Chemical characterisation of spent rechargeable batteries

A chemical characterisation of used batteries can give useful information to implement suitable recycling techniques and to estimate the flux of the different materials recovered. This work is aimed to provide quantitative data about the composition of mixed batteries (in particular, Ni–Cd, Ni-MH and Li-ion batteries) collected in a Northern Italian town in order to evaluate the feasibility of recovery processes applied to the selected material. The higher concentration of metals in the <3 mm fraction suggested that significant quantities of valuable elements could be recovered: in particular, for a kg of the <3 mm fraction deriving from disassembled batteries, about 390 g Ni and 330 g Cd can be recovered from Ni–Cd, 630 g Ni, 80 g Co from Ni-MH and 250 g Co, 110 g Ni, 120 g Cu from Li-ion ones. Leaching tests applied to the same fractions, to assess possible contaminant releases, resulted in low metal content in aqueous solutions (except for Al and Fe, the concentrations of all metals remained below 1 mg/kg). Even so, great care is required in all handling activities due to the high pH values of leachate solutions.     

Use of phytoproductivity data in the choice of native plant species to restore a degraded coal mining site amended with a stabilized industrial organic sludge

Coal mining-related activities result in a degraded landscape and sites associated with large amounts of dumped waste material. The arid soil resulting from acid mine drainage affects terrestrial and aquatic ecosystems, and thus, site remediation programs must be implemented to mitigate this sequential deleterious processes. A low-cost alternative material to counterbalance the affected physico-chemical-microbiological aspects of the degraded soil is the amendment with low contaminated and stabilized industrial organic sludge. The content of nutrients P and N, together with stabilized organic matter, makes this material an excellent fertilizer and soil conditioner, fostering biota colonization and succession in the degraded site. However, choice of native plant species to restore a degraded site must be guided by some minimal criteria, such as plant survival/adaptation and plant biomass productivity. Thus, in this 3-month study under environmental conditions, phytoproductivity tests with five native plant species (Surinam cherry Eugenia uniflora L., C. myrianthum–Citharexylum myrianthum, Inga–Inga spp., Brazilian peppertree Schinus terebinthifolius, and Sour cherry Prunus cerasus) were performed to assess these criteria, and additional biochemical parameters were measured in plant tissues (i.e., protein content and peroxidase activity) exposed to different soil/sludge mixture proportions. The results show that three native plants were more adequate to restore vegetation on degraded sites: Surinam cherry, C. myrianthum, and Brazilian peppertree. Thus, this study demonstrates that phytoproductivity tests associated with biochemical endpoint measurements can help in the choice of native plant species, as well as aiding in the choice of the most appropriate soil/stabilized sludge proportion in order to optimize biomass production.

     

On shadow prices for the measurement of sustainability

The objective of this research is to discuss the direction of the bias of the existing estimates of genuine savings (also known as adjusted net savings). Such estimates rely on observed prices and quantities of investment and natural resource extraction. This has two consequences: first, it causes an overestimation of the shadow price of productive natural resources; second, it leads to omitting the depreciation of environmental services and amenities. We use simple numerical models to determine the path of optimal development under different assumptions. We find that the existing estimates of genuine savings are likely to be biased upward for countries with high levels of pollution, and biased downward for natural resource extracting countries.