Browsing by Author "Godley, Andrew R."
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Item Open Access Application of DR4 and BM100 Biodegradability tests to treated and untreated organic wastes(2007-10) Godley, Andrew R.; Lewin, Kathy; Frederickson, Jim; Smith, Richard; Blakey, N.The aerobic DR4 and anaerobic BM100 biodegradability tests are currently applied in England and Wales for monitoring the reduction in biological municipal waste (BMW) achieved by mechanical biological treatment (MBT) plants (Environment Agency 2005). The protocol is applied only when outputs are landfilled and is based on estimating the reduction in potential biogas production between the MBT input, municipal solid waste (MSW), and all of the landfilled outputs, using the BM100 test. As this is a long term 100 day test the more rapid 4 day DR4 test may also be applied as this has been shown to correlate with the BM100 test. We have now applied the DR4 and BM100 tests to 132 organic waste samples including untreated and treated BMW and specific organic wastes. The results indicate that the correlation between the DR4 and BM100 tests has proved valid for mixed MSW derived BMW wastes. However when both tests are applied to specific organic wastes such as turkey feathers, cardboard packaging waste and pizza food wastes the correlation between the tests is less strong. It is concluded that the use of the DR4 and BM100 test correlation is valid for its designed application (monitoring MBT processes treating MSW derived mixed BMW), but that caution should be exercised when applying both tests to specific single component organic wastes.Item Open Access Biodegradability determination of municipal waste: an evaluation of methods(The Waste Conference Limited, 2004-09) Godley, Andrew R.; Lewin, Kathy; Graham, Adele; Barker, H.; Smith, RichardThe Environment Agency is required to monitor the diversion of biodegradable municipal waste (BMW) from landfill. Reliable methods are needed to measure the biodegradability of municipal waste, both as mixed municipal waste and as individually separated fractions. An evaluation of several methods was carried out using a variety of organic materials typically found in municipal solid waste. The assessment considered biological and non-biological methods to determine which provides the bestfit surrogate measurement for relative waste biodegradability. The biological methods tested were: the aerobic specific oxygen uptake rate, dynamic respiration index tests, and the anaerobic biochemical methane potential test. The non-biological methods evaluated were: dry matter, loss on ignition, total organic carbon, total nitrogen, water extractable dissolved organic carbon, biological oxygen demand, chemical oxygen demand, lignin and cellulose content and cellulase hydrolysis. This paper also reviews how such tests can be used to measure the relative biodegradation of municipal waste and benchmark the relative diversion from landfill achieved by the pre-treatment of municipal waste in a mechanical biological treatment (MBT) process.Item Open Access Characterisation of untreated and treated biodegradable wastes(2007-10) Godley, Andrew R.; Frederickson, Jim; Lewin, Kathy; Smith, Richard; Blakey, N.As part of a Defra sponsored project (WRT220), approximately 40 biodegradable wastes were characterised according to biodegradability (DR4 and BM100), total PTE content, C:N ratio and biochemical composition. Two leaching tests were employed; upflow percolation test and a one step LS10 test; eluates were analysed for TOC, pH, electrical conductivity, PTEs and a range of cations and anions. This paper contains a limited set of data for a selection of untreated and treated waste types representing four waste treatment processes (composting, MBT, MHT, anaerobic digestion). The DR4 and BM100 tests were found to be appropriate for a wide range of waste types but where possible they should be used in conjunction with other related tests. Longer-term MBT composting processes appeared to produce compost material with reduced ammonium concentrations and extractability of some PTEs. Carbon content (carbon analyzer - LECO) could be estimated as C = LOI/1.9 which is a routine operation. N LECO values were approximately 12% greater than the equivalent N Kjeldahl values.Item Open Access Charaterisation of treated wastes to support an evidence base for sustainable waste management.