Imperial College London

DrGeoffFowler

Faculty of EngineeringDepartment of Civil and Environmental Engineering

Research Fellow
 
 
 
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Contact

 

+44 (0)20 7594 5973g.fowler

 
 
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Location

 

413Skempton BuildingSouth Kensington Campus

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Summary

 

Publications

Publication Type
Year
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49 results found

Reyna-Bensusan N, Wilson DC, Davy PM, Fuller GW, Fowler GD, Smith SRet al., 2019, Experimental measurements of black carbon emission factors to estimate the global impact of uncontrolled burning of waste, Atmospheric Environment, Vol: 213, Pages: 629-639, ISSN: 1352-2310

Open burning is a widely practiced method of solid waste disposal in many regions of the world and represents a significant source of air pollution. Black carbon (BC) is a particularly serious air pollutant emitted from the uncontrolled burning of waste in open fires because it has a global warming potential (GWP) up to 5000 times greater than carbon dioxide (CO2) and is also linked to detrimental health impacts. However, few quantitative measurements of BC from open burning have been completed to establish the extent and impacts of this emission source on the environment. Emission factors (EFs) for BC from burning mixed solid waste samples were measured in the laboratory based on waste compositions in a representative developing country (Mexico). Black carbon EFs were also derived for individual waste types, including: green waste, different types of plastics, textiles and paper and cardboard. Individual waste BC EFs were combined using waste composition data from different areas of the world to estimate regional and global BC emissions from this source. The results demonstrated that BC emissions from open burning of waste have a significant climate impact, equivalent to 2–10% of global CO2Eq emissions. Global BC CO2Eq emissions from burning waste are 2–8 times larger compared to methane (CH4) CO2Eq emissions arising from the decomposition of equivalent amounts of combustible biodegradable waste disposed at dumpsites. Action to reduce open burning of waste would have a significant and immediate benefit to improving air quality and reducing the potential impact on climate change.

Journal article

Bond T, Tse Q, Chambon C, Fennell P, Fowler GD, Krueger BC, Templeton MRet al., 2018, The feasibility of char and bio-oil production from pyrolysis of pit latrine sludge, Environmental Science: Water Research and Technology, Vol: 4, Pages: 253-264, ISSN: 2053-1400

Sustainable methods are required in developing regions to treat and recover value from pit latrine sludge. One strategy is to pyrolyse pit latrine contents and generate char and bio-oil, which can then be used as a soil enhancer and fuel, respectively. Despite the many benefits associated with the process, there is very limited relevant literature available. This study examines its feasibility. Initially, the energy balance for the pyrolysis of sewage sludge was calculated using data from 14 literature studies. The average net energy recovery from pyrolysis of dewatered and dried sewage sludge followed by use of bio-oil as fuel was calculated as 4.95 ± 0.61 MJ kg−1. For dewatered sewage sludge, an average net energy input of 2.23 ± 0.31 MJ kg−1 was required. Parallel calculations were undertaken where pit latrine sludge with 0–100% water content was the hypothetical feedstock. On average, net energy recovery from produced bio-oil was achievable when pit latrine sludge with a water content of ≤∼55% was the feedstock. When both bio-oil and char were utilised, net energy recovery was feasible at a water content value of ≤∼65%. Char production is more favourable from stabilised pit latrine sludge with lower moisture and volatile solids content. Barriers to the pyrolysis of pit latrine sludge include its heterogeneous composition and the difficulty of collecting high-viscosity sludge. Overall, this study demonstrates the potential of pyrolysis as a disposal and value addition method for pit latrine sludge. Innovative methods for sludge drying and pit emptying will expedite the process becoming a reality.

