Solar sludge drying. The Wendewolf moves and aerates up to 250 m³/h of sludge! The automatic programme ensures a continuous flow of the freshly pressed sludge through the drying bed. The required energy consists of electricity only, between 10 kWh to 30 kWh per ton of water evaporated. Industrial dryers require between 800 and 1000 kWh in thermal energy and electricity. Therefore the running cost of Wendewolf is extremely low!

Company details

Business Type:
Industry Type:
Water and Wastewater
Market Focus:
Internationally (various countries)
1,000,000 - 10,000,000 €


More than 30 years of experience in the field of applications with solar energy have been the reliable and substantiated base to realize projects with solar dryers – always following the objective to design ecologic and energy conserving projects.

IST-Anlagenbau GmbH has been founded as a spin off by a consulting engineering firm for solar technology. The – meanwhile worldwide recognized - WendeWolf process has been developed based on this know-how.
The company has been operating the worldwide first activated solar sludge dryer as contractor. The knowledge and experience gained is used in the further evolvement of the machine and process technology.

Solar sludge dryers utilizing the WendeWolf process and technology are currently in 11 countries installed. The WendeWolf technology is leading the market regarding the efficiency, reliability and easiness of operation.
The worldwide largest solar sludge drying system – in Nicaragua - has been built according to the design and the layout of IST-Anlagenbau GmbH and it is operated with the WendeWolf machine technology.


IST-Anlagenbau GmbH is situated at the bottom of the Black Forest at the border triangle Germany/Switzerland/France – just in the heart of Europe.
The closed proximity to Basel (15 km) secures a well maintained infrastructure with Highway, high speed trains and the Euro-Airport Basel/Mulhouse/Freiburg.

In projects, IST-Anlagenbau GmbH is furnishing the know-how as well as the machine and control equipment. The sizing, the design and layout of a plant is based on our calculations, experience and suggestions. We are consulting the local design engineers and contractors relating to the civil works and buildings. We deliver the machine and control technology and do the on-site commissioning of the system.

We bear the responsibility for the process and the equipment delivered by us and monitor the realized systems during and after the warranty period.