Partial nitritation of landfill leachate in a SBR prior to an anammox reactor : operation and modelling

Els lixiviats d'abocadors urbans són aigües residuals altament contaminades, que es caracteritzen per les elevades concentracions d'amoni i el baix contingut de matèria orgànica biodegradable. El tractament dels lixiviats a través dels processos de nitrificació-desnitrificació convencionals és costós a causa de la seva elevada demanda d'oxigen i la necessitat d'addició d'una font de carboni externa. En els darrers anys, la viabilitat del tractament d'aquest tipus d'afluents per un procés combinat de nitritació parcial-anammox ha estat demostrada. Aquesta tesi es centra en el tractament de lixiviats d'abocador a través d'un procés de nitritació parcial en SBR, com un pas preparatori per a un reactor anammox. Els resultats de l'estudi han demostrat la viabilitat d'aquesta tecnologia per al tractament de lixiviats d'abocador. El treball va evolucionar des d'una escala inicial de laboratori, on el procés va ser testat inicialment, a uns exitosos experiments d'operació a llarg termini a escala pilot. Finalment, la tesi també inclou el desenvolupament, calibració i validació d'un model matemàtic del procés, que té com a objectiu augmentar el coneixement del procés.

Control and optimization of an SBR for nitrogen removal: from model calibration to plant operation

En aquesta tesis s'ha desenvolupat un sistema de control capaç d'optimitzar el funcionament dels Reactors Discontinus Seqüencials dins el camp de l'eliminació de matèria orgànica i nitrogen de les aigües residuals. El sistema de control permet ajustar en línia la durada de les etapes de reacció a partir de mesures directes o indirectes de sondes. En una primera etapa de la tesis s'ha estudiat la calibració de models matemàtics que permeten realitzar fàcilment provatures de diferents estratègies de control. A partir de l'anàlisis de dades històriques s'han plantejat diferents opcions per controlar l'SBR i les més convenients s'han provat mitjançant simulació. Després d'assegurar l'èxit de l'estratègia de control mitjançant simulacions s'ha implementat en una planta semi-industrial. Finalment es planteja l'estructura d'uns sistema supervisor encarregat de controlar el funcionament de l'SBR no només a nivell de fases sinó també a nivell cicle.

SBR technology for wastewater treatment: suitable operational conditions for a nutrient removal

