Suchergebnisse

Cities have the capacity to play a key role in resource and pollution management through their decisions about organic waste. Often overlooked, but nevertheless essential, is the role that cities can play in increasing phosphorus (P) recycling because cities are consumers of large amounts of P-dense food and producers of vast amounts of P-rich waste. Most cities do not take advantage of this potential, seeing P as simply another part of organic waste to be disposed of elsewhere. For example, in Montreal, Canada, only 6% of P in waste is currently recycled. We used semi-structured interviews with key stakeholders (19), participant observation (over 1.5 years), and document review to identify key barriers and facilitators for Montreal to achieve a high level of organic waste recycling through composting. We found that a provincial law mandating 100% recycling of organic matter has great potential to facilitate increased P recycling. However, lack of a shared vision about the role of government, private sector, and citizens in producing high quality compost from waste products is a barrier that inhibits this potential. Cultural inertia, lack of knowledge, and lack of infrastructure also act as barriers to increasing composting in Montreal. Urban agriculture could be a means to overcome some of these barriers as it currently benefits from strong citizen support and is both a consumer and producer of compost. However limited access to potential garden space and training and diversity in desired fertilizer qualities among gardeners somewhat limit this potential. Investing in increasing social capital, and specifically in connecting urban agriculture to waste management objectives, and in linking key stakeholders to co-create shared visions about how to produce high quality compost may act as a stepping stone towards increasing Montreal citizens' knowledge about, and support for, increasing organic waste and thus P recycling.

Biogas production through anaerobic digestion is an integral part of the transition toward a biobased and circular economy and its expansion is foreseen in many parts of the world as well as in Europe. In Sweden, a governmental inquiry suggested biogas production to be increased from about 2 TWh today to 7 TWh by 2030. This rapid expansion would require installation of several new biogas plants across the country. However, the location of biogas plants can greatly affect its business performance and there are several geographic and socio-political factors that would limit the choice of location. Through dialogue with existing biogas producing companies and a few other related actors, we identified 12 factors that are commonly considered in the site-selection of biogas plants in Sweden or are considered to be important in the years to come. These factors are grouped into those related to supply and demand (feedstock supply, biogas demand, digestate demand, and carbon dioxide demand), infrastructure and synergies (available infrastructure, adjacent existing industries), land-use and zoning (nearby housing, zoning, and historic preservation sites), and socio-political context (political strategies and goals, organizational capability, and local social acceptance). We discuss how these factors can be used under rapidly transforming conditions in Sweden through different site-selection logics and highlight the importance of spatially explicit analysis for individual or coordinated decision making in future. Our method of enquiry and analysis, and to a certain degree the factors, can be also relevant for other countries, particularly in Europe. This study paves the way for more in-depth investigation of the question of site-selection of biogas plants in Sweden; both in the direction of detailed analysis at the local level, or screening analysis on the regional or national level for improved coordinated actions. ; Funding: This research was performed with the support of the Biogas Research Center (BRC) which is funded ...

Phosphorus (P) is subject to global management challenges due to its importance to both food security and water quality. The European Union (EU) has promoted policies to limit fertiliser over-application and protect water quality for more than 20 years, helping to reduce European P use. Over this time period, the EU has, however, become more reliant on imported agricultural products. These imported products require fertiliser to be used in distant countries to grow crops that will ultimately feed European people and livestock. As such, these imports represent a displacement of European P demand, possibly allowing Europe to decrease its apparent P footprint by moving P use to locations outside the EU. We investigated the effect of EU imports on the European P fertiliser footprint to better understand whether the EU's decrease in fertiliser use over time resulted from P demand being 'outsourced' to other countries or whether it truly represented a decline in P demand. To do this, we quantified the 'virtual P flow' defined as the amount of mineral P fertiliser applied to agricultural soils in non-EU countries to support agricultural product imports to the EU. We found that the EU imported a virtual P flow of 0.55 Tg P/yr in 1995 that, surprisingly, decreased to 0.50 Tg P/yr in 2009. These results were contrary to our hypothesis that trade increases would be used to help the EU reduce its domestic P fertiliser use by outsourcing its P footprint abroad. Still, the contribution of virtual P flows to the total P footprint of the EU has increased by 40% from 1995 to 2009 due to a dramatic decrease in domestic P fertiliser use in Europe: in 1995, virtual P was equivalent to 32% of the P used as fertiliser domestically to support domestic consumption but jumped to 53% in 2009. Soybean and palm tree products from South America and South East Asia contributed most to the virtual P flow. These results demonstrate that, although policies in the EU have successfully decreased the domestic dependence on mineral P fertiliser, in order to continue to limit global potential mineral P supply depletion and consequences of P losses to waterways the EU may have to think about its trading partners.

Global food production and current reliance on meat-based diets requires a large share of natural resource use and causes widespread environmental pollution including phosphorus (P). Transitions to less animal-intensive diets address a suite of sustainability goals, but their impact on societys wastewater P burden is unclear. Using the UK as our example, we explored historical diet changes between 1942 and 2016, and how shifting towards plant-based diets might impact the P burden entering wastewater treatment works (WWTW), and subsequent effluent P discharge to receiving water bodies. Average daily per capita P intake declined from its peak in 1963 (1599 mg P pp(-1)d(-1)) to 1354 mg P pp(-1)d(-1)in 2016. Since 1942, the contribution of processed foods to total P consumption has increased from 21% to 52% in 2016, but consumption of total animal products has not changed significantly. Scenario analysis indicated that if individuals adopted a vegan diet or a low-meat (EAT- Lancet) diet by 2050, the P burden entering WWTW increased by 17% and 35%, respectively relative to baseline conditions in 2050. A much lower P burden increase (6%) was obtained with a flexitarian diet. An increasing burden of P to WWTW threatens greater non-compliance with regulatory targets for P discharge to water, but also presents an opportunity to the wastewater industry to recycle P in the food chain, and reduce reliance on finite phosphate rock resources. Sustainable diets that reduce food system P demand pre-consumption could also provide a source of renewable fertilizers through enhanced P recovery post-consumption and should be further explored. ; Funding Agencies|BBSRCBiotechnology and Biological Sciences Research Council (BBSRC); ESRCEconomic & Social Research Council (ESRC); NERCNERC Natural Environment Research Council; Scottish Government under the UK Global Food Security research programme [BB/R005842/1]