CERES :: Browsing by Author "Pollard, Simon J. T."

Browsing by Author "Pollard, Simon J. T."

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Open Access
Appraisal for options of solid recovered fuel (SRF) utilisation within the UK
(2006-11-29T00:00:00Z) Hill, D.; Garg, A.; Smith, Richard; Pollard, Simon J. T.; Longhurst, Philip J.
In view of the rising prices of non-renewable fossil fuels and regulatory obligations affecting waste management, interest is growing for the use of waste derived fuels in energy intensive facilities in Europe. However, major concerns with the use of such fuels include the quality of fuels, its source of generation, gaseous emissions and public acceptability. This paper presents the various production methods for solid recovered fuels (SRF) from municipal solid waste (MSW) and the potential options for its use in the UK. SRF can be produced by mechanical biological treatment (MBT) methods using bio-drying process or by extensive mechanical treatment. MBT involves a series of mechanical and biological steps, depending upon the input waste properties, aimed at producing an SRF. SRF compositions vary according to the application and can comprise of paper, plastic, wood, textile and organics. The European Technical Committee CEN/TC 343 “Solid Recovered Fuels” classifies SRF on the basis of net calorific value (NCV), chlorine content and mercury content. This classification system was prepared after extensive consultation with end-users. In the UK, the main potential outlets for MSW derived SRF include cement kilns, power plants, industrial boilers (such as pulp and paper mill), dedicated SRF incineration facilities and advanced thermal treatment plants (such as gasification and Venice 2006: Biomass and Waste to Energy Symposium. Cini Foundation, Venice, Italy. 29 November – 1 December 2006. pyrolysis). Cement kiln operators prefer high NCV fuel, however, in spite of its lower CV in comparison to other waste derived fuels (like liquid solvents, tyres and MBM), it remains attractive due to its biomass fraction and cheap availability. Power plants are much more concerned with the biomass fraction, as it may bring revenues for them in the form of Renewable Obligation Certificates (ROCs). Similarly, gasification and pyrolysis techniques are also eligible for ROCs, but these are still not fully proven in the UK. The use of SRF is also of interest because of its potential to reduce greenhouse gas emissions, as the biomass rich fraction is considered ‘carbon neutral’. Thus, this assists energy facilities to meet the EU Emissions Trading Scheme targets. However, the application of SRF is not straightforward as legislation exists at EU and National level, which users need to comply with. In addition, technical, environmental and economic issues need to be addressed. On the other hand if more SRF can be used then this will greatly help the UK meet its obligations under the Landfill Directive and the mitigation of greenhouse gases.
Open Access
Appraising longitudinal trends in the strategic risks cited by risk managers in the international water utility sector, 2005-2015
(Elsevier, 2017-11-02) Chalker, Rosemary T. C.; Pollard, Simon J. T.; Leinster, Paul; Jude, Simon
We report dynamic changes in the priorities for strategic risks faced by international water utilities over a 10 year period, as cited by managers responsible for managing them. A content analysis of interviews with three cohorts of risk managers in the water sector was undertaken. Interviews probed the focus risk managers' were giving to strategic risks within utilities, as well as specific questions on risk analysis tools (2005); risk management cultures (2011) and the integration of risk management with corporate decision-making (2015). The coding frequency of strategic (business, enterprise, corporate) risk terms from 18 structured interviews (2005) and 28 semi-structured interviews (12 in 2011; 16 in 2015) was used to appraise changes in the perceived importance of strategic risks within the sector. The aggregated coding frequency across the study period, and changes in the frequency of strategic risks cited at three interview periods identified infrastructure assets as the most significant risk over the period and suggests an emergence of extrinsic risk over time. Extended interviews with three utility risk managers (2016) from the UK, Canada and the US were then used to contextualise the findings. This research supports the ongoing focus on infrastructure resilience and the increasing prevalence of extrinsic risk within the water sector, as reported by the insurance sector and by water research organisations. The extended interviews provided insight into how strategic risks are now driving the implementation agenda within utilities, and into how utilities can secure tangible business value from proactive risk governance. Strategic external risks affecting the sector are on the rise, involve more players and are less controllable from within a utility's own organisational boundaries. Proportionate risk management processes and structures provide oversight and assurance, whilst allowing a focus on the tangible business value that comes from managing strategic risks well.
