Disinfection Byproducts 2020 Update Introductions

Josh Schimmel Executive Director

Jim Laurila Director of Water Operations

Christina Jones Deputy Director of Water Operations

Sue Tower Laboratory Manager

Domenic Pellegrino Director of Finance Agenda

Overview of DBPs

Current Regulatory Situation

Pilot Plant

Short-Term Strategies & Long-Term Solutions

Proportional Cost Sharing

Looking Ahead Drinking Water System Disinfection Byproducts How They Form Current Regulatory Situation May 1, 2020 Sampling - Longmeadow TTHM • Maximum Contaminant Level (MCL) is Location Running Annual Average (LRAA) of 80 ppb • Current range for 4 locations: 62.4-66.9 ppb • Longmeadow under the MCL for first 2 quarters in 2020 (previous 5 quarters had exceeded the MCL)

HAA5 • MCL is LRAA of 60 ppb • One sample location currently exceeds MCL at 62.3 ppb • Three other sample locations in compliance WPF Water Production 2 017 -2020 Weekly Average

2017 2018 2019 2020 45

40

35 Longmeadow QTR2 2020 DBP Sampling 30 Million Gallons of Water per Day Gallons of Million Water 25

20 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Pilot Water Treatment Plant Underway - Evaluates Process Performance

Schedule • Season 1: Oct 7, 2019 – Dec 18, 2019 • Season 2: May 4, 2020 – June 12, 2020 • Season 3: Aug 17, 2020 – Sept 25, 2020 First Season Complete • Pre-oxidation process ruled out/ineffective • (DAF) – shows promise • Study effectiveness of coagulants in seasons 2 and 3 for DAF and for Direct Possible Short Term Process Improvement • Use of ferric sulfate as a new coagulant • Promising significant DBP reduction • Fall trial at full scale (1/2 plant flow) Pilot Water Treatment Plant Underway - Evaluates Process Performance Short Term Strategies - Ongoing Optimize System Performance

Optimized dosing • Reviewed daily Coagulant optimization trials • Pilot plant evaluation through Sept 2020 • Fall 2020 – Half-plant trial planned Reduce water storage time (age) • Reducing water storage in winter months Added storage tank mixing Maximize NOM removal • Slow vs. Rapid Sand Filtration Distribution System Flushing • Aids in reducing chlorine dosage Long Term Solutions – Capital Planning New West Parish Filters Treatment Process

New Treatment Plant – Preliminary Based on Pilot Plant • 60 MGD Dissolved Air Floatation (DAF) Clarification Process • Rapid Sand Filter Upgrades • New Electrical System • New Chemical Storage and Feed Building New Treatment Plant - Design • Design scheduled for FY22 - FY23 • $1.944 million New Treatment Plant - Construction • FY24 - FY27 • $86.04 million Proportional Cost Sharing

Rates • Support current projects and debt service on past projects • Based on proportion of use/consumption

Rate-Setting Process • Longmeadow provided one-year prediction in December • Prediction revised in April • Five-year plan provided in June Looking Ahead

Treatment – Next Steps • Completion of the Pilot Treatment Plant • Commence Fall 2020 Coagulant Trial (1/2 plant – full scale) • Begin Design of New Process Upgrades • Commission will provide assistance with Longmeadow MassDEP reports if there are data needs