At Kungsberget ski-resort in Gävleborg county all wastewater produced at the facility is treated on-site. The treatment takes place at their own wastewater treatment plant in a so-called Sequence Batch Reactor (SBR), which has been in operation for about a year before this study. Kungsberget AB is currently in charge of the facility but their goal is to hand responsibility over to Sandviken Energy AB. In order for this handover to occur Kungsberget has to produce three approved treatment results. This means that the concentrations of BOD7 needs to lie under 0.3 mg/l and total phosphorous under 10 mg/l in the effluent water for three consecutive samples. The results show momentaneous values. These limits are stated in the permit Kungsberget received from the Environmental Protection Division. Kungsberget has had problems with high and fluctuating phosphorous concentrations and therefore the transfer has not yet taken place. In this project several parameters have been analysed in order to obtain an overview of prevailing influent and effluent concentrations. Some of the parameters that have been analysed are; phosphorous, nitrogen, BOD7, suspended solids and pH. A lot of time and effort has been put into elucidating operational routines at the wastewater treatment plant (WWTP) and gaining knowledge from available literature regarding different parameters’ effect on treatment results.   Kungsberget has had problems adapting operating routines and reaching stable treatment results as the load is highly effected of seasonal fluctuation. This has not been taken into account earlier and the WWTP has been operated in the same manner all year around. Suggestions to how operating routines can be modified in to better meeting the needs have been produced and alternative treatment methods have been presented in the report. Two of the suggestions include biological phosphorous removal and adding carrier media to increase bacteria growth. An aerobic solids retention time has been calculated in order to evaluate whether nitrifying bacteria have enough time for grow and maintain a stable population. The calculation was carried out by measuring suspended solids and aeration time and the result was a solids retention time of approximately 6 days.

Sludge accumulation, treatment and disposal can represent a high percentage of the operating cost for a wastewater system. This is especially important for small-scale and onsite wastewater treatment systems, where sludge removal can be one of the few operating costs of the system. In 2000, as a result of a large number of septic system failures, the community of Wardsville installed a Clearford Industries Inc. Small Bore Sewer™ (SBS™) system which included two-chamber 3600 L tanks located on the properties of individual homes. The tanks were collectively attached to a small bore piping system to deliver the effluent from the tanks to a small community wastewater treatment system. During the summer of 2007, a field study was initiated with a community survey, followed by a review of candidate sites, leading to the selection of 29 sites for site investigation and sampling. Sampling involved the collection of samples for sludge characterization along with the measurements of the height of solids (scum and sludge) within the tank. The data were analyzed to determine the factors having a statistically significant impact on solids accumulation rates within each of the two chambers of the tank. Household water usage was found to be the variable having the strongest association with sludge and scum accumulation, and models were estimated relating solids accumulation to water usage in order predict pump out frequency. A second field sampling program was conducted in Wardsville during April 2008, involving only the first chamber of 13 primary clarifier tanks. Overall contributions have been made in understanding and quantifying solids accumulation rates and sludge characterization in onsite primary clarifier tanks. As well, the information gained from the analysis of the data collected provides a meaningful insight into the factors influencing solids accumulation within individual residential primary clarifier tanks, and points to future research directions for understanding the factors influencing solids accumulation. / Thesis (Master, Civil Engineering) -- Queen's University, 2009-04-25 15:34:46.243

Sludge accumulation, treatment and disposal can represent a high percentage of the operating cost for a wastewater system. This is especially important for small-scale and onsite wastewater treatment systems, where sludge removal can be one of the few operating costs of the system. In 2000, as a result of a large number of septic system failures, the community of Wardsville installed a Clearford Industries Inc. Small Bore Sewer™ (SBS™) system which included two-chamber 3600 L tanks located on the properties of individual homes. The tanks were collectively attached to a small bore piping system to deliver the effluent from the tanks to a small community wastewater treatment system. During the summer of 2007, a field study was initiated with a community survey, followed by a review of candidate sites, leading to the selection of 29 sites for site investigation and sampling. Sampling involved the collection of samples for sludge characterization along with the measurements of the height of solids (scum and sludge) within the tank. The data were analyzed to determine the factors having a statistically significant impact on solids accumulation rates within each of the two chambers of the tank. Household water usage was found to be the variable having the strongest association with sludge and scum accumulation, and models were estimated relating solids accumulation to water usage in order predict pump out frequency. A second field sampling program was conducted in Wardsville during April 2008, involving only the first chamber of 13 primary clarifier tanks. Overall contributions have been made in understanding and quantifying solids accumulation rates and sludge characterization in onsite primary clarifier tanks. As well, the information gained from the analysis of the data collected provides a meaningful insight into the factors influencing solids accumulation within individual residential primary clarifier tanks, and points to future research directions for understanding the factors influencing solids accumulation. / Thesis (Master, Civil Engineering) -- Queen's University, 2009-04-25 15:34:46.243

No abstract available. / Thesis (Ph.D.)-University of Natal, Durban, 1991.

