A method for pathogen destruction in dilute sewage sludge or other dilute streams containing pathogens, including Helminth ova, while minimizing vapor generation and atmospheric emissions. In addition to conventional waste treatment steps, including grit removal, clarification, and concentration of waste material, vaporized waste treatment compounds are recycled to treat divert untreated waste in a scrubber. In the scrubber, waste material is treated while also acting as a reactive agent to scrub potentially hazardous or noxious gas, particularly gaseous MITC, from the treatment system. Recycling of vaporized treatment compounds provides a reduction of potentially toxic emissions and increased efficiency during treatment.