AWWA WSC69990

This powerpoint presentation begins by providing a brief overview of distribution system decontamination research. The experimental plan includes: contaminate pipe by equilibrating with contaminated tap water; initially using dichlorvos, an organophosphorus pesticide; cement-lined steel pipe and iron pipe; contamination confirmed via solvent extraction and GC-MS analysis; and, decontaminate by flushing, chlorine, and Simple Green. Method development included: contaminated pipe with ~1000 mg/L dichlorvos overnight (approximately 150 mg dichlorvos available for binding); and, tested extraction with tap water rinses and acetone/ dichloromethane solvent rinses. Decontamination results are presented and preliminary conclusions were that: dichlorvos binds more to cement-lined pipe than iron; flushing provides significant removal of dichlorvos from cement-lined iron pipe and iron pipe; and, decontamination agents such as chlorine and Simple Green seem to be efficacious. Includes figures.