Medium-Temperature Belt Dryers
Our HUBER Middle Temperature Belt Dryers BT are automatically and continuously operated and optimally suitable for energy-saving and eco-friendly drying of municipal and industrial sludges.
They are heated with medium-temperature heat of 90 – 130 °C, e.g. with cooling water from a combined heat power (CHP) cogeneration system. Sludge detention time in the dryer is about 150 minutes.
Thereby our Belt Dryers ensure a granular, disinfected (class A), easy and safe to handle biosolids product in compliance with European and international standards.
Advantages of HUBER Medium-Temperature Belt Dryers
- Dry, granular and safe to handle product
- Dryness can be selected from 65 % to over 90 %DS
- Suitable for simultaneous sludge disinfection
- Continuous automized operation, independent of the climate
- Low wear, moderate temperature
- Safe operation due to little dust generation
- Exhaust deodorization with scrubber and bio-filter
- Low heat consumption (ca. 0.9 kWh per kg water evaporation)
- Supply of medium-temperature heat, e.g. from a cogeneration system
- Low operation and maintenance costs
Disinfection in HUBER Medium-Temperature Belt Dryers
As long as the sludge is humid, water is rapidly evaporated and the sludge does not become hotter than 50 to 55 °C, because it is kept cool by the evaporation enthalpy. After the sludge has travelled on the belts about half way through the dryer, it reaches solids contents of 70 – 80 %DS, water evaporation slows and its cooling effect is reduced. Now the sludge is heated up further and reaches temperatures over 70 °C, only slightly less than the temperature of the drying air.
If the sludge is maintained at a temperature of minimum 70 ° for at least 30 minutes, it is safely disinfected. We investigated the situation in one of our full-size belt dryer installations and could prove that this requirement was met. Analysis of faecal coliforms and salmonella confirmed sufficient disinfection.