(The Waste Conference Limited, 2006-09) Lewin, Kathy; Godley, Andrew R.; Turrell, J.; Smith, Richard; Frederickson, Jim; Graham, Adele; Gronow, Jan R.; Blakey, N.Defra must consider policies and strategies to manage environmental challenges such as climate change and sustainability. At a basic level the strategies need good quality data on waste characteristics. The dataset for UK wastes, in particular the new generation of treated wastes, is not fit for this purpose. This paper outlines the gaps in knowledge needed to underpin policy development and initial findings from a new project funded under Defra’s Waste and Resource Management Research Programme. The project team from WRc, Open University and Cranfield University aims to improve understanding of the characteristics of treated organic and inorganic wastes, methods of testing and knowledge of treatment process performance. Potential opportunities from the research are also described. New data will be collated into the presentation.Item Open Access Comparison of a novel enzymatic biodegradability test method with microbial degradation methods(2008-01-01T00:00:00Z) Wagland, Stuart Thomas; Godley, Andrew R.; Frederickson, Jim; Tyrrel, Sean F.; Smith, RichardA novel enzymatic hydrolysis test (EHT) has been evaluated as a surrogate for conventional microbial biodegradability methods, using 37 assorted organic waste samples collected from diverse sources. The results of the EHT method are compared with those obtained from two conventional tests; the 4 day aerobic DR4 and 100 day anaerobic BM100 test methods currently applied in England and Wales. The EHT is based on the enzymatic hydrolysis of cellulosic materials and can be completed in less than 24 hours. Linear regression for 37 samples against the BM100 data showed the DR4 provided a correlation coefficient of r = 0.58; the EHT method gave a correlation of r = 0.62 for the total DOC release; and r = 0.77 for the DOC released from enzymatic hydrolysis. The correlations suggest that the EHT method may be better suited to a wider range of waste types when correlating with anaerobic BM100 test results since it more closely mimics the full extent of decomposition rather than that from the readily biodegradable fraction.Item Open Access Development and application of an Enzymatic Hydrolysis test to assess the biodegradability of organic waste material(2007-10-01T00:00:00Z) Wagland, Stuart Thomas; Smith, Richard; Godley, Andrew R.; Tyrrel, Sean F.; Blakey, N.A novel and rapid biodegradability test method has been developed based on the enzymatic hydrolysis of cellulose. The test method consists of three phases, in which the first two phases consist of the pH buffer addition, and then autoclaving of the mixture and the final phase is the addition of the enzyme mixture and incubation. An initial investigation was carried out to determine the optimum conditions for the enzymes using standard commercial cellulose as the substrate. The optimised test was then applied to a wide range of organic waste samples including untreated and treated MSW derived mixed BMW, and specific wastes such as waste wood, packaging waste (cardboard), turkey feathers and green waste. The DOC released by enzymatic hydrolysis indicates that this could give an indication of the sample biodegradability. However the DOC released in phases 1 and 2 may also contain some biodegradable components (depending on the extent of biological treatment applied to the waste sample) and these would need to be differentiated from the non-biodegradable DOC and used together with the DOC from phase 3 to give the best possible biodegradability indication.Item Open Access Development and evaluation of a rapid enzymatic hydrolysis test method to assess the biodegradability of organic waste(Cranfield University, 2008-11) Wagland, Stuart Thomas; Tyrrel, Sean; Godley, Andrew R.The amount of biodegradable municipal waste (BMW) that can be disposed of in a landfill must be reduced, in accordance with the landfill allowance trading scheme (LATS) in England and Scotland (LAS in Wales). Biodegradability test methods are used to monitor the quantities of BMW diverted by waste treatment processes. This research has outlined the requirements for timescale improvements on the currently used methods. The rapid (<24 h) enzymatic hydrolysis test (EHT) has been developed and the relationship of this with the long-term BM100 test has been compared with that of the established DR4 method. A range of untreated and treated organic waste materials taken from a number of treatment processes, and samples taken over a period of 9 months from a single treatment facility were analysed using each test method. The EHT is completed within 1 day, compared with 4 days for the current DR4 method, and was shown to possess a stronger correlation with the long- term BM100 test. This finding indicated the suitability of the EHT as an alternative short-term test method. A humic substance extraction step was added to the EHT procedure, which was expected to provide a more accurate estimation of sample biodegradability. This technique was, however, found to be unsuitable for use in a short-term test method based on the results presented, although further understanding of the processes involved in the EHT has been discussed. This thesis presents a new biodegradability test method, which has been developed, applied and evaluated. The processes of the EHT have been investigated, understood and discussed. Further developments are suggested based on the findings and observations throughout the thesis.Item Open Access Environment Agency review of methods for determining organic waste biodegradability and municipal waste diversion.