Mitigation of large-scale organic waste damage incorporating a demonstration of a closed loop conversion of poultry waste to energy at the point of source (2000-LS-1-M2) Final Report

peer-reviewedThe increase in the world population and urbanisation, have changed the way the world produces food. As the demand for cheap and readily available food in the developed world increases, high-density, intensive farming practices have replaced subsistence farming to allow for the mass production of food. An unavoidable consequence of these farming\ud practices is the generation of significant quantities of organic waste

Biosecurity on poultry farms from on-farm fluidized bed combustion and energy recovery from poultry litter

peer-reviewedThe spreading of poultry litter in recent years has led to a serious increase in levels of eutrophication, nitrate leaching, high Biological Oxygen Demand (BOD), ammonia toxicity, high chlorine concentrations and pathogen contamination. The review presented here details the optimum standards that should be met when storing litter for On-Farm Fluidized Bed Combustion. Storage conditions are paramount to a fuel combusting to its highest possible potential. Safety measures such as the prevention of leaching and spontaneous combustion must be adhered to, so too should the prevention and containment of possible diseases and pathogens to minimize the effects of contamination

Utilisation of poultry litter as an energy feedstock

peer-reviewedThis paper examines poultry litter (PL) as a resource in fuel quality terms and illustrates how the small scale application of fluidised bed technology solves both energy and waste problems, while producing a nutrient rich ash. PL was found to have a higher heating value (HHV) of 18 GJ t−1 on a dry basis (db). On an as received basis (ar), it had an ash mass fraction of 9% and the elemental phosphorous content of the ash was 110 g kg−1. The resultant mineral matter can be utilised as a nutrient substitute for mineral fertiliser

Ash agglomeration and deposition during combustion of poultry litter in a bubbling fluidized-bed combustor

peer-reviewedn this study, we have characterized the ash resulting from fluidized bed combustion of poultry litter as being dominated by a coarse fraction of crystalline ash composed of alkali-Ca-phosphates and a fine fraction of particulate K2SO4 and KCl. Bed agglomeration was found to be coating-induced with two distinct layers present. The inner layer (0.05–0.09 mm thick) was formed due to the reaction of gaseous potassium with the sand (SiO2) surface forming K-silicates with low melting points. Further chemical reaction on the surface of the bed material strengthened the coating forming a molten glassy phase. The outer layer was composed of loosely bound, fine particulate ash originating from the char. Thermodynamic equilibrium calculations showed slag formation in the combustion zone is highly temperature-dependent, with slag formation predicted to increase from 1.8 kg at 600 °C to 7.35 kg at 1000 °C per hour of operation (5.21 kg of ash). Of this slag phase, SiO2 and K2O were the dominant phases, accounting for almost 95%, highlighting the role of K-silicates in initiating bed agglomeration. The remaining 5% was predicted to consist mainly of Al2O3, K2SO4, and Na2O. Deposition downstream in the low-temperature regions was found to occur mostly through the vaporization–condensation mechanism, with equilibrium decreasing significantly with decreasing temperatures. The dominant alkali chloride-containing gas predicted to form in the combustion zone was KCl, which corresponds with the high KCl content in the fine baghouse ash

Digital network of writers helps to foster spirit of collaboration.

Nurse Liz Charalambous has shown how a Facebook group can help boost writing (careers, June 3). We would like to take this idea one step further and argue that, contrary to a commonly held notion, 'too many cooks do not spoil the broth' when it comes to group writing. Instead, this approach fosters collaboration between writers, as Ms Charalambous suggests, and which has also been our experience

Biosecurity on Poultry Farms from On-Farm Fluidized Bed Combustion and Energy Recovery from Poultry Litter

The spreading of poultry litter in recent years has led to a serious increase in levels of eutrophication, nitrate leaching, high Biological Oxygen Demand (BOD), ammonia toxicity, high chlorine concentrations and pathogen contamination. The review presented here details the optimum standards that should be met when storing litter for On-Farm Fluidized Bed Combustion. Storage conditions are paramount to a fuel combusting to its highest possible potential. Safety measures such as the prevention of leaching and spontaneous combustion must be adhered to, so too should the prevention and containment of possible diseases and pathogens to minimize the effects of contamination.biosecurity; storage; welfare; sustainable; energy

