NOVELTY - A sludge drying process comprises using waste heat from tunnel furnace (201) and solar energy absorbed by polycarbonate (PC) sunshine plate on ceiling of drying room (203) to heat, dehumidify and dry the sludge in the drying room, and conveying the dry sludge out the drying room. Internal of material platform located in the drying room is provided with gas duct. The gas duct connects cooling zone of the tunnel furnace for producing bricks.    USE - A sludge drying method.    ADVANTAGE - The sludge is processed in closed environment without directly exposing to the air such that poisonous and harmful gas brought by sludge does not pollute the environment. By employing the waste heat of the brick kiln and the solar energy to dry, the physical heat of the baking bricks back part in the tunnel kiln is fully used, the heat itself is increased, and plenty of energy is saved. After being tested, the water content of dried sludge is low, reaching 10-25%.    DETAILED DESCRIPTION - A sludge drying process comprises firstly transporting the municipal sludge with 80-85% water content to sludge warehouse (106) to seal and store, controlling grab bucket (102) by programmable logic control (PLC) system to grab the sludge in the sludge warehouse and send to feed hopper of sludge feeding device (101), while adding curing agent to the feed hopper and fully stirring, transporting the sludge to drying room (203) of drying device, using waste heat from tunnel furnace (201) and solar energy absorbed by PC sunshine plate on ceiling of the drying room to heat, dehumidify and dry the sludge in the drying room, and conveying the dry sludge out the drying room by dry material delivering machine. Internal of material platform located in the drying room is provided with gas duct that passes through the drying room. The gas duct connects cooling zone of the tunnel furnace for producing bricks. The sludge feeding device conveys the sludge to collection hopper of sludge paver (207) above the material platform and turns over and throws the sludge, taking waste heat by pipe on the cooling zone of the material platform and sending to the drying room, using waste heat from the gas duct and the solar energy absorbed by the PC sunshine plate on the ceiling of the drying room to heat, dehumidify and dry the sludge on the material platform.    DESCRIPTION OF DRAWING(S) - The drawing is a schematic diagram illustrating an apparatus for drying sludge.    Sludge feeding device (101)    Grab bucket (102)    Sludge warehouse (106)    Tunnel furnace (201)    Drying room (203)    Sludge paver (207)