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StormCon 2017 - Stormwater Management at Facilities - Draining to Sediment Superfund Sites


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The presentation focuses on the relationship between stormwater runoff and sediment contamination in marine and port areas

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StormCon 2017 - Stormwater Management at Facilities - Draining to Sediment Superfund Sites

  1. 1. Philip Spadaro, TIG Environmental, Seattle Jeff Gabster, TIG Environmental, Seattle Stefano Biondi, StormwaterItalia, Venice, IT Francesca Sambo, StormwaterItalia, Venice, IT Barry Kellems, Integral Consulting Inc., Seattle August 27–31 Bellevue, Washington Stormwater Management at Facilities Draining to Sediment Superfund Sites
  2. 2. Copyright © 2017 TIG Environmental2 Introduction • Stormwater is largely an issue managed under the Clean Water Act • The intersection of the Clean Water Act and the Superfund Law has many challenges • Managing stormwater at facilities draining to sediment Superfund sites is particularly challenging – Emphasis on pollutant source control – Substantial financial exposure – Potential for sediment contamination – Threat of future recontamination
  3. 3. Copyright © 2017 TIG Environmental3 Environmental Management in Urban Industrial Waterways
  4. 4. Copyright © 2017 TIG Environmental4 Hypothetical Facility • A recreational marina and boatyard – Typical site activities: • Upland boat storage • Light boat maintenance and repair • Boat cleaning via pressure washing • Vehicle traffic onsite – Goals: • Evaluate and reduce the impact of stormwater on water/sediment quality in the adjacent waterway • Reduce typical marina/boatyard related Contaminants of Concern (COCs) – Copper, Zinc, Lead, etc.
  5. 5. Copyright © 2017 TIG Environmental5 Conceptual Site Model of a Boatyard
  6. 6. Copyright © 2017 TIG Environmental6 Reducing Stormwater Loads to the Receiving Waterbody – spent abrasive grit – spent solvent – spent oil – wastewater from pressure- washing – paint over-spray – paint drips – various cleaners and anticorrosive compounds – paint chips – scrap metal – welding rods – wood – plastic – resin – glass fibers – miscellaneous trash such as paper and glass • Wastes generated by boatyard activities include:
  7. 7. Copyright © 2017 TIG Environmental7 Reducing Stormwater Loads to the Receiving Waterbody • Means of pollutants entering the wastewater stream: – the application of paint and preparation or cleaning of and painted surfaces – the handling, storage, and accidental spills of chemicals, leaks, or drips of paints, solvents, or thinners – the fracturing and breakdown of abrasive grits – and the repair and maintenance of mechanical equipment
  8. 8. Copyright © 2017 TIG Environmental8 Progress in Reducing Environmental Footprint • NDPES permit requirements provided the initial impetus for improving management of boatyard stormwater and effluents • Washington State specific permit requirements: – Limitation of discharges – Implementation of mandatory best-management practices (BMPs) – Implementation of monitoring and sampling requirements – Development and management of a stormwater pollution prevention plan (SWPPP) – Report submittal and record maintenance
  9. 9. Copyright © 2017 TIG Environmental9 Voluntary, Incentive-based Programs • Clean Boatyard Washington was created in 2005 – Puget Soundkeeper Alliance, Northwest Marine Trade Association, and EnviroStars Cooperative. – Supported by funded by Washington Department of Ecology – Certified 14 marinas
  10. 10. Copyright © 2017 TIG Environmental10 Result: Mean Copper Concentration in Boatyard Runoff, 1998-2014 Year Mean Copper Concentration (µg/L) 1998-2002 410 µg/L 2006-2008 110 µg/L 2011-2014 31 µg/L
  11. 11. Copyright © 2017 TIG Environmental11 Proposed Approach • At boatyards, vessel hulls are commonly cleaned via pressure washing, a water-consuming process • Typical contaminants in boat wash water may include suspended solids, volatile and semi-volatile organic compounds, detergents, and metals • Approaches to wastewater management: – Collection of wastewater for truck transport to a disposal facility, such as a publicly owned treatment works (POTW) – Discharge to a sewer for treatment at a POTW – Onsite treatment for reuse
  12. 12. Copyright © 2017 TIG Environmental12 Closed-Loop Wastewater System • Example system for treating wastewater onsite for reuse in pressure washing – Process Steps: • Flocculation and settling: wastewater dosed with flocculant is conveyed to settling tank where flocculated particles settle out, and removed as settled solids • Filtration: wastewater passes through a polishing filter to remove additional fine materials • Storage: holding tank is used to provide a continuous, on-demand feed to the pressure washer – Additional treatment options: • pH control, precipitation, adsorption, ion exchange, electrocoagulation, and/or membrane treatment
  13. 13. Copyright © 2017 TIG Environmental13 Concerns Related to Closed-Loop System • Removal and disposal of settled solids – Municipal landfill vs. hazardous-waste disposal – Loss of water from system requires replacement • Interaction between stormwater and wastewater system – Wastewater cannot pass to stormwater system – Stormwater overflow cannot flood wastewater system • Solutions – Separate treatment systems for stormwater and wastewater • Stormwater: variable volume, low contaminant concentration • Wastewater: regular volume, high contaminant concentration • Allows treated stormwater to be diverted to replace lost wastewater during solids disposal
  14. 14. Copyright © 2017 TIG Environmental14 Process Flow Diagram (PFD) of Onsite Wastewater and Stormwater Management System
