The water factory in Dierenpark Emmen zoo is a beautiful example of how sustainable water treatment can be combined in an appealing way with saving, recycling, experiencing and learning about drinking water. All the wastewater in Dierenpark Emmen is treated and recycled. Only water that enters people’s mouths is clean drinking water. Use of the latest treatment methods in the water factory results in an almost closed, sustainable water system.
In 2002, as part of the zoo’s expansion, the water pavilion and the water factory were opened up to the public. At the heart of the water factory is a Living Machine: a hothouse with tropical plants that are part of the treatment process.
Dierenpark Emmen records around 1,500,000 visitors every year. The zoo uses a great deal of water. Realising the water factory led to a reduction in the amount of drinking water used from 180,000 m3 to 30,000 m3. Most of the water is used as industrial water for flushing toilets and cleaning buildings and animal enclosures. More than 40 separate animal basins for flamingos, crocodiles, elephants and other animals are also filled with industrial water.
All of the zoo’s wastewater is treated in a membrane filtration process. The cleaning water in the membrane filtration is treated in the Living Machine using biological methods. This creates a closed water cycle in the water factory: all the wastewater is recycled.
The Living Machine is housed in a hothouse to create a more constant climate and so to optimise the biological processes. Living Machines use plants and a range of different micro-organisms to treat wastewater.
In membrane filtration systems, wastewater undergoes physical treatment. The wastewater is forced through pipes with small capillaries that filter out all pollutants, even viruses and bacteria. The pipes are hosed clean regularly. In Emmen, the effluent is treated in the Living Machine. This very clean treatment method only has one drawback: it consumes relatively large amounts of energy. If that energy is generated using sustainable methods, that drawback ceases to be a problem.
The water pavilion houses a permanent exhibition about the drinking water cycle, how the Living Machine works, and the central control system of the drinking water supply in southeastern Drenthe. Pötz et al., 2009; H2O magazine, 2002