The development and validation of a decision aid to enhance shared decision-making for the management of actinic keratosis.

Actinic keratoses (AKs) are common pre-malignant lesions. There are numerous management options including active surveillance, multiple topical therapies, cryotherapy, curettage and cautery, and photodynamic therapy, each with their own risks, benefits and efficacy. Best practice currently involves shared decision-making between patient and clinician, particularly in the setting of multiple management options. Patient decision aids have been shown to be beneficial in the shared decision-making process. In view of this, we have developed and validated a decision aid for the management of AKs, in concordance with the International Patient Decision Aids Standards.

Sustainability assessment of alternative waste-to-energy technologies for the management of sewage sludge.

The management of sewage sludge still represents a challenge in the EU sustainability plan for biowaste. Although there are consolidated alternatives for the valorization of sewage sludge (incineration, pyrolysis and gasification), technical issues related to heavy metals and other pollutants are not sufficiently understood considering the whole waste-to-energy process. In addition, societal-economic and environmental aspects are usually not included in the evaluation of these conversion technologies. In this study, we propose an integrated assessment from a sustainability perspective to evaluate the valorization of sewage sludge by thermal conversion, comparing different alternatives based on existing Waste-to-energy (WtE) technologies. The results provide an insightful vision on the challenges to manage the sewage sludge disposal and to transform the obtained waste into new raw materials with added value. In addition, the evaluation of the WtE alternatives shows that they face important challenges preventing their application, being the gasification the best performing technology according to the sustainability assessment. Finally, a decentralized scheme based on sewage sludge gasification is further evaluated using real data from wastewater treatment plants in Andalusia.

Tar yield and composition from poultry litter gasification in a fluidised bed reactor: effects of equivalence ratio, temperature and limestone addition.

Air gasification of poultry litter was experimentally investigated in a laboratory scale bubbling fluidised bed gasifier. Gasification tests were conducted at atmospheric pressure using silica sand as the bed material. This paper examines the effect of the equivalence ratio (ER) in the range of 0.18-0.41, temperature between 700 and 800 °C, and the addition of limestone blended with the poultry litter on the yield and composition of tar. An off-line solid phase adsorption method was employed in order to quantify tar compounds heavier than styrene, whereas lighter species such as benzene and toluene were measured by means of on-line micro gas chromatography. Total tar yields were in the range from 15.7 to 30.7 gtotal tar kgpoultry litter (dry and ash free basis) -1. These values are considered low with respect to the feedstocks with a higher organic fraction. It also needs to be noted that the yields of benzene and toluene were measured by on-line micro gas chromatography, a technique which inherently delivers higher tar values compared to commonly employed off-line techniques. By varying the ER, poultry litter blended with limestone showed a reduction in total tar yield whereas poultry litter on its own showed an increasing tar yield over the ER range tested. In the presence of limestone, polycyclic aromatic hydrocarbons (PAHs), heterocyclic compounds, toluene and benzene showed a tendency to reduce over the ER range tested. Since the ER also plays a crucial role in tar reduction, the reduction in tar cannot be unambiguously attributed to calcined limestone/lime (CaCO3/CaO). Increasing the temperature was shown to be effective for reducing the total tar yield but the amounts of polycyclic aromatic hydrocarbons increased. However, no definitive correlation could be established between limestone/lime catalytic activity for tar reduction and elevated gasification temperature, because there was no possibility to study their effects separately. The chemical composition of the tar arising from poultry litter is distinctive compared with conventional lignocellulosic fuels linked to the fact that poultry litter has a higher nitrogen content (≈6.5% w/w (dry and ash free basis)). Nitrogen-containing hydrocarbons such as pyridine, 2-methylpyridine, 2-methyl-1H-pyrrole and benzonitrile were identified in significant amounts. This study has demonstrated that poultry litter gasified in a bubbling fluidised bed yielded a product gas with relatively low tar content while its composition reflects the chemical nature of the feedstock.

Implementation of waste-to-energy options in landfill-dominated countries: Economic evaluation and GHG impact.

The economic and environmental impact of several waste-to-energy (WtE) schemes to produce electricity from municipal solid waste (MSW) refuse is evaluated and compared with landfill disposal. Both incineration and gasification alternatives are considered. The gasification option includes three different configurations: (1) a fluidized bed gasifier (FBG) with internal combustion engine (ICE), (2) a FBG with organic Rankine cycle (ORC) and (3) a grate gasifier with steam Rankine cycle (SRC). The study is primarily applied to regions where the management system is based on Mechanical Biological Treatment (MBT) plants, generating a large share of refuse (>70%), which is currently landfilled. The specific case of Andalusia, a region in the south of Spain with 23 MBT plants distributed over a region of 87.000 km2, where about 80% of municipal solid waste (MSW) is currently landfilled, is taken as main reference; thereafter, the study is further extended to preliminary assess other regions of some European landfill-dominated countries with similar characteristics. The results show that both incineration and gasification improve landfill disposal, contributing favorably to greenhouse gas (GHG) reduction and fulfilling EU environmental regulations, although the three gasification options analyzed yield lower GHG emissions than incineration. In addition, gasification enables better integration of WtE into existing MBT plants, especially in the particular case of Andalusia, where MBT plants are widespread on the region, making it a more promising option than incineration, which is mainly based on large centralized plants, and less socially accepted. From the options analyzed, the WtE scheme based on FBG with ICE gives the highest profitability for a given gate fee, due to much higher electrical efficiency. However, FBG with ORC seems to be a better option in the short-term for landfill-dominated countries, due to its higher technical reliability and the low gate fee currently available in these countries.