The Cleantech Playground (CTP) is a testbed for clean, innovative technologies in the heart of the city of Amsterdam. The concept, which aims at closing the (biological) loop, is set up in North Amsterdam in two adjoining areas: an incubator for creative entrepreneurs (De Ceuvel) and a floating residential neighbourhood (Schoonschip).
The production of food (partly under glass) is combined with decentralised energy generation, water treatment and processing of organic waste using innovative technologies. This TKI ‘Loop-Closure Cleantech Playground’ research project focuses on the watercycle at De Ceuvel, which consists of 15 small office spaces (former houseboats) and one restaurant.
The general objective of the project was to demonstrate a local loop-closure in the city. The primary goal of the small-scale pilot project in North Amsterdam was to achieve maximal local loop-closure of the cycle by applying innovative concepts and technological solutions. In particular, the performances of the water-related technology were monitored and evaluated in this TKI project in order to show their applicability in a sustainable circular economy. The approach revealed the suitable technologies and developments that still need to be realised.
The effectiveness and related aspects of the following water technologies were researched for and/or at the De Ceuvel site:
- (Possible) use of local water source(s) and (innovative) water treatment techniques to achieve drinking water quality.
- Processing of toilet (waste)water and fruit and vegetable and waste in a small-scale treatment unit, with resource recovery.
- Individual (grey) wastewater treatment per office unit.
- Analysis of the mainly central watercycle system (existing practice in Amsterdam/the Netherlands) with a view to a more decentralised, local watercycle (De Ceuvel), using, among others, Life Cycle Assessment and Quantitative Microbial Risk Assessment.
Attention was also directed at the legal framework, costs, and user behaviour and satisfaction.
Among the conclusions to be drawn from the De Ceuvel research is that the composting of faecal matter requires a long time: after an 11-month period of composting, the streptococci reduction still did not meet WHO recommended levels. The use of composting toilets is thus not recommended. However, the separate collection of wastewater streams and treatment has potential and can support a circular economy, for instance, in the recovery and reuse of nutrients. Low-tech treatment of limited volumes of grey water, using biofiltration and plants, is possible. Local production of drinking water can lighten the environmental impact compared to the current centralised drinking water production system, but only if renewable energy sources are used. Although locally-produced drinking water can meet safety standards, the required monitoring and maintenance is very challenging and costly, so that it is not recommendable, for the time being. Technically, local loop-closure is feasible, but user acceptance, and the legal framework in particular, could limit its further implementation. The legal and institutional aspects regarding local water treatment and loop-closure are currently under development and therefore still not always clear. The De Ceuvel experience has already shown that it is not easy to implement local loop-closure in the Netherlands, but that further research and experience, with larger, more representative projects, is called for. This should involve additional research into key questions concerning responsibilities, user acceptance, health and safety risks, sustainability and cost reduction.