To provide a method and system for waste combustion treatment, capable of reducing an exhaust gas quantity to be treated in an exhaust gas treatment facility and improving a boiler efficiency.

The system for waste combustion treatment comprises a combustion furnace 10 having a primary combustion area 13 for burning wastes and a secondary combustion area 14 formed above it and burning the unburnt portion thereof by introduction of secondary air; and a boiler 20 recovering heat from combustion exhaust gas from the furnace. This system further comprises an exhaust gas recirculating line 22 extracting a part of the combustion exhaust gas discharged from the boiler 20 and circulating the extracted recirculating exhaust gas to the secondary combustion area 14, and a middle temperature dust collecting device 26 collecting the recirculating exhaust gas, provided on the exhaust gas recirculating line. As occasion demands, slaked lime 25 is supplied to the exhaust gas recirculating line 22 on the upstream side from the middle temperature dust collecting device 26.