Process for combusting dewatered sludge waste in a municipal solid waste incinerator

In a process for the co-incineration of a solid waste and sewage sludge containing solid particulate matter in an incineration system comprising a combustion zone containing a grate on which the solid waste is combusted, means for introducing the solid waste onto the grate, means for introducing a flow of combustion supporting air into the combustion zone including primary air inlet means for introducing combustion supporting air at a point beneath the grate and secondary air inlet means for introducing combustion supporting air at a point above the grate, and means for introducing sewage sludge into the combustion zone, which process comprises combusting the solid waste on the grate, introducing combustion supporting air, and combusting the sewage sludge in the combustion zone, the improvement which comprises:

• a) dewatering the sludge to a solids content from in the range of about 15 to about 30 percent by weight;
• b) finely dividing the solid particulate matter in the dewatered sludge to particles smaller than about 1000 microns;
• c) introducing the dewatered sludge into the combustion zone at a point above the solid waste on the grate and not above the point at which the secondary air is introduced to the combustion zone;
• and
• d) enriching at least a portion of the flow of combustion supporting air with oxygen to an oxygen concentration of at least about 21 percent by volume.