Siemens' Thermal Drying System Installed at Italian Plant
Will help reduce plant's sludge production by approximately 75%
The Italian company Multiservizi will install a Sludge Belt Dryer (SBD) from Siemens Industry Automation Division at its plant in the city of Jesi, Ancona. The belt dryer evaporation capacity is 2000 kg/hr. Once the dryer becomes operational in 2012, it will allow the Jesi plant to reduce the amount of biosolids produced annually by roughly 75%.
Multiservizi, a publicly owned Italian company, operates water and wastewater treatment plants for 45 communities in Italy. The plant in Jesi serves 60,000 residents. Its new SBD from Siemens will reduce sludge production from 16,500 to 4,125 tons per year. The plant, which also has a natural gas boiler, is designed to recover thermal energy from the cogeneration plant, thus reducing CO2 emissions.
With the SBD, evaporation takes place when biosolids come in contact with the heated air. Biosolids are uniformly distributed on the entire belt width to cause uniform evaporation. The dryer is supplied in a two-belt system configuration. The belt speed and the temperature of the process air can be adjusted for different residence times. Varying residence time in the drying zone provides the means to adjust the product moisture to meet final use or disposal requirements.
The Siemens' thermal drying system was selected because of the technology's high reliability and safety, low maintenance and high automation level. Other advantages include high energy-efficiency, minimal environmental impact and agriculture-grade pathogen reduction.
Italy produces approximately 4 million tons of biosolids annually – almost half of which is currently sent to landfill and another quarter used for agricultural purposes. Limited landfill space and rising transportation costs are heightening the need to use technologies that reduce sludge volume.