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Harmful Algal Blooms July Water / Wastewater Commission Brian Haws, P.E. Operations Manager Environmental Engineering & Technical Services July 14, 2021 2 Agenda  Background – Algae in the Highland Lakes  Source water sampling and monitoring  Austin Water analytical strategies  Austin Water Harmful Algal Bloom (HAB) mitigation strategies and treatment readiness Harmful Algal Blooms July 14, 2021 Algae in the Highland Lakes  Composed of photosynthesizing bacteria (cyanobacteria) 3 • some types produce toxic compounds (cyanotoxins) • a.k.a. “blue-green algae” • common in natural water  Contributing Factors • Warm water • Low or stagnant flow • Abundance of nutrients Harmful Algal Blooms July 14, 2021 Planktonic vs. Benthic Algae  Planktonic blooms 4 Toledo, Ohio • Free floating microscopic cells • Suspended in the water column or floating as scum on surface  Benthic proliferations • Originate on bottom of lake in shallow water Lake Erie • Globs or mats remain on the bottom or float to the surface 5 Harmful Algal Blooms July 14, 2021 Detecting a HAB:  Routine plankton counts at WTP intakes • Focus on blue / green totals • Observe trending • Adjust monitoring frequency based on current conditions  Continuous exchange of information • Watershed Protection Department • Lower Colorado River Authority Monitoring the Source – Plankton Counts Blue Green Phytoplankton Count 2017 - present 6 60,000 50,000 40,000 30,000 20,000 10,000 ) l m / . g r o ( t n u o c n o t k n a p o t y h p l 0 Harmful Algal Blooms July 14, 2021 7 Cyanotoxin Monitoring: History  Cyanotoxins are unregulated • No maximum contaminant levels (MCLs) established by EPA  Austin Water first sampled in 2015 • Detected cylindrospermopsin (just above detection) at WTP intakes • No other cyanotoxin “detects” in Austin Water monitoring history  Unregulated Contaminant Monitoring Rule (UCMR) sampling in 2019 (all non-detect) Harmful Algal Blooms July 14, 2021 8 Cyanotoxin Monitoring: 2021  Biweekly sampling since February 2021  Collected at intake and tap at all 3 plants  All results non-detect LCRA Monitoring 9 Biweekly at Hudson Bend • Dihydroanatoxin detected in water in Mid- March o Levels just above detection • All water samples non-detect since then Sampled 12 sites in Late March • Dihydroanatoxin detected in the water at 4 sites o Levels just above detection • Future sampling o Deploying SPATT bags at multiple reservoirs o Above the dam at each reservoir 10 Watershed Protection Department Monitoring • Biweekly sampling • Ladybird Lake (3 sites) • Lake Austin (3 sites) • Cyanotoxins detected in algae only 11 Austin Water Analytical Strategies • Weekly algae counts • Evaluate trends • Compare against published triggers • FloCam purchase (July Commission) • Biweekly cyanotoxin sampling (contract lab) • Developing ELISA method at AW Water Quality Lab • Quicker turnaround at a lower cost • Method still in development Harmful Algal Bloom Mitigation Strategies 12  Adjusting monitoring frequency based on conditions  Utilizing available AWWA resources  Reviewing existing literature  Coordinating with other agencies (APH; Watershed; LCRA; HSEM)  Developing communications plans  Evaluating effectiveness of treatment and operational options  Participating in Water Research Foundation (WRF) study Water Treatment Plant Readiness 13 • EPA preferred method – conventional treatment • Additional treatment methods – PAC and oxidation • Retrofitting for additional chemical capabilities • Ongoing testing to confirm effectiveness of treatment methods • Engage consultants for guidance and broader perspective