The ‘park of the 21st century’: agriculture in the city A. van Timmeren1, 2, J. Eble3 , H. Verhaagen4 & M. Kaptein5 1Department Building & Sustainable Technology and Design (MTO) and DOSIS Research, Sustainable Development of City and InfraStructure, Delft University of Technology, Faculty of Architecture, the Netherlands 2Atelier 2T Architecten, Haarlem, the Netherlands 3Joachim Eble Architektur, Tübingen, Germany 4Copijn Tuin & Landschaps architecten, Utrecht, the Netherlands and Hyco Verhaagen Garten- & Landschaftsarchitekt, Osnabrück, Germany 5Stichting E.V.A. Lanxmeer, Culemborg, the Netherlands Abstract There is a rising need to interconnect different ‘essential’ flows inside cities at scales closer to users. Integration strategies for wastewater management and sanitation, even possibly together with energy-generation, comprise direct linking with neighboring subjects like agriculture, aquaculture, etc, as well as waste management in general and the organisation, maintenance and assurance of indispensable parts of closed cycles. Ecological sanitation within these integrated projects will have to be based on a closed-cycle flow of nutrients. Permaculture forms a good basis, as it is based on the observation of natural systems, combined with the experience of traditional farming methods and modern science and technology, to create a cultivated ecology in which people actively get involved. Existing green places and parks in and around urbanised areas are pressurized by changed use or even misuse, governance based on lowering maintenance costs, and new urban extensions (and ‘in’-tensions). There is a rising call for additive functions to preserve these green places against (claimed) more economical developments. Within the process of enduring worldwide urbanisation, in the 21st century the introduction of agriculture, horticulture and aquacultures may help to interconnect necessary green places with social activities, sustainable solutions concerning neighbouring flows and combined urban ‘red/green’ development. This will be the guideline for the ‘park of the 21st century’. Keywords: decentralisation, red/green mixture, city-agriculture, integrated design. The Sustainable City III, N. Marchettini, C. A. Brebbia, E. Tiezzi & L. C. Wadhwa (Editors) © 2004 WIT Press, www.witpress.com, ISBN 1-85312-720-5 304 The Sustainable City III 1 Introduction The background of this research is the recognition of a need to compare alternative sustainable concepts, techniques and belonging structures on more aspects than the ones being indicated by the existing paradigms and dominant actors. A paradigm is the whole of scientific performances of predecessors that by researchers and specialists on a certain field, on a certain moment in the development of science is being considered for normative (Siemensma [1]). Dominant actors in this light can be defined as: actors which are normative and who are dominant in the determination of development-processes for a certain technology or structure. A paradigm, however is never the ultimate solution. Not even in case of unison of the dominant actors. Linear approaches to problems, in which resources are used and converted into wastes, only to be disposed of, represent a failure in human ingenuity and a flaw in technology design. If we are to create a recycling society, we need to capture the wastes, render them safe and return them to productive resources again. The linear thinking and actions follow an unconscious pattern, more and more being fed only by endogenous changes and existing centralisation paradigms. Although useful, we should try to prevent the existing developments to become a ‘regressio ad infinitum’, due to ongoing displacements of goals or aims. A reflection on the structures that are underlying to urban development is a necessary condition for Sustainable Development. Integration strategies for wastewater management and sanitation, even possibly together with energy-generation, comprise direct linking with subjects like agriculture -especially urban farming-, aquaculture, horticulture, health care and food security. The basis forms an urban planning that is based on ‘interconnection’, as well as waste management in general and the organisation, maintenance and assurance of indispensable parts of closed cycles. The methodology of the research is based on the ‘regulative cycle’ of Van Strien (Hertog et al. [2]), with a theoretic- and practice-related subdivision. Besides of six different case studies, the outcome will be tested in one ‘integration case’ with a developed device. The idea is to make urban development, mostly resulting in buildings and infrastructures, following to the social needs and goals, which form the basis of physical networks of the logistical chains, and not the other way around, like it can often be qualified today. In this way it will be possible to uncouple sustainable solutions from the existing ‘centralisation- paradigm’, without the release of other relevant criteria for today’s society. 