Since 2016, NASSCO has supported independent research to better understand the effects, if any, of styrene used in the cured-in-place pipe process. Research phases 1, 2, and 3 focused on air emissions resulting from steam cure.
The current research, Phase 4, focuses on cure water and potential impact of styrene on publicly owned treatment works (POTW). Partnering with Buried Asset Management Institute – International and headed up by Principal Investigator Dr. Tom Iseley, P.E., and Lead Research Engineer Dr. Hanouf M. Alhumaidi, Phase 4 is broken out into three separate tasks:
- Task 1: International literature review
- Task 2: Survey among POTW
- Task 3: Lab studies and white paper
Tasks 1 and 2, now completed, concluded that there is no literature on the topic of CIPP styrenated cure water on POTW and determined a need to test wastewater quality and identify the styrene concentration in wastewater for POTW. Below is an excerpt from the final report:
“The findings of Task 1 of this NASSCO Phase 4 Study indicate that existing studies/reports did not adequately capture any documentation of CIPP cure water discharge in wastewater treatment plants. The comments received from industry experts using both direct emails and questionnaire Task 2 results indicate no direct impact of CIPP cure water discharge on wastewater treatment plants. Task 3 includes chemical testing of styrene concentrations in wastewater treatment plants and is expected to resolve all concerns related to CIPP impact on WWTP.”
The study recommendations for future research and testing:
- It is recommended that NASSCO perform additional sampling, studies and evaluations of different factors that impact CIPP styrenated cure water during CIPP installations and its effect on wastewater going into POTW.
- It is recommended that NASSCO perform additional sampling, studies and evaluations of different CIPP installations including curing with hot water, steam or ultraviolet and their effect on wastewater going into POTW.
- Discrepancies in the literature in reported testing protocols and practices for CIPP styrenated cure water indicate a necessity to suggest a unified testing procedure, using appropriate engineering and testing principles to assess the true implications of CIPP rehabilitation/maintenance technology in culvert and storm sewer.
- Discrepancies in the literature in reported incidents of CIPP styrenated cure water indicate a necessity to re-evaluate these incidents and further examine whether these contaminations are caused by CIPP rehabilitation/maintenance or other causes such as contractor errors, improper installations, testing errors, etc. for culvert and stormwater.
- It is further recommended that the underground industry establish styrene monitoring stations at key influence locations of WWTP where significant CIPP work is being done.
As a result of these recommendations, Task 3 of the study is now underway, and results will be available soon.
Full reports and recommendations may be found at nassco.org/safety.
Sheila Joy is executive director of NASSCO. She can be reached at director@nassco.org.
