Cold weather cannot stop the HUBER Solar Dryer SRT

Solar drying of sewage sludge is a technique that is increasingly used to reduce sludge disposal costs and at the same time protect the environment. Today, operators of even medium-sized and large wastewater treatment plants from all over the world appreciate our innovative and reliable solar dryers.

While skiers have fun moving down the slopes obviously without effort, the HUBER sludge turners move through the sludge bed no less easily
While skiers have fun moving down the slopes obviously without effort, the HUBER sludge turners move through the sludge bed no less easily
General view of the system
General view of the system
Free-flowing dried granulate with low dust content
Free-flowing dried granulate with low dust content

The HUBER Solution for sewage sludge drying with solar energy is working with a continuous drying process, that is odourless due to complete restacking of the sludge. Its unique combination of sludge turning and transport performs both spreading and turning of the sludge as well as baxmixing and its transport from one side to the other. Due to their high efficiency our solar dryers can be operated the whole year round even in temperate climate zones with solar power alone. This gives of course an outstanding eco-balance and cost-efficency.

So, the first HUBER SRT installations in the Rocky Mountains have been in operation for almost a year now, even during winter.

The site is located near Salt Lake City, in one of the most attractive skiing regions in North America. When the sun shines on the greenhouse the temperature in the drying bed can easily rise higher than 15 °C despite sub-freezing temperatures outside. The plant is operated the whole year round even though drying results are naturally better in summer.

Under this project HUBER SE supplied not only three of the biggest size solar dryers (type SRT 11) but also a new sludge dewatering system. HUBER thus ensures trouble-free operation on site from thin sludge treatment to the dry sludge granulate. Due to the automated feeding system no pasty sludge from the dewatering units needs to be handled.

In North America golf sport is very popular, even on the dry and nutrient-poor soils in Utah. The Tooele sewage treatment works where the HUBER solar dryer is installed becomes the lifeline for the local recreational areas: The clarified wastewater can be used to irrigate greens while the dried sludge is a good fertiliser which is especially hygienic during summer. Valuable raw materials for the golf course are recovered from dirty wastewater – a good reason to nominate this golf resort for an award.

Thanks to these positive experiences with HUBER equipment more solar drying projects are already in the planning stage in the USA. HUBER's solar drying systems have been recognized as well-proven technology in Europe for many years already. Now they become increasingly accepted even overseas as innovative yet solid solutions.

Facts and figures:

  • 3 units HUBER Solar Dryers SRT, size 11
  • 2 units ROTAMAT® Screw Presses RoS 3 for upstream sludge dewatering
  • Hall lenth: 3x 100 m
  • 3.000 m² drying area
  • 5.800 t dewatered sludge / year
  • Sludge dried from 18 % DS to 70 % DS (average)
  • Special feature: operation during the whole year only with solar power - no external thermal energy


Utah's local TV channel Fox 13 has sent an informative report on the innovative plant that can be retrieved via the link below: