Metaldehyde removal from drinking water by adsorption onto filtration media: mechanisms and optimisation

Trace micropollutants should be removed during drinking water production without increasing the disinfection-by-product formation potential or energy demand of the treatment process. We demonstrate the efficacy of different filtration media to remove metaldehyde through controlled batch experiments on water augmented with metaldehyde. Equilibrium concentrations of metaldehyde and surrogate organics were successfully described by the Freundlich isotherm. Metaldehyde can be attenuated to varying degrees with activated carbon and sand with an active and inactive biofilm with kf values ranging from 0.006–0.3 (mg g−1)(L mg−1)1/n. The presence of the active biofilm improved metaldehyde adsorption by sand media, due to additional biosorption mechanisms, a greater surface area or biodegradation. Baseline levels of competing natural organic matter surrogates (NOM) reduced overall adsorption efficacy but increasing concentrations of NOM did not impact metaldehyde removal efficacy in a significant way. Biological activated carbon was identified as the most suitable adsorbent of metaldehyde (94% removal) but sand with an acclimated biofilm was capable of acting as a bio-adsorbent of metaldehyde even under environmentally relevant concentrations (41% adsorption from 0.002.5 mg L−1). Moreover, we observed that thermal hydrolysis of metaldehyde occurred at 60 °C, suggesting that thermal regeneration of GAC for this pesticide was possible at relatively low temperatures. Biological adsorption and thermal hydrolysis approaches presented herein offered a way forward to increase efficiency and cost effectiveness of existing treatments for metaldehyde

Hidden Narrative: A Family of Objects

My artwork aims to create an ephemeral world filled with metaphorical materials. I examine and use my own experiences and perspectives, presenting fluctuations between childhood and adulthood. The personal objects that represent these times frame an implied sentience. The objects, gathered and installed in specific groupings, connote familial relationships

Heritage, Hermeneutics and Hegemony

In recent times, the concept of ‘intangible heritage’ has gained credence within the international heritage community, reflecting wider concerns relating to the cultural impact of global economic, technological and political forces. For many, intangible heritage represents a vital living mediation of the material past (i.e. tangible heritage) which deepens its significance and meaning-conferring qualities. This thesis explores how in recent times, the intangible heritage became ‘separated’ from the tangible heritage in such a way as to bring about ideological division within the field of heritage preservation and a sense of discontinuity with the past – particularly relating to the practice of restoration and its patrimony of expertise. The thesis argues that this has been attributable to an ‘institutionalised’ conception of heritage based essentially on a historiography of materials located in the ideological site of the museum – the repository where tangible heritage is housed, organised, interpreted, conserved, restored and displayed in such ways as to confer meaning upon the material world. By drawing extensively upon evidence from the literature and engaging the conservation-restoration field, the thesis develops discussion around the emergence (and subsequent institutionalisation) of a relatively recent scientific paradigm of practice – ‘scientific restoration’ – largely shaped by this ‘museological’ vision of heritage. It also considers how the work of Cesare Brandi came to be instrumental in the formulation of this vision but argues that such conceptions have been predicated upon a misappropriation of his ideas and a misreading of historical heritage preservation ideologies that has done much to contribute to tensions evident within the heritage community. To this end, the thesis aims to redress this historical impasse by reconsidering the function of restoration – especially in terms of what is added to the historical document – and reconciling the competing claims of the tangible and intangible by developing the concept of ‘authentic process’

Exploring the importance of reflection in the control room

While currently difficult to measure or explicitly design for, evidence suggests that providing people with opportunities to reflect on experience must be recognized and valued during safety-critical work. We provide an insight into reflection as a mechanism that can help to maintain both individual and team goals. In the control room, reflection can be task-based, critical for the 'smooth' day-to-day operational performance of a socio-technical system, or can foster learning and organisational change by enabling new understandings gained from experience. In this position paper we argue that technology should be designed to support the reflective capacity of people. There are many interaction designs and artefacts that aim to support problem-solving, but very few that support self-reflection and group reflection. Traditional paradigms for safety-critical systems have focussed on ensuring the functional correctness of designs, minimising the time to complete tasks, etc. Work in the area of user experience design may be of increasing relevance when generating artefacts that aim to encourage reflection

Contrived competition and manufactured uncertainty: understanding managerial job insecurity narritives in large corporations

The article addresses the debate over insecurity and precarity in managerial work. It notes while some commentators suggest advanced economies are characterized by managerial job insecurity, others argue the same economies possess stable managerial tenure rates. To make sense of this conundrum, qualitative data from semi-structured interviews with managers working in large corporations in liberal-market (USA, UK) and coordinated-market (Japan) societies are analysed. The aim is to assess whether sensitivity to managerial job insecurity is widespread and if so reflects wider corporate strategies of ‘contrived competition’ and ‘manufactured uncertainty’. It is argued such notions can influence managers’ understanding of their work situation through (re)producing narratives of employment precarity. Contrary to the message from many database and questionnaire studies, evidence from this international and longitudinal study suggests awareness of job insecurity is indeed widespread and does affect managers’ views of their employment situation and prospects

Rotating biological contactors for wastewater treatment - A review

Rotating biological contactors (RBCs) for wastewater treatment began in the 1970s. Removal of organic matter has been targeted within organic loading rates of up to 120 g m−2 d−1 with an optimum at around 15 g m−2 d−1 for combined BOD and ammonia removal. Full nitrification is achievable under appropriate process conditions with oxidation rates of up to 6 g m−2 d−1 reported for municipal wastewater. The RBC process has been adapted for denitrification with reported removal rates of up to 14 g m−2 d−1 with nitrogen rich wastewaters. Different media types can be used to improve organic/nitrogen loading rates through selecting for different bacterial groups. The RBC has been applied with only limited success for enhanced biological phosphorus removal and attained up to 70% total phosphorus removal. Compared to other biofilm processes, RBCs had 35% lower energy costs than trickling filters but higher demand than wetland systems. However, the land footprint for the same treatment is lower than these alternatives. The RBC process has been used for removal of priority pollutants such as pharmaceuticals and personal care products. The RBC system has been shown to eliminate 99% of faecal coliforms and the majority of other wastewater pathogens. Novel RBC reactors include systems for energy generation such as algae, methane production and microbial fuel cells for direct current generation. Issues such as scale up remain challenging for the future application of RBC technology and topics such as phosphorus removal and denitrification still require further research. High volumetric removal rate, solids retention, low footprint, hydraulic residence times are characteristics of RBCs. The RBC is therefore an ideal candidate for hybrid processes for upgrading works maximising efficiency of existing infrastructure and minimising energy consumption for nutrient removal. This review will provide a link between disciplines and discuss recent developments in RBC research and comparison of recent process designs are provided (Section 2). The microbial features of the RBC biofilm are highlighted (Section 3) and topics such as biological nitrogen removal and priority pollutant remediation are discussed (Sections 4 and 5). Developments in kinetics and modelling are highlighted (Section 6) and future research themes are mentioned