Physico-chemical and biological treatment of MSW landfill leachate

This paper analyses the evolution of the physico-chemical characteristics of the leachate from the Central Landfill of Asturias (Spain), which has been operating since 1986, as well as different treatment options. The organic pollutant load of the leachate, expressed as chemical oxygen demand (COD), reached maximum values during the first year of operation of the landfill (around 80,000 mg/L), gradually decreasing over subsequent years to less than 5000 mg/L. The concentration of ammonium, however, has not decreased, presenting values of up to 2000 mg/L. When feasible, recirculation can greatly decrease the organic matter content of the leachate to values of 1500–1600 mg COD/L. Applying anaerobic treatment to leachates with a COD between 11,000 and 16,000 mg/L, removal efficiencies of 80–88% were obtained for organic loading rates of 7 kg COD/m³ d. For leachates with lower COD (4000–6000 mg/L), the efficiency decreased to around 60% for organic loading rates of 1 kg COD/m³ d.Applying coagulation–flocculation with iron trichloride or with aluminium polychloride, it was possible to reduce the non-biodegradable organic matter by 73–62% when treating old landfill leachate (COD: 4800 mg/L, BOD₅: 670 mg/L), also reducing turbidity and colour by more than 97%. It is likewise possible to reduce the non-biodegradable organic matter that remains after biological treatment by adsorption with activated carbon, although adsorption capacities are usually low (from 15 to 150 mg COD/g adsorbent). As regards ammonium nitrogen, this can be reduced to final effluent values of 5 mg/L by means of nitrification/denitrification and to values of 126 mg/L by stripping at pH 12 and 48 h of stirring.     

Use of FGD gypsum in fire resistant panels

Gypsum from power plant flue gas desulphurization units (FGD gypsum) is a combustion by-product produced in high quantities. In this paper, gypsum panels composed of 100% FGD gypsum from two power plants have been subjected to different physico-chemical (density, pH, humidity), mechanical (flexural and compressive strength, surface hardness, impact resistance), fire resistance and environmental tests (leaching and radioactivity). The results obtained have been compared with the requirements established in some European standards for commercial gypsum and other standards for similar products. In addition, the panels manufactured have been compared with commercial gypsum panels in order to determine the recycling possibilities of this kind of material in this application.     

Persistent organochlorine residues in livers of six species of Ciconiiformes (aves) from Spain

Liver samples of 42 birds belonging to 6 species of Ciconiiformes (grey heron (n = 17), little egret (n = 12), cattle egret (n = 1), glossy ibis (n = 1), little bittern (n = 1), and white stork (n = 10)), collected from two different zones of Spain (Ebro Delta and Madrid) in 1992-1997, were analyzed for organochlorine pesticides and PCBs. SigmaPCBs (sum of concentrations of individual congeners), p,p'-DDE, HCB, gamma-HCH, and heptachlor epoxide were the most prevalent residues detected in all samples (occurrence > 95%). There were no statistically significant differences in organochlorine levels between grey herons and little egrets, while levels of SigmaPCBs, p,p'-DDE, HCB, gamma-HCH, and heptachlor were significantly lower for white storks. These results could be explained by the different habitat of these species, aquatic in the Ebro Delta (grey herons, little egrets) and dry in Madrid (white stork), and their diverse feeding habits.     

Eco-efficiency in the SMEs of Venezuela. Current status and future perspectives

This paper presents a comparison analysis of eco-efficiency in the small and medium sized enterprises (SMEs) of Venezuela. The research can be divided into three parts: the first part reviews similar studies in the literature on the level of eco-efficiency exhibited by the companies of Venezuela and other countries. In the second place, the findings of a survey conducted on Venezuelan SMEs allowed the definition of 54 eco-efficiency profiles. Thirdly, six national experts in cleaner production and eco-efficiency were interviewed. The interview was based on a questionnaire similar to that used in the survey of the Venezuelan SMEs. At a second meeting, the experts were asked to discuss on the similarities and differences between their answers and those of the company's managers.The findings of the survey allow us to conclude that Venezuelan SMEs understand the legal environmental regulations that affect them but they do not perceive the influence of external driving forces like customers demand for green products or institutional incentives. The adoption of eco-efficiency practices is not perceived as an incentive to improve competitiveness so that the environmental strategies adopted generally aim at reducing costs or avoiding non-compliance sanctions and negative effects on the company image. Materials recycling and reuse, especially packaging materials, are common practices; however, other environmental tools or practices have not been implemented yet, e.g. environmental management systems (EMS), process, product and services design tools based on the product life cycle, renewable energy resources or green marketing. There are also differences among the eight industrial sectors analyzed, food and chemical industries having the higher index of eco-efficiency practices, and plastic and wood industries the lower.     