Open Access
Assessing interdependent operational, tactical and strategic risks for improved utility master plans
(Elsevier, 2015-02-20) Luís, Ana; Lickorish, Fiona A.; Pollard, Simon J. T.
Risk management plays a key role in water utilities. Although risk tools are well-established at operational levels, approaches at the strategic level are rarely informed by systemic assessments of the water supply and lack a long-term perspective. Here, we report a baseline strategic risk analysis, founded on a systemic analysis of operational risks developed ‘bottom-up’ and validated in a large water utility. Deploying an action-oriented research method, supported by semi- structured interviews with in-house water utility risk experts, deep connections are established between operational risk and strategic risk that surpass those existing elsewhere in the sector. Accessible presentational formats – influence diagrams, risk ”heat-maps” and supporting narratives are used to promote Board-level risk discussions, and characterise a baseline set of strategic risks core to forward utility master planning. Uniquely, the influence of operational events, exposures and potential harms, together with the mitigating measures in place to mediate these risks are linked to corporate objectives on business sustainability, profitability, water quality, water quantity, supply disruption and reputation.
Open Access
Assessing significant harm to terrestrial ecosystems from contaminated land.
(Blackwell Publishing Ltd., 2005-12-01T00:00:00Z) Smith, Richard; Pollard, Simon J. T.; Weeks, J. M.; Nathanail, C. Paul
Abstract. Terrestrial ecosystem risk assessment remains in its infancy by comparison with the aquatic discipline, yet it is advancing quickly in response to increasing concerns surrounding soil quality and the sustainable use of soil. Several international frameworks have been developed during the last decade to aid decision-makers as the need for scientifically derived tools for determining ecological risk from land contamination has been recognized. From the regulatory viewpoint, the priority is establishing what to protect in order to prevent ecological harm. This is a complex issue requiring clear objectives in a risk assessment context. The most important factor in assessing ecological harm is whether or not ecosystem function is altered as a result of land contamination and, if it is, judging the significance. A consensus is developing that ecological risk assessment should aim to protect populations rather than individuals. This paper critically reviews recent developments in risk assessment for terrestrial ecosystems and land contamination in the UK, with emphasis on deriving a measure of ecological harm to assess ecosystem function. We seek to further justify the use of earthworms as a favoured indicator species for protecting ecological function. Guidance on how to measure harm in relation to ecological function is, however, still lacking.
Open Access
Assessment of consequences of notifiable fish disease incursions in England and Wales
(Taylor & Francis, 2013-01-02T00:00:00Z) Morant, M. P.; Prpich, George; Peeler, E.; Thrush, M.; Rocks, Sophie A.; Pollard, Simon J. T.
A consequence assessment framework was developed to evaluate the economic and environmental consequences of an exotic disease in the context of supporting policy level decisions on mitigation strategies. The framework adopted a semi-qualitative analysis of impacts supported by expert judgement. The efficacy of the framework was illustrated via assessment of the notifiable fish disease, Gyrodactylus salaris. In this example, the economic cost of an illustrative outbreak of G. salaris ranged from £0.22 million to £90 million. The cost of the most likely scenario (regional spread) was estimated to be £7.5 million (minimum to maximum range of £2–22 million), reflecting the uncertainty in the extent of spread of the parasite before detection. The environmental impacts vary by a factor of 35 between incursion scenarios reflecting the number of affected catchments in the scenarios.