Journal article

Bond T, Tse Q, Chambon CL, Fennell P, Fowler GD, Templeton MRet al., 2017, The feasibility of char and bio-oil production from pyrolysis of pit latrine sludge (Retraction of 10.1039/C7EW00132K, 2017), ENVIRONMENTAL SCIENCE-WATER RESEARCH & TECHNOLOGY, Vol: 3, Pages: 1171-1171, ISSN: 2053-1400

Journal article

Bond T, Tse Q, Chambon CL, Fennell P, Fowler GD, Templeton MRet al., 2017, The feasibility of char and bio-oil production from pyrolysis of pit latrine sludge, Environmental Science: Water Research and Technology, Vol: in press

Journal article

Dong S, Gonzalez RO, Harrison RM, Green D, North R, Fowler G, Weiss Det al., 2017, Isotopic signatures suggest important contributions from recycled gasoline, road dust and non-exhaust traffic sources for copper, zinc and lead in PM10 in London, United Kingdom, Atmospheric Environment, Vol: 165, Pages: 88-98, ISSN: 1352-2310

The aim of this study was to improve our understanding of what controls the isotope composition of Cu, Zn and Pb in particulate matter (PM) in the urban environment and to develop these isotope systems as possible source tracers. To this end, isotope ratios (Cu, Zn and Pb) and trace element concentrations (Fe, Al, Cu, Zn, Sb, Ba, Pb, Cr, Ni and V) were determined in PM10 collected at two road sites with contrasting traffic densities in central London, UK, during two weeks in summer 2010, and in potential sources, including non-combustion traffic emissions (tires and brakes), road furniture (road paint, manhole cover and road tarmac surface) and road dust. Iron, Ba and Sb were used as proxies for emissions derived from brake pads, and Ni, and V for emissions derived from fossil fuel oil.The isotopic composition of Pb (expressed using 206Pb/207Pb) ranged between 1.1137 and 1.1364. The isotope ratios of Cu and Zn expressed as δ65CuNIST976 and δ66ZnLyon ranged between −0.01‰ and +0.51‰ and between −0.21‰ and +0.33‰, respectively. We did not find significant differences in the isotope signatures in PM10 over the two weeks sampling period and between the two sites, suggesting similar sources for each metal at both sites despite their different traffic densities. The stable isotope composition of Pb suggests significant contribution from road dust resuspension and from recycled leaded gasoline. The Cu and Zn isotope signatures of tires, brakes and road dust overlap with those of PM10. The correlation between the enrichments of Sb, Cu, Ba and Fe in PM10 support the previously established hypothesis that Cu isotope ratios are controlled by non-exhaust traffic emission sources in urban environments (Ochoa Gonzalez et al., 2016). Analysis of the Zn isotope signatures in PM10 and possible sources at the two sites suggests significant contribution from tire wear. However, temporary additional sources, likely high temperature in

Journal article

Fan Y, Fowler GD, Norris C, 2017, Potential of a Pyrolytic Coconut Shell as a Sustainable Biofiller for Styrene-Butadiene Rubber, INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH, Vol: 56, Pages: 4779-4791, ISSN: 0888-5885

Journal article

Kumar S, Smith SR, Fowler G, Velis C, Kumar SJ, Arya S, Rena, Kumar R, Cheeseman Cet al., 2017, Challenges and opportunities associated with waste management in India, Royal Society Open Science, Vol: 4, ISSN: 2054-5703

India faces major environmental challenges associated withwaste generation and inadequate waste collection, transport,treatment and disposal. Current systems in India cannotcope with the volumes of waste generated by an increasingurban population, and this impacts on the environment andpublic health. The challenges and barriers are significant,but so are the opportunities. This paper reports on aninternational seminar on ‘Sustainable solid waste managementfor cities: opportunities in South Asian Association for RegionalCooperation (SAARC) countries’ organized by the Councilof Scientific and Industrial Research-National EnvironmentalEngineering Research Institute and the Royal Society. A priorityis to move from reliance on waste dumps that offer noenvironmental protection, to waste management systems thatretain useful resources within the economy. Waste segregationat source and use of specialized waste processing facilitiesto separate recyclable materials has a key role. Disposal ofresidual waste after extraction of material resources needsengineered landfill sites and/or investment in waste-to-energyfacilities. The potential for energy generation from landfill viamethane extraction or thermal treatment is a major opportunity,but a key barrier is the shortage of qualified engineers andenvironmental professionals with the experience to deliverimproved waste management systems in India.

