Biosolids Improvements for Energy Recovery

The Municipal Utilities Board of Albertville engaged Krebs Engineering to design the biosolids improvements for energy recovery. Class A biosolids are heated at higher temperatures to destroy pathogens, so they can be used in residential gardens, landscaping, and crop farms without restrictions on public access. The project consisted of a biosolids dryer, biogas compressor and storage tanks, digester mixing, grit removal system at the headworks. The new grit removal system reduces the amount of grit in the digestion process, thus increasing biogas production. The new digester mixing system improves solids dewatering, which reduces energy required to dry biosolids. The production of Class A biosolids enables Albertville to largely reduce its annual sludge hauling and disposal costs by reducing the volume of biosolids and by producing a renewable fertilizer/soil amendment that is sold to the public. TVA and ADEM awarded the project a $900,000 grant for energy efficiency.