Open Access
An assessment of different extraction and quantification methods of penta- and hexa-chlorobenzene from SRF fly-ash
(Elsevier, 2017-01-26) Balampanis, Dimitris E.; Coulon, Frederic; Simms, Nigel; Longhurst, Philip J.; Pollard, Simon J. T.; Fenech, Cecilia; Villa, Raffaella
Highly chlorinated benzenes, produced in the presence of organic matter and chlorine, are considered PCDD/Fs precursors, and are used as cost and time convenient substitute indicators for the indirect measurement of the latter. In this study penta- and hexa-chlorobenzene are quantified for the determination of the organochloride load of fly ash from solid recovered fuel incineration. Some of the chlorobenzenes are formed under ‘de novo’ conditions, through heterogeneous (ash particles/flue gases) reactions and are therefore deeply incorporated within fly ash. Accelerated solvent extraction (ASE) and ultrasonic solvent extraction (USE), along with the equivalent clean-up methods suggested by literature were compared to traditional Soxhlet. The extraction efficiencies achieved were 83 ± 7.5% for Soxhlet, 111 ± 19% for PFE, and 67 ± 17% for ultrasonication. Soxhlet extraction and clean-up through a multilayer silica gel column gave more precise results compared to the other sample preparation methods. Furthermore, performance comparison of gas chromatography fitted with either a mass spectrometer operated in single ion monitoring mode (GC-MS-SIM), or electron capture detector (GC- ECD) highlighted that ECD can be used for measuring chlorobenzenes traces down to 0.21 ng g−1, when the equivalent LOQ for MS-SIM was 3.26 ng g−1. The results further suggest that ECD can provide better peak integration than MS-SIM in the detection of chlorobenzenes in fly ash extracts, due to the detector's sensitivity to halogenated compounds.
Open Access
Assessment of municipal waste compost as a daily cover material for odour control at landfill sites.
(Elsevier Science B.V., Amsterdam., 2005-01-01T00:00:00Z) Hurst, C.; Longhurst, Philip J.; Pollard, Simon J. T.; Smith, Richard; Jefferson, Bruce; Gronow, Jan R.
The ability of municipal waste compost as a daily cover material to reduce the odorous emissions associated with landfill surfaces was investigated. Trials were carried out using landfill gas, a certified sulphurous gas mix and ambient air as a control. Odorous gas was passed through portable test column filled with compost at different densities (590 kg/m3 and 740 kg/m3). Gas samples were taken from the inlet, outlet and at varying column depths and examined using a combination of sensory analysis (olfactometry) and a novel analytical method (Transportable Selected Ion Flow Tube – TSIFT). Results for the trials using landfill gas showed a 69% odour reduction (OU/m3) through the column for compost with a bulk density of 590 kg/m3, and a reduction of 97% using compost with a bulk density of 740 kg/m3. TSIFT analysis showed an overall decrease in the concentration of terpenes, and sulphurous compounds in the outlet gas from the column for both bulk densities. No significant trend could be identified for the concentrations at different depths within the column. Results show the ability of compost to reduce landfill odours under differing conditions. The inconclusive data provided by TSIFT analysis may be due to the analysis of compounds that are not contributing to odour, and thus highlights the potential for synergetic effects and the importance of sensory measurement when examining odorous emission
Open Access
Benchmarking risk management within the international water utility sector. Part I: Design of a capability maturity methodology.
(Taylor & Francis, 2007-01-31T00:00:00Z) MacGillivray, Brian H.; Sharp, J. V.; Strutt, J. E.; Hamilton, Paul D.; Pollard, Simon J. T.
Risk management in the water utility sector is becoming increasingly explicit. However, due to the novelty and complexity of the discipline, utilities are encountering difficulties in defining and institutionalising their risk management processes. In response, the authors have developed a sector specific capability maturity methodology for benchmarking and improving risk management. The research, conducted in consultation with water utility practitioners, has distilled risk management into a coherent, process-based framework. We identified eleven risk management processes, and eight key attributes with characterise the extent to which these processes are defined, controlled and institutionalised. Implementation of the model should enable utilities to more effectively employ their portfolio of risk analysis techniques for optimal, credible and defensible decision making.
Open Access
Benchmarking risk management within the international water utility sector. Part II: A survey of eight water utilities.
(Taylor & Francis, 2007-01-31T00:00:00Z) MacGillivray, Brian H.; Sharp, J. V.; Strutt, J. E.; Hamilton, Paul D.; Pollard, Simon J. T.
Risk management in the water utility sector is fast becoming explicit. Here, we describe application of a capability model to benchmark the risk management maturity of eight water utilities from the UK, Australia and the USA. Our analysis codifies risk management practice and offers practical guidance as to how utilities may more effectively employ their portfolio of risk analysis techniques for optimal, credible, and defensible decision making. For risk analysis, observed good practices include the use of initiation criteria for applying risk assessment techniques; the adoption of formalised procedures to guide their application; and auditing and peer reviews to ensure procedural compliance and provide quality assurance. Additionally, we have identified common weaknesses likely to be representative of the sector as a whole, in particular a need for improved risk knowledge management and education and training in the discipline.