Journal article

Hua X, Fan Y, Wang Y, Fu T, Fowler GD, Zhao D, Wang Wet al., 2017, The behaviour of multiple reaction fronts during iron (III) oxide reduction in a non-steady state packed bed for chemical looping water splitting, Applied Energy, Vol: 193, Pages: 96-111, ISSN: 0306-2619

Owing to the unclear temporal and spatial variations of axial solid conversion in a packed bed using iron (III) oxide as an oxygen carrier, we directly observe these variations by means of a sub-layer approach. The results indicate that the behaviour of the multiple reaction fronts during iron (III) oxide reduction by CO or H2 within a packed bed for chemical looping water splitting (CLWS) is strongly dependent on the reaction temperature. When the reaction temperature is lower than the merging temperature, three reaction fronts, i.e., Fe2O3-Fe3O4, Fe3O4-Fe0.947O and Fe0.947O-Fe, and three product zones, i.e., Fe3O4, Fe0.947O and Fe, will appear in the packed bed. In contrast, when the reaction temperature is higher than the merging temperature, the Fe2O3-Fe3O4 and Fe3O4-Fe0.947O fronts merge, leading to the disappearance of the Fe3O4 zone. As a result, only the Fe2O3-Fe0.947O and Fe0.947O-Fe fronts, as well as Fe0.947O and Fe zones will appear in the packed bed. These reduction behaviours are verified by two breakthrough curves, one for T < Tm and one for T > Tm, from the thermodynamically controlled reduction of iron (III) oxide in the packed bed. The reaction front movement model, which is proposed based on the reduction behaviour, can be used to determine the maximum solid conversion of the reduction step, i.e., the thermodynamic limitation of the reduction step, in the packed bed CLWS. The maximum solid conversion can reach 0.409 for the CO case and 0.554 for the H2 case. The first discovery of both the behaviours of the reaction fronts movement and the thermodynamic limitations of the reduction step standardizes the criteria for both the oxygen carrier evaluation and the optimization of the operating conditions and provides theoretical support for scaling up the packed bed and developing new technology for packed bed CLWS.

Journal article

Yu W, Graham NJD, Fowler GD, 2016, Coagulation and oxidation for controlling ultrafiltration membrane fouling in drinking water treatment: Application of ozone at low dose in submerged membrane tank, Water Research, Vol: 95, Pages: 1-10, ISSN: 1879-2448

Coagulation prior to ultrafiltration (UF) is widely applied for treating contaminated surface water sources for potable supply. While beneficial, coagulation alone is unable to control membrane fouling effectively in many cases, and there is continuing interest in the use of additional, complementary methods such as oxidation in the pre-treatment of raw water prior to UF. In this study, the application of ozone at low dose in the membrane tank immediately following coagulation has been evaluated at laboratory-scale employing model raw water. In parallel tests with and without the application of ozone, the impact of applied ozone doses of 0.5 mg L−1 and 1.5 mg L−1 (approximately 0.18 mg L−1 and 0.54 mg L−1 consumed ozone, respectively) on the increase of trans-membrane pressure (TMP) was evaluated and correlated with the quantity and nature of membrane deposits, both as a cake layer and within membrane pores. The results showed that a dose of 0.5 mgO3 L−1 gave a membrane fouling rate that was substantially lower than without ozone addition, while a dose of 1.5 mgO3 L−1 was able to prevent fouling effects significantly (no increase in TMP). Ozone was found to decrease the concentration of bacteria (especially the concentration of bacteria per suspended solid) in the membrane tank, and to alter the nature of dissolved organic matter by increasing the proportion of hydrophilic substances. Ozone decreased the concentration of extracellular polymeric substances (EPS), such as polysaccharides and proteins, in the membrane cake layer; the reduced EPS and bacterial concentrations resulted in a much thinner cake layer, although the suspended solids concentration was much higher in the ozone added membrane tank. Ozone also decreased the accumulation and hydrophobicity of organic matter within the membrane pores, leading to minimal irreversible fouling. Therefore, the application of low-dose ozone within the UF membrane tank is a potentially

