Performance of a new household composter during in-home testing

This article presents the methodology and the results of the performance testing of a prototype system for the production of high quality compost from biodegradable household waste separated at the source. Selected households in three municipalities of the Attica Region in Greece constituted the users of the home composter. The results indicated the effective operational performance of the prototype household composter in practice (use of the system by the householders on a daily basis), as well as the high level of response of the householders in adopting the composting practice in their daily activities as common practice. The compost that was produced in the households was characterized by high quality, which is in accordance with the quality standards that are set for its use. In only a few cases (in the first cycle of the pilot implementation) the quality of the compost was not high due to the fact that some householders were not yet familiar with the use of the composter, but these operational problems were solved and the compost that was later produced was considered high quality.     

Ecosystem development in roadside grasslands: biotic control, plant-soil interactions, and dispersal limitations

Roadside grasslands undergoing secondary succession are abundant, and represent ecologically meaningful examples of novel, human-created ecosystems. Interactions between plant and soil communities (hereafter plant-soil interactions) are of major importance in understanding the role of biotic control in ecosystem functioning, but little is known about these links in the context of ecosystem restoration and succession. The assessment of the key biotic communities and interactions driving ecosystem development will help practitioners to better allocate the limited resources devoted to roadside grassland restoration. We surveyed roadside grasslands from three successional stages (0-2, 7-9, and >20 years) in two Mediterranean regions of Spain. Structural equation modeling was used to evaluate how interactions between plants, biological soil crusts (BSCs), and soil microbial functional diversity (soil microorganisms) affect indicators of ecosystem development and restoration: plant similarity to the reference ecosystem, erosion control, and soil C storage and N accumulation. Changes in plant community composition along the successional gradient exerted the strongest influence on these indicators. High BSC cover was associated with high soil stability, and high soil microbial functional diversity from late-successional stages was associated with high soil fertility. Contrary to our expectations, the indirect effects of plants, mediated by either BSCs or soil microorganisms, were very weak in both regions, suggesting a minor role for plant-soil interactions upon ecosystem development indicators over long periods. Our results suggest that natural vegetation dynamics effectively improved ecosystem development within a time frame of 20 years in the grasslands evaluated. They also indicate that this time could be shortened if management actions focus on: (1) maintaining well-conserved natural areas close to roadsides to enhance plant compositional changes towards late-successional stages, (2) increasing BSC cover in areas under strong erosion risk, to avoid soil loss, and (3) enhancing soil microbial functional diversity in resource-limited areas, to enhance soil C and N accumulation.     

Implications of life history for genetic structure and migration rates of southern African coastal invertebrates: planktonic,abbreviated and direct development

The amount of genetic structure in marine invertebrates is often thought to be negatively correlated with larval duration. However, larval retention may increase genetic structure in species with long-lived planktonic larvae, and rafting provides a means of dispersal for species that lack a larval dispersal phase. We compared genetic structure, demographic histories and levels of gene flow of regional lineages (in most cases defined by biogeographic region) of five southern African coastal invertebrates with three main types of larval development: (1) dispersal by long-lived planktonic larvae (mudprawn Upogebia africana and brown mussel Perna perna), (2) abbreviated larval development (crown crab Hymenosoma orbiculare) and (3) direct development (estuarine isopod Exosphaeroma hylecoetes and estuarine cumacean Iphinoe truncata). We hypothesized that H. orbiculare, having abbreviated larval development, would employ a strategy of larval retention, resulting in genetic structure comparable to that of the direct developers rather than the planktonic dispersers. However, regional population structure was significantly lower in all species with planktonic larvae, including H. orbiculare, than in the direct developers. Moreover, nested clade analysis identified demographic histories resulting from low levels of gene flow (isolation by distance and allopatric fragmentation) in the direct developers only, and migration rates were significantly higher in all three species having planktonic larvae than in the direct developers. We conclude that the amount of genetic structure within marine biogeographic regions strongly depends on the presence or absence of free-swimming larvae. Whether such larvae are primarily exported or retained, whether they have long or short larval duration, and whether or not they are capable of active dispersal seems to have little effect on connectivity among populations.     

