Water Treatment Plant Slow Sand Filter Bed Operations and - PowerPoint PPT Presentation

Water Treatment Plant Slow Sand Filter Bed Operations and Maintenance Presentation

Stayton Water Treatment Plant Located at 200 North First Avenue

Water Treatment Plant Configuration • Three ½ acre slow sand filter basins • Control Room • Monitors flow in, flow out, head loss, turbidity, and PH in the ponds • Adds 12.5% sodium hypochlorite for disinfection • Adds soda ash to minimize corrosion in pipes due to low PH • Clear well • Provides contact time to reduce chlorine in water before leaving plant

Water Treatment Plant Map

Slow Sand Filter Configuration Slow Sand Filter Bed 3 - 4 feet deep typical 15-24 inches typical Schmutzdecke (cleaning zone)

Slow Sand Filter Beds • Filter Beds 1 and 2 reconstructed in 1993 • Filter Bed 3 reconstructed in 2010 • Slow Sand Filter Beds use natural occurring processes to clean water • Tried and true and very reliable system • North Santiam River is the source of Stayton water that flows onto the slow sand filter beds

Slow Sand Filter Maintenance • After a period of time of infiltrating water through the sand the Schmutzdecke zone becomes less pervious • When this occurs maintenance personnel drain the water from the filter bed and skim off the top 1-inch of sand and remove it from the filter bed • Each filter bed is skimmed approximately once every 8- 9 months

Slow Sand Filter Cleaning Public Works crew skimming Filter Bed 3 Approximately 1-inch of sand is skimmed off the entire Filter Bed and removed

Slow Sand Filter Resanding Project • In December while cleaning Filter Bed 1, a crew member noticed pea gravel dispersed around the top of the sand • Public Works engineers performed a survey on Filter Beds 1 and 2 • Filter Bed 1 is in need of sand immediately • Filter Bed 2 will need sand in the next 2 years • Filter Bed 3 will need sand in the next 3 years

Slow Sand Filter Resanding Project • Public Works put a Request for Bids out on March 4, 2019 • The bid opening is March 28 th , 2019 • Engineers Estimate for the project is $650,000 - $750,000 • This is an unplanned expense • Project funding alternatives will be discussed by Andy Parks, the City’s Financial Consultant

Financial Impacts Water System Slow Sand Filter Maintenance Project March 2019

Stayton Water CIP – Updated with sand filter capital 2019-2028

Water Fund Financial Projection Key Metrics FY 2019-2028 – full CIP; no borrowing

Water Fund Financial Projection Key Metrics FY 2019-2028 – full CIP; no borrowing

Water Fund Financial Projections FY 2019-2028 – full CIP; 5.0% annual rate adjustments through FY 2025; 3.5% after

Water Fund Financial Projection Key Metrics FY 2019-2028-including full CIP; incremental rates; borrowing

Stayton Water CIP – scaled back version 2019-2028 (used with 2.0% CPI rate adjustments only)

Water Fund Financial Projections FY 2019-2028 – scaled back CIP - 2.0% CPI rate adjustments

Water Fund Financial Projection Key Metrics FY 2019-2028 – 2.0% CPI rate adjustments only; scaled back CIP

Summary • Rate increases will be necessary to fund present level of service and maintain sand filters • If no borrowing – approximately a 35% increase is needed • If borrowing of approximately $3.5 million during next 5 years, rate increases of approximately 5.0%/year through FY 2025 will be necessary • A comprehensive rate study may be desirable • Rate components – can be looked at prior to a master plan update • Revenue requirements will need to be updated after master plan update

Water Treatment Plant Slow Sand Filter Resanding Project • Questions?