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Better by design: Business preferences for environmental regulatory reform
(Elsevier, 2015-01-26) Taylor, Christopher Michael; Pollard, Simon J. T.; Rocks, Sophie A.; Angus, Andrew
We present the preferences for environmental regulatory reform expressed by 30 UK businesses and industry bodies from 5 sectors. While five strongly preferred voluntary regulation, seven expressed doubts about its effectiveness, and 18 expressed no general preference between instrument types. Voluntary approaches were valued for flexibility and lower burdens, but direct regulation offered stability and a level playing field. Respondents sought regulatory frameworks that: are coherent; balance clarity, prescription and flexibility; are enabled by positive regulatory relationships; administratively efficient; targeted according to risk magnitude and character; evidence-based and that deliver long-term market stability for regulatees. Anticipated differences in performance between types of instrument can be undermined by poor implementation. Results underline the need for policy makers and regulators to tailor an effective mix of instruments for a given sector, and to overcome analytical, institutional and political barriers to greater coherence, to better coordinate existing instruments and tackle new environmental challenges as they emerge.
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Better environmental decision making - Recent progress and future trends.
(Elsevier Science B.V., Amsterdam., 2008-08-01T00:00:00Z) Pollard, Simon J. T.; Davies, Gareth J.; Coley, F. J. S.; Lemon, Mark
Recent trends in risk-based decision making are reviewed in relation to novel developments in comparative risk analysis, strategic risk analysis, weight of evidence frameworks, and participative decision making. Delivery of these innovations must take account of organisational capabilities in risk management and the institutional culture that implements decision on risk. We stress the importance of managing risk knowledge within organisations, and emphasise the use of core criteria for effective risk-based decisions by reference to decision process, implementation and the security of strategic added value.
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Better environmental regulation - contributions from risk-based decision-making
(Elsevier Science B.V., Amsterdam., 2009-09-14T00:00:00Z) Gouldson, A.; Morton, A.; Pollard, Simon J. T.
Internationally, pressure is being put on governments and regulators to develop more modern forms of regulation that deliver more for less and in better ways. This review considers the ways in which one large regulator, the Environment Agency for England and Wales, has responded to such pressure by developing and implementing risk-based approaches to regulation. After exploring the context for and key elements of risk-based environmental regulation, we consider the evolving influence of such approaches. We discuss the impacts of risk-based approaches against the UK Government’s principles for better regulation and against the key criteria for policy evaluation before considering some of the key challenges that still need to be addressed in this area of regulatory activity. These relate to the need to i) understand best practice and promote consistency in risk based regulation; ii) develop reliable, responsive forms of risk assessment and monitoring; iii) build capacities for responsive risk regulation; iv) evaluate the influence of different regulatory styles; and v) better understand the potential role of the private secto
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Biodrying for mechanical-biological treatment of wastes: A review of process science and engineering
(Elsevier Science B.V., Amsterdam., 2009-06-01T00:00:00Z) Velis, C. A.; Longhurst, Philip J.; Drew, Gillian H.; Smith, Richard; Pollard, Simon J. T.
Biodrying is a variation of aerobic decomposition, used within mechanical–biological treatment (MBT) plants to dry and partially stabilise residual municipal waste. Biodrying MBT plants can produce a high quality solid recovered fuel (SRF), high in biomass content. Here, process objectives, operating principles, reactor designs, parameters for process monitoring and control, and their effect on biodried output quality are critically examined. Within the biodrying reactors, waste is dried by air convection, the necessary heat provided by exothermic decomposition of the readily decomposable waste fraction. Biodrying is distinct from composting in attempting to dry and preserve most of biomass content of the waste matrix, rather than fully stabilise it. Commercial process cycles are completed within 7–15 days, with mostly H2O(g) and CO2 loses of ca. 25–30% w/w, leading to moisture contents of <20% w/w. High airflow rate and dehumidifying of re-circulated process air provides for effective drying. We anticipate this review will be of value to MBT process operators, regulators and end-users o
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The biogenic content of process streams from mechanical-biological treatment plants producing solid recovered fuel. Do the manual sorting and selective dissolution determination methods correlate?
(Elsevier Science B.V., Amsterdam., 2010-07-31T00:00:00Z) Severin, M.; Velis, C. A.; Longhurst, Philip J.; Pollard, Simon J. T.
