Soil sterilization under the conditions you describe are all but impossible. The best thing you can do is to remove all the solid residue and allow nature to take its course in breaking down the bacteria that might remain. Rainfall and regular turf irrigation would accelerate the clean-up of the soil system. The microbial system in turfgrass soils is complex and dynamic, breaking down and 'digesting' things organic (solid dog waste) as well as things inorganic, like lawn herbicides.

Ron Smith, PhD
NDSU Professor Emeritus
Department of Plant Sciences