Taste and Odor Evaluation of Polyurethane and Epoxy Lining Materials

摘要

The Southern Nevada Water Authority (SNWA) is considering the use of polyurethane and epoxy lining systems in lieu of traditional cement mortar lining for over 200 miles of large diameter steel pipe to transport groundwater from east-central Nevada. The materials being considered meet the criteria for NSF 61 certification, making them acceptable lining materials for potable water treatment and transmission. However, experience of these alternative lining systems for the transport of potable or raw water is limited in the water industry. For this reason, SNWA chose to perform a water quality evaluation to investigate the potential for leaching. Leaching could result in the release of microcontaminants, taste and odor issues, or formation of disinfection byproducts. In order to evaluate the suitability of these materials for use in the SNWA transmission system, seven buckets were lined with either an epoxy or polyurethane material. Each bucket was given a letter designation to hide the supplier’s identity as this was not a “pre-qualification” effort for design of the pipeline. Water quality analysis included profile attribute analysis, chlorine demand, and VOC production. Results showed that the epoxy materials appeared to exert more chlorine demand than polyurethane materials. Two lining products performed well based upon taste (total intensity of flavor (TIF), odor (total intensity of aroma (TIA), VOC production, and chlorine demand. However, the results indicate that a flushing program will be required for either lining system if chlorinated groundwater is to be stored in the pipeline for a long period of time.