Workshop 2: Need for a Paradigm Shift: New Technologies and New Lifestyles 61
Water for an Urban Cradle-to-Cradle Resource Management
Author: Mr. Martin Regelsberger, AEE – Institue for Sustainable Technologies, Austria Co-Authors: Prof. Ranka Junge, Zurich University of Applied Sciences, Switzerland
Dr. Thorsten Schütze, Delft University of Technology, The Netherlands
Keywords: sustainable sanitation, sustainable urban drainage sys, mass flow management, cradle to cradle, household centred approach
Introduction/Problem Identification
We face increasing water scarcity, phosphorus depletion and environmental damages due to steadily growing production of reactive nitrogen: urban water use plays a significant role here. On the other hand increasingly extreme rainfall events overstress our urban water infrastructure and threaten our settlements and aquatic environment. Innovative technologies and system approaches in urban sustainable water management, allowing reuse of water and nutrients, have been developed but need further research and trans-disciplinary integration.
Given the threat of climate change and modified patterns of water availability or pressure, this paper is striving to put a new impetus to our dealing with the challenges presented to water in the urban context. The expertise of water experts, architects, urban planners, agronomists, sociologists and economists is used to develop cradle to cradle concepts turning waste into resources and working towards zero emission sustainable systems.
Analysis/Results and Implications for Policy and/or Research
Many European countries, especially along the Mediterranean shore, experience water scarcity, not least due to climate change, and suffer from shortages to the point of considering recycling wastewater for potable use. Population fluctuations and changes in user behaviour cause large variations in water demand and consequently serious problems to water utilities. Farmers are confronted with the deple-tion of the world phosphorus reserves while coastal zones are degraded by the input of nitrogen from sewer outlets and land erosion. Architects are appalled by the destruction caused to the environment by our infrastructure and seek to develop restorative buildings and settlements. Wastewater contains water, nutrients and energy, which widely remain unused.
Endeavours in the building sector so far nevertheless mainly target energy efficiency. Research about “restorative buildings” in Australia, “green buildings” in Europe, America or Asia lack the aspect of re-using nutrients from human excreta for food production while Sustainable Urban Drainage Systems (SUDS) focus on stormwater alone.
The examples show that in order to reduce the urban footprint an integrated multi-disciplinary ap-proach has to be used. Experts from various disciplines ought to combine their knowledge to identify links between and beyond water sectors and mobilise synergies along these links in order to realise cradle-to-cradle solutions of an urban water infrastructure with a maximum positive impact on the environment and relying on exclusively reusable or renewable resources.
Infrastructure for energy and water supply, as well as waste and wastewater management in contem-porary cities are based on complex centralised supply, collection as well as discharge and disposal systems – most of them representing end-of-pipe-solutions. They still mainly focus on a flow of energy
62 Workshop 2: Need for a Paradigm Shift: New Technologies and New Lifestyles
and substances. Besides the well-known advantages, they have system immanent disadvantages, which are barriers for effective integrated resource management, e.g. inflexibility, high implementa-tion cost, slow adaptaimplementa-tion to changing technologies. Hence, enhancing the efficiency of centralised systems cannot solve the basic problems. In contrast, the decentralisation of infrastructure systems and an integrated trans-sectoral supply of services instead of materials can contribute to a more sustainable development.
The extent of the global crisis in respect of our natural resources is only beginning to trickle down into the consciousness of society. New ways are necessary to re-connect citizens to nature – also in order to make them more sensitive to a provident handling of natural resources. Urban green spaces, including open water, play a major role in this since they have huge importance and potentials not only in purely ecological (biodiversity) or aesthetic terms but also on a socio-cultural and a health promoting level, documented by various studies. They could and should offer citizens more possibili-ties for an appropriation of urban space and thus more immediate contact with nature.
For urban agriculture in particular, there is considerable activity that is not being captured or critiqued, while concurrently there is growing demand to know what actions are in place and to gauge their significance. They have yet to be combined with the urban water cycle within a risk management approach.
Cities could be recognised as extremely complex systems with many processes and interactions, a plethora of interests and objectives. As in cleaner production approaches to industry, processes in cities can be rethought along a cradle-to-cradle approach. A goal is to imitate natural cycles within the human built environment and provide two types of cycles, one organic and one industrial, where all materials are constantly kept in use and are not consumed and disposed of.
Presently cities more or less use a common set of infrastructure systems with only a very simple user interface and professional management with a top-down decision making structure. While these systems are subject to evolutionary change, users are not expected to be directly involved. This has changed for solid waste management where source separation has become common practice and is discussed in the energy sector with smart metering and similar appliances. A rapid change and fundamental improvement of our cities towards cradle to cradle flows will not only have to rely on a high acceptance for new approaches but request the participation of users at all levels. This comprises decision-making, with new forms of participatory processes, as well as new operation and manage-ment models being explored. This may require on the one hand the active involvemanage-ment of residents and on the other hand the emergence of new forms of service supplies. Service providers, municipal or private utilities may own decentralised facilities and provide the required services.