The carbon emissions trading market has created a need for standard methods for the determination of biogenic content (chi(B)) in solid recovered fuels (SRF). We compare the manual sorting (MSM) and selective dissolution methods (SDM), as amended by recent research, for a range of process streams from a mechanical biological treatment (MBT) plant. The two methods provide statistically different biogenic content values, as expressed on a dry mass basis, uncorrected for ash content. However, they correlate well (r(2) > 0.9) and the relative difference between them was <5% for chi(B) between 21% (w)/W-d and 72% (w)/W-d (uncorrected for ash content). This range includes the average SRF biogenic content of ca. 68% (w)/W-d. Methodological improvements are discussed in light of recent studies. The repeatability of the SDM is characterised by relative standard deviations on triplicates of <2.5% for the studied population. (C) 2010 Elsevier Ltd. All rights reserved.
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Characterisation of weathered hydrocarbon wastes at contaminated sites by GC- simulated distillation and nitrous oxide chemical ionisation GC/MS, with implications for bioremediation
(Royal Society of Chemistry, 2004-08-03T00:00:00Z) Pollard, Simon J. T.; Hrudey, Steve E.; Rawluk, Marv; Fuhr, Bryan J.
An extended analytical characterisation of weathered hydrocarbons isolated from historically contaminated sites in Alberta is presented. The characterisation of soil extracts, chromatographically separated into component classes, by GC- simulated distillation and nitrous oxide (N2O) chemical ionisation (CI) GC-MS provides new insights into the composition of the residual oil at these sites, the principal partition medium for risk critical components. The combined polar and asphaltene content of representative soil extracts ranged from 40% w/w to 70% w/w of the oils encountered. An abundance of C14–C22 2–4 ring alicyclics, alkylbenzenes and benzocycloparaffins is prevalent within the saturate fractions of site soils. Implications for the partitioning of risk critical compounds at sites with weathered hydrocarbons and the practical application of bioremediation technologies are discus
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Characteristics of environmental harm in the context of air pollution.
(WIT Press, 2002) Irwin, J. G.; Duarte-Davidson, Raquel; Pollard, Simon J. T.
A framework that allows a qualitative assessment of technical and socio-economic aspects of environmental harm has been developed; capturing not only the physical aspects of damage but also how society may feel about it. Technical characteristics of harm include spatial and temporal extent, severity, irreversibility and uniqueness. Social aspects include dread, distrust, equity and imposition. By representing these on separate axes of a graph it is possible to assess those attributes of greatest concern, draw conclusions as to the nature of the harm and the public perception of that harm and gain some insight into appropriate courses of action. The results of applying the methodology to a radioactive release are presented and placed in the context of a range of other air pollution hazards.
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China's soil and groundwater management challenges: Lessons from the UK's experience and opportunities for China
(Elseveir, 2016-03-10) Coulon, Frederic; Jones, Kevin; Li, Hong; Hu, Qing; Gao, Jingyang; Li, Fasheng; Chen, Mengfang; Zhu, Yong-Guan; Liu, Rongxia; Liu, Ming; Canning, Kate; Harries, Nicola; Bardos, Paul; Nathanail, C. Paul; Sweeney, Rob; Middleton, David; Charnley, Maggie; Randall, Jeremy; Richell, Martin; Howard, Trevor; Martin, Ian; Spooner, Simon; Weeks, Jason; Cave, Mark; Yu, Fang; Zhang, Fang; Jiang, Ying; Longhurst, Philip J.; Prpich, George; Bewley, Richard; Abra, Jonathan; Pollard, Simon J. T.
There are a number of specific opportunities for UK and China to work together on contaminated land management issues as China lacks comprehensive and systematic planning for sustainable risk based land management, encompassing both contaminated soil and groundwater and recycling and reuse of soil. It also lacks comprehensive risk assessment systems, structures to support risk management decision making, processes for verification of remediation outcome, systems for record keeping and preservation and integration of contamination issues into land use planning, along with procedures for ensuring effective health and safety considerations during remediation projects, and effective evaluation of costs versus benefits and overall sustainability. A consequence of the absence of these overarching frameworks has been that remediation takes place on an ad hoc basis. At a specific site management level, China lacks capabilities in site investigation and consequent risk assessment systems, in particular related to conceptual modelling and risk evaluation. There is also a lack of shared experience of practical deployment of remediation technologies in China, analogous to the situation before the establishment of the independent, non-profit organisation CL:AIRE (Contaminated Land: Applications In Real Environments) in 1999 in the UK. Many local technology developments are at lab-scale or pilot-scale stage without being widely put into use. Therefore, a shared endeavour is needed to promote the development of technically and scientifically sound land management as well as soil and human health protection to improve the sustainability of the rapid urbanisation in China.
