Physical separation,mechanical enrichment and recycling-oriented characterization of spent NiMH batteries

Nickel–metal hydride (NiMH) batteries contain high amount of industrial metals, especially iron, nickel, cobalt and rare earth elements. Although the battery waste is a considerable secondary source for metal and chemical industries, a recycling process requires a suitable pretreatment method before proceeding with recovery step to reclaim all valuable elements. In this study, AA- and AAA-type spent NiMH batteries were ground and then sieved for size measurement and classification. Chemical composition of the ground battery black mass and sorted six different size fractions were determined by an analytical technique. Crystal structures of the samples were analyzed by X-ray diffraction. Results show that after mechanical treatment, almost 87 wt% of the spent NiMH batteries are suitable for further recycling steps. Size classification by sieving enriched the iron content of the samples in the coarse fraction which is bigger than 0.25 mm. On the other hand, the amounts of nickel and rare earth elements increased by decreasing sample size, and concentrated in the finer fractions. Anode and cathode active materials that are hydrogen storage alloy and nickel hydroxide were mainly collected in finer size fraction of the battery black mass.     

A case study for a cost-benefit-based,stepwise optimization of thermo-chemical WAS pre-treatment for anaerobic digestion

Waste-activated sludge (WAS) may be considered a resource generated by wastewater treatment plants and used for biogas-generation but it requires pre-treatment (PT) for enhanced biogas-yields and reduced WAS disposal costs. To date, a number of studies on the optimization of such PT focused on improved biogas yields but neglected inferred energy and resource consumption. Here, we aimed to identify the most promising thermo-chemical PT-strategy in terms of net energy output and cost-efficiency by optimizing PT temperature and the amount and sort of the alkaline reagent used. We compared methane-potentials and disposal costs of untreated and treated WAS and conducted an annual cost-benefit calculation. We defined 70 °C and 0.04 M NaOH as ideal PT-conditions being both, low-energy demanding and efficient. Applying these conditions, enhanced biogas-yields and improved dewaterability led to reduced electricity and disposal costs of 22 and 27%, respectively, resulting in savings of approx. 28% of the yearly WAS-related expenditures of a wastewater treatment plant. Despite multiple benefits in running costs, the implementation of WAS-PT was not recommendable in the presented case study due to high investment costs.

     

Handling the phosphorus paradox in agriculture and natural ecosystems: Scarcity,necessity, and burden of P

This special issue of Ambio compiles a series of contributions made at the 8th International Phosphorus Workshop (IPW8), held in September 2016 in Rostock, Germany. The introducing overview article summarizes major published scientific findings in the time period from IPW7 (2015) until recently, including presentations from IPW8. The P issue was subdivided into four themes along the logical sequence of P utilization in production, environmental, and societal systems: (1) Sufficiency and efficiency of P utilization, especially in animal husbandry and crop production; (2) P recycling: technologies and product applications; (3) P fluxes and cycling in the environment; and (4) P governance. The latter two themes had separate sessions for the first time in the International Phosphorus Workshops series; thus, this overview presents a scene-setting rather than an overview of the latest research for these themes. In summary, this paper details new findings in agricultural and environmental P research, which indicate reduced P inputs, improved management options, and provide translations into governance options for a more sustainable P use.     

Reviving wood-pastures for biodiversity and people: A case study from western Estonia

Wood-pastures are associated with high cultural and biodiversity values in Europe. However, due to their relatively low productivity, large areas of wood-pastures have been lost over the last century. In some areas, incentive schemes have been developed to revive wood-pastures. We investigated the effects of one such scheme in western Estonia. We compared the structure of grazed wood-pastures (old and restored) to those of abandoned wood-pastures and ungrazed forest stands to explore the effects of management, and conducted interviews with 24 farmers to investigate their motivations to carry out the management. We found a positive influence of active management on the semi-open structure of wood-pastures. Financial support was vital for management, but personal values related to tradition also played an important role. The interviewees differed widely in their range of motivations, suggesting that other strategies in addition to financial incentives would further improve the management of wood-pastures in the region.

Electronic supplementary material

The online version of this article (doi:10.1007/s13280-015-0719-8) contains supplementary material, which is available to authorized users.     

Integrated spatial health assessment of yellow perch (<Emphasis Type="Italic">Perca flavescens</Emphasis>) populations from the St. Lawrence River,Quebec, Canada) part A: physiological parameters and pathogen assessment

A multi-disciplinary approach was used to evaluate the health of yellow perch (Perca flavescens) in the St. Lawrence River (Quebec, Canada), which is experiencing a severe population decline in the downstream portion of the river. Physiological parameters, liver alterations, trace metal concentrations, parasite prevalence and abundance, stable isotope composition, and the presence/absence of the viral hemorragic septicemia virus (VHSV) were evaluated in perch collected at six sites along the river: Lake St. François, Lake St. Louis (north and south), Beauregard Island, and Lake St. Pierre (north and south). Trace metal concentrations in surface water were higher in Lake St. Louis and downstream of a major urban wastewater treatment plant discharge, indicating that this effluent was a significant source of Cu, As, Ag, Zn, and Cd. Levels of Pb in surface water exceeded thresholds for the protection of aquatic life in Lake St. Louis and were negatively correlated with body condition index in this lake. In Lake St. Pierre, Cu, Ag, and Cd bioaccumulated significantly in perch liver and lower body condition index and greater liver damage were observed compared to upstream sites. Parasite analyses indicated a higher abundance of metacercariae of the trematodes Apophallus brevis and Diplostomum spp. in Lake St. Louis, and VHSV was not detected in the liver of yellow perch for all studied sites. Overall, results suggested that the global health of yellow perch from Lake St. Pierre is lower compared to upstream studied sites, which could contribute to the documented population collapse at this site.     

