A wastewater treatment plant utilizes waste heat to dry sewage sludge

Two KULT BT 80 Huber belt dryers were put into operation on STP Ingolstadt in August 2005. The installed total dryer surface is 160 square meters, which is the same as that of new dryer type BT 16.

The scope of supply of Huber SE included not only the drying plants but also the sludge bunkers and thick sludge pumps. The exhaust air treatment system had already been installed.

The special feature of sewage sludge drying on STP Ingolstadt is that the drying process takes place on a very low temperature level. Warm water with a temperature of 53 C is available as a heat carrier medium. This warm water is heated in the adjacent waste incineration plant via a water-vapor heat exchanger. The exhaust steam from a condensation turbine is available all year round. As this hot water is free for the sewage treatment plant, their operating costs for sewage sludge drying are very low. The dry sewage sludge, which is dried to 90 percent DS, is thermally utilized in the waste incineration plant, which closes the loop.

Related: Watch How Thermal Drying Reduces Sludge

Due to the fact that the wastewater treatment plant is within intermediate proximity to the waste incineration plant Ingolstadt, the following advantages could be achieved:

  • 294,000 driving kilometers saved per year
  • 88,000 liters of diesel saved per year
  • CO2 emissions reduced by 225,000 kg per year
  • No use of primary energy
  • Utilization of secondary energy in the form of cost-free exhaust heat from the waste incineration plant
  • Use of current that has been generated from regenerative sources on the waste incineration plant

Most maintenance work (e.g. cleaning the pelletizing system) can normally be carried out without having to interrupt plant operation. There are hardly any standstill times; most of the time the dryers operate seven days a week. The sludge drying plants therefore achieve an average annual operation time of significantly more than 8,000 hours.

The technical plant manager, Rudolf Beck, is especially enthusiastic about the low maintenance requirements.

Related: Converting Sludge to Useful Biosolids

Click here to see the technical data of the sludge drying plant and related case studies.

About Huber Technology
Huber Technology provides state-of-the-art equipment for municipal and industrial water and wastewater treatment. Our main focus is liquid/solid separation in general and headworks equipment in particular. We offer a comprehensive line of stainless steel equipment. For more information, visit www.huber-technology.com.

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