CHLOROFORM IN INDOOR AIR AND WASTE-WATER - THE ROLE OF RESIDENTIAL WASHING MACHINES

A residential washing machine was studied in order to determine the ex tent of chloroform formation following the application of a laundry bl each containing sodium hypochlorite. A dynamic model was also develope d to estimate chloroform formation, mass transfer, and gaseous emissio ns during a typical wash cycle. A series of 22 experiments was complet ed to determine model parameters, including chemical reaction and mass transfer rate coefficients, as well as headspace air exchange rates. Three additional experiments were completed to evaluate model performa nce. Experimental and model results suggest that washing machine envir onments are very conducive to chloroform formation, with chloroform le vels frequently exceeding 1 mg/L in washwater. Chloroform stripping ef ficiencies were observed to be greater than those previously reported for ethanol, but less than those reported for radon. Mass emissions of chloroform to indoor air during a ten-minute wash cycle were predicte d to be between 5.3 and 9.8 mg. On a unit activity basis, chloroform e missions associated with hypochlorite-containing bleach addition to wa shing machines far exceeded emissions from showers. Each source was es timated to emit similar quantities of chloroform on an annual basis. F inally, it was estimated that the use of hypochlorite-containing laund ry bleaches may contribute a significant fraction of chloroform mass l oadings to municipal wastewater.