Potential of fly ash for neutralisation of acid mine drainage

Lignite (PK), bituminous (FI) and biomass (SE) fly ashes (FAs) were mineralogically and geochemically characterised, and their element leachability was studied with batch leaching tests. The potential for acid neutralisation (ANP) was quantified by their buffering capacity, reflecting their potential for neutralisation of acid mine drainage. Quartz was the common mineral in FAs detected by XRD with iron oxide, anhydrite, and magnesioferrite in PK, mullite and lime in FI, and calcite and anorthite in SE. All the FAs had high contents of major elements such as Fe, Si, Al and Ca. The Ca content in SE was six and eight times higher compared to PK and FI, respectively. Sulphur content in PK and SE was one magnitude higher than FI. Iron concentrations were higher in PK. The trace element concentrations varied between the FAs. SE had the highest ANP (corresponding to 275 kg CaCO₃?tonne^?1) which was 15 and 10 times higher than PK and FI, respectively. The concentrations of Ca²⁺, SO₄ ^2?, Na⁺ and Cl^? in the leachates were much higher compared to other elements from all FA samples. Iron, Cu and Hg were not detected in any of the FA leachates because of their mild to strong alkaline nature with pH ranging from 9 to 13. Potassium leached in much higher quantity from SE than from the other ashes. Arsenic, Mn and Ni leached from PK only, while Co and Pb from SE only. The concentrations of Zn were higher in the leachates from SE. The FAs used in this study have strong potential for the neutralisation of AMD due to their alkaline nature. However, on the other hand, FAs must be further investigated, with scaled-up experiments before full-scale application, because they might leach pronounced concentrations of elements of concern with decreasing pH while neutralising AMD.     

Globalization’s limits to the environmental state? Integrating telecoupling into global environmental governance

Globalization entails increased interdependence and interconnectivities among distal regions and social-ecological systems. This global interregional connectedness – telecoupling – gives rise to specific sustainability challenges, which require new governance solutions. Moving beyond ‘scaling-up’ governance to address global environmental problems, and exploring the implications of telecoupling for state-led environmental governance, ways the state can effectively address telecoupled environmental issues both within and beyond national borders are addressed, drawing on the example of soy trade between Brazil and Germany. This builds on recent contributions to the literature on governance of interregional ecological challenges to elaborate potential policy and governance options, ranging from classical bilateral, multilateral, and international agreements, to information-based, economic, and hybrid governance modes. While telecoupled environmental problems create governance challenges related to scale, knowledge gaps, coordination, and state capacity, the state has an important role to play. To explore this further, interdisciplinary inquiry is required that includes but moves beyond the state.     

Wood-Specific Polycyclic Aromatic Hydrocarbon (PAH) Patterns in Soot Using Gas Chromatography-Atmospheric Pressure Laser Ionization-Mass Spectrometry (GC-APLI-MS)

If organic matter is burnt, the combustion of wood produces the highest amounts of polycyclic aromatic hydrocarbons (PAHs) compared with other fossil energy sources such as oil, coal, or gas. Emissions from wood combustion are increasingly of special interest due to the rising use of wood as a renewable energy source in residential heating in Europe. To the authors' knowledge, reproducible wood-specific PAH patterns in soot were identified for the first time by use of a sampling interval of only 5 min in this study. The short sampling interval was enabled by the very sensitive analytical method of gas chromatography–atmospheric pressure laser ionization–mass spectrometry (GC-APLI-MS) applied. The analysis of 40 PAH of soot from wood logs of spruce, pine, larch (softwood) and beech, birch, oak (hardwood), and wood pellets, as well as wood briquettes, showed 13.46–250.62 mg/kg for ∑40 PAH and 10.75–177.94 mg/kg for the U.S. Environmental Protection Agency PAH standard (without acenaphthylene and anthracene). Highest concentrations occurred in the samples from birch with bark, beech, and wood briquettes. Indeno[1,2,3-cd]pyrene, naphthalene, and alkylated naphthalenes were also detected. Significant concentrations of the very toxic dibenzopyrenes (up to 11.30 mg/kg) are reported. Softwood soot contained highest amounts of 2–4-ring PAH, followed by hardwood which is in accordance with the presence of highest amounts of abietic acid in softwood, a known precursor of retene and phenanthrene. PAH in soot from five spruce samples from different locations show a mean ∑40 PAH concentration of 13.46 mg/kg (n = 5, minimum 8.03, maximum 23.32 mg/kg, SD = 5.65) and exhibited a typical pattern that differed from all other wood soot samples. The distributions of alkylated naphthalenes of the spruce samples show a bell-shape distribution in contrast to the alkylated phenanthrenes/anthracenes of all samples (except the wood pellets), showing a slope distribution. The data indicate that wood-specific PAH patterns exist and under the applied conditions, spruce logs produced the least toxic soot.