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SummaryThe German government has adopted a law that requires sewage plants to go beyond the recovery of phosphorus from wastewater and to promote recycling. We argue that there is no physical global short‐ or mid‐term phosphorus scarcity. However, we also argue that there are legitimate reasons for policies such as those of Germany, including: precaution as a way to ensure future generations’ long‐term supply security, promotion of technologies for closed‐loop economics in a promising stage of technology development, and decrease in the current supply risk with a new resource pool.

ABSTRACTAn overview is given of an International Atomic Energy Agency Coordinated Research Project (CRP) on the treatment of irradiated graphite (i-graphite) to meet acceptance criteria for waste disposal. Graphite is a unique radioactive waste stream, with some quarter-million metric tons worldwide eventually needing to be disposed of. The CRP has involved 24 organizations from 10 Member States. Innovative and conventional methods for i-graphite characterization, retrieval, treatment and conditioning technologies have been explored in the course of this work, and offer a range of options for competent authorities in individual Member States to deploy according to local requirements and regulatory conditions.

Reducing energy consumption, increasing energy efficiency technologies and solutions, decreasing emissions are very effective tools towards EU environmental policy. The constant demand for domestic hot water (DHW) throughout the year creates great benefits for drain water heat recovery (DWHR) systems in hotels, which is the most promising and significant feature of energy saving potential for the hotel sector in Poland. This paper determines the feasibility of heat recovery in a typical hotel in Poland. The energy analysis was carried out for the installed DWHR system (from washbasins and showers) at the hotel building. To evaluate the energy saving potentiality, daily, monthly and yearly calculation results were performed for an exemplary hotel in Poland. Two types of heat exchangers were adopted for further calculations: vertical (System 1) and horizontal (System 2), this intention aimed to find the most efficient type and relevant solution of energy saving and reduction of CO2 emissions in the analysed hotel. The analysis and calculations were repeated to enhance the saving potentiality of the proposed DWHR systems for various parameters like constant and variable temperature of supply cold water, daily hot water consumption profiles, the efficiency of heat recovery, reduction of annual carbon dioxide emission (CDE), facility standard of operating procedure, the impact of hotel size, etc. The obtained results of the conducted calculations ensure a significant potential of energy savings by implementing the proposed DWHR systems in analysed hotel, which allow to save energy demand and to reduce CO2 emission by 27.3% and improve the efficiency of the DHW preparation system.

The European Union is currently in the process of transformation toward a circular economy model in which different areas of activity should be integrated for more efficient management of raw materials and waste. The wastewater sector has a great potential in this regard and therefore is an important element of the transformation process to the circular economy model. The targets of the circular economy policy framework such as resource recovery are tightly connected with the wastewater treatment processes and sewage sludge management. With this in view, the present study aims to review existing indicators on resource recovery that can enable efficient monitoring of the sustainable and circular solutions implemented in the wastewater sector. Within the reviewed indicators, most of them were focused on technological aspects of resource recovery processes such as nutrient removal efficiency, sewage sludge processing methods and environmental aspects as the pollutant share in the sewage sludge or its ashes. Moreover, other wide-scope indicators such as the wastewater service coverage or the production of bio-based fertilizers and hydrochar within the wastewater sector were analyzed. The results were used for the development of recommendations for improving the resources recovery monitoring framework in the wastewater sector and a proposal of a circularity indicator for a wastewater treatment plant highlighting new challenges for further researches and wastewater professionals.

A priority of the industrial applications of microalgae is the reduction of production costs while maximizing algae biomass productivity. The purpose of this study was to carry out a comprehensive evaluation of the effects of pH control on the production of Nannochloropsis gaditana in tubular photobioreactors under external conditions while considering the environmental, biological, and operational parameters of the process. Experiments were carried out in 3.0 m3 tubular photobioreactors under outdoor conditions. The pH values evaluated were 6.0, 7.0, 8.0, 9.0, and 10.0, which were controlled by injecting pure CO2 on-demand. The results have shown that the ideal pH for microalgal growth was 8.0, with higher values of biomass productivity (Pb) (0.16 g L-1 d-1), and CO2 use efficiency ([Formula: see text]) (74.6% w w-1); [Formula: see text]/biomass value obtained at this pH (2.42 [Formula: see text] gbiomass-1) was close to the theoretical value, indicating an adequate CO2 supply. At this pH, the system was more stable and required a lower number of CO2 injections than the other treatments. At pH 6.0, there was a decrease in the Pb and [Formula: see text]; cultures at pH 10.0 exhibited a lower Pb and photosynthetic efficiency as well. These results imply that controlling the pH at an optimum value allows higher CO2 conversions in biomass to be achieved and contributes to the reduction in costs of the microalgae production process.

