Recovery of valuable metals from electronic and galvanic industrial wastes by leaching and electrowinning

In the present paper, a study on laboratory scale to perform a treatment for valuable metals recovery from electronic and galvanic industrial wastes, is reported. The characterisation of the waste, performed by XRD, SEM, EDX and chemical analysis, showed a high metals content in the sludge, such as Cu, Ni, Mn, Pb, Sn, W. A leaching process, coupled by electrowinning, is then proposed in order to reduce the volume of the waste material and to recover selectively valuable metals, such as Cu and Ni. During the leaching step, carried out by using H(2)SO(4), several factors were investigated (acid concentration, temperature and time of treatment). The leached liquor has been successfully treated with an electrowinning process, to recover copper and nickel. The copper and nickel depositions, were performed in acid and alkaline conditions, respectively. The Faraday yield was of about 95%. The energy consumption was 2.13 and 4.43 kWh per kg of copper and nickel recovered, respectively. At the end of the process, about 94-99% of the initial content of Cu and Ni was recovered at the cathode. The experimental results obtained, showed the technical feasibility of the process.     

Assessing soil biodiversity across Great Britain: national trends in the occurrence of heterotrophic bacteria and invertebrates in soil

An assessment of the biodiversity of soils was a component of the Countryside Survey 2000 (CS2000). This was the first integrated survey of soil biota and chemical properties at a national scale. A total of 1052 soil samples were collected across Great Britain during CS2000 and analysed for a range of soil microbial and invertebrate characteristics resulting in the production of a series of robust datasets. A principal objective was to use these datasets to investigate relationships between soil biota and environmental factors such as geographical location, vegetation, land use, land cover, soil type and pollutant levels as first stages in characterising the inherent biodiversity of British soils and investigating the potential of soil biodiversity as indicators of soil health at a regional or national scale. Preliminary results for culturable heterotrophic, invertebrate taxa, Acari, Collembola and Oribatid mites are presented here to illustrate the nature of the data collected and the patterns of soil biodiversity in relation to large-scale regional, vegetation and soil characteristics across the British countryside.     

Analysis of the exterior colour of agroindustrial buildings: a computer aided approach to landscape integration

The visual and aesthetic aspects of any object are defined by its colour, form, line and texture, to which might be added compositional reference elements such as scale and, in the case of three dimensional scenes, spatial character. This paper investigates one of these colour and proposes a method for predicting the value of a building's integration into the landscape. Based on psychological aspects, the method uses computers to analyse and measure the pertinent attributes. The designer can analyse visual elements in terms of the properties that define them. For example, colour, the subject of this paper, is defined by its hue, saturation and lightness. Tables are proposed to study the relationship between buildings and their background using computers. This paper offers a tool, based on the digital examination of scenes and on people's integration preferences with respect to agroindustrial buildings, which it is hoped will help project designers select appropriate colour schemes.     

Combination of magnetic parameters: an efficient way to discriminate soil-contamination sources (south France)

Biplots combining magnetic parameters allow to identification and differentiation different pollutant emission sources. A major problem in soil pollution is the characterization of the relative contributions of different anthropogenic particles sources. This paper demonstrates the efficiency of magnetic techniques to provide identification and differentiation of contaminating emission sources. About 100 soil samples were collected across a mixed agricultural and industrial area (Crau plain/Berre-Fos basin) in southern France. Nine soil profiles were realized. They are aligned along a transect, from the Mediterranean cost to the north. Measurements of initial magnetic susceptibility (chi) and remanent magnetization (ARM, IRM) have been carried out at room temperature. Several ratios of magnetic parameters were calculated and tested. Bivariate analyses allow to characterize different pollution sources and graphic results suggest three dominant contributions originated from road traffic, airport and steel industry. Moreover, magnetic grain-size discrimination between surface-soil samples and bottom-soil samples is obtained. An increase of hard magnetic components from topsoil towards the bottom of the profiles is evidenced.     

Electrical separation of plastics coming from special waste

Minimisation of waste to landfilling is recognised as a priority in waste management by European rules. In order to achieve this goal, developing suitable technologies for waste recycling is therefore of great importance. To achieve this aim the technologies utilised for mineral processing can be taken into consideration to develop recycling systems. In particular comminution and separation processes can be adopted to recover valuable materials from composite waste. In this work the possibility of recycling pharmaceutical blister packaging has been investigated. A suitable comminution process has been applied in order to obtain the liberation of the plastic and aluminium components. Experiments of electrical separation have been carried out in order to point out the influence of the process parameters on the selections of the different materials and to set up the optimum operating conditions.     