Multi-criteria analysis for the determination of the best WEEE management scenario in Cyprus

Waste from electrical and electronic equipment (WEEE) constitutes one of the most complicated solid waste streams in terms of its composition, and, as a result, it is difficult to be effectively managed. In view of the environmental problems derived from WEEE management, many countries have established national legislation to improve the reuse, recycling and other forms of recovery of this waste stream so as to apply suitable management schemes. In this work, alternative systems are examined for the WEEE management in Cyprus. These systems are evaluated by developing and applying the Multi-Criteria Decision Making (MCDM) method PROMETHEE. In particular, through this MCDM method, 12 alternative management systems were compared and ranked according to their performance and efficiency. The obtained results show that the management schemes/systems based on partial disassembly are the most suitable for implementation in Cyprus. More specifically, the optimum scenario/system that can be implemented in Cyprus is that of partial disassembly and forwarding of recyclable materials to the native existing market and disposal of the residues at landfill sites.     

Preliminary study for the management of construction and demolition waste

This paper refers to the management of the construction and demolition (C&D) waste since, according to the EU Waste Strategy, C&D waste is considered to be one of the priority waste streams and appropriate actions need to be taken with respect to its effective management. Initially, the paper presents the state-of-the-art of the problem of C&D waste, including the amount and composition of C&D waste in EU countries, differences in the characteristics of this waste stream depending on its origin, as well as collection and management practices that are applied. A methodology is described for the estimation of the quantities of the waste stream under examination, since in most cases quantitative primary data is not available. Next, the fundamentals for the development of an integrated scheme for the management of C&D waste are presented and discussed, such as appropriate demolition procedures and location of waste management (off-site waste management, on-site waste management, direct on-site recovery, centralized on-site recovery). Finally, taking into consideration all relevant parameters, alternative systems that could be applied for the management of the C&D waste are suggested.     

Electric Field Prediction for a Human Body-Electric Machine System

A system consisting of an electric machine and a human body is studied and the resulting electric field is predicted. A 3-phase induction machine operating at full load is modeled considering its geometry, windings, and materials. A human model is also constructed approximating its geometry and the electric properties of tissues. Using the finite element technique the electric field distribution in the human body is determinedfor a distance of 1 and 5 m from the machine and its effects are studied. Particularly, electric field potential variations are determined at specific points inside the human body and for these points the electric field intensity is computed and compared to the limit values for exposure according to international standards.     

Characteristics of wastes from electric and electronic equipment in Greece: results of a field survey.

The lifespan of electric and electronic equipment is becoming shorter and the amount of related waste is increasing. This study aimed to contribute to the knowledge about qualitative and quantitative characteristics of such wastes in Greece. Specifically, results are presented from a field survey, which took place in the city of Thessaloniki, Greece, during the year 2002. The survey was conducted with suitable questionnaires in department stores and in households of various municipalities. Household appliances were grouped as follows: (A) large (refrigerator, freezer, washing machine, clothes dryer, electric cooker, microwave oven, electric heater), (B) small (vacuum cleaner, electric iron, hair dryer), (C) information technology and telecommunication equipment (PC, laptop, printer, phone) and (D) consumer equipment (radio, TV, video, DVD, console). The analysis indicated that the lifespan of all new goods is gradually reducing (apart from refrigerators, for which the lifespan was surprisingly found to be increasing) and provided linearized functions for predicting the lifespan, according to the year of manufacture, for certain large appliances.     

Trace Metals in Different Crop/Cultivation Systems in Greece

Typical soils in Greece are neutral or alkaline and frequently are lime-rich, conditions that favour the accumulation of trace elements. The traditional use of metal-based fungicides in orchards and vineyards may have led to the accumulation of trace metals. Concentrations of Fe, Cu, Mn, Zn (aqua regia digestion) and some other soil parameters were measured in organically and conventionally cultivated soils (0–30 cm) from vineyards, olive groves and citrus groves of varying ages, and in uncultivated soils. Many vineyards and olive groves are situated in hilly or mountainous areas with sloping ground or terraces in contrastto citrus, which is cultivated in lower lying areas. Due to the difficulty of access, these crops often are cultivated extensively in both systems. Trace metal concentrations were found to lie withinthe ranges expected for the predominant soil types. Cu concentrations were relatively high (>100 mg kg^-1) in a few samples, but were not correlated with the age of the cultivation. A two-way ANOVA analysis showed larger differences in the mean concentrations of Cu, Mn and Zn between different crops (p≤ 0.001 for Cu, p≤ 0.05 for Zn, and p≤ 0.1 for Mn) than between different cultivation systems (no significant differences). The crop by cultivation interaction was not statistically significant for any metal (p > 0.8). Strong correlations (p≤ 0.001) were found between Fe, Mn and Zn and both clay concentration and CEC, although these relationshipswere not uniform throughout the different crop and cultivation systems. Concentrations of Cu were related to clay concentrations only for vineyards and to CEC only for citrus. Correlations were not found with organic matter or pH.