Zooming in on Particle Size: Understanding Metals in Industrial Stormwater

Transcription

1 Zooming in on Particle Size: Understanding Metals in Industrial Stormwater Alan Flemming, PE, CPSWQ Engineer Project Manager Kennedy/Jenks Consultants Portland, Oregon

2 What we ll be looking at today: Particle Size Distributions, and why they matter Metals Associations CASE STUDIES Small Industrial Site 4 acres Medium Bulk Materials acres (depends...) Large Container Terminal 90+ acres Russ Crutcher MicrolabNW Photomicrograph Gallery

3 Size Matters

4 How to Measure?

5 Dissolved vs. Particulate - Filterable Fraction

6 Dissolved vs. Particulate Analytical: 40% dissolved Cu 70% dissolved Zn

7 Transport - Wet Road Agglomerate

8 Transport - Airborne Dust

9 What about Sweeping?

10 How Much Particulate Poses a Problem?

11 Case Study 1 - Small Industrial Fabricator Located in an Industrial Area in SW Washington Approximately 4 acre site, 100% impervious (including gravel areas) Level 3 Corrective Action Requirement for Total Zinc Also had Benchmark Exceedances for Turbidity and Total Copper Two primary outfalls Where and how to treat?

12 Case Study 1 - Small Industrial Fabricator Outfall 1 on the left, Outfall 2 on the right More activity at Outfall 2 also higher Turbidity, Zn & Cu Low percentage dissolved metals (especially at Outfall 2.) Outfall 1 Outfall 2

13 Case Study 1 Treatment Solutions PSDs indicate metals are particulate associated concentrations support treatment at one outfall. Four treatment systems considered: MWS, MFS, CESF, CABS Decision based on footprint, cost (shallow conveyance), and O&M One MWS, two MFS, and some source control Favor simple solutions that replicate complex natural processes Mike Siegel / The Seattle Times

14 What about that 20 micrometer spike? Western Red Alder Pollen (?)

15 Case Study 2 Bulk Materials Handling Located in an Industrial Area in SW Washington Level 3 Corrective Action Requirement for Turbidity and Total Zinc Approximately 70 acres flowing to the monitoring point, 80% impervious Transfer and storage of material in warehouses Not all of the area is active Not all of basin under one operator s control Targeted treatment locations?

16 Case Study 2 Source Analysis Sampling Identified 8 locations for supplemental sampling Analyzed for total and dissolved zinc and copper turbidity, total suspended solids particle size distributions. Categorized particle size distribution shapes as A, B or C to help identify relationships between pollutant concentrations and basin characteristics.

17 Case Study 2 Source Analysis Sampling A Moderate turbidity, low TSS, high zinc, low % dissolved normal industrial sample B High turbidity, high TSS, low % dissolved zinc Consider pretreatment & O&M C Very high total & dissolved zinc, low TSS

18 Case Study 2 Treatment Selections Treat in 5 locations for a total of approximately 14 acres Media Filtration, Biofiltration, Biofiltration Swale Simple Systems (again) Put in the right places to meet treatment goals

19 Problem Solved? This is what 1 µm looks like.

20 Case Study 3 Large Container Terminal Terminal 46, Seattle, WA Level 3 Corrective Action Requirement; high levels of total zinc, total copper, and turbidity 91.3 acres, 100% impervious 4 basins & outfalls Complicated relationships: Tenant/Consultant/Ecology/Port

21 Case Study 3 Analytical Very limited applicable historical data Only time to collect one round of data Some operational differences reflected Zinc/copper 60%-80% particulate High turbidity, moderate TSS, fine particulate predominates

22 Case Study 3 Tire Particles Light Particles High turbidity and Low TSS

23 Case Study 3 Pilot Testing 2 Systems Low tides, ship operations, rainfall timing Got 4 events, data at 4 basins.

24 Case Study 3 Pilot Testing Results Pilot influent sample results were <10% of historical results consistently across all 4 basins for all 4 storms Almost everything dissolved Both pilot units still removed between 30% - 90% of both total and dissolved metals

25 Case Study 3 Simple, but VERY BIG

26 Bonus Mini Case Study

27 Particles to Take With You Size matters, but other factors often matter more. You need data to understand your situation, but stormwater = variability, so you ll probably never have all the data you want. Getting the particles and metals out of stormwater is just the first step, Maintenance is Mandatory:

28 Questions? Kennedy/Jenks Stormwater Blog