Box 10O Urban environmental technology in Berlin

In Berlin, some 75 environmentally sound renewal projects of housing quarters and of inner-city districts have been realised. Many of these projects started at the grass-roots level: small groups of citizens took the initiative to improve their immediate surroundings. These small-scale initiatives had a great multiplier effect in the city and created the basis for developing larger projects of ecologically sound urban development.

An example is a building complex with l06 dwellings at Dessauer Straße, focusing on urban water management. This was the first in a range of projects aimed at developing a decentralised inner-city water management system. The housing units are equipped with water-saving devices widely available on the market. These include toilets that can be flushed with 4 to 6 litres instead of the usual 9; flow rate limiting devices (with a saving of 20 to 40 per cent); one-tap systems to mix warm and cold water which enable quick regulation of water temperature (with water savings of 5 to 10 per cent); water meters in every house for individual payment; separate piping systems for clean and recycled wastewater. Each apartment in the block can be easily connected to or disconnected from the water recycling system, according to user requirements.

All the wastewater leaving the apartments connected to the recycling system is collected in a sedimentation pond in the courtyard of the housing block. It is then led through a small area of vegetated wetlands and ends up in a purification pond. At this stage it is purified to such an extent that it can be used to flush toilets and to water green spaces and gardens.

Most of the rainwater is kept in the area: it is not disposed of through the municipal sewerage system, but is collected in a filtration basin with plants, from which it is drained in a pond. All measures brought together in this decentralised water management system led to a 50 per cent saving of the amount of piped drinking water compared to the average elsewhere.

Although this project focused on water conservation, this is not the only environmental aspect. When integrated with other decentralised infrastructures and supply systems, various other environmental benefits can be realised. An example is a special installation to derive heat from wastewater; this heat is used to warm up clean water to be used in homes.

Another element is green spaces: 60 per cent of the project area is covered by plants, on roofs and gardens. This helps to catch rainwater and keep the area humid, and to filter the air and trap dust particles. It also contributes to insulation and energy conservation in buildings. In a 'regular' project of this size only 10 to 30 per cent of the area would be covered by plants.

A third element is waste reduction. In this project, information is given to residents on how to prevent waste, and to separate waste for collection and recycling. The various waste fractions are collected and processed separately. The project was the first social housing project with facilities designed to store glass, paper, plastics, metal, textiles, organic waste and chemicals. The separate collection of organic waste yields 7 m3 of compost annually: sufficient for the maintenance of the whole green area of the project.

Another important element is visibility: local people can observe the immediate impacts of their behaviour on the management of green spaces and on the volume and composition of solid wastes and the possibilities for re-use. It is only a small step from environmental technology and design to environmentally sound behaviour.