Suchergebnisse

Cover -- Copyright -- Contents -- Authors for this volume -- Preface -- Guidance Report II.1: Improving integrated assessment in model-supported river basin management -- Preface -- Keywords -- 1. Integrated Assessment - Issues Addressed -- 2. Supporting River Basin Management with Computer-based Modelling Tools -- 2.1. The role of modelling in water resources management: expectations and reality -- 2.2. Modelling and decision making in water resources management: (dis-)entangling two processes -- 2.3. Confidence in modelling tools: a matter of uncertainty? -- 2.4. Looking at the interface: communication and user-friendliness -- 2.5. Participatory approaches: acknowledging the human dimension in modelling and management -- 3. Recommendations for Improving the Structure of the Science-policy Interface -- 3.1. Communication -- 3.2. Incentives for interaction: recommendations for funding -- 3.3. Managing of expectations-reflections on the role of research -- 4. Content-related Issues for a Future Research Agenda -- 4.1. Issues to be addressed by models to support the WFD -- 4.2. Economic aspects of the WFD -- 4.3. Data availability, accessibility and use in modelling -- 5. Summary and Conclusion -- 6. References -- 7. Annex: Research Directions Identified in Harmoni-CA/WP5 Workshops -- Participatory Research Processes and Research Directionsfrom 1st Methods Workshop -- Recommendations of 2nd Harmoni-CA/WP5 Policy Workshop on Models Supporting the Interaction of Agricultural and Water Management -- Summary and Conclusions from 4th Harmoni-CA/WP5 Policy Workshop: Elements of a Future Research Agenda -- Guidance Report II.2: Data availability and accessibility in view of model-based water management -- Preface -- Keywords -- Executive Summary -- 1. Data for Modelling - What are the Problems?.

Although to date some technologies producing bio-based phosphorus (P) fertilizers have been proposed and implemented, the efficient use of the recovered products is still limited due to legislative constraints and lack of insights in the P release with time and in the corresponding mechanisms. The aim of this work was to evaluate the fertilizer performance in terms of P release and use efficiency of recovered struvite, FePO4-sludge, digestate, and animal manure as compared to fossil reserve-based mineral triple superphosphate (TSP). First, product physicochemical characteristics and P fractions in the context of European fertilizer legislation were assessed. Next, a controlled greenhouse experiment was set up to evaluate plant reactions as well as changes of P availability in a sandy soil with high P status and a Rheinsand soil with low P status. Soil P fractions were determined in the extracts with water, ammonium lactate and CaCl2, and in soil solution sampled with Rhizon soil moisture samplers. Based on all results, it is worth conducting long-term field trials to evaluate the P release effect of struvite and digestate as compared to animal manure and TSP on different soil types with varying P status. These products showed promise as sustainable substitutes for conventional P fertilizers and could contribute to a more efficient use of P in agriculture. A refined classification of P application standards/recommendations in terms of soil P status, soil texture, and fertilizer characteristics, next to the crop P demand, is recommended. Moreover, the additional use of Rhizon samplers for determination of direct available P, including dissolved organic P, is proposed for better understanding and categorization of different P fertilizers in environmental and fertilizer legislations.

Anaerobic digestion is an established technology to convert biowaste into renewable energy and nutrient-rich digestates. Nutrient recovery from these digestates as renewable fertilizers with high-nutrient use efficiency or as P-poor alternative fertilizers has gained increased attention in order to meet both regulatory drivers and market demands, while producing an internal revenue source. However, until now, this opportunity has been difficult to realize due to obstacles and inconsistencies in legislative systems, and lack of insights into the composition and properties of these products, as well as in their impact on crop yield and soil quality. The aim of this review is to prove the effectiveness of fertilization strategies using biodigestion waste derivatives as compared to conventional practices using animal manure and chemical fertilizers. As adequate field-scale data are lacking in the literature, a ground-breaking three-year field trial has been performed. The value and impact of these biobased fertilizers are demonstrated by the use of high-level performance indicators measuring farming pressure on the environment and how that pressure is changing over time. Bottlenecks for marketing and legislative constraints are discussed. An economic and ecological evaluation is also assessed. The proof of concept provided in this chapter should help to better classify these biobased products into fertilizer and environmental legislations and serve as a support to stimulate their use in the farming community. Moreover, this review should stimulate and provide guidance for further field research on biobased fertilizers, which is highly essential in the development and implementation of more effective and environmentally friendly farming strategies.

Nutrient recovery from digested biodegradable waste as marketable products has become an important task for anaerobic digestion plants to meet both regulatory drivers and market demands, while producing an internal revenue source. As such, the present waste problem could be turned into an economic opportunity. The aim of this study was to provide a comprehensive overview and critical comparison of the available/emerging technologies for nutrient recovery from digestate, and a classification of the resulting end-products according to their fertilizer characteristics. Based on the stage of implementation, the technical performance, as well as financial aspects, struvite precipitation/crystallization, ammonia stripping and (subsequent) absorption using an acidic air scrubber were selected as best available technologies to be applied at full-scale for nutrient recovery as marketable fertilizer commodities. The resulting end-products can and should be classified as renewable nitrogen–phosphorus (N/P) precipitates and nitrogen–sulfur (N/S) solutions, respectively, in fertilizer and environmental legislations. This would stimulate their use and foster nutrient recovery technology implementation.