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A commentary on recent water safety initiatives in the context of water utility risk management.
(Elsevier Science B.V., Amsterdam., 2006-12-01T00:00:00Z) Hamilton, Paul D.; Gale, Paul; Pollard, Simon J. T.
Over the last decade, suppliers of drinking water have recognised the limitations of relying solely on end-product monitoring to ensure safe water quality and have sought to reinforce their approach by adopting preventative strategies where risks are proactively identified, assessed and managed. This is leading to the development of water safety plans; structured ‘route maps’ for managing risks to water supply, from catchment to consumer taps. This paper reviews the Hazard Analysis and Critical Control Point (HACCP) procedure on which many water safety plans are based and considers its appropriateness in the context of drinking water risk management. We examine water safety plans in a broad context, looking at a variety of monitoring, optimisation and risk management initiatives that can be taken to improve drinking water safety. These are cross-compared using a simple framework that facilitates an integrated approach to water safety. Finally, we look at how risk management practices are being integrated across water companies and how this is likely to affect the future development of water safety pl
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Comparative evaluation of SRF and RDF co-combustion with coal in a fluidised bed combustor
(2007-10-01T00:00:00Z) Garg, A.; Smith, Richard; Longhurst, Philip J.; Pollard, Simon J. T.; Simms, Nigel J.; Hill, D.
The experimental study reported here was carried out to assess the feasibility of municipal solid waste (MSW) derived solid recovered fuel (SRF) in energy recovery applications. SRF was prepared by grinding and blending the major MSW constituents such as paper, plastics, wood and textile. The percentage of various constituents was the same as from the Ecodeco process employing bio- drying followed by mechanical treatment. The heating value of synthetic SRF was ca. 21 MJ/kg (as received basis). The metal emission results from the SRF co- combustion with coal were compared with that obtained from coal mono-combustion and refuse derived fuel (RDF) co-combustion with coal. RDF was also derived from MSW and was obtained from a local mechanical treatment waste facility. Use of SRF as co-fuel does not increase the emissions of metals to the environment in the flue gas stream when compared to coal mono-combustion. In addition, use of MSW derived fuel reduces the arsenic release to the atmosphere. The results showed that most of the metals are retained in the ash components (except mercury). The mobility of metals depends on the volatility and type of feedstock.
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Comparison of coal/solid recovered fuel (SRF) with coal/refuse derived fuel (RDF) in a fluidised bed reactor.
(Elsevier Science B.V., Amsterdam., 2011-06-01T00:00:00Z) Wagland, Stuart Thomas; Kilgallon, P.; Coveney, R.; Garg, A.; Smith, Richard; Longhurst, Philip J.; Pollard, Simon J. T.; Simms, Nigel J.
An experimental study was undertaken to compare the differences between municipal solid waste (MSW) derived solid recovered fuel (SRF) (complying with CEN standards) and refuse derived fuel (RDF). Both fuels were co-combusted with coal in a 50kW fluidised bed combustor and the metal emissions were compared. Synthetic SRF was prepared in the laboratory by grinding major constituents of MSW such as paper, plastic, textile and wood. RDF was obtained from a local mechanical treatment plant. Heavy metal emissions in flue gas and ash samples from the (coal+10% SRF) fuel mixture were found to be within the acceptable range and were generally lower than that obtained for coal+10% RDF fuel mixture. The relative distribution of heavy metals in ash components and the flue gas stream shows the presence of a large fraction (up to 98%) of most of the metals in the ash (except Hg and As). Thermo-gravimetric (TG) analysis of SRF constituents was performed to understand the behaviour of fuel mixtures in the absence and presence of air. The results obtained from the experimental study will enhance the confidence of fuel users towards using MSW-derived SRF as an alternative fuel.