immo!nvest – Die Plattform für Standorte und Immobilien

Tag: Ressourcennutzung

  • Decentralized wastewater solutions are gaining in importance

    Decentralized wastewater solutions are gaining in importance

    In Switzerland, as in other European countries, wastewater from households is disposed of and treated centrally. Wastewater from toilets, kitchens, washing machines and dishwashers are mixed together. This makes recycling much more difficult. In order to reduce this problem, researchers at the Eawag water research institute in Dübendorf are working on possible decentralized solutions, according to a press release.

    The aim of these solutions is to separate the various wastewater streams at the point of origin. They could then be treated on site or nearby and resources such as clean water, nutrients and energy could be recovered. The Water Research Institute has now launched a toolbox to provide architects and construction planners with an overview of technologies and practical applications. Among other things, it presents various examples of implementation. These range from solutions for individual households to wastewater treatment for entire neighborhoods. The toolbox contains three groups of fact sheets ranging from the definition of objectives and the selection of a strategy to possible application technologies.

  • The versatile world of wood

    The versatile world of wood

    Utilisation of the wood
    After a certain time, the tree reaches its growth limit. This is the perfect time to fell the tree – it is ready for harvesting. Depending on the tree species, the time until it is ready for harvesting varies between 60 and 150 years. Until then, the tree has had enough time to reproduce through seeds in the gaps in the forest. The plants in the young forest that are best adapted to the local climatic conditions prevail. In this way, the forest remains healthy thanks to natural selection. During thinning, desirable and well-grown trees are left standing as future trees. The abundance of light in the gaps created by felled trees allows a variety of shrubs and annual plants to colonise the ground – increasing biodiversity in a forest managed in this way.

    The majestic forest of Switzerland
    Around a third of Switzerland’s total land area is covered by protected forest. This forest provides protection against natural disasters, is a habitat for animals and plants, a place for recreation and leisure and a source of wood. Sustainability is a fundamental principle that requires the forest to fulfil all these functions in the long term without harvesting more wood than grows back. Enough wood grows in the Swiss forest every ten minutes to build a detached house. Around 60% of Swiss forests consist of conifers and 40% of deciduous trees. A large proportion of the wood felled is processed into sawn timber and planed products, while 10% is used for the production of paper and wood-based panels. A quarter is used directly as firewood. Around 10 million cubic metres of wood grow in Switzerland every year, only half of which is used. Wood is a durable material that regrows itself and plays an important role in the ecological balance. It is therefore sensible and advisable to use our own wood.

    Characteristics of wood
    Wood is a light yet strong material that can bear fourteen times more weight in relation to its weight than steel. Due to its natural cell structure, the static properties of wood are directional. Wood is most resistant along the grain, as it can withstand a hundred times higher tensile forces and four times higher compressive forces in this direction than across the grain. Understanding these static properties is of crucial importance when building with wood. In addition, the warm and pleasant feel of wood gives rooms a special atmosphere. The wood fibres in the installed wood constantly react to the air humidity and thus contribute to a balanced room climate.

    Variety of wood species – differences in the forest and in the home
    Not all woods are identical. The characteristics and appearance of wood vary depending on the tree species – there is a wide range from light to heavy, soft to hard and light to dark. Each type of wood therefore has specific properties that are suitable for different purposes. For example, the heartwood of sweet chestnut or oak, which is preserved with natural tanning agents, is particularly suitable for outdoor use, while long-fibre ash is used for parts subject to heavy wear. Fine-fibre woods such as beech or maple are used in furniture production. Promoting different tree species by using different types of wood helps to increase biodiversity. Each tree grows individually, so its wood may have more or fewer knots, wider or narrower annual rings, be slightly lighter or darker in colour and grow crooked or straight. Each tree trunk and section is utilised according to its qualities. Selected logs of high quality are processed in sawmills into a variety of sawn products such as beams, boards, laths, posts and glulam. Timber that is crooked and knotty or small diameter logs are converted into chipboard and fibreboard in panel mills. The best qualities are processed into veneer. From both an ecological and an economic point of view, it is crucial to determine the appropriate quality for the respective area of application in advance with the supplier.