Actualment, la legislació ambiental ha esdevingut més restrictiva pel que fa a la descàrrega d'aigües residuals amb nutrients, especialment en les anomenades àrees sensibles o zones vulnerables. Arran d'aquest fet, s'ha estimulat el coneixement, desenvolupament i millora dels processos d'eliminació de nutrients. El Reactor Discontinu Seqüencial (RDS) o Sequencing Batch Reactor (SBR) en anglès, és un sistema de tractament de fangs actius que opera mitjançant un procediment d'omplerta-buidat. En aquest tipus de reactors, l'aigua residual és addicionada en un sol reactor que treballa per càrregues repetint un cicle (seqüència) al llarg del temps. Una de les característiques dels SBR és que totes les diferents operacions (omplerta, reacció, sedimentació i buidat) es donen en un mateix reactor. La tecnologia SBR no és nova d'ara. El fet, és que va aparèixer abans que els sistema de tractament continu de fangs actius. El precursor dels SBR va ser un sistema d'omplerta-buidat que operava en discontinu. Entre els anys 1914 i 1920, varen sorgir certes dificultats moltes d'elles a nivell d'operació (vàlvules, canvis el cabal d'un reactor a un altre, elevat temps d'atenció per l'operari...) per aquests reactors. Però no va ser fins a finals de la dècada dels '50 principis del '60, amb el desenvolupament de nous equipaments i noves tecnologies, quan va tornar a ressorgir l'interès pels SBRs. Importants millores en el camp del subministrament d'aire (vàlvules motoritzades o d'acció pneumàtica) i en el de control (sondes de nivell, mesuradors de cabal, temporitzadors automàtics, microprocessadors) han permès que avui en dia els SBRs competeixin amb els sistemes convencional de fangs actius. L'objectiu de la present tesi és la identificació de les condicions d'operació adequades per un cicle segons el tipus d'aigua residual a l'entrada, les necessitats del tractament i la qualitat desitjada de la sortida utilitzant la tecnologia SBR. Aquestes tres característiques, l'aigua a tractar, les necessitats del tractament i la qualitat final desitjada determinen en gran mesura el tractament a realitzar. Així doncs, per tal d'adequar el tractament a cada tipus d'aigua residual i les seves necessitats, han estat estudiats diferents estratègies d'alimentació. El seguiment del procés es realitza mitjançant mesures on-line de pH, OD i RedOx, els canvis de les quals donen informació sobre l'estat del procés. Alhora un altre paràmetre que es pot calcular a partir de l'oxigen dissolt és la OUR que és una dada complementària als paràmetres esmentats. S'han avaluat les condicions d'operació per eliminar nitrogen d'una aigua residual sintètica utilitzant una estratègia d'alimentació esglaonada, a través de l'estudi de l'efecte del nombre d'alimentacions, la definició de la llargada i el número de fases per cicle, i la identificació dels punts crítics seguint les sondes de pH, OD i RedOx. S'ha aplicat l'estratègia d'alimentació esglaonada a dues aigües residuals diferents: una procedent d'una indústria tèxtil i l'altra, dels lixiviats d'un abocador. En ambdues aigües residuals es va estudiar l'eficiència del procés a partir de les condicions d'operació i de la velocitat del consum d'oxigen. Mentre que en l'aigua residual tèxtil el principal objectiu era eliminar matèria orgànica, en l'aigua procedent dels lixiviats d'abocador era eliminar matèria orgànica i nitrogen. S'han avaluat les condicions d'operació per eliminar nitrogen i fòsfor d'una aigua residual urbana utilitzant una estratègia d'alimentació esglaonada, a través de la definició del número i la llargada de les fases per cicle, i la identificació dels punts crítics seguint les sondes de pH, OD i RedOx. S'ha analitzat la influència del pH i la font de carboni per tal d'eliminar fòsfor d'una aigua sintètica a partir de l'estudi de l'increment de pH a dos reactors amb diferents fonts de carboni i l'estudi de l'efecte de canviar la font de carboni. Tal i com es pot veure al llarg de la tesi, on s'han tractat diferents aigües residuals per a diferents necessitats, un dels avantatges més importants d'un SBR és la seva flexibilitat.

The low-latitude boundary layer: Application of ISTP advances to past data

The destruction of the four Cluster craft was a major loss to the planned ISTP effort, of which studies of the magnetopause and low-latitude boundary layer (LLBL) were an important part. While awaiting the re-flight mission, Cluster-II, we have been applying advances in our understanding made using other ISTP craft (like Polar and Wind) and using ground-based facilities (in particular the EISCAT incoherent scatter radars and the SuperDARN HF coherent radars) to measurements of the LLBL made in 1984 and 1985 by the AMPTE-UKS and -IRM spacecraft pair. In particular, one unexplained result of the AMPTE mission was that the electron characteristics could, in nearly all cases, order independent measurements near the magnetopause, such as the magnetic field, ion temperatures and the plasma flow. Studies of the cusp have shown that the precipitation is ordered by the time-elapsed since the field line was opened by reconnection. This insight has allowed us to reanalyse the AMPTE data and show that the ordering by the transition parameter is also due to the variation of time elapsed since reconnection, with the important implication that reconnection usually coats most of the dayside magnetopause with at least some newly-opened field lines. In addition, we can use the electron characteristics to isolate features like RDs, slow-mode shocks and slow-mode expansion fans. The ion characteristics can be used to compute the reconnection rate. We here retrospectively apply these new techniques, developed in the ISTP era, to a much-studied flux transfer event observed by the AMPTE satellites. As a result, we gain new understanding of its cause and structure.