Ash Agglomeration and Deposition during Combustion of Poultry Litter in a Bubbling Fluidized-Bed Combustor

In this study, we have characterized the ash resulting from fluidized bed combustion of poultry litter as being dominated by a coarse fraction of crystalline ash composed of alkali-Ca-phosphates and a fine fraction of particulate K₂SO₄ and KCl. Bed agglomeration was found to be coating-induced with two distinct layers present. The inner layer (0.05–0.09 mm thick) was formed due to the reaction of gaseous potassium with the sand (SiO₂) surface forming K-silicates with low melting points. Further chemical reaction on the surface of the bed material strengthened the coating forming a molten glassy phase. The outer layer was composed of loosely bound, fine particulate ash originating from the char. Thermodynamic equilibrium calculations showed slag formation in the combustion zone is highly temperature-dependent, with slag formation predicted to increase from 1.8 kg at 600 °C to 7.35 kg at 1000 °C per hour of operation (5.21 kg of ash). Of this slag phase, SiO₂ and K₂O were the dominant phases, accounting for almost 95%, highlighting the role of K-silicates in initiating bed agglomeration. The remaining 5% was predicted to consist mainly of Al₂O₃, K₂SO₄, and Na₂O. Deposition downstream in the low-temperature regions was found to occur mostly through the vaporization–condensation mechanism, with equilibrium decreasing significantly with decreasing temperatures. The dominant alkali chloride-containing gas predicted to form in the combustion zone was KCl, which corresponds with the high KCl content in the fine baghouse ash

Emissions modeling of fluidised bed co-combustion of poultry litter and peat

Gaseous emissions from the fluidised bed co-combustion of 50% w/w chicken litter and peat were monitored and recorded. Emission data were used to create a dispersion model for a proposed site on a poultry farm in Ireland. Variables within the combustion unit influenced both combustion and emission levels of pollutants such as SO2 and NOx, CO. Concentrations of atmospheric pollutants decreased with use of the correct ratio between fluidising and secondary air. Dispersion modelling of combustion at a proposed poultry unit predicted that ground level concentrations for the set of emissions data would be below the limits and guidelines set by air quality standards

Behavior of heavy metals during fluidized bed combustion of poultry litter

In this study, we have examined the behavior of heavy metals during fluidized bed combustion of poultry litter. Heavy metals examined include As, Cd, Co, Cr, Cu, Hg, Mn, Mo, Ni, Pb, V, and Zn. Solid and gaseous streams were analyzed and compared with relevant guidelines to determine the potential environmental impact of combustion and subsequent land spreading or landfill of the resulting ash. The majority of heavy metals were associated with the solid ash fraction, with low gaseous emissions. Pb and As were concentrated in the fine baghouse ash (160 °C) due to their volatility. The remaining heavy metals, excluding Cd, were enriched in the heat exchangers and cyclone, where flue gas temperatures ranged from 580 to 220 °C. Under the waste acceptance criteria, all samples of process ash, excluding bed ash, exceeded the limits for nonhazardous landfill waste, as a result of high levels of water-soluble Cr. Water-soluble Cr indicated the presence of Cr(VI), and its presence was confirmed using X-ray absorption near-edge structure spectroscopy (18.4% to 38.3%). The source of Cr was identified as the bedding material (wood shavings), and its conversion to Cr(VI) was temperature-dependent and could be facilitated by the high alkali content found in poultry litter

Methodological challenges and issues of recruiting for mental health and substance use disorders trials in primary care.

Background: Poor recruitment to controlled trials is a frequently reported problem. Challenges related to study design, communication, participants, interventions, outcomes and clinician workload hinder recruitment, and the effectiveness of interventions used by trialists to increase recruitment rates is unknown. Objectives: To explore the methodological challenges and issues in recruiting for mental health and substance use disorders trials in primary care, and to consider how these methodological challenges can be addressed. Method: The presentation will recount the authors’ experience of recruiting for cluster randomised trials in primary care. Methodological challenges, such as clarity of instruction, patient characteristics, patient-doctor relationship, effects of intervention on patients and clinic, and personal benefits for clinicians will be described. The authors will consider how these might relate to and be used for peer-learning and peer-support in primary care research. Conclusion: The presentation will conclude with an overview of how lessons learned from past studies may be used to improve recruitment for trials of mental health and substance use disorders in primary care