Water and energy conservation are indispensable commitments to achieve the sustainable development of the iron and steel industry. Hereby, this study established an evaluation framework to model the water and energy consumption in the iron and steel industry. This framework quantitatively assessed the energy and water saving with adoption of conventional and emerging technologies. Thirty mainstream technologies, among which 21 focused on energy saving and the remaining 9 focused on water saving, were selected for analysis. Five scenarios were developed to examine systematic water- and energy-saving potentials, including benchmark (BM) scenario, constrained product (CP) scenario, business as usual (BAU) scenario, and benefit/cost-driven (BD) scenario and strengthened policy (SP) scenario. The results show that the energy-saving potentials of BAU, BD and SP scenarios are 1.75 PJ, 1.21 PJ and 1.65 PJ, respectively. The water-saving potentials of BAU, BD and SP scenarios are 4.83 billion m3, 5.71 billion m3 and 9.15 billion m3, respectively. The specific energy consumption and water consumption decreased to 15.01-15.59 GJ/t and 54.13-58.77 m3/t, respectively. This study suggested to implement encouraging policies in prompt popularity rate of technologies, and promote energy-saving and water-saving technologies to achieve sustainable development of iron and steel industry.

Climate change is expected to exacerbate drought conditions over many global regions. However, the future risk posed by droughts depends not only on the climate-induced changes but also on the changes in societal exposure and vulnerability to droughts. Here we illustrate how the consideration of human vulnerability alters global drought risk associated with runoff (hydrological) and soil moisture (agriculture) droughts during the 21st-century. We combine the changes in drought frequency, population growth, and human development as a proxy of vulnerability to project global drought risk under plausible climate and socioeconomic development pathways. Results indicate that the shift toward a pathway of high greenhouse gas emissions and socioeconomic inequality leads to i) increased population exposure to runoff and soil moisture droughts by 81% and seven folds, respectively, and ii) a stagnation of human development. These consequences are more pronounced for populations living in low than in very high human development countries. In particular, Sub-Saharan Africa and South Asia, where the majority of the world's less developed countries are located, fare the worst in terms of future drought risk. The disparity in risk between low and very high human development countries can be substantially reduced in the presence of a shift toward a world of rapid and sustainable development that actively reduces social inequality and emissions. Our results underscore the importance of rapid human development in hotspots of drought risk where effective adaptation is most needed to reduce future drought impacts.

Dissolved organic carbon (DOC) concentration and fluxes from four rivers draining the catchment of the Puck Lagoon in southern Baltic are presented. Water samples from rivers and coastal zone close to the rivers' mouth were collected from April 2015 to March 2017. DOC was measured using high temperature catalytic oxidation with an NDIR detection. DOC concentration in rivers as well as area specific load discharged to the lagoon reflected variations of land use along their course. Area specific load of DOC discharged by rivers with high proportion of forests, meadows, and pastures in the catchment was significantly higher as compared to rivers with catchment dominated by arable land. However, the main controlling factor of the total discharged loads of DOC was the water flow. The highest loads were observed during the downpour. That was due to the larger volumes of water transported with rivers and the higher concentration of DOC resulting from increased leaching from the catchment area. The obtained results are especially important in the light of climate change in the southern Baltic region. According to the forecasts, we can expect increased precipitation and flooding and consequently increased leaching from the catchment and transport of DOC to the sea via rivers.

Green technologies presented in Polish power generation are based on biomass. Poland has considerable potential for biomass produced using forest, agricultural, and municipal waste. Currently, biomass is used in several hundred power stations, co-incineration of biomass with coal powers 39 CHP and power plants. The largest estab- lishments producing bioethanol are located in Starogard Gdanski, Oborniki, and Wroclaw. The largest producer of biodiesel is the Trzebinia Refinery S.A., located in the villages of Surochow, Tychy, and Malbork. Electricity and heat are produced through cogeneration of biogas in 76 water treatment biogas plants, 94 biogas plants on muni- cipal waste landfills, and 29 agricultural biogas plants. The Polish target share of energy produced from renewable sources in final gross energy consumption is projected to be 15 % in 2020.