsammans med GTIN (Global Trade Item Number) och RFID (Radio Frequency Identification) kan vara en lösning på spårbarhet och samling av dokumentation. Om information ska vara tillgänglig om 100 år behövs ett tidlöst och oberoende format utvecklas för att samla och lagra information och dokumentation.Hänsyn till demontering måste tas redan i projekteringen vilket innebär att arkitekter och andra projektörer kan påverka om byggnaden skall vara demonterbar. För att säkerställa att det är möjligt att genomföra bör även leverantören involveras tidigt. Ska demontering och återanvändning bli en verklighet måste framförallt krav komma från beställare och politiker. Nyttan som ges är långsiktig och det är förvaltarna som kan ta del utav den nyttan. Förutom beställare och myndigheter kan även branschorganisationer driva frågan framåt. Slutligen är det de som kan göra ekonomisk vinning på demontering som kommer driva den frågan framåt. / The EU-commission has decided to use resources more efficiently to promote sustainable development. For the building sector, this means Design for Deconstruction (DfD). A previous study for DfD has been conducted to map disassembly for superstructures. Uncertainties about the difficulty to disassemble and this requires further examination. This study therefore aims to make a qualitative study of what it looks like in practice in Sweden among consultants and suppliers. The main issue dealt with in this study is how disassembly and reuse can be considered in an early stage.A literature study was conducted to provide an overview of the state of knowledge and application of DfD, which was subsequently verified and supplemented by an interview survey.Design for deconstruction is of great importance for increasing the resource efficiency of the building sector. Hollow core- and solid slab elements are suitable for deconstruction and reuse. A general rule for DfD is that connections must be reversible. Mechanical connections are therefore most suitable. To enable reuse, the connection- and lifting systems needs to be further developed.In order to establish a circular economy, documentation and traceability are needed. Disas-sembly instructions or assembly instructions that can be used for disassembly must be available. Material passport along with Global Trade Item Number (GTIN) and Radio Frequency Iden-tification (RFID) can be a solution to traceability and collection of documentation. For inform-ation to be available in 100 years, a timeless and independent solution is needed.Consultants together with architects can design the building to enable deconstruction. To ensure that it is possible to implement, the supplier should be involved early on. If deconstruction and reuse are to become a reality, requirements must come from clients or authorities. In addition to the client and the authorities, industry organizations can push the issue forward.

The space systems industry is moving towards smaller multi-vendor satellites, known as Small Space. This shift is driven by economic and technological factors that necessitate hardware and software components that are modular, reusable, and secure. This research addresses two problems associated with the development of modular, reusable, and secure space systems: developing software for space systems (the Development Problem) and securing space systems (the Security Problem). These two problems are interrelated and this research addresses them together. The Development Problem encompasses challenges that space systems developers face as they try to address the constraints induced by reduced budgets, design and development lifecycles, maintenance allowances, multi-vendor component integration and testing timelines. In order to satisfy these constraints a single small satellite might incorporate hardware and software components from dozens of organizations with independent workforces and schedules. The Security Problem deals with growing need to ensure that each one of these software or hardware components behaves according to policy or system design as well as the typical cybersecurity concerns that face any information system. This research addresses the Development Problem by exploring the needs and barriers of Small Space to find the best path forward for the space systems industry to catch up with the methodology advancements already being widely used in other software fields. To do this exploration a series of five surveys, referred to as SISDPA, was conducted to assess current attitudes and state of practice among space system developers. This crystallized a need in space system development — modular reusable open networks can help Small Space realize its potential, but there is still need to address certain security threats. This research addresses the Security Problem by augmenting a modular reusable open-network software development framework, called SSM, by adding policy enforcement in the form of authentication, access control, and encryption provisions, to create a new development framework, SSSM. This design and implementation adds security provisions while minimizing the impact on developers using the framework. SSSM is evaluated in terms of developer and system resource burden and shows that SSSM does not significantly increase developer burden and preserves the ease-of-use of SSM.

No description available.

The current pressure on water bodies is a structural problem that may compromise the satisfaction of future water demand and the good status of the natural environment. Activities such as wastewater reuse or desalination provide an additional source of water resources to meet demand without the need to increase natural water abstractions. In addition, reuse also contributes to improving water quality by limiting abstractions and reducing discharges. However, reuse has not been widespread as a source of supply in resource-rich contexts. In resource-abundant areas, the high cost of reusing water is a strong disincentive to its use, which puts the focus on reducing pollution through discharge without assessing the potential of reuse as an additional source of resources. The use of reclaimed water has a great margin for development that should be exploited in the coming years to obtain a guarantee of supply and an improvement in the environmental quality of water in the current context of increasing scarcity. However, the financial and environmental situation of reuse requires the involvement of the public sector. In this work, two instruments with the potential to facilitate the development of reuse have been studied. The first of these is photovoltaic self-consumption, in order to reduce the cost of energy consumption of wastewater treatment plants, given that this is their main financial operating cost. This possibility, however, has shown little capacity to reduce these costs since, except in the case of the floating photovoltaic installation, the cost of electricity from self-consumption is higher or similar to the market price. If we consider the reduction of greenhouse gas emissions derived from self-consumption, this alternative is much more competitive. The situation is, once again, of an activity that presents financial losses and environmental benefits derived from the current excess of emissions. The responsibility lies with the public sector in the same way as in the case of reuse. Water tariffs, as one of the main revenues from water treatment, is an instrument that can be evaluated with a view to increasing revenues through an increase in the price of water. The results obtained show large differences in the impact of such an increase depending on the region but make it clear that the potential for additional revenue from this possibility is small. This analysis has also shown that there is a problem in the current tariffs that reduces their effectiveness by not valuing the type of household. The problem lies not in the structure of the tariff or the number of household members, but in the characteristics of the household. By not taking these into account and calculating the bill without these details, the tariffs are not fully effective. In conclusion, both reuse and photovoltaic self-consumption are beneficial activities for society, but the financial costs involved in their implementation require the involvement of a public sector with a reduced capacity to increase current revenues.