  15. 15. Copyright © 2017 TIG Environmental15 Preventing Spills from Reaching the Waterbody • A monitoring and emergency response system should be implemented to prevent spilled materials from reaching the waterway. • Unintended discharges may result from either accidental events or incorrect operation of the treatment system. • Once such an event occurs, unintended contaminants and/or untreated water can be rapidly conveyed through the drainage system to the receiving waterbody.
  16. 16. Copyright © 2017 TIG Environmental16 Requirements for Controlling Unintended Discharges • Detection of unintended discharges, including those of unknown or unpredicted substances • Rapid detection of changes in water quality to identify spills and treatment system failures as they occur • Rapid reaction to immediately divert untreated flow away from the outfall and sound an alarm. • Simple operation and maintenance. • Flexibility to be applied at multiple locations, yet adaptable for site-specific needs.
  17. 17. Copyright © 2017 TIG Environmental17 SWERM®: Stormwater Emergency Risk Management • Developed to manage and control spills, and thus prevent potential acute impacts to the waterbody • Continuously monitors and records a number of basic parameters (e.g. pH, turbidity) in a pipeline. • Automatically closes valve upon detection of significant change in water quality.
  18. 18. Copyright © 2017 TIG Environmental18 Features/Functions of the SWERM® • Capable of diverting flow immediately upon detection of changes in water quality. • Measurement range can be adjusted by the operator to account for the site history. • Continuously monitors the drainage system and can detect an abnormal condition in real time • Activates an alarm and closes the pipeline to prevent unintended discharges from reaching the waterbody. • Flow is diverted to a holding tank, rather than to the outfall, to collect the potentially contaminated water and allow time for system operators to respond.
  19. 19. Copyright © 2017 TIG Environmental19 Modeling the Potential Impact on Sediment Quality • Accurate estimation of the potential impact of discharges from a facility on sediment quality is important in assessing treatment priorities and cost-benefit analyses. – Particularly pertinent for facilities located on a waterway Superfund site, where costs and potential liability may increase significantly.
  20. 20. Copyright © 2017 TIG Environmental20 Modeling Process Components • Modeling mass COC loading via stormwater discharge – Identifying the concentrations of COCs present in stormwater at a site or discharge location. – Calculate volumetric flow from the precipitation rate and connected drainage area. – Annual estimates of loading can then be estimated via the Simple Method, which defines annual loading as the product of annual flow volume and COC concentrations in stormwater.
  21. 21. Copyright © 2017 TIG Environmental21 Modeling Process Components • Modeling fate and transport of particulate-associated COCs once they enter the waterway to estimate where they will settle – As COCs enter a waterway their fate is primarily determined by the hydrodynamics and sediment transport characteristics of the receiving waterbody. – Requires development of coupled hydrodynamic and sediment transport models of the waterway – Provides detailed quantitative annual COC loading estimate across the waterway sediment bed.
  22. 22. Copyright © 2017 TIG Environmental22 Modeling Process Components • Modeling COC concentrations in sediments due to deposition over time – Using the SEDCAM model, annual COC load to sediments calculation can be used to estimate the long-term sediment concentration of COCs due to stormwater loading from a specific source – The SEDCAM model is a one-dimensional mixing model that evaluates source loading, sediment deposition, chemical-specific degradation rate, and mixing
  23. 23. Copyright © 2017 TIG Environmental23 What is SEDCAM? • Sediment attenuation model that follows a mass balance approach to evaluate source loading, sediment deposition, and chemical- specific degradation rates developed by Jacobs, Barrick, and Ginn in 1988 (Jacobs et al. 1988) • Three main processes included in model important in predicting future sediment concentrations: burial, mixing, and loss by diffusion and/or degradation (Jacobs et al. 1988). • Assumes sediment mixing layer (user defined).
  24. 24. Copyright © 2017 TIG Environmental24 Model Predicted Sediment COC Contribution from Stormwater • SEDCAM model was developed for the Washington Department of Ecology to estimate natural recovery of contaminated sediment • SEDCAM model has also been used at other sites as a screening step for contaminants • SEDCAM model is relatively conservative and simple model which is one of its main strengths • Can be used in conjunction as a “stacked model” with results from hydrodynamic model used to define sediment depositional areas
  25. 25. Copyright © 2017 TIG Environmental25 Model Predicted Sediment COC Contribution from Stormwater
  26. 26. Copyright © 2017 TIG Environmental26 Result of Modeling Process • Three modeling steps applied in combination to provide a detailed estimate of potential stormwater impacts on sediment quality: – Simple Method to estimate stormwater loading – Coupled hydrodynamic and sediment transportation model to estimate bed depositional loading – SEDCAM to estimate sediment bed COC concentrations over time
  27. 27. Copyright © 2017 TIG Environmental27 Conclusions • Revisiting the key steps: – Implementation of BMPs to reduce stormwater contamination from typical facility activities – BMP application record and maintenance log – Implementation of an integrated management treatment plan that: • Treats and recycles pressure washing water • Separates stormwater for efficient treatment • Provides the possibility to reuse treated stormwater onsite – Implementation of SWERM® devices to monitor outfall water quality and to automatically divert abnormal flows in real time to prevent unintended discharges. – Modeling of stormwater impacts to sediments to assist in stormwater management planning and design.
  28. 28. Copyright © 2017 TIG Environmental28 Thank You Questions?