CAN POLYETHYLENE PIPES IMPART ODORS IN DRINKING-WATER

A case study is reported which demonstrates the appearance of numerous organic compounds associated with an intense taste and odor problem during the passage of a drinking water through a 300 m polyethylene pipe. Batch experiments showed that two principal mechanisms are involved in the occurrence of organoleptic changes caused by defective polyethylene tubings: dissolution of the polymer additives (e.g. alkylphenols...) and oxidation of the internal surface of the pipe during extrusion with subsequent release of the resulting polar compounds (aldehydes, ketones...). Twenty per cent of the pipes tested (n = 264) appeared to be defective and the total release time may exceed several months under low flow rate conditions.