Drying sludge has several advantages, including:
- Sanitization: sludge is dried at over 80°C during more than one hour, removing pathogenic germs (USEPA Class A);
- Stabilization: biological activity in sludge is stopped by drying;
- Tonnage reduction: water in sludge is almost completely removed which reduces sludge tonnage to 1/5 - 1/3;
- Better sludge utilization: it can be used without causing problems, storage is easier, and spreading is feasible with conventional fertilizer spreading resources. Sludge is a high quality fuel which is suited to various combustion methods.
BioCo™ principle: indirect drying on belts
The BioCo™ dryer is completely air-tight and sealed. It is equipped with 2 stainless steel belts placed one above the other. The sludge retention time in the dryer exceeds 60 minutes.
The sludge drying process is undertaken by circulating hot drying air through the sludge layer on the belts. The drying conditions provide a dry solid content in the sludge of 90% minimum at the dryer outlet.
The unique distributor system lays sludge strings uniformly over the width of the start belt by means of special rubber nozzles, providing optimal sludge drying conditions.
The drying air is heated by thermal fluid heat exchangers. This can be produced by a boiler (steam or thermal oil), an air heater, an incinerator or by cogeneration.