The Biocon process is a safe, simple, and efficient sludge drying technology developed by Veolia / Kruger. The drying process is comprised of a drying cabinet, circulation fans, heat exchangers, heating system, condenser, and two stainless steel wire mesh belts. The sludge drying process employs indirect, convective heating to reduce sludge volume and produce a Class A biosolids product.
In order to minimize potential odors, the dryer cabinet is operated under a vacuum. The drying air is recycled in a closed loop minimizing the make-up air requirement and the wastewater plant’s odor control system demand.
The gentle product handling inside the dryer cabinet ensures low dust generation, a safer system, and a high quality, marketable end product meeting Class A requirements. The BioCon™ dryer does not utilize any back-mixing which further reduces dust generation inside the dryer building creating a cleaner facility with low maintenance.
The low temperature nature of the thermal sludge dryer enables the BioCon™ dryer to utilize various thermal energy sources including thermal oil, air, or steam. Thermal efficiency can be further increased by employing Kruger’s BioCon™ Energy Exchange System. Fuel sources for the Biocon system include natural gas, biogas, or fuel oil. Additionally, the dryer can be fueled by the biosolids end product by incorporating the BioCon™ Energy Recovery System (ERS) which can result in an autogenous system by combusting the end product and utilizing the heat of combustion to fuel the dryer.
Utilizing Biosolids as a Fuel in Buffalo, MN
The BioCon™ biosolids dryer and Energy Recovery System (ERS) were installed at the Buffalo Wastewater Treatment Plant. The processes allowed the plant to increase it’s biosolids capacity to 1,850 tons of dry solids per year. The ERS provides over 80% of heat for the dryer from renewable fuels, and reduces the biosolids mass by 95%.
Buffalo Wastewater Treatment Plant recieved several awards in 2009 including:
- The American Council of Engineering Companies Engineering Excellence Grand Award
- The Minnesota American Council of Engineering Companies Grand Award
- The Minnesota Society of Professional Engineers (MSPE) 2009 Seven Wonders of Engineering Award