Impact of Infrastructure Coating Materials on Stormwater Quality: A Review and Experimental Study
A literature review and 30 day leaching regime were conducted to determine the extent stormwater infrastructure coatings affect water quality. Newly installed polymer enhanced cement mortar (PECM) and polyurea (PEUU) stormwater pipe coatings were removed from the field and underwent ten three day water immersion periods. For both materials, the greatest water quality alterations occurred during the first water contact period followed by significant reductions in water quality alterations. Mineral release from PECM consistently elevated pH from 7.1 to 10.1–11.8 throughout the entire study. Organic contaminant release (TOC and UV254) was also detected for PECM during the first two water contact periods only. Alkalinity increased by 534 mg/L as CaCO3 because of the first contact period and 18–50 mg/L as CaCO3 for each remaining periods. Isocyanate resin from PEUU reacted with water and reduced water pH by 1.0 to 1.2 pH units during the early contact periods and lesser magnitude for the remaining exposure period. COD, TOC, and UV254 results showed that organic contaminants were released from PEUU. A limited quantity of organic contaminants released by PEUU was biodegradable. Nitrogen compounds were detected only during the first PEUU water contact period.
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