(Aqua Enviro Technology Transfer, 2003-11) Godley, Andrew R.; Lewin, Kathy; Graham, Adele; Smith, RichardThe Environment Agency is required to regulate the landfilling of biodegradable organic wastes and their diversion from landfilling. Simple, cost effective, reliable and widely applicable methods for the measurement of organic waste and its biodegradability are needed for this activity. A review of such methods was carried out in order to select promising methods for an experimental screening exercise. The review considered both biological and non-biological methods including simple methods that may provide a surrogate measurement of waste biodegradability instead of the time-consuming biological methods. The biological methods selected for further evaluation were the aerobic specific oxygen uptake rate (SOUR) and dynamic respiration index (DRI) tests, and the anaerobic biochemical methane potential (BMP) test. The non-biological methods selected for further evaluation were dry matter (DM), loss on ignition (LOI), total organic carbon (TOC), total nitrogen (TN), water extractable dissolved organic carbon (DOC), BOD and COD, the lignin and cellulose content and the cellulase hydrolysis method. These tests are being evaluated on a wide variety of typical organic materials that might be found in municipal solid waste (MSW) such as newspaper corrugated paper, compost, kitchen waste (vegetable and animal), garden wastes (grass and twigs), nappies, cotton and wool textiles.Item Open Access In situ remediation of atrazine contaminated groundwater(Cranfield University, 2006-09) Pearson, Robert; Cartmell, Elise; Godley, Andrew R.The natural attenuation of groundwater pesticides by biological degradation, is widely accepted to occur at concentrations > 1 mg 1-1. However from observations of groundwater monitoring data it can be indicated that the occurrence of pesticides in groundwater is primarily at trace μg 1-1 concentrations, with 45 % of UK groundwater samples that failed the EC Drinking Water Directives PV of 0.1 μg 1-1 between 1995 – 2000, accounting for an average concentration of 64 μg 1-1. However, there are limited directed studies of in situ biological degradation of pesticides at μg concentrations. Therefore, this work was designed provided an insight as to whether any prevalent microbial adaptation can occur to degrade atrazine at μg 1-1 concentrations in groundwater. Laboratory batch studies were performed using a groundwater exposed to 0.2 μg 1-1 of the herbicide atrazine, for an excess of 10 years. Bacterial enrichment using a glucose minimal salts medium resulted in no biological degradation of atrazine, when amended at concentrations between 10 μg to 50 mg 1-1. Batch studies using the atrazine degrader Pseudomonas sp. Strain ADP as a positive control, indicated a capability to degrade atrazine within sterilised groundwater, at 50 mg 1-1 (0.92 mg 1-1 day-1) and 1 mg 1-1 (0.14 mg 1-1 day-1), but no degradation of atrazine at 100 or 10 μg 1-1. Therefore, biological degradation of trace μg 1-1 concentrations of atrazine by groundwater in situ bacteria does not readily occur. It is expected that changes in atrazine groundwater concentrations, are resulting purely from dilution, sorption or chemical degradation. Consequently, it cannot be assumed that microbial adaptation can occur to degrade atrazine at μg 1-1 concentrations in groundwaters even if in situ bioaugmentation methods are applied.Item Open Access Investigating the in situ degradation of atrazine in groundwater(Wiley, 2006) Pearson, Robert; Godley, Andrew R.; Cartmell, EliseThis study focused on whether or not atrazine could be degraded by indigenous groundwater bacteria as part of an in situ remediation approach. Groundwater was taken from an unconfined middle upper chalk site where concentrations of atrazine and nitrate were typically in the ranges 0.02-0.2 µg litre-1 and 11.6-25.1 mg NO3-N litre-1 respectively. Sacrificial batch studies were performed using this groundwater spiked with atrazine at a concentration of 10 µg litre-1 in conjunction with a minimal mineral salts liquid (Glu-MMSL) medium which contained glucose as the sole carbon source. Treatments comprised either the Glu-MMSL groundwater cultured bacteria or Pseudomonas sp. strain ADP. Results from sacrificial batches indicated the occurrence of bacterial growth and denitrification as monitored by optical density (absorbance at 600 nm) and NO3-N content. Analysis of atrazine content by solid phase extraction coupled with high-performance liquid chromatography showed no degradation of atrazine over a period of 103 days in either treatment. These results indicated that no acclimatised bacterial community featuring positive degraders to the herbicide atrazine had become established within this