Effects of processing methods on amaranth starch digestibility and predicted glycemic index

Amaranth has attracted a great deal of interest in recent decades due to its valuable nutritional, functional, and agricultural characteristics. Amaranth seeds can be cooked, popped, roasted, flaked, or extruded for consumption. This study compared the in vitro starch digestibility of processed amaranth seeds to that of white bread. Raw seeds yielded rapidly digestible starch content (RDS) of 30.7% db and predicted glycemic index (pGI) of 87.2, the lowest among the studied products. Cooked, extruded, and popped amaranth seeds had starch digestibility similar to that of white bread (92.4, 91.2, and 101.3, respectively), while flaked and roasted seeds generated a slightly increased glycemic response (106.0 and 105.8, respectively). Cooking and extrusion did not alter the RDS contents of the seeds. No significant differences were observed among popped, flaked, and roasted RDS contents (38.0%,46.3%, and 42.9%, respectively), which were all lower than RDS content of bread (51.1%). Amaranth seed is a high glycemic food most likely because of its small starch granule size, low resistant starch content (< 1%), and tendency to completely lose its crystalline and granular starch structure during those heat treatments.

Deakin Online: an evolving case study

This paper describes the planning, implementation and current progress of the Deakin Online Project which aims to establish a virtual campus for Deakin University. The project is built upon the WebCT Vista© learning management system. Strategies for eTeaching and eLearning are analysed and the dangers and opportunities are identified. Approaches to the preparation of both students and faculty for working in the online environment are discussed including online training, mentoring schemes and a dedicated teaching and learning support unit. An in-depth account of the project is presented which is potentially useful to any organization considering embarking on online teaching on a large scale.

In vitro carbohydrate digestibility of whole-chickpea and chickpea bread products

Pulses such as the chickpea are generally considered to be valuable dietary sources of slowly digestible starch, a form of starch that is considered beneficial to health since it results in relatively low post-meal blood glucose levels compared with more rapidly digested starch. The development of novel chickpea-based foods is necessary to help expand the worldwide consumption of the chickpea. However, the effect of different processing methods on the starch digestibility of chickpea-based foods has not been widely investigated. This study used an in vitro method simulating human carbohydrate digestion to determine levels of slowly digestible starch, rapidly digestible starch (RDS), resistant starch, total starch and rapidly available glucose (RAG) of: (i) whole-chickpea products (domestically boiled, commercially canned and commercially precooked/vacuum-packaged); and (ii) standard white bread, chickpea flour bread (25% replacement of wheat flour by chickpea flour) and extruded chickpea flour bread (25% replacement of wheat flour by extruded chickpea flour). The RAG levels were then used to predict the relative in vivo glycaemic indices of the products. The commercially precooked/vacuum-packaged whole chickpeas demonstrated higher levels of RDS than the commercially canned and domestically boiled products (P<0.05). In addition, the domestically boiled product had lower levels of RAG (g/100 g available carbohydrate) compared with the canned and precooked/vacuum-packaged products (P<0.05). There were no significant differences between any of the carbohydrate digestibility measures of the white bread, chickpea flour bread and extruded chickpea flour bread (P>0.05) and all bread products demonstrated far higher RAG (g/100 g available carbohydrate) values than the whole-chickpea products. The findings suggest that the commercially precooked/vacuum-packaged whole chickpeas and the canned product may have higher and less beneficial glycaemic indices than the domestically boiled chickpeas. It appears unlikely that the use of chickpea flour or extruded chickpea flour, at the incorporation rate investigated in this study, would modify the glycaemic index of bread. It is probable, however, that the chickpea bread products investigated would demonstrate higher and potentially less beneficial glycaemic indices than the whole-chickpea products.

Duality and organizing forms in change management

Although the fervour proclaiming new forms of organizing as the latest management panacea has not yet subsided, the calls for caution and further investigation have been bolstered by empirical findings. A common outcome of studies concerned with new organizing forms has been a greater awareness of the tensions or dualities between traditional and new forms. In particular, the conventional assumption that the two forms represent contradictory, incompatible forces is coming under increasing scrutiny. The resulting either/or approach to organizing form may be viewed as an inappropriate perspective for researching organizational change as it ignores the complexity and subtlety of organizing form. The reality is that, as new forms of organizing are introduced, they are more likely to supplement rather than supplant existing forms (Sanchez-Runde and Pettigrew 2003). The way forward therefore is to learn how to work with, rather than eliminate, dualities in organizing forms. This paper contends that dualities represent a superior perspective for interpreting organizing forms, and perhaps, foreshadows the direction of a future organizational change research paradigm.

