Sewage sludge ash to phosphorus fertiliser: variables influencing heavy metal removal during thermochemical treatment

The aim of this study was to improve the removal of heavy metals from sewage sludge ash by a thermochemical process. The resulting detoxified ash was intended for use as a raw material rich in phosphorus (P) for inorganic fertiliser production. The thermochemical treatment was performed in a rotary kiln where the evaporation of relevant heavy metals was enhanced by additives. The four variables investigated for process optimisation were treatment temperature, type of additive (KCl, MgCl(2)) and its amount, as well as type of reactor (directly or indirectly heated rotary kiln). The removal rates of Cd, Cr, Cu, Ni, Pb, Zn and of Ca, P and Cl were investigated. The best overall removal efficiency for Cd, Cu, Pb and Zn could be found for the indirectly heated system. The type of additive was critical, since MgCl(2) favours Zn- over Cu-removal, while KCl acts conversely. The use of MgCl(2) caused less particle abrasion from the pellets in the kiln than KCl. In the case of the additive KCl, liquid KCl - temporarily formed in the pellets - acted as a barrier to heavy metal evaporation as long as treatment temperatures were not sufficiently high to enhance its reaction or evaporation.     

Human exposure to polybrominated diphenyl ethers (PBDE), as evidenced by data from a duplicate diet study, indoor air, house dust, and biomonitoring in Germany

Polybrominated diphenyl ethers (PBDE) are used as flame retardants in a wide variety of products. As part of the Integrated Exposure Assessment Survey (INES), this study aimed to characterize the exposure of an adult German population using duplicate diet samples, which were collected daily over seven consecutive days, and indoor air and house dust measurements. Our study population consisted of 27 female and 23 male healthy subjects, aged 14–60 years, all of whom resided in 34 homes in southern Bavaria. In these 34 residences the air was sampled using glass fiber filters and polyurethane foams and the dust was collected from used vacuum cleaner bags.The median (95th percentile) daily dietary intake of six Tetra- to HeptaBDE congeners was 1.2 ng/kg b.w. (3.3 ng/kg b.w.) or 67.8 ng/day (208 ng/day) (calculated from the 7-day median values of each study subject). Concentrations in indoor air and dust (cumulative Tri- to DecaBDE congener readings) ranged from 8.2 to 477 pg/m³ (median: 37.8 pg/m³) and 36.6 to 1580 ng/g (median: 386 ng/g), respectively. For some congeners, we identified a significant correlation between air and dust levels.The median (95th percentile) blood concentration of total Tetra- to HexaBDE congener readings was 5.6 (13.2) ng/g lipid. No significant sex differences were observed, but higher blood concentrations were found in younger participants. Using a simplified toxicokinetic model to predict the body burden from exposure doses led to results that were of the same order of magnitude as the measured blood concentrations.Based on these measurements and given our exposure assumptions, we estimated for the total tetra- to heptabrominated congener count an average (high) comprehensive total daily intake of 1.2 ng/kg b.w. (2.5 ng/kg b.w.). Overall, our results suggest that dietary exposure is the dominant intake pathway at least in our study population, responsible for 97% (average intake) and 95% (high intake) of the total intake of an adult population.     

A cross-scale impact assessment of European nature protection policies under contrasting future socio-economic pathways

Regional Environmental Change - Protection of natural or semi-natural ecosystems is an important part of societal strategies for maintaining biodiversity, ecosystem services, and achieving overall...     

Synergetik: Nichtgleichgewichte,Phasenübergänge und Selbstorganisation

The formation of ordered structures seems to contradict fundamental principles of physics according to which disorder should ever increase. Synergetics deals with the question how in spite of these laws structures can arise. We shall give a number of explicit examples. Large classes of ordered states in open systems are determined by a new principle based on the growth rates of collective configurations. In contrast, concepts such as entropy or entropy production are inadequate to treat such phenomena.