Journal article

Smith KM, Fowler GD, Pullket S, Graham NJDet al., 2012, The production of attrition resistant, sewage-sludge derived, granular activated carbon, SEPARATION AND PURIFICATION TECHNOLOGY, Vol: 98, Pages: 240-248, ISSN: 1383-5866

Journal article

Stuber F, Smith KM, Baricot Mendoza M, Marques RRN, Fabregat A, Bengoa C, Font J, Fortuny A, Pullket S, Fowler GD, Graham NJDet al., 2011, Sewage sludge based carbons for catalytic wet air oxidation of phenolic compounds in batch and trickle bed reactors, APPLIED CATALYSIS B-ENVIRONMENTAL, Vol: 110, Pages: 81-89, ISSN: 0926-3373

Journal article

Abbe OE, Grimes SM, Fowler GD, 2011, Decision support for the management of oil well drill cuttings, Proceedings of Institution of Civil Engineers: Waste and Resource Management, Vol: 164, Pages: 213-220, ISSN: 1747-6526

Depending on the hole size and mud type used in the drilling process, oil well drill cuttings can be a relatively high-volume solid waste stream from drilling operations in the oil and gas exploration and production industry. Current management practices tend to involve thermal treatment followed by landfill disposal. The waste-to-resource conversion approach, however, provides opportunities that are not reflected in the current management system. The drill cuttings waste management decision support tool described in this work allows for the consideration of alternative reuse applications such as in construction materials, oil well reinjection, wetlands restoration, and the manufacture of stable leach-resistant material such as glass ceramics, in a move to divert treated drill cuttings from landfill towards zero waste disposal.

Journal article

Lampris C, Stegemann JA, Pellizon-Birelli M, Fowler GD, Cheeseman CRet al., 2011, Metal leaching from monolithic stabilised/solidified air pollution control residues, JOURNAL OF HAZARDOUS MATERIALS, Vol: 185, Pages: 1115-1123, ISSN: 0304-3894

Journal article

Marques RRN, Stueber F, Smith KM, Fabregat A, Bengoa C, Font J, Fortuny A, Pullket S, Fowler GD, Graham NJDet al., 2011, Sewage sludge based catalysts for catalytic wet air oxidation of phenol: Preparation, characterisation and catalytic performance, APPLIED CATALYSIS B-ENVIRONMENTAL, Vol: 101, Pages: 306-316, ISSN: 0926-3373

Journal article

Lebigue CJ, Andriantsiferana C, Krou N, Ayral C, Mohamed E, Wilhelm A-M, Delmas H, Le Coq L, Gerente C, Smith KM, Pullket S, Fowler GD, Graham NJDet al., 2010, Application of sludge-based carbonaceous materials in a hybrid water treatment process based on adsorption and catalytic wet air oxidation, JOURNAL OF ENVIRONMENTAL MANAGEMENT, Vol: 91, Pages: 2432-2439, ISSN: 0301-4797

Journal article

Abbe OE, Grimes SM, Fowler GD, Boccaccini ARet al., 2009, Novel sintered glass-ceramics from vitrified oil well drill cuttings, JOURNAL OF MATERIALS SCIENCE, Vol: 44, Pages: 4296-4302, ISSN: 0022-2461

Journal article

Smith KM, Fowler GD, Pullket S, Graham NJDet al., 2009, Sewage sludge-based adsorbents: A review of their production, properties and use in water treatment applications, WATER RESEARCH, Vol: 43, Pages: 2569-2594, ISSN: 0043-1354

Journal article

Pullket S, Smith KM, Fowler GD, Graham NJDet al., 2009, Influence of Source and Treatment Method on the Properties of Activated Carbons Produced from Sewage Sludge, European Conference on Sludge Management, Publisher: DESTECH PUBLICATIONS, INC, Pages: 43-49, ISSN: 1544-8053

Conference paper

Graham N, Fang G, Fowler G, Watts M, Camm Ret al., 2009, Evaluation of a tannin-based cationic polymer as a coagulant for coloured humic water, JOURNAL OF WATER SUPPLY RESEARCH AND TECHNOLOGY-AQUA, Vol: 58, Pages: 75-84, ISSN: 0003-7214

