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The Science of Nature -     

Integrated pollution prevention and control in large industrial installations on the basis of best available techniques – The Sevilla Process

With respect to emissions from industry, the IPPC Directive is one of the key instruments of the environmental legislation of the European Union. The purpose of this Directive is to achieve integrated pollution prevention and control from large industrial installations. The conditions of required permits have to be based on Best Available Techniques (BAT). In 1997, the so-called Sevilla Process was established to develop these BAT. Since then, 33 Best Available Techniques REFerence Documents (BREFs) were drafted, adopted and published. This Sevilla Process with its actors is described. The BREFs are unique documents containing ambitious consumption and emission levels which cannot be found anywhere else.     

The impact of climate change and its uncertainty on carbon storage in Switzerland

Projected future climate change will alter carbon storage in forests, which is of pivotal importance for the national carbon balance of most countries. Yet, national-scale assessments are largely lacking. We evaluated climate impacts on vegetation and soil carbon storage for Swiss forests using a dynamic vegetation model. We considered three novel climate scenarios, each featuring a quantification of the inherent uncertainty of the underlying climate models. We evaluated which regions of Switzerland would benefit or lose in terms of carbon storage under different climates, and which abiotic factors determine these patterns. The simulation results showed that the prospective carbon storage ability of forests depends on the current climate, the severity of the change, and the time required for new species to establish. Regions already prone to drought and heat waves under current climate will likely experience a decrease in carbon stocks under prospective ‘extreme’ climate change, while carbon storage in forests close to the upper treeline will increase markedly. Interestingly, when climate change is severe, species shifts can result in increases in carbon stocks, but when there is only slight climate change, climate conditions may reduce growth of extant species while not allowing for species shifts, thus leading to decreases in carbon stocks.     

Eelgrass fairy rings: sulfide as inhibiting agent

Distinct ‘fairy rings’ consisting of narrow fringes of eelgrass (Zostera marina L.) expand radially over a bottom of chalk plates outside the calcium carbonate cliffs of the island of Møn, Denmark. We conducted a survey to evaluate possible explanations for the formation of the rings and, more specifically, for the apparent die-off of eelgrass shoots on the inner side of the rings. The fairy rings were up to 15 m in diameter consisting of 0.3- to 1-m-wide zones of sea grass shoots at densities of up to 1,200 shoots m^?2 and rooted in an up to 10-cm-thick sediment layer. On the outer side, shoots expanded over the bare chalk plates. On the inner side, shoots were smaller, had lower absolute and specific leaf growth, shoot density was lower and the sediment eroded leaving the bare chalk with scattered boulders behind. Sediment organic matter and nutrients and tissue nutrient contents were not different among positions. Sediment pools of acid volatile sulfides and chromium-reducible sulfur increased from outer to the middle positions of the rings, and so did total sulfur content of eelgrass tissues, while tissue δ³⁴S isotope ratios, regardless of position in the fringes, were low reflecting substantial invasion of sulfide from the sediment. Neither the clonal growth pattern of eelgrass, sediment burial of shoots, hydrodynamic forcing nor nutrient limitation could explain the ring-shaped pattern. We conclude that the most likely explanation must be found in invasion of eelgrass shoots by toxic sulfide accumulating in the sediment due to low iron availability in the carbonate-rich environment.     

RecoPhos: Full-scale fertilizer production from sewage sludge ash

The substitution potential of sewage sludge for German primary phosphate imports has been estimated as 40%. Yet, a marketable option for the full scale recovery has been lacking. This study focuses on a full-scale process for the manufacture of a P-fertilizer from sewage sludge ash (SSA) adapted from the production of Triple Superphosphate. Given (i) conformity of the input with phosphate ores mined from sedimentary deposits, (ii) comparability of the product with a commercially available P-fertilizer regarding contaminant levels, P-fractionation and yield effects, and (iii) compliance of the output with the German Fertilizer Ordinance the RecoPhos P 38 fertilizer was discharged from the waste legislation regime. The fertilizer is currently being produced at a rate of 1000 tonnes per month and sold at a competitive price.