Solid foams have been studied for years for their ability to mitigate damage from sudden impact. Small explosive attacks threaten to damage or destroy key structures in some parts of the world. A newly developed material, carbon foam, may offer the ability to mitigate the effects of such blasts. This project investigates the energy absorbing properties of carbon and polyurethane based foams in dynamic compression to illustrate their viability to protect concrete structures from the damaging effects of pressure waves from a small blast. Cellular solid mechanics fundamentals and a survey of the microscopic cellular structure of each type of foam are discussed. Experiments were performed in three strain rate regimes: low strain rate compression testing, middle strain rate impact testing, and high strain rate blast testing to reveal mechanical behavior. Experiments show a 7.62 cm (3”) thick hybrid composite layered foam sample can protect a concrete wall from a small blast.

A review of the literature indicates that the understanding of the mixing phenomena in anaerobic digesters is limited and the ability to measure digester mixing characteristics is lacking. Moreover, rheological characteristics of the sludge are largely ignored. The need for a more thorough understanding of fundamental mixing relationships and the ability to measure these relationships in the anaerobic digester is recognized. To this end, investigations using experimental and numerical methods to visualize flow patterns and quantify mixing that impact biogas yields is reported. Results from this research identifies optimum mixing regimes for digesters depending on their sludge rheology, operational regimes, digester dimensions and mixing systems, and also produces an industrial guide to improve digester design. The results show that in order to accurately predict the optimum mixing regime for a particular anaerobic digester, it is necessary to determine to what extent biogas output is dependent upon, and can be influenced by flow patterns in an anaerobic digester. These flows are in turn determined by physical characteristics of the digester, the feed regime, the mixing system and the rheological properties of the sludge. Mixing regimes are tailored to produce flow patterns that could potentially increase biogas production and/or reduce mixing energy input of the digester. An all-inclusive anaerobic digester model is developed and validated using advanced experimental techniques that can be used to optimize the digestion process in terms of physical and biological parameters. In either case, the model provides an ongoing management of anaerobic digester process to improve overall energy yield from the digester and reduce its environmental impact.

Three problems are being investigated in this thesis. The first two relate to the modelling and analysis of martensitic phase transitions, while the third is concerned with some mathematical tools used in this setting. After a short introduction (Chapter 1) and overviews of the calculus of variations and martensitic phase transformations (Chapter 2), the research part of this thesis is divided into three chapters. We show in Chapter 3 that for the two wells $\mathrm{SO}(3)U$ and $\mathrm{SO}(3)V$ to be rank-one connected, where the $3\times 3$ symmetric positive definite $U$ and $V$ have the same eigenvalues, it is necessary and sufficient that $\mathrm{det}(U-V)=0$, a result that does not hold in higher dimensions. Using this criterion and a result of Gurtin, formulae for the twinning plane and the shearing vector are obtained, which yield an extremely simple condition for the occurrence of so-called compound twins. Our results also provide a simple classification of the twinning mode of the two wells by looking at the crystallographic properties of the eigenvectors of the difference $U-V$. As an illustration, we apply our results to cubic-to-tetra gonal,tetragonal-to-monoclinic and cubic-to-monoclinic transitions. Chapter 4 focuses on the mathematical analysis of biaxial loading experiments in martensite, more particularly on how hysteresis relates to metastability. These experiments were carried out by Chu and James and their mathematical treatment was initiated by Ball, Chu and James. Experimentally it is observed that a homogeneous deformation $y_1(x)= U_1x$ is the stable state for `small' loads while $y_2(x)=U_2x$ is stable for `large' loads. A model was proposed by Ball, Chu and James which, for a certain intermediate range of loads, predicts crucially that $y_1(x)=U_1x$ remains metastable i.e., a local - as opposed to global - minimiser of the energy). This result explains convincingly the hysteresis that is observed experimentally. It is easy to get an upper bound for when metastability finishes. However, it was also noticed that this bound (the Schmid Law) may not be sharp, though this required some geometric conditions on the sample. In this chapter, we rigorously justify the Ball-Chu-James model by means of De Giorgi's $\Gamma$-convergence, establish some properties of local minimisers of the (limiting) energy and prove the metastability result mentioned above. An important part of the chapter is then devoted to establishing which geometric conditions are necessary and sufficient for the counter-example to the Schmid Law to apply. Finally, Chapter 5 investigates the structure of the solutions to the two-well problem. Restricting ourselves to the subset $K=\{H\}\cup \mathrm{SO}(2)V \subset\mathrm{SO}(2)U\cup\mathrm{SO}(2)V$ and assuming the two wells to be compatible, we let $T_1$ and $T_2$ denote the two (not necessarily distinct) twins of $H$ on $\mathrm{SO}(2)V$ and ask the following question: if $\nu_x$ is a non-trivial gradient Young measure almost everywhere supported on $K$, does its support necessarily contain a pair of rank-one connected matrices on a set of positive measure? Although we do not provide a solution for the general case, we show that this is true whenever (a) $\nu_x\equiv \nu$ is homogeneous and $\mathrm{supp}\nu\cap \mathrm{SO}(2)V$ is connected, (b) $\nu_x\equiv \nu$ is homogeneous and $T_1=T_2$ i.e., when the two wells are trivially rank-one connected) or (c) $\mathrm{supp}\nu_x \subset F$ a.e., for some finite set $F$. We also establish a more general case provided a strong `rigidity' conjecture holds.

