Using urban mining techniques to capture phosphorus from agricultural run-off Will this be possible in an ecologically and economically sustainable manner? Verschoor en Omen, 2014 Bart Hoekstra 10645705 Renee Snoek 10761330 Stefan van der Wal 10537252 Course: Interdisciplinary Project Teacher: Anneke ter Schure Expert: Andres Verzijl Word count: Abstract Phosphorus is essential to life on Earth and frequently limits the productivity of ecosystems. Nowadays, a substantial portion of the global human population relies on finite phosphate rock resources used for chemical fertilizer production. In order to meet the growing food demand, agricultural land per unit area required to achieve maximum efficiency. Poor management of these resources and continued efforts to enhance soil fertility have stimulated interest in phosphorus recycling and recovery. In the Netherlands agricultural land belongs to the most intensively used land in Europe. Recent studies, however, show the harmful effects of these fertilizers. This research report aims to address useful ‘urban mining’ techniques for recapturing phosphorus. Content Introduction Page 3 Research question Page 3 Methods Page 4 Theoretical background Page 4 Analysis of the methods Page 8 Discussion Page 9 Conclusion Page 9 Literature Page 10 Data Management Table Page 11 2 Introduction Agricultural land in The Netherlands belongs to the most intensively used land in Europe. One of the factors enabling such intensive use, is the use of (artificial) fertilisers. Application of these fertilisers provides plants with necessary nutrients (nitrogen, phosphate and potassium), but is not without negative consequences: agricultural run-off from fields often causes eutrophication in both adjacent surface water and distant estuaries. Another issue is the limited supply of these nutrients which are so essential to our welfare. Contrary to nitrogen, which is extracted from the air, phosphate is currently a non-renewable resource, as it is mined, used and then disappears in the environment. Alarmingly, ‘peak phosphorus’ is forecast somewhere in the 2030’s, which can have significant negative effects on the global food supply (Elser & Bennett, 2011). Tilman et al. (2001) projected that the demand for phosphate fertilizer would increase from 3.43 × 107 tons in 2000 to 4.76 × 107 in 2020 and to 8.37 × 107 in 2050. Its rapid consumption is fast diminishing the natural supplies annually (Pastor et al., 2010). In order to have a sustainable supply of phosphorus, recovering these nutrients from agricultural run-off therefore seems imperative. Recovering, or ‘mining’, these nutrients from agricultural run-off can thus have a positive effect on both the ecological status of waterbodies and riparian areas as well as provide us with a constant supply of essential nutrients. In this research our objective is to identify and analyse the efficiency, impact and feasibility of urban mining techniques with regards to the recovery of nutrients from agricultural run-off. Therefor our research question is: How can urban mining techniques be used to re-use agricultural run-off in an ecologically and economically sustainable manner in the Netherlands? This requires a thorough interdisciplinary analysis of both hydro-ecological effects of these solutions as well as an analysis of the economics and factors that can positively influence the viability of related business models. Because of the aforementioned relevance, we focus on the recovery of phosphorous in particular, although other nutrients may be present in (parts of) the feasibility study. An essential part of this study will be comprised of a comparison between different organizational structures, that could be used by an actor aiming to recapture phosphorous. This will be followed by a feasibility study. Feasibility studies are a tried and tested tool in the implementation of sustainable and socially responsible enterprises and government initiatives (Shen et al., 2010). Each technological process and organizational structure for recapturing agri-runoff phosphorus, will be analysed and its strengths and weakness catalogued. Research question How can urban mining techniques be used to re-use phosphorus from agricultural run-off in an ecologically and economically sustainable manner in the Netherlands? Sub questions 1: What is urban mining, which techniques can be used to capture argicultural run-off and on what scale is this already happening? 2: What are the characteristics of phosphorous within runoff, and runoff events? 3: How can the substances found in the agricultural run-off be re-used (what is their value)? 4: How is the discharge of these substances distributed spatially? What kind of urban mining techniques are applicable for capturing them? 5: What kind of viable business model can be used or set-up for re-using the substances? 3 Methods The “Urban mining” techniques will be researched through a literature research. Specifically attention will be focused on the efficiency, costs, modes of action (distributed vs. point-based) and impact on the environment (hydro- and ecology) of available technologies. A point-based system has been made to compare and rank different technologies. Next to find the potential solutions, the techniques, there will also be a literature research on agricultural run-off. In particular the focus will be on the phosphorus content of agricultural run-off and the effects on the surface water quality. Research will also be done on the effect of phosphorus on the environment. E.g. it may have significant downsides in terms of water flow or the migration of fish. In order to do a proper assessment of techniques, such factors need to be taken into account. The technological processes that could be used to recapture phosphorous vary, therefore the organizational structures that could be used, are similarly varied. It could be that recapturing P is most effectively managed by a private enterprise, or that a joint effort by industry and government actors would be most successful. Therefore this study will examine which structure could be most effective by looking at similar projects completed in the past. These structures and technological process will then be analysed by means of a feasibility study. Feasibility studies aim to be objective and rational descriptions of the strengths and weaknesses of future endeavours, and ultimately determine the potential success of the proposed endeavour (Justis & Kreigsmann, 1979). The basic concept of a feasibility study is to determine the costs and benefits that are incurred during a certain process. These costs and benefits are found through a detailed description of the operations and management of the process in question, accounting statements, marketing research and policies, financial data, legal requirements, tax obligations, stakeholder issues (ibid) and in this case a look at the process from an ecosystem service perspective. Literature research into what is possible with urban mining techniques. Literature research into what kind of business model would fit these urban mining techniques. Another method that will be used includes a feasibility study. This study aims to rationally and objectively uncover the opportunities and threats present in the environment, the strengths and weaknesses of proposed venture, and ultimately the prospects for success. Moreover, in this research two criteria to judge feasibility are value to be attained and cost required. Theoretical background In order to determine the economic and ecological feasibility of technological solutions to mine P from agricultural runoff, the nature of runoff first needs to be understood, technologies need to be researched and compared in a standardized fashion, and relevant economical models and factors need to be analysed. In the following section we therefore address the cause and characteristics of runoff, the economics of profitably mining nutrients from run-off and the technologies that are at the core of the concept. The methods for capturing phosphorus from water There is a large variety of methods available for capturing or removing phosphorus from water. Within each of the overarching methods there are also multiple techniques available, each with their own advantages and disadvantages. Even within the individual techniques more variety is possible, for example by using different materials to achieve the same process. De-Bashan and Bashan (2004) give an overview of some of the most common ways to remove phosphorus from water. Following here is an overview of the methods they address. 4 The first overarching method is the precipitation of phosphorus by metal salts. This is a chemical process, which creates a sludge in which the phosphorus can be found, bound to the chemicals from the metal salts. This is the currently most used way to remove phosphorus from wastewater, but it comes with significant downsides, like high cost and an increased sludge production by up to 40 percent (Lenntech, d.u.). There are however options to make it cheaper, one way is by choosing different sources for the materials that are used. It is for example possible to use oyster shells as a source of calcium, which is relatively cheap and also ecologically more attractive because you recycle waste materials (Lee et al., 2009). The second main method that is addressed is the cultivation of microorganisms in wastewater. These microorganisms are divided into two techniques: one uses bacteria and the other uses algae. The example de-Bashan and