chalk aquifer in response to the trace levels encountered. Copyright © 2006 Society of Chemical Industry.Item Open Access Investigation of the application of an enzyme-based biodegradability test method to a municipal solid waste biodrying process(Elsevier Science B.V., Amsterdam., 2011-07-01T00:00:00Z) Wagland, Stuart Thomas; Godley, Andrew R.; Tyrrel, Sean F.This paper presents a study to evaluate the recently developed enzymatic hydrolysis test (EHT) through its repeated application to a waste treatment process. A single waste treatment facility, involving a biodrying process, has been monitored using three different methods to assess the biodegradable content of the organic waste fractions. These test methods were the anaerobic BMc, aerobic DR4 and the EHT, which is a method based on the enzymatic hydrolysis of the cellulosic content of waste materials. The input municipal solid waste (MSW) and the output solid recovered fuel (SRF) and organic fines streams were sampled over a period of nine months from a single mechanical biological treatment (MBT) facility. The EHT was applied to each stream following grinding to <10 mm and <2 mm, in order to investigate the effect of particle size on the release of dissolved organic carbon (DOC) from enzyme hydrolysis. The output organic fines were found to more biodegradable than the MSW input and SRF output samples in each of the test methods, significantly (p<0.05) for the EHT and DR4 methods, on the basis of DOC released and oxygen consumed respectively. The variation between sample replicates for the EHT was higher where sample sizes of <2 mm were analysed compared to sizes of <10 mm, and the DOC release at each phase of the EHT was observed to be higher when using particle sizes of <2 mm. Despite this, additional sample grinding from the <10 mm to a smaller particle size of <2 mm is not sufficiently beneficial to the analysis of organic waste fractions in the EHT method. Finally, it was concluded that as similar trends were observed for each test method, this trial confirms that EHT has the potential to be deployed as a practical operational biodegradability monitoring tool.Item Open Access Is pre-biological treatment of organic wastes the best option for recycling organic matter to soil?(2004-11-01T00:00:00Z) Godley, Andrew R.; Smith, Richard; Tothill, Ibtisam E.Organic wastes are produced from a variety of sources such as agriculture, horticulture, forestry, industry, sewage treatment and households. These wastes are mainly derived from crops grown on land and contain elements, such as N, P, K, and S, originally found in the soil as nutrients. The major element of organic matter (C) is however derived from the CO2 taken up by the plant from the atmosphere. The current trend is to recycle and reuse organic wastes as a resource, and their disposal in landfill is being actively discouraged 7,8,10,11 . Recycling organic wastes to land would benefit soil quality, sequestrate C into soils, return the nutrients removed from the soil in crop offtake, and help to establish a more sustainable use of soil and fertilizers.Item Open Access Priority research questions for the UK food system(Springer Science Business Media, 2013-10-01T00:00:00Z) Ingram, John S. I.; Wright, Hugh L.; Foster, Lucy; Aldred, Timothy; Barling, David; Benton, Tim G.; Berryman, Paul M.; Bestwick, Charles S.; Bows-Larkin, Alice; Brocklehurst, Tim F.; Buttriss, Judith; Casey, John; Collins, Hannah; Crossley, Daniel S.; Dolan, Catherine S.; Dowler, Elizabeth; Edwards, Robert; Finney, Karen J.; Fitzpatrick, Julie L.; Fowler, Mark; Garrett, David A.; Godfrey, Jim E.; Godley, Andrew R.; Griffiths, William; Houlston, Eleanor J.; Kaiser, Michel J.; Kennard, Robert; Knox, Jerry W.; Kuyk, Andrew; Linter, Bruce R.; Macdiarmid, Jennie I.; Martindale, Wayne; Mathers, John C.; McGonigle, Daniel F.; Mead, Angela; Millar, Samuel J.; Miller, Anne; Murray, Calum; Norton, Ian T.; Parry, Stephen; Pollicino, Marilena; Quested, Thomas E.; Tassou, Savvas; Terry, Leon A; Tiffin, Richard; Pieter, van de Graaf; Vorley, William; Westby, Andrew; Sutherland, William J.The rise of food security up international political, societal and academic agendas has led to increasing interest in novel means of improving primary food production and reducing waste. There are however, also many ‘post-farm gate' activities that are critical to food security, including processing, packaging, distributing, retailing, cooking and consuming. These activities all affect a range of important food security elements, notably availability, affordability and other aspects of access, nutrition and safety. Addressing the challenge of universal food security, in the context of a number of other policy goals (e.g. social, economic and environmental sustainability), is of keen interest to a range of UK stakeholders but requires an up-to-date evidence base and continuous innovation. An exercise was therefore conducted, under the auspices of the UK Global Food