1,4-Dioxane at LACSD Ann Heil Section Head Reuse & Compliance - - PowerPoint PPT Presentation

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Mar 05, 2024 46 likes •166 views

Converting Waste Into Resources 1,4-Dioxane at LACSD Ann Heil Section Head Reuse & Compliance June 28, 2019 Topics that will be covered today LACSD overview 1,4-dioxane regulations 1,4-dioxane data LACSD operates large interconnected

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1,4-Dioxane at LACSD

June 28, 2019

Converting Waste Into Resources

Ann Heil Section Head Reuse & Compliance

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Topics that will be covered today

LACSD overview 1,4-dioxane regulations 1,4-dioxane data

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LACSD operates large interconnected wastewater systems in LA County

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LACSD is a major recycled water producer

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Groundwater recharge is highest volume use

Montebello Forebay LVL Water Treatment Facility MWD Demo Project

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1,4-Dioxane is regulated in groundwater recharge projects

CA Notification Level = 1 µg/L EPA IRIS = 0.35 µg/L (10-6 cancer risk) 0.5 log removal via AOP for subsurface injection

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1,4-dioxane concentrations vary by treatment plant

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1,4 dioxane concentrations vary by treatment plant

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1,4-Dioxane is not removed in tertiary treatment

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1,4-dioxane concentrations are remaining relatively steady

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Montebello Forebay WRPs are right at current regulatory levels

CA NL= 1 µg/L EPA IRIS 10-6 = 0.35 µg/L

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Take away messages

✓ 1,4-dixoane is ubiquitous at our treatment plants, indicating a domestic source ✓ 1,4-dioxane isn’t removed with tertiary treatment ✓ 1,4-dioxane concentrations are remaining relatively steady ✓ Some industrial sources at some of the treatment plants ✓ 1,4-dioxane concentrations hover right at current Notification Level at Montebello Forebay plants ✓ Further reduction in regulatory standards would necessitate expensive treatment