    Wood-based materials
    The large formats of wood-based materials have made an important contribution to the development of modern timber construction. The production of wood-based materials follows a simple principle: the wood is chopped into boards, chips or fibres and then shaped into a new form with the help of glue. This results in products with standardised properties in a fixed thickness and size. Wood-based materials therefore offer added value and open up a wide range of design possibilities with wood. As a cost-effective building material for everyday use, wood-based materials are indispensable and are available in a wide range from timber merchants and DIY stores.

  • Leading by example: circular building in the city of Zurich

    Leading by example: circular building in the city of Zurich

    The circular economy is an important lever for achieving the political net-zero targets. Like many other cities around the world, Zurich is also committed to the circular economy: in 2022, a strategy for the circular economy was adopted with “Circular Zurich”. in 2023, Zurich became the first Swiss city to sign the “Circular Cities Declaration”.

    The intelligent use of resources is particularly important in construction. With the “Charter for Circular Construction”, politicians and businesses set an example in 2023 and made a joint commitment to conserving primary resources and landfill space and reducing CO2 emissions from their own construction activities.

    Initial findings from two pilot projects
    But how do the political commitments affect specific construction projects? What challenges does circular construction pose? And how are the planning and construction processes changing? The City of Zurich’s Office for Buildings is gaining answers to these questions through two pilot projects.

    The city gained initial experience with the procurement, storage and processing of reused building components during the renovation of the Mööslistrasse 2023 kindergarten (Bischof Föhn Architekten, Zurich). Washbasins and toilets were dismantled, cleaned and refurbished on site. Plant troughs from the balconies were reused as outdoor space boundaries. Where possible, the built-in furniture was sourced from the city’s own stock. Thanks to component screening, steel beams, wooden pergolas, fire doors and kitchen elements from other buildings were identified, dismantled and reinstalled. So-called “component hunters” were deployed for everything that was not found in the city’s used parts warehouse.

    The second pilot project, the new “Juch-Areal” recycling centre, is much more comprehensive. The Office for Buildings launched an architectural competition with re-use requirements for the project in 2022. The competition participants were able to use a digital catalogue of components or use other available components from non-urban sources for their designs. The buildings also had to be designed in such a way that they could later be used as a component mine themselves (design for disassembly).

    The projects submitted show that it is possible: Yes, it is possible. The jury was particularly impressed by the high quality of the competition entries, which were created despite – or perhaps thanks to – the new specifications. The building material of the winning project by Graber Pulver Architekten AG (Zurich) dismantles the hall of the previous recycling centre and rebuilds it at the new location with only minor adjustments. Disposed books, magazines and clothes are used as insulation material. Sheets of recycled glass and aluminium, old kitchen covers, doors and table tops protect the façade from the weather. Discarded scaffolding is turned into storage shelves.

    It is in the nature of things that pilot projects precede a standardised introduction on a broad scale. This is also the case with circular construction. The realisation of the two projects in Zurich shows that many questions still need to be clarified: How can components be catalogued? How can availability be checked? Where will they be stored? Who assumes legal liability?

    The planning and construction processes will change as a result of cycle-orientated construction, because the component mines must be known as early as possible, preferably at the beginning of the planning phase. Building Information Modelling (BIM) facilitates the reuse of components, the planning of their dismantlability and the development of future component mines.

    Significant savings in indirect greenhouse gas emissions in the pilot projects
    The pilot projects show that this approach is worthwhile. According to a subsequent calculation, the consistent reuse of building components saved a good 30% of greenhouse gas emissions during the renovation of the Mööslistrasse kindergarten. Current calculations even predict a 40% saving in greenhouse gas emissions for the Juch-Areal recycling centre compared to a conventional new building.