The world’s first semi-central supply and disposal system for a future metropolis

Megacities, water scarcity, and air pollution—these challenges demand innovative solutions for the future. SEMIZENTRAL, the innovative supply and disposal center located in the Chinese city of Qingdao, represents just such a ground-breaking solution. The supply and disposal center was opened in early 2014 as part of the World Garden Show. It is the first reference installation in the world for a semi-central, integrated infrastructure approach, and will supply 12,000 people.

SEMIZENTRAL is a project by the Technical University of Darmstadt in cooperation with Tongji University in Shanghai. As a specialist in pumps and pump systems, Wilo was involved in the project’s planning and implementation, and supplied a wide range of pump systems in the areas of building services and water management. In 2015, the project was recognized in the ‘Urbanization’ category of the GreenTec Awards, one of the most prestigious environmental and business awards in Europe.

Qingdao—a metropolis soon to become a megacity

The Chinese port city of Qingdao, in the Shandong province of East China, has been suffering from an acute water shortage for several years. The reason for this is the city’s rapid population growth. The population of the entire metropolitan region has grown to almost eight million inhabitants. Qingdao is already a megacity, and continues to grow. In order to accommodate this enormous settlement development and supply the region with water and energy, a radical new approach was required.

Semizentral—a flexible middle ground

‘Semizentral’—a flexible infrastructure approach for the cities of the future; a middle ground between decentralized and centralized sewage treatment.Each new district has the requisite infrastructure at its disposal. Instead of processing and distributing water using expansive systems with long lead times, Semizentral grows with the megacity. The world’s first semi-central water supply and disposal system integrates sewage and organic waste flows in a modular solution concept.The ground-breaking infrastructure approach reduces not only drinking water requirements but also the amount of sewage generated in the catchment area by about 30-40%. Process water is not transferred directly to the preparation system, but is reused. For example, sewage from showers is reused to flush toilets.The energy required to do so is produced by directing the resultant sewage sludge and domestic organic waste to the integrate biogas plant. In so doing, Wilo high-efficiency pumps make a significant contribution at the project’s pilot plant. They help to produce industrial water and energy from sewage and organic waste. The heat generated in this process can be used for heating. This means the supply and disposal center operates autonomously in terms of energy supply, and is largely climate-neutral.In total, around 56 high-efficiency submersible motor-mixers, pumps, pressure-boosting systems, and fire extinguishing systems have been deployed. The adaptable water infrastructure uses resources efficiently, is flexible, and can grow with its urban surroundings. This means the center is always “as large as necessary and as small as possible”.

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