Carding is an essential pre-spinning process whereby masses of dirty tufted fibres are cleaned, disentangled and refined into a smooth coherent web. Research and development in this `low-technology' industry have hitherto depended on empirical evidence. In collaboration with the School of Textile Industries at the University of Leeds, a mathematical theory has been developed that describes the passage of fibres through the carding machine. The fibre dynamics in the carding machine are posed, modelled and simulated by three distinct physical problems: the journey of a single fibre, the extraction of fibres from a tuft or tufts and many interconnecting, entangled fibres. A description of the life of a single fibre is given as it is transported through the carding machine. Many fibres are sparsely distributed across machine surfaces, therefore interactions with other neighbouring fibres, either hydrodynamically or by frictional contact points, can be neglected. The aerodynamic forces overwhelm the fibre's ability to retain its crimp or natural curvature, and so the fibre is treated as an inextensible string. Two machine topologies are studied in detail, thin annular regions with hooked surfaces and the nip region between two rotating drums. The theoretical simulations suggest that fibres do not transfer between carding surfaces in annular machine geometries. In contrast to current carding theories, which are speculative, a novel explanation is developed for fibre transfer between the rotating drums. The mathematical simulations describe two distinct mechanisms: strong transferral forces between the taker-in and cylinder and a weaker mechanism between cylinder and doffer. Most fibres enter the carding machine connected to and entangled with other fibres. Fibres are teased from their neighbours and in the case where their neighbours form a tuft, which is a cohesive and resistive fibre structure, a model has been developed to understand how a tuft is opened and broken down during the carding process. Hook-fibre-tuft competitions are modelled in detail: a single fibre extracted from a tuft by a hook and diverging hook-entrained tufts with many interconnecting fibres. Consequently, for each scenario once fibres have been completely or partially extracted, estimates can be made as to the degree to which a tuft has been opened-up. Finally, a continuum approach is used to simulate many interconnected, entangled fibre-tuft populations, focusing in particular on their deformations. A novel approach describes this medium by density, velocity, directionality, alignment and entanglement. The materials responds to stress as an isotropic or transversely isotropic medium dependent on the degree of alignment. Additionally, the material's response to stress is a function of the degree of entanglement which we describe by using braid theory. Analytical solutions are found for elongational and shearing flows, and these compare very well with experiments for certain parameter regimes.

Over the past 30 years the study of free boundary problems has stimulated much work. However, there exists a widely occurring, but little studied subclass of free boundary problems in which the free boundary has dimension two fewer than that of the underlying space rather than the more commonly studied case of one less. These problems are called `codimension-two' free boundary problems. In Chapter 1 the typical geometries required for such problems, the main mathematical techniques and the methodology used are discussed. Then, in Chapter 2, the techniques required to solve them are demonstrated using the particular example of the water entry problem. Further results for the water entry problem are then derived including an analysis of the relatively poorly understood water exit problem. In Chapter 3 a review is given of some classical contact and crack problems in solid mechanics. The inclusion of a cohesive zone in a dynamic type-III crack problem is considered. The Muskhelishvili potential method is presented and used to solve both a contact and crack problem. This enables the solution of a type-I crack problem relating to an ink delivery system to be found. In Chapter 4 a problem posed by car windscreen forming is addressed. A local solution near a corner is analysed to explain when and how point forces occur at the corners of the frame on which the simply supported windscreen rests. Then the full problem is solved numerically for different types of boundary condition. Chapters 5 and 6 deal with several sintering problems in viscous flow highlighting the value of the methodology introduced in Chapter 1. It will be shown how the Muskhelishvili potential method also carries over to Stokes flow problems. The difficulties of matching to an inner as opposed to an outer region are investigated. Last two interface problems between immiscible liquids are considered which show how the solution procedure is adapted when the field equation in the thin region is non-trivial. In the final chapter results are summarised, open problems listed and conclusions drawn.