Topology based packet marking for IP traceback

IP source address spoofing exploits a fundamental weakness in the Internet Protocol. It is exploited in many types of network-based attacks such as session hijacking and Denial of Service (DoS). Ingress and egress filtering is aimed at preventing IP spoofing. Techniques such as History based filtering are being used during DoS attacks to filter out attack packets. Packet marking techniques are being used to trace IP packets to a point that is close as possible to their actual source. Present IP spoofing  countermeasures are hindered by compatibility issues between IPv4 and IPv6, implementation issues and their effectiveness under different types of attacks. We propose a topology based packet marking method that builds on the flexibility of packet marking as an IP trace back method while overcoming most of the shortcomings of present packet marking techniques.

Literacy in the new media age: creativity as multimodal design

Much of the current discourse of adolescence is best described as emblematic of modernity, as colonial, as gendered, and as administrative (Lesko, 2001) working to maintain “progressive” school literacy practices that ignore adolescents’ new “cyber-techno subjectivity” (Luke & Luke, 2001) and creativity in the “new media age” (Kress, 2003). School curricula often do not acknowledge the range of skills adolescents acquire outside formal education. Youths’ new multimodal social and cultural practices—as they fashion themselves creatively in multiple modes as different kinds of people in “New Times” (Luke, 1998)— oints to the liberating power of new technologies that embrace their imagination and creativity. In two middle years classes, adolescents’ creativity was recognised and validated when they were encouraged to re-represent curricular knowledge through multimodal design (New London Group, 1996). The results suggest the changed classroom habitus (Bourdieu, 1980) produced new and emergent discursive and material practices where creativity, through imaginative collaboration, emerges as capital in an economy of practice (Bourdieu, 1996). The findings suggest schools should recognize adolescents’ creativity—that often manifests itself through their cultural and social capital resources—as they integrate and adapt to the new affordances acquired through their out-of-school literacy practices.

Using problem based learning to teach future Australian IS professionals

Teaching Information Systems (IS) to Australian tertiary students has become increasing problematic with many of them relying on a surface level approach to study. This will surely affect their understanding of IS material and in turn affect their effectiveness in the workplace.

This paper examines the issues behind this trend and considers Problem Based Learning (PBL) asan aid to counteract it.

Conservation and management of hydromyine rodents in Victoria, Australia

Of the 15 species of native rodents recorded from Victoria, Australia, six became extinct within 70 years of European settlement, and two of the remaining nine are classified as ‘threatened’ and four are classified as ‘near threatened’. Thus, only three species are considered to be adequately conserved. This represents one of the most dramatic mammalian species declines recorded in Australia. All the threatened species belong to the subfamily Hydromyinae, the Australian ‘old endemics’. Of the extinct species, four were recorded only from the semi-arid north-west of the state and two from dry woodlands in the central and southern regions. The two  endangered species are the smoky mouse, which has a disjunct distribution from near-coastal to sub-alpine habitats, and the New Holland mouse, which is the most geographically restricted species. Discovered in Victoria only in 1970, it has become extinct at several locations and is the subject of a major recovery program that includes captive breeding and reintroduction. Conservation protocols and practices for Victoria’s native rodents are implemented under state legislation, but lack of basic ecological information makes their conservation a difficult task.

Tackling domestic violence : exploring the health service contribution

This report is one of a series of reports, which specifically reports on the findings from the evaluation of a number of domestic violence projects. The report aims to explore the health service contribution to tackling domestic violence, and draws upon the findings from four projects, which had developed and implemented interventions within a number of health settings. It places the findings from these projects in the context of the literature.