Andritz – Belt Drying System – provides highly desired Class A Biosolids in a highly marketable sludge pellet / granual. The process granulates the dewatered sludge in a mixer with product that has already been dried. The moist granulate produced here is distributed evenly over the belt in the dryer by a specially designed feed module. The even layer of material on the belt creates optimum conditions for even distribution of the drying air. This, in turn, is necessary for even heating and drying of the sewage sludge. The layer of material on the belt forms a
filter medium for the air flowing onto the granulate layer from above and thus prevents entrainment of dust. The low temperature of the drying gases (< 150°C) and the low dust content in the system facilitate safe operation. The dried material is not exposed to mechanical stress during drying and is pre-cooled before the dryer discharge. The technology – simple, convincing, and successful.
The belt dryer is particularly attractive economically because it uses waste heat with a low temperature.
- The belt dryer is particularly attractive economically because it uses waste heat with a low temperature.
- Highly product quality of different sludges qualities due to variable back feeding.
- Modular structure and simple design.
- High availability.
- Combination of tried-and-tested components from ANDRITZ SEPARATION sludge drying technologies.
- More than 30 reference plants drying around 800,000 tons of dewatered sludge per year.
- Installations include St. Joseph, Missouri and Cape Girardeau, Missouri.
Case Study – Cape Girardeau
- Population: 38,000
- Avg Design Flow: 11 mgd
- Peak Flow: 50 mgd
- Class A Biosolids
- Xylem Sanitaire SBR
- Andritz Belt Dryer
- Andritz Centrifuge: Qty 2 D5LX
WAS from the aerated holding tanks (0.85% to 2 TS)
180 gpm at 25% TS cake solids
- Andritz Belt Dryer; BDS-15
- Low-temperature air (approximately 130°C) to dry the biosolids
- Evaporate 2,887 lb/hr of water
- Hard pellet, 92% TS, meeting the Class A requirements (EPA 40 CFR Part 503 Regulations).