Time filter

Source Type

Harwell, United Kingdom

Wagland S.T.,Cranfield University | Godley A.R.,Aea Environment And Energy | Tyrrel S.F.,Cranfield University
Waste Management | Year: 2011

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. © 2011.

Webb J.,Aea Environment And Energy | Pain B.,Creedy Associates | Bittman S.,Agriculture and Agri Food Canada | Morgan J.,Creedy Associates
Agriculture, Ecosystems and Environment | Year: 2010

Based on simple averages of the reported abatement efficiencies of NH3 emissions, abatement is greater from the use of trailing shoe (TS) (65%) and open-slot injection (OSI) (70-80%) machines than from the trailing hose (TH) (35%). There is considerable variation in the efficiencies reported, especially for trailing hose (0-75%) but also open-slot injection (23-99%). Variation in emissions following the use of the trailing shoe appeared to be somewhat less (38-74%), although this may be due to there being fewer studies reported of the trailing shoe. When slurries or solid manures are applied to arable land immediate incorporation by plough is the most effective abatement technique reducing emissions by at least 90%. Even short (4-6 h) delays in incorporating manures after application will greatly reduce the efficacy of rapid incorporation as a means of NH3 abatement. These reduced-NH3 emission application techniques will also increase crop uptake of manure-N, increasing the value of manures and reducing the net cost of reduced-NH3 application techniques. While there are circumstances under which reduced-NH3 application techniques may increase emissions of N2O, such increases are not inevitable and concern over such emission trade offs should not be allowed to compromise advice on reducing emissions of NH3. The rapid incorporation of solid manures may reduce emissions of NH3 while not increasing, or even reducing, those of N2O. Slurry needs to be injected to depths which increase the diffusion path to the soil surface sufficiently to lead to the majority of denitrified N being emitted as di-nitrogen in order to avoid increasing emissions of N2O. Crown Copyright © 2010.

Atkinson R.W.,St Georges, University of London | Carey I.M.,St Georges, University of London | Kent A.J.,Aea Environment And Energy | Van Staa T.P.,Datalink | And 2 more authors.
Epidemiology | Year: 2013

Background: Evidence based largely on US cohorts suggests that long-term exposure to fine particulate matter is associated with cardiovascular mortality. There is less evidence for other pollutants and for cardiovascular morbidity. By using a cohort of 836,557 patients age 40 to 89 years registered with 205 English general practices in 2003, we investigated relationships between ambient outdoor air pollution and incident myocardial infarction, stroke, arrhythmia, and heart failure over a 5-year period. Methods: Events were identified from primary care records, hospital admissions, and death certificates. Annual average concentrations in 2002 for particulate matter with a median aerodynamic diameter <10 (PM10) and <2.5 microns, nitrogen dioxide (NO2), ozone, and sulfur dioxide at a 1 × 1 km resolution were derived from emission-based models and linked to residential postcode. Analyses were performed using Cox proportional hazards models adjusting for relevant confounders, including social and economic deprivation and smoking. Results: While evidence was weak for relationships with myocardial infarction, stroke, or arrhythmia, we found consistent associations between pollutant concentrations and incident cases of heart failure. An interquartile range change in PM10 and in NO2 (3.0 and 10.7 μg/m, respectively) both produced a hazard ratio of 1.06 (95% confidence interval = 1.01-1.11) after adjustment for confounders. There was some evidence that these effects were greater in more affluent areas. Conclusions: This study of an English national cohort found evidence linking long-term exposure to particulate matter and NO2 with the development of heart failure. We did not, however, replicate associations for other cardiovascular outcomes that have been reported elsewhere. © 2012 by Lippincott William & Wilkins.

Carey I.M.,St Georges, University of London | Atkinson R.W.,St Georges, University of London | Kent A.J.,Aea Environment And Energy | Van Staa T.,Datalink | And 4 more authors.
American Journal of Respiratory and Critical Care Medicine | Year: 2013

Rationale: Cohort evidence linking long-term exposure to outdoor particulate air pollution and mortality has come largely from the United States. There is relatively little evidence from nationally representative cohorts in other countries. Objectives: To investigate the relationship between long-term exposure to a range of pollutants and causes of death in a national English cohort. Methods: A total of 835,607 patients aged 40-89 years registered with 205 general practices were followed from 2003-2007. Annual average concentrations in 2002 for particulate matter with a median aerodynamic diameter less than 10 (PM10) and less than 2.5 μm (PM2.5), nitrogen dioxide (NO2), ozone, and sulfur dioxide (SO2) at 1 km2 resolution, estimated from emission-based models, were linked to residential postcode. Deaths (n = 83,103) were ascertained from linkage to death certificates, and hazard ratios (HRs) for all- and cause-specific mortality for pollutants were estimated for interquartile pollutant changes from Cox models adjusting for age, sex, smoking, body mass index, and area-level socioeconomic status markers. Measurements and Main Results: Residential concentrations of all pollutants except ozone were positively associated with all-cause mortality (HR, 1.02, 1.03, and 1.04 for PM2.5, NO 2, and SO2, respectively). Associations for PM 2.5, NO2, and SO2 were larger for respiratory deaths (HR, 1.09 each) and lung cancer (HR, 1.02, 1.06, and 1.05) but nearer unity for cardiovascular deaths (1.00, 1.00, and 1.04). Conclusions: These results strengthen the evidence linking long-term ambient air pollution exposure to increased all-cause mortality. However, the stronger associations with respiratory mortality are not consistent with most US studies in which associations with cardiovascular causes of death tend to predominate. Copyright © 2013 by the American Thoracic Society.

Phillimore A.B.,University of Edinburgh | Phillimore A.B.,Imperial College London | Stalhandske S.,Imperial College London | Stalhandske S.,University of Stockholm | And 2 more authors.
American Naturalist | Year: 2012

Phenology affects the abiotic and biotic conditions that an organism encounters and, consequently, its fitness. For populations of high-latitude species, spring phenology often occurs earlier in warmer years and regions. Here we apply a novel approach, a comparison of slope of phenology on temperature over space versus over time, to identify the relative roles of plasticity and local adaptation in generating spatial phenological variation in three interacting species, a butterfly, Anthocharis cardamines, and its two host plants, Cardamine pratensis and Alliaria petiolata. All three species overlap in the time window over which mean temperatures best predict variation in phenology, and we find little evidence that a day length requirement causes the sensitive time window to be delayed as latitude increases. The focal species all show pronounced temperaturemediated phenological plasticity of similar magnitude. While we find no evidence for local adaptation in the flowering times of the plants, geographic variation in the phenology of the butterfly is consistent with countergradient local adaptation. The butterfly's phenology appears to be better predicted by temperature than it is by the flowering times of either host plant, and we find no evidence that coevolution has generated geographic variation in adaptive phenological plasticity. © 2012 by The University of Chicago.

Discover hidden collaborations