Biofiltration Stormwater Treatment for a Waterfront Log Sort Yard Anita Fichthorn, Port of Tacoma Environmental Project Manager, Water Quality Ben Fuentes, P.E. Kennedy/Jenks Consultants StormCon 2014 Agenda • West Hylebos Log Yard • What the Industrial Stormwater General Permit (ISGP) requires • Conceptual treatment evaluation • Pilot study & results • Preliminary & Final Design • Construction • System Startup • System Performance Port of Tacoma’s Industrial Activities • The Port of Tacoma, WA America’s 5th largest Port • Containers • Breakbulk • Autos • Grain • Logs West Hylebos Pier Log Yard • 25 acre log yard Why We’re Treating Stormwater • WA State stormwater regulations are the most stringent in the country • Industrial Stormwater General Permit (ISGP) • Port facilities generally have difficulty with solids & metals • Log yards have particular challenges What the ISGP Requires • SWPPPs & BMPs Parameter Benchmark and Comparison to Benchmarks Turbidity (NTU) 25 pH (SU) 5-9 • Corrective Actions if Oil & Grease No visible sheen Zinc (ug/L) 117 Copper (ug/L) 14 Total Suspended Solids (mg/L) 100 Chemical Oxygen Demand (mg/L) 120 • Sampling of Runoff Benchmarks Exceeded • Level 1 – Operational • Level 2 – Structural • Level 3 – Treatment Log Yard Stormwater • Log yard operations • Runoff high in solids, metals, COD, color/turbidity • Bark flour • Sweeping is difficult Treatment Alternatives Analysis • Engineered wetland • Discharge to Sanitary • Biofiltration • Advanced treatment, DAF, oxidation, GAC • Combination • Bench-Scale Testing • Chitosan Enhanced Sand Filtration • Electrocoagulation Biofiltration Pilot Study • Evaluate biofiltration for log yard runoff treatment • Test different media • Establish treatment • Four test cells • 18” media depth • Plants vs. media alone • Varied flow rates 3”, 6”, 12”, 24”/hr. • Analyzed samples for TSS, total and dissolved Cu, Zn, BOD, COD, DO, turbidity, & pH Pilot Study: Influent Characteristics • Colloidal range solids • Color Pilot Study Results • Dry December • Wet thereafter • > 85% reduction Preliminary Design • Intercept existing drainage • Treat water quality flow rate & bypass higher flows • Pretreatment media filtration & biofiltration • Sized for 12”/hr based on pilot results • Obtain Agency approval Final Design • Finalize conveyance, pretreatment method, biofiltration mix, aggregate, plantings, etc. • Evaluate options for innovative treatment methods • Tiered Treatment (Series/Parallel) Bench-Scale and Pilot Testing (Round 2) • Bench-Scale • Granular Activated Carbon • Biochar • Variable Mix Percentage • Layering • Pilot Testing (Round 2) • Infiltration Rates Relocate! (after 90% design) From one side of the road: To the other: How it Works Construction Kickoff (September 2013) • Contractor awarded • Once you start digging… Concrete – Rebar and Formwork • Large Footprints • Favorable Weather Internals – Underdrain and Drain Rock • Well draining system • Pipes sized for flow capacity & maintenance Internals – Distribution Piping & Media Placement • Main line with branches • Conveyer belt to install media Internals – Media, Plants, & Valves • Install to grade • Valves for maintenance Can’t forget those pumps! • Variable Speed • Heavy Wheel Loads Or the valves for tiered treatment! • Low Flows / High Flows Looks ready…. Let’s turn it on! (December 2013) Pretreatment Biofiltration System Startup / Fine Tuning • Tiered Treatment Adjustments • Equal Flow Distribution Plant Growth (July 2014) Enjoying the Summer Sun! System Performance • Immediately met Influent Effluent benchmarks for 5 out of 6 ISGP parameters: • pH • Zinc • Copper • Turbidity • TSS • After some fine tuning 6 out of 6: • COD! Up to 80% - 90% reduction in concentrations for all ISGP parameters. Questions? www.kennedyjenks.com/blog
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