The urban sprawl creates a gap between producers and consumers and the a sustainable circuitof nutrients and energy is difficult to maintain. Many times the waste that is created in urbanareas is not reused and the circuit is lost. In this project, wastewater treatment is looked atwith the view point that resource recovery is possible through energy production and reuse ofnutrients. In order to optimally run each process step at a wastewater treatment plant forimproved resource recovery, more knowledge is needed in order to not disregard the finaleffluent quality. The goal of this project was to develop a model in MATLAB/Simulink for achemically enhanced primary clarifier at a wastewater treatment plant. The potential ofproducing more biogas and reducing the aeration energy needed in the biological treatmentstep was looked at by focusing on describing the settling velocity of suspended solids.Experimental analysis on settling properties for solids was performed on sampled wastewaterentering the primary settler after changing the addition of chemicals prior in the process line.The wastewater samples were homogenized and then rapidly vacuum pumped up in a column.The solids in the column could thereafter settle and was retained in a cup at the bottom. Themass of total suspended solids (TSS) was classified in five different settling velocity classes,each class assigned a characteristic settling velocity. The experimental procedure followed theViCA's protocol (French acronym for Settling Velocity for Wastewater). A settler, much likethe secondary settler in the Benchmark Simulation Model No. 2 (BSM2), a 10 layer nonreactivetank was modeled. The mass balance in each layer of the settler was decided by thevertical solid flux in the tank and built on the characteristic settling velocity gained from theexperiments. Re-circulation of excess sludge from the subsequent steps at the plant showed toeffect the settling properties of the sludge in the primary settler. The components of TSSshowed to have the largest effect on the distribution of settling velocity. The variation in doseof both coagulant and cationic polymer prior the primary settling tank showed to effect theparticle settling distribution somewhat. A first simulation with an applicable dynamic influentscenario was run. Despite any proper calibration the model gave fairly good predictions ofmeasured TSS in the effluent and sludge outtake water. / När urbana områden växer uppstår svårigheter i att bibehålla ett hållbart kretslopp av energioch näringsämnen. Avståndet mellan producent och konsument ökar och många gångeråteranvänds inte det avfall som städerna producerar och det hållbara kretsloppet bryts. Dettaprojekt har fokuserat på resursåteranvändningen i avloppsvattenhanteringen genommöjligheterna som finns i energiproduktion i form av biogas samt återanvändning avnäringsämnen genom slamåterförsel. Mer kunskap behövs inom varje processteg för attoptimalt använda avloppsreningsverk för förbättrad resurs-återvinning så att inte utgåendevattenkvalitet blir lidande. Målet med projektet var att utveckla en modell iMATLAB/Simulink för primärsedimentering med kemisk fällning. Experimentelltanalyserades sedimentationsegenskaperna hos primärslam genom provtagning avavloppsvatten inkommande till försedimenteringen efter tillsatser av fällnings-kemikalier.Proverna homogeniserades och vakuumpumpades sedan snabbt upp i en kolonn. Detpartikulära materialet i kolonnen kunde därefter sedimentera och fångades upp i en kopp ibotten. Den sedimenterade massan av totalt suspenderat material (TSS) klassificerades i femolika sedimenteringshastighetsklasser och varje klass tilldelades en karakteristisksedimentationshastighet Det experimentella förfarandet följde ViCA’s protokoll (franskförkortning för sedimentationshastigheter för avloppsvatten). En modell av ensedimentationstank, ungefär som för sekundär-sedimenteringen i Benchmark SimulationModel No. 2 (BSM2), utvecklades som en 10 lager icke reaktiv tank. Massbalansen i varjelager bestämdes av det vertikala flödet av partiklar och beräknades med de experimentelltframtagna karakteristiska sedimentationshastigheterna. Återcirkulering av överskottsslam frånde efterföljande reningsstegen visade sig ha stor påverkan på slammetssedimentationsegenskaper i försedimenteringen. Typen av TSS-komponenter hade den störstainverkan på fördelningen av sedimentationshastigheter. Variationen i dos av bådefällningskemikalie och katjonspolymer före primär-sedimenteringstanken hade en visspåverkan på fördelningen. En första simulering med ett sannolikt dynamisk inflödesscenariokördes. Utan någon riktig kalibrering av modellen gav den ändå en relativt realistisk prognospå TSS i utgående vatten och i slamuttaget. / I samarbete med forskningsgruppen ModelEAU, Quebec, Kanada