Organochlorine pesticides,PCBs and heavy metals in tissues of the mullet Liza aurata in lake Ganzirri and Straits of Messina (Sicily,Italy)

The aim of this research was to investigate the presence of organochlorine pesticides, PCBs and heavy metals (Cd, Cr, Cu, Ni, Pb and Zn) in fish living in lake Ganzirri and the Straits of Messina, using the mullet Liza aurata as a "biological indicator". Different tissues of Liza aurata, which include the muscle, gill and vertebral column, were taken for analyses. Quantitative determination of the organochlorine compounds was performed by GC-ECD and confirmed with GC-MS. The concentrations of "essential" and "toxic" heavy metals were determined by Atomic Absorption Spectrophotometry. For the mullets of lake Ganzirri, the study showed DDE in three samples of gills and one of muscle, at concentrations below the MRL; no appreciable residues of PCBs (Aroclor 1232 series) were found. The concentrations of Zn and Cu were much higher than those of the "toxic" metals. No traces of organochlorine pesticides and PCBs were found in the individuals from the Straits of Messina. Therefore, these results indicate that these two environments are not at toxicological risk.     

These studies were conducted to assess the effects of lead toxicity on exploratory behavior and running. Effects of lead on exploratory behavior and running speed in the shrew, Blarina brevicauda (Insectivora)

These studies were conducted to assess the effects of lead toxicity on exploratory behavior and running speed in the short-tailed shrew, Blarina brevicauda. Shrews from the experimental group received 25 mg/kg/day of lead acetate in their drinking water for a period of 90 days. Control subjects received sodium acetate. Exploratory behavior was determined using a computerized activity chamber where movements of test subjects broke infrared beams projected onto the floor of the apparatus. Time spent (sec) in exploration was recorded over eight 6-min intervals. Running speed (km/hr) was measured in a microprocessor-controlled rectangular racetrack fitted with photocell timers. With respect to time spent in exploration, there were significant differences between lead-exposed (20.5-23.9 sec per 6-min testing session) and control subjects (6.8-8.1 sec) after the sixth testing interval in the activity chamber. With respect to maximal running speed, control subjects ran significantly faster (mean: 14.8 km/hr) than their lead-exposed counterparts (5.83 km/hr). Lead-exposed animals exhibited hyperactivity and increased random locomotor movements. They would frequently bump into the walls and their movements were more random. Controls typically ran along the racetrack in a straight line. These results represent the first data for the effects of lead exposure on exploratory behavior and running speed for shrews.     

Identification of ecologically significant habitats for urban nature conservation: a case study in Turkey

Given the rapid urbanization of Turkey, sustained productivity of natural resources should be an integral part of any urban development policy. The biogeochemical cycles and ecosystem services link urban and rural ecosystems. It is, therefore, essential that ecologically significant habitats along urban-rural continuum be protected to secure public and environmental health. This necessitates their identification and the establishment of administrative and legal foundations for urban nature conservation in the management of urban habitats, should be established Ecological analysis of urban habitats of Kar?iyaka led to the identification of 19 ecologically significant habitats. Nature conservation priority was rated, using rarity, species richness, stratification, site age, and area of the habitats. Ecologically significant habitats made up about 54 ha of the total urban green space of 289 ha in Kar?iyaka. The total number of plant species was estimated to be 273.     

Aniline degradation by electrocatalytic oxidation

The degradation of aniline solution in alkaline medium of pH 11.0 by electrocatalytic oxidation has been studied using an electrochemical reactor containing a SnO₂–Sb₂O₃–PtO anode and a Ti cathode, both of 54 cm² area. Hydroxyl radicals (HO^√) are produced at the anode, being tested with the trace catcher salicylic acid and phenol by spectrophotometery and high performance liquid chromatography. Intermediates dianiline, 4-anilino phenol and azobenzol were detected by gas chromatography–mass spectrometry. The existence of HO^√ produced in the aniline degradation was assayed with scavenger tertiary butanol. The results showed that electrocatalytic oxidation is an effective process for the degradation of aniline. A general reaction pathway that accounts for aniline degradation to CO₂ involving those intermediates is proposed.     

Inoculation of an atrazine-degrading strain,Chelatobacter heintzii Cit1, in four different soils: effects of different inoculum densities

The possibility to improve atrazine degradation in soils by bioaugmentation was studied. The atrazine-mineralizing strain, Chelatobacter heintzii Cit1, was inoculated in four sterile and four non-sterile soils, at varying inoculum densities. Two soils, which had shown enhanced atrazine mineralization, were used to determine which inoculum density was capable of restoring their original mineralizing capacity after sterilization. The two other soils, with intermediate and low capacity to mineralize atrazine, were used in order to demonstrate that atrazine mineralization in such soils could be improved by inoculation. Mineralization kinetics were fitted using the Gompertz model. In the case of soils adapted to atrazine mineralization, inoculation of C. heintzii did not accelerate the rate of atrazine mineralization, which was essentially performed by the indigenous microflora. However, with soils that did not mineralize atrazine, the introduction of 10(4) cfug(-1) resulted in a 3-fold increase of atrazine mineralization capacity.