Two sets of WJG-2500 rotary-wing fluidized dryers are used, with a rated evaporating water volume of 2800kg/h, equivalent to a wet sludge treatment volume of 4.17t/h, imported coal slime moisture content ≤80%, and sludge moisture content after drying ≤40 %. The wet sludge with a moisture content of 80%-90% from the water treatment plant is dried into sludge with a moisture content of 40% through a dryer, and the dried sludge is sent to the boiler for combustion through a conveying device. The high-temperature flue gas and sludge are directly contacted in the dryer for drying. The dried flue gas is sent to the air inlet of the dust collector through the induced draft fan, and then enters the chimney after the boiler flue gas is dedusted and discharged into the atmosphere.