Method for coating dry pellets made of waste bio-solids with waste bio-solids

A method for treating dry pellets made from waste bio-solids with wet sludge of waste bio-solids to change the size and/or liquid to solid density of the pellets for delivery to a dryer comprising:

• supplying dry pellets and wet sludge to an inlet of a generally horizontal screw feed conveyor and mixing the dry pellets and wet sludge to form a mixture while being conveyed to an outlet of the feed conveyor;
• and
• supplying the mixture from the feed conveyor outlet to an inlet of a lower end of a sealed shaftless screw material combining conveyor having an open center which extends generally vertically, conveying the mixture from the inlet of the material combining conveyor upwardly along the length of the conveyor to an outlet at its upper end from which to be discharged to a dryer, the pellets being coated with sludge during the upward conveying of the mixture and higher density dry pellets falling by gravity back through the conveyor open center to the material combining conveyor inlet to further mix with the mixture from the feed conveyor.