Genetic Analyses Through DNA Fingerprinting of Captive Populations of Hawaiian Geese

DNA fingerprinting was used to assess levels of genetic variation in 106 Hawaiian Geese, or Nene ( Branta sandvicensis ), from two captive colonies in Hawaii and Slimbridge, England. Mantel tests were used to determine differences in mean similarity coefficients obtained from DNA fingerprints between unrelated and related Nene within and between captive colonies and to determine whether pedigree-based estimates of relatedness correlated with DNA fingerprint-based estimates. Between colonies, mean similarity coefficients for unrelated and related Slimbridge Nene were higher than those for Hawaiian Nene. Within each colony, related Nene bad higher mean similarity coefficients than did unrelated Nene. A positive relationship was found between coancestry coefficients and similarity coefficients. A greater number of founders for the Hawaiian colony contributed to the lower mean similarity coefficients. As genetic variation decreases, difficulty in distinguishing relatedness among individuals using DNA fingerprinting may increase. Lower genetic variation also may increase tine error in estimating the relationship between coancestry and similarity coefficients. DNA fingerprinting of Nene identified unique alleles and can determine optimal pairings between individuals. The calibrated similarity coefficient distributions can help determine the relatedness of individuals in wild populations of Nene.     

Management of domoic acid monitoring in shellfish from the Catalan coast

Monitoring of amnesic shellfish poisoning (ASP) toxins in shellfish from the Catalan coast started in 2001. No ASP toxins were detected in any of the analyses performed before 2008. On 22 January 2008, domoic acid (DA) was detected in Donax trunculus (0.5 mg?kg^?1) and confirmed by rapid resolution liquid chromatography–tandem mass spectrometry (0.6 mg?kg^?1). A total of 974 shellfish samples were analyzed from January 2008 to December 2011, covering all the Catalan production areas and the most important marketed species. DA was detected in 23.8 % of the samples and was recorded every month in all areas and all species, except Ostrea edulis, although the percentage of samples with DA and DA content varied widely among samples. DA exceeded the regulatory level of 20 mg?kg^?1 twice: in Callista chione sampled on February 2008 and in D. trunculus sampled on April 2010. DA content in Bolinus brandaris appeared constant and close to 4.5 mg?kg^?1 for months in 2009. Mytilus galloprovincialis, Crassostrea gigas, and Ruditapes sp. presented very low concentrations of DA in the Ebro Delta bays, despite 113 alert situations according to Pseudo-nitzschia spp. abundances and the high number of shellfish samples analyzed. The origin of DA in Catalan shellfish remains unknown.     

Use of environmental DNA in assessment of fish functional and phylogenetic diversity

Assessing the impact of global changes and protection effectiveness is a key step in monitoring marine fishes. Most traditional census methods are demanding or destructive. Nondisturbing and nonlethal approaches based on video and environmental DNA are alternatives to underwater visual census or fishing. However, their ability to detect multiple biodiversity factors beyond traditional taxonomic diversity is still unknown. For bony fishes and elasmobranchs, we compared the performance of eDNA metabarcoding and long-term remote video to assess species’ phylogenetic and functional diversity. We used 10 eDNA samples from 30 L of water each and 25 hr of underwater videos over 4 days on Malpelo Island (pacific coast of Colombia), a remote marine protected area. Metabarcoding of eDNA detected 66% more molecular operational taxonomic units (MOTUs) than species on video. We found 66 and 43 functional entities with a single eDNA marker and videos, respectively, and higher functional richness for eDNA than videos. Despite gaps in genetic reference databases, eDNA also detected a higher fish phylogenetic diversity than videos; accumulation curves showed how 1 eDNA transect detected as much phylogenetic diversity as 25 hr of video. Environmental DNA metabarcoding can be used to affordably, efficiently, and accurately census biodiversity factors in marine systems. Although taxonomic assignments are still limited by species coverage in genetic reference databases, use of MOTUs highlights the potential of eDNA metabarcoding once reference databases have expanded.     

Effects of development of wind energy and associated changes in land use on bird densities in upland areas

Wind energy development is the most recent of many pressures on upland bird communities and their habitats. Studies of birds in relation to wind energy development have focused on effects of direct mortality, but the importance of indirect effects (e.g., displacement, habitat loss) on avian community diversity and stability is increasingly being recognized. We used a control-impact study in combination with a gradient design to assess the effects of wind farms on upland bird densities and on bird species grouped by habitat association (forest and open-habitat species). We conducted 506 point count surveys at 12 wind-farm and 12 control sites in Ireland during 2 breeding seasons (2012 and 2013). Total bird densities were lower at wind farms than at control sites, and the greatest differences occurred close to turbines. Densities of forest species were significantly lower within 100 m of turbines than at greater distances, and this difference was mediated by habitat modifications associated with wind-farm development. In particular, reductions in forest cover adjacent to turbines was linked to the observed decrease in densities of forest species. Open-habitat species’ densities were lower at wind farms but were not related to distance from turbines and were negatively related to size of the wind farm. This suggests that, for these species, wind-farm effects may occur at a landscape scale. Our findings indicate that the scale and intensity of the displacement effects of wind farms on upland birds depends on bird species’ habitat associations and that the observed effects are mediated by changes in land use associated with wind-farm construction. This highlights the importance of construction effects and siting of turbines, tracks, and other infrastructure in understanding the impacts of wind farms on biodiversity.