The technology of urine separation and the recycling of anthropogenic nutrients as fertilizer in agriculture are considered as major innovations to improve the sustainability of today's urban wastewater management. The acceptance of consumers will be key for the introduction of the new technology. Citizens will have to make important decisions in their role as tenants and owners of houses and as consumers buying products fertilized with urine. Consumer attitudes towards the new technology were explored in a number of citizen focus groups in Switzerland. Focus groups are deliberate, moderated group discussions with informed citizens on a certain topic. The information was provided by a computer based information system specifically designed for this purpose. The acceptance of individual citizens for the new technology proved to be quite high. The majority of the citizens expressed their willingness to move into an apartment with NoMix toilets and to buy food fertilized with urine. However, they were not willing to accept additional financial costs or efforts. Arguments related to long-term sustainability (closing nutrient cycles) were of less importance than arguments that relate directly to the effects of micropollutants on human and ecosystem health. For the introduction of the new technology on a wide scale it will thus be crucial to explore the fate and effects of micropollutants.

Women seem to have a higher vulnerability to Alzheimer's disease (AD), but the underlying mechanisms of this sex dichotomy are not well understood. Here, we first determined the influence of sex on various aspects of Alzheimer's pathology in transgenic CRND8 mice. We demonstrate that beta-amyloid (Aβ) plaque burden starts to be more severe around P180 (moderate disease stage) in female transgenics when compared to males and that aging aggravates this sex-specific difference. Furthermore, we show that female transgenics suffer from higher levels of neurovascular dysfunction around P180, resulting in impaired Aβ peptide clearance across the blood-brain-barrier at P360. Female transgenics show also higher levels of diffuse microgliosis and inflammation, but the density of microglial cells surrounding Aβ plaques is less in females. In line with this finding, testosterone compared to estradiol was able to improve microglial viability and Aβ clearance in vitro. The spatial memory of transgenics was in general poorer than in wildtypes and at P360 worse in females irrespective of their genotype. This difference was accompanied by a slightly diminished dendritic complexity in females. While all the above-named sex-differences emerged after the onset of Aβ pathology, kallikrein-8 (KLK8) protease levels were, as an exception, higher in female than in male brains very early when virtually no plaques were detectable. In a second step, we quantified cerebral KLK8 levels in AD patients and healthy controls, and could ascertain, similar to mice, higher KLK8 levels not only in AD-affected but also in healthy brains of women. Accordingly, we could demonstrate that estradiol but not testosterone induces KLK8 synthesis in neuronal and microglial cells. In conclusion, multiple features of AD are more pronounced in females. Here, we show for the first time that this sex-specific difference may be meditated by estrogen-induced KLK8 overproduction long before AD pathology emerges.

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In the past decades, the search for a more sustainable way of global development has increased in importance in international politics and economy. A driving force is the continuing degradation of the environment in many areas of the world, often caused or accelerated by population growth and climate change. Sustainable development is seen as key approach to mitigate these processes. It has been defined as “development that meets the needs of the present without compromising the ability of future generations to meet their own needs.” But how can this ambitious goal be achieved in the light of numerous global challenges? Engineering is a very influential human practice and must be addressed in this context. Engineers are crucially involved in design and construction of our built environment and thus in shaping almost its entire development. However, when designing a solution for a given problem, effects caused outside of the system borders are often not considered. If this is combined with a narrowly confined linear problem-solving approach, it is inherently prone to create new environmental challenges. We postulate that the development of a new design paradigm for engineering must be part of the progress towards sustainable development. We think that this new paradigm needs to integrate a sound understanding of ecological principles, processes, and interdependencies as well as thorough system thinking. We call this ecology-inspired approach to engineering “ecological engineering” and redefine it as follows: Ecological Engineering integrates ecological principles, processes, and organisms with existing engineering practice to a holistic approach for problem-solving. In this paper, we explore the historical development of earlier definitions of Ecological Engineering in the light of their underlying value systems. Based on this analysis, we propose a new conceptual approach for Ecological Engineering and define seven principles that point the way towards a future label that can be conferred to Good Ecological Engineering Practice.

Biochar is increasingly being applied as a soil amendment in agriculture. Biochar is typically produced from plant biomass and contains relatively low amounts of plant nutrients (e.g., N, P, and K), thus providing limited fertilizer value. Human excreta contains plant nutrients that could be recycled to create sustainable agricultural nutrient cycles. This study investigated the potential of biochar derived from a dry toilet substrate as soil amendment. The substrate consisted of urine, faeces, and wood chips, and was pyrolyzed at 500–650 °C for 10 min. The biochar was analyzed for plant available P, water leachable P and K, carbon stability, pH, electrical conductivity, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), dioxins, and germination tests with barley and lettuce were conducted to estimate the biochar fertilizer value and potential bio-toxicity. The biochar contained 25.0 ± 1.0 g N/kg dry mass (DM), 33.1 ± 2.1 g P/kg DM and 20.7 ± 0.2 g K/kg DM. 65% DM P was extractable by formic acid solution, 31.7% DM P and 60.5% DM K were water leachable in a ten-day column water-leaching experiment. The biochar complied with European regulations for PAHs, PCBs, dioxins and heavy metal concentrations, except for Zn and Ni. Germination of salt-resistant barley was not affected by biochar doses < 50% DM, while salt-sensitive lettuce germination was inhibited at doses ≥ 2% DM, indicating that the dry toilet substrate biochar induced salt stress. Based on these results, it is recommended that urine separation should be considered for biochar of excreta, which could reduce salt stress while maintaining concentrations of “fixed” or bioavailable nitrogen. Graphic Abstract