Journal article

Mathias SA, Butler AP, Fowler G, Fielding I, Shields A, Barber J, Daly Pet al., 2009, Beneficial hydraulic fracture propagation during in situ chemical oxidation, Contaminant Source Zone Characterisation and Remediation, Publisher: The Geological Society - Hydrogeological Group

Conference paper

Graham N, Gang F, Fowler G, Watts Met al., 2008, Characterisation and coagulation performance of a tannin-based cationic polymer: A preliminary assessment, COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS, Vol: 327, Pages: 9-16, ISSN: 0927-7757

Journal article

Cheeseman CR, Fowler GD, Zhou X, 2005, Effect of different binder systems on the stabilisation/solidification of metal finishing wastes, Stabilisation/Solidification Treatment and Remediation: Advances in S/S for Waste and Contaminated Land - Proc. of the International Conf. on Stabilisation/Solidification Treatment and Remediation, Pages: 31-37

The end of co-disposal in the UK and implementation of the EU Landfill Directive and waste acceptance criteria are expected to have a significant impact on how wastes from the metal finishing industry are managed. It is likely that stabilisation/solidification technologies will have a role in pre-treatment prior to disposal in cells for 'stable, non-reactive hazardous wastes' within non-hazardous waste landfills. There are a wide range of commercial solidification systems that could be used to treat metal finishing wastes and achieve the relevant waste acceptance criteria. Portland cement, pulverised fuel ash and wastepaper sludge ash have been used to treat a metal finishing waste at a range of binder/waste ratios. Properties and performance of the materials formed have been characterised in terms of acid neutralisation capacity, metal leaching and physical properties. Recommendations are made on the selection of binder systems and effect of binder content on performance. © 2005 Taylor & Francis Group.

Journal article

San Miguel G, Fowler GD, Sollars CJ, 2003, A study of the characteristics of activated carbons produced by steam and carbon dioxide activation of waste tyre rubber, CARBON, Vol: 41, Pages: 1009-1016, ISSN: 0008-6223

Journal article

San Miguel G, Fowler GD, Sollars C, 2002, The leaching of inorganic species from activated carbons produced from waste tyre rubber, WATER RESEARCH, Vol: 36, Pages: 1939-1946, ISSN: 0043-1354

Journal article

Clark KD, Costen PG, Fowler GD, Lockwood FC, Yousif Set al., 2002, The influence of combustion configuration and fuel type on heavy-metal emissions from a pulverizedfuel-fired combustor, 29th International Combustion Symposium, Publisher: COMBUSTION INST, Pages: 433-440, ISSN: 0082-0784

Conference paper

San Miguel G, Fowler GD, Dall'Orso M, Sollars CJet al., 2002, Porosity and surface characteristics of activated carbons produced from waste tyre rubber, JOURNAL OF CHEMICAL TECHNOLOGY AND BIOTECHNOLOGY, Vol: 77, Pages: 1-8, ISSN: 0268-2575

Journal article

San Miguel G, Fowler GD, Sollars CJ, 2002, Adsorption of organic compounds from solution by activated carbons produced from waste tyre rubber, SEPARATION SCIENCE AND TECHNOLOGY, Vol: 37, Pages: 663-676, ISSN: 0149-6395

Journal article

Fowler GD, Sollars CJ, Ouki SK, Perry Ret al., 2000, Treating contaminated soil by conversion into carbonaceous adsorbents - An investigation of activation procedures, Journal of Chemical Technology and Biotechnology, Vol: 75, Pages: 121-130

Journal article

Beaman MS, Marzetti MP, Fowler GD, Sollars CJet al., 1999, Development of TGA-FTIR hyphenated technique for analysing contaminated soils, "European Perspectives on Contaminated Land", A research symposium organised by the Environment and Water Group, Publisher: Society of Chemical Industry

Conference paper

Dall'Orso M, San Miguel G, Fowler GD, Sollars CJet al., 1999, Scrap tyres-alternative uses and disposal options, Rifiuti Solidi, Vol: 13, Pages: 1-13

Journal article

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