Hydrolysis of organic matter during autoclaving of commingled household waste

Commingled household waste (HW) that had a controlled composition was autoclaved at elevated pressures in the presence of saturated steam for one hour at the nominal temperature levels of 130 °C, 160 °C and 200 °C. The focus of this study was the impact of temperature/pressure on hydrolysis of organic matter during autoclaving and the extent of its hydrolysis. The pH decreased with autoclaving temperature with which it had a linear relationship, and ranged from 7.4 and 6 in floc, and 6.7 and 3.6 in steam condensate. Overall, organic matter solubilisation, as indicated by dissolved organic carbon, biological and chemical oxygen demands, and total dissolved solids, increased with temperature. Lignin did not appear to hydrolyse. Hemicellulose hydrolysed and degraded the most, followed by cellulose. The highest recoveries of hemicellulose and cellulose in solution were achieved at 160 °C, although the latter could be due to experimental error. The largest losses of hemicellulose and cellulose were recorded at 200 °C. The performance of the system in respect to hydrolysis was inferior compared to other hydrothermal systems, particularly those employing wet oxidation.     

An investigation on the physical,chemical and ecotoxicological characteristics of particulate matter emitted from light-duty vehicles

Particulate matter (PM) emitted from three light-duty vehicles was studied in terms of its physicochemical and ecotoxicological character using Microtox^® bioassay tests. A diesel vehicle equipped with an oxidation catalyst emitted PM which consisted of carbon species at over 97%. PM from a diesel vehicle with a particle filter (DPF) consisted of almost equal amounts of carbon species and ions, while a gasoline vehicle emitted PM consisting of ～90% carbon and ～10% ions. Both the DPF and the gasoline vehicles produced a distinct nucleation mode at 120 km/h. The PM emitted from the DPF and the gasoline vehicles was less ecotoxic than that of conventional diesel, but not in direct proportion to the emission levels of the different vehicles. These results indicate that PM emission reductions are not equally translated into ecotoxicity reductions, implying some deficiencies on the actual environmental impact of emission control technologies and regulations.     

Identifying and quantifying nitrogen and phosphorus loadings from agriculture and livestock waste in the Penios River Basin District

The nitrogen and phosphorus loadings coming from diffuse, non-point pollution sources related to agriculture and animal husbandry in the Penios river basin in the region of Thessaly, Greece, were estimated. Detailed data on types of crops and field area as well as types and numbers of animals bred in the municipal districts included in the Penios River Basin District were collected from agricultural cooperatives and rural agencies in Thessaly. Related nitrogen and phosphorus loadings were calculated and all data were mapped in a geographic information system (GIS) environment to show how diffuse pollution is spatially distributed in the Penios basin and to identify areas with the highest anthropogenic pressures. This type of data is useful to a driving forces–pressures–state–impacts–responses (DPSIR) analysis – a tool suitable for the analysis of environmental decisions in the direction of sustainable development.     

Road casualties and enforcement: distributional assumptions of serially correlated count data

OBJECTIVE: Road safety data are often in the form of counts and usually temporally correlated. The objective of this research is to investigate the distributional assumptions of road safety data in the presence of temporal correlation. METHODS: Using the generalized linear model framework, four distributional assumptions are considered: normal, Poisson, quasi-Poisson and negative binomial, and appropriate models are estimated. Monthly casualty and police enforcement data from Greece for a period of six years (January 1998-December 2003) have been used. The developed models include sinusoidal latent terms to capture the temporal serial correlation of observations. Several statistical goodness-of-fit diagnostic tests have been performed for the results of the estimated models, and the predictive capabilities of the models are investigated. RESULTS: The residuals of the quasi-Poisson and negative binomial models do not show any serial correlation. The signs of the estimated coefficients for all models are consistent and intuitive. In particular, a negative coefficient value for the number of breath alcohol controls indicates that the number of persons killed and seriously injured decreases as the intensity of breath alcohol controls increases. The Poisson model fails to capture the overdispersion in the data, thus underestimating the standard errors of the estimated coefficients. CONCLUSION: The results suggest that the quasi-Poisson and negative binomial outperform the normal and Poisson models in this application. The findings of this research demonstrate a clear link between the intensification of police enforcement and the reduction of traffic accident casualties. In particular, an increase in the number of breath alcohol controls in Greece after 1998 contributed to a reduction in the number of persons killed and seriously injured from traffic accidents.     