Security Programme, to identify priority research questions with a focus on the UK food system (though the outcomes may be broadly applicable to other developed nations). Emphasis was placed on incorporating a wide range of perspectives (‘world views') from different stakeholder groups: policy, private sector, non-governmental organisations, advocacy groups and academia. A total of 456 individuals submitted 820 questions from which 100 were selected by a process of online voting and a three-stage workshop voting exercise. These 100 final questions were sorted into 10 themes and the ‘top' question for each theme identified by a further voting exercise. This step also allowed four different stakeholder groups to select the top 7-8 questions from their perspectives. Results of these voting exercises are presented. It is clear from the wide range of questions prioritised in this exercise that the different stakeholder groups identified specific research needs on a range of post-farm gate activities and food security outcomes. Evidence needs related to food affordability, nutrition and food safety (all key elements of food security) featured highly in the exercise. While there were some questions relating to climate impacts on production, other important topics for food security (e.g. trade, transport, preference and cultural needs) were not viewed as strongly by the participants.Item Open Access Reduction of Bromate Source Contamination(2005-01-01T00:00:00Z) Butler, R.; Ehrenberg, S.; Godley, Andrew R.; Lake, R.; Lytton, L.; Cartmell, EliseA potential source remediation technique for an aquifer contaminated by bromate has been investigated, utilising biological bromate reduction to bromide by augmentation of indigenous microbial populations. This technique, involving addition of a carbon source to contaminated groundwater, is analogous to the methodology used in commercial denitrification systems. Experimental work is aimed at development of an ex-situ pump-to-waste or pump, treat-and-reinject strategy, but the technique may also have in-situ applications. Trials initially focussed on a laboratory-scale anaerobic suspended growth chemostat system, investigating glucose addition to real groundwater supplies. Following targeted enrichment of the microbial population, reduction of 32 mgl-1 bromate within a 40 hour residence time was obtained with specific reduction rates of up to 160.48 µmol Br.g dry wt-1.hr-1, which suggested the presence of high-rate bromate reducing bacterial strains. Use of a pilot-scale fixed-film upflow bioreactor seeded with enriched chemostat biomass subsequently confirmed stoichiometric bromate reduction to bromide with 87-90% bromate reduced from an influent concentration of 1.08 mgL-1 over retention times of 40-80 hours. Nitrate reduction of 97-99% from a 30.7 mgL-1 nitrate (as NO3-) influent also occurred at retention times of 10-80 hours, although an increase in nitrite production to 2.7 mgL-1 was observed with a 10 hour retention time. A period of batch operation during the startup phase was shown to be critical to stable operation, but backwashing was not required during the timescale of the experimental run. Further process optimisation will be required, but this study has demonstrated the potential of biological bromate reduction for remediation of a bromate contaminated groundwater sourceItem Open Access Test methods to aid in the evaluation of the diversion of biodegradable municipal waste (BMW) from landfill(Elsevier Science B.V., Amsterdam., 2009-01-01T00:00:00Z) Wagland, Stuart Thomas; Tyrrel, Sean F.; Godley, Andrew R.; Smith, RichardA wide range of waste characterization methods are available, each developed for a specific purpose such as determining compost stability, or for landfill acceptance criteria. Here test methods have been evaluated for the purpose of assessing waste treatment process performance and monitoring the diversion of biodegradable municipal waste (BMW) from landfill. The suitability factors include the timescale of the method, applicability to a wide range of materials and ability to indicate the long-term biodegradability of organic waste samples. The anaerobic test methods, whilst producing reliable results, take at least several weeks to complete, therefore not allowing for regular routine analysis often required for diversion assessments. Short-term tests are required which can correlate with, and therefore estimate, values obtained from long-term anaerobic methods. Aerobic test methods were found to offer a significantly improved timescale compared with anaerobic test methods; however they have limitations due to not measuring the full extent of sample biodegradability. No single test method was found to be completely sufficient for routine biodegradability analysis suitable for monitoring the BMW diversion from landfill. Potential areas for further research include spectrographic FT-IR or enzyme-based approaches such as the ECD or EHT methods.