2 Interconnecting flows and networks 2.1 Environmental circuit For the notion ‘environment’ many definitions exist, varying in more or less generality. Kristinsson [3] defines it for instance according to the way Laou Tse approached life [4] on earth (between 604 and 163 AD): “environment is like the hole in a wheel, the nothing around which everything rotates. If it is not situated in the centre, it will start bumping, dislocate and stop rotating, start dragging and The Sustainable City III, N. Marchettini, C. A. Brebbia, E. Tiezzi & L. C. Wadhwa (Editors) © 2004 WIT Press, www.witpress.com, ISBN 1-85312-720-5 The Sustainable City III 305 leave indelible traces”. Most of the Dutch environment related research however uses the definition which describes environment as ‘the physical, non-living and living, surroundings of society with which it has a reciprocal relation” (Haes [5]), or “environment is the collection of conditions, necessary for life” (De Jong [6]). The Dutch environmentalist Van Leeuwen [7] introduced the eco- device model with incoming and outgoing flows (fig.1a). Later the D.U.T. (Duijvestein [8]) linked the primary harmful aspects for the environment to the in- and outgoing flows, while the secondary aspects were coupled to the investigated system or area (fig.1b). Tjallingii [9] introduced different scales concerning the eco-device model. region IN OUT city source problems: internal problems: sink problems: district - depletion adverse effects on - pollution - pollution - disturbance S.I. - disturbance - human health - ... NOT OUT - ... NOT IN building - urban functions - plants, animals Figure 1: Eco-device model for different scales (Van Leeuwen [7]), and connection of in- and outgoing flows to environmental problems (Duijvestein [8]). It is important to realise that environmental-effects not only have to be negative. There can be positive aspects too, which can possibly compensate to some extent negative effects (Lettinga et al. [10]). The disadvantage of this scheme is its constrain to the stochastic behaviour of input and output. It is important to see the eco-device in a larger framework, as a part of what is called the ‘environment-circuit’ (Kop [11]). In this ‘E-circuit’ the chain in/out is specified to the three main units: extraction, production and consumption, which through so-called leakage-flows have a continuous relation with the ecological basis (fig.2). recirculation of recirculation of materials and energy materials and energy (raw)materials products + energy + energy extraction production consumption return materials return materials different fractions + energy (mainly raw mat.) of waste + energy leakage flow leakage flow leakage flow waste disposal ("end of pipe") leakage flow 'ecological basis' / 'ecological field' (=self-sustainin Figure 2: The ‘environmental circuit’ (Kop [11]). The Sustainable City III, N. Marchettini, C. A. Brebbia, E. Tiezzi & L. C. Wadhwa (Editors) © 2004 WIT Press, www.witpress.com, ISBN 1-85312-720-5 306 The Sustainable City III An important link in the desired transformation of our society from one based on linear attitudes of resources and wastes, towards a circular one, is a changed way of sanitation: ecological sanitation. Ecological sanitation is not merely about a new latrine design. It comes down to thinking more in nutrients and raw materials than in wastes, which ‘are to be disposed. It’s a new way of thinking: a ‘closed-loop-approach’ to sanitation, in which excreta are returned to the soil instead of water. It comes down to a (better) formalisation of the (existing) ‘leakage flows’ between the cultural world and the natural world, or ‘ecological field’ as a self-sustaining environment. In this way the closed-loop approach in non-polluting, keeping fresh and marine water bodies free of pathogens and (too many) nutrients, while the environmental and human health risks are minimised or eliminated. Unfortunately, half of humanity still does not have access to any type of sanitation. On the one hand this is a threat to the ecological field. On the other hand it still might be the basis for a critical look upon existing, ‘conventional’ approaches, which have been realised so far, and (mostly) are planned to be realised in these parts of the world too. The dilemma is: fast-arrangement of sanitation systems for the people who do not have access to sanitation (being a human right) and additional global environmental consequences, or ecological sanitation: on site systems (excreta treated and processed