Matt Tabor, Maryam Salehi, Ph. D., Jesus Estaba, Andrew J. Whelton, Ph.D. Department of Civil Engineering University of South Alabama August 6, 2012 Influence of Infrastructure Rehabilitation Liners on Rinse Water Quality: Polymer Enhanced Cement Mortar and Polyurea Liners

Significance of stormwater infrastructure rehabilitation Laboratory leaching testing – Objectives – Methods – Results Conclusions, Recommendations Overview

To Avoid Expensive Open Trench Techniques Trenchless Technologies are Being Used Open-trench repair: Traffic, Heavy Equip. Excavation, Inconvenience Installation, Cover Trenchless Technologies CIPP Polyurethane (PU) Polyurea (PEUU) PU/PEUU Blends Cement Mortar (CM) Polymer Enhanced CM (PECM) Stormwater Study

Polymer Enhanced Cement Mortar (PECM) Provides Structural Strength to Host Pipe Ingredients Calcium silicate cement, Crushed stone or gravel, Sand, Mineral clays, Fly ash, Crystalline silica Polymer type unspecified Crosslinked coating achieved when fully cured Cures in 24 hr Extreme temperature resistance High early and long-term strength Low porosity Possibly Water Quality Impacts? No Data for PECM

Polyurea Coatings Only Require Minutes for Complete Cure and are Reportedly Economical Coating cures within minutes Thin wall thickness Cold temperature curing ability Low cost because of ingredient versatility Possibly Water Quality Impacts? No Data for Polyurea

Specific Objectives: 1.Expose newly installed lining materials to synthetic water for 30 days 2.Document inorganic and organic contaminant levels in those contact waters 3.Analyze and interpret results Our Goal was to Characterize the potential that PECM and PEUU alter rinse water quality

Methods: A Static Leaching Procedure was Applied Synthetic Water Water pH Alk mg/L as CaCO 3 3-day water changes, 22° C PEUU PECM Control 1 day InstallRemoval 10 days Testing Aquatic Significance TN, BOD 5 Inorganic pH, Alkalinity Organic TOC, COD, UV 254 Water Quality was Characterized

Results: Water pH was Significantly Affected by both PECM and PEUU Coatings PECM Control PEUU * Every 3 days old water was replaced

Water pH Changes can be Explained by Understanding Material Chemistry! 14=pH + pOH Diisocyanate ResinCarbamic Acid Functional Group Diamine

Results: PECM Increased Alkalinity due to the Addition of Hydroxide Ions PECM

PEUU Consistently Released Organics to the Water For 30 days while PECM Released Organics for Only 6 Days PEUU

COD Results Imply Organics Released from PEUU have an Oxygen Demand PEUU

BOD 5 Results Demonstrated that the Majority of Contaminants Released were Not Readily Consumed by Aerobic Organisms BOD 5 Raw Data Control 0 PEUU mg/L PECM0 Biodegradability Ratios RatiosWWTPPEUU 3-day COD/BOD to COD/TOC2.0 to

Total Nitrogen was Detected in PEUU Leachate Waters After the first Three Day Exposure Period mg/L of Total Nitrogen Detected Average TN naturally occurring in rivers of Virginia is between 0.21 mg/L to 0.87 mg/L of TN US EPA (2000) Fate of Nitrogen Unknown Biodegradation (Nitrification) Chemical Transformation Recalcitrant

Based on Experimental Data Contaminant Concentrations Should Increase as Pipe Diameter Decreases Pipe Interior Diameter, inches Material and Contaminant Concentration, mg/L † PECMPEUU TOCAlkalinityCODTOCTN ,9946, ,3009, ,577180,21717,3431, † Results were calculated by applying experimentally data to a 10 foot long pipe where surface area and water volume calculations were completed.

Conclusions 1.PECM and PEUU altered water quality for 30 days 2.PECM raised the pH and alkalinity for 30 days and released TOC for 6 days 3.PEUU released organics for 30 days (COD and TOC) and nitrogen and BOD 5 for 3 days  Dynamic test procedure is needed  Document water quality impacts caused by different formulations, installation procedures  Cautious approach: Rinse coatings after installation and responsibly dispose of waters

Acknowledgement Ms. Laura Linn (Dauphin Island Sea Laboratory) Ms. Bridget Donaldson ( Virginia Department of Transportation) Ms. Eddy Colmenarez (University of South Alabama) Dr. Kevin White (University of South Alabama) Ms. Suzanne Lindblom (Mobile Area Water and Sewer System)

Dr. Andrew J. Whelton Department of Civil Engineering University of South Alabama Matthew Tabor Department of Civil Engineering University of South Alabama