A preliminary investigation of socio-economic problems following the 1978 Thessaloniki (Greece) earthquake

The consequences of social and economic disruption in the city of Thessaloniki following the large earthquake in 1978 are investigated. Specifically, the phenomenon of organized life in camps for Thessaloniki residents over a long period of time is studied. With the use of a questionnaire, all data regarding each person in the camps were assembled and processed with the correspondence analysis method.     

When may road fatalities start to decrease?

Introduction

The comparative analysis of macroscopic trends in road safety has been a popular research topic. The objective of this research is to propose a simple and, at the same time, reliable multiple regime model framework for international road safety comparisons, allowing for the identification of slope changes of personal risk curves and respective breakpoints.

Method

The trends of road traffic fatalities in several EU countries have been examined through the temporal evolution of elementary socioeconomic indicators, namely motorized vehicle fleet and population, at the country level.

Results

Piece-wise linear regression models have been fitted, using a methodology that allows the simultaneous estimation of all slopes and breakpoints. The number and location of breakpoints, as well as the slope of the connecting trends, vary among countries, thus indicating different road safety evolution patterns.

Impact on industry

Macroscopic analysis of road accident trends may be proved beneficial for the identification of best examples and the implementation of appropriate programmes and measures, which will lead to important benefits for the society and the economy through the reduction of road fatalities and injuries. Best performing countries and the related programmes and measures adopted may concern several safety improvements at the processes of the road, the vehicle and the insurance industries.

Conclusions

Lessons from the analysis of the past road safety patterns of developed countries provide some insight into the underlying process that relates motorization levels with personal risk and can prove to be beneficial for predicting the road safety evolution of developing countries that may have not yet reached the same breakpoints. Furthermore, the presented framework may serve as a basis to build more elaborate models, including more reliable exposure indicators (such as vehicle-km driven).     

Accident risk of foreign drivers in various road environments

INTRODUCTION: This paper reports on the accident risk of foreign and native drivers in various road environments in Greece. In particular, the analysis aims to determine the combined effect of driver nationality, area type (inside/outside urban area), junction (yes/no), and lighting conditions (day/night) on accident fault risk. METHODS: Data from the national accident database of Greece are used in a hierarchical log-linear analysis. The induced exposure technique is applied due to the lack of exposure data. Estimated and observed odds ratios are then examined for the quantification of the various effects in terms of relative risk. RESULTS: The initial examination of a saturated model leads to the rejection of all three- and higher-order effects within variables, without providing an adequate fit to the data. On the contrary, a non-saturated second-order model presents a very satisfactory overall fit. The examination of single and combined effects indicates that the most significant effect on accident risk rises from the presence of foreign drivers at junctions. CONCLUSIONS: Results confirm that foreign drivers in Greece are at increased risk. However, immigrant permanent residents appear to have a lower risk compared to tourists, regardless of the road environment.     

Estimation of the real number of road casualties in Europe

Within this research, the police under-reporting of non-fatal road accident casualties in eight European countries was examined by means of a common methodology applied in each country. Eight national studies were carried out using the common methodology, and this allowed to prepare valid estimates of the level of under-reporting of non-fatal road casualties in Europe in a disaggregate form (namely by country, road user type and injury severity). This provided an insight into the variation of road casualty under-reporting in Europe. Moreover, a new common definition for road casualty severity was proposed that makes use of internationally recognised medical standards. This was established by examining two different injury severity standards, the casualty’s length of stay in hospital and the casualty’s maximum AIS score. The under-reporting coefficients developed within this research were applied to estimate the real number of non-fatal serious road accident casualties, according to the new proposed common definition. For almost all countries, the actual number of serious casualties according to the new proposed definition was found lower than the number of police-recorded serious casualties. With the newly estimated number of serious casualties, the values of the ratio of serious casualties to fatalities are much less widespread across countries. These remaining differences can thus be attributed to real differences in road safety between the countries, after having controlled for the different under-reporting levels and injury severity definitions.