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Managing Construction Site Water2015

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Outline

• WT Introduction

• Evaluating Construction Projects• Discharge Locations• Permitting• Design Factors• BMPs (Passive vs. Active)

• Quick Project Checklist

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We Treat Water

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Company Overview

• Permanent and Temporary Water Treatment Systems

• Hundreds of Treatment Projects Completed Since 1999– Permitting, Design, R&D– Manufacture, Integrate, Install– Turnkey Operations & Maintenance – Training Courses, Remote Monitoring & Assistance

• Based in Everett, WA 

• 60+ employees

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Team of Experts

Research & Development

Design

Manufacturing Field Operations

Engineering

Project Management

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Pre‐Construction Services

Confidential & Proprietary

COST ANALYSISPrepare project cost 

estimates and alternate analyses..

PERMITTING/PLAN PREPDetermine permitting needs, apply for permits, negotiate with AHJ, prepare SWPPPs, 

Technical Water Management Plans (EPA)

TREATABILITY STUDIESIn‐house testing & analysisLab & field‐scale programs

QAPP plans

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Construction Services

TRAINING COURSESDOE‐certified courses in 

various treatment technologies, both field and classroom training 

modules

EQUIPMENT SUPPLIER & FIELD SERVICE

Provide equipment to meet discharge requirements,  

Mobilization/DemobilizationMaintenance support, both remote and on‐site 

as needed.  

MONITORING

CESCL inspections and associated DMR reporting & 

compliance, water quality monitoring and 

analytical sample collection

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Construction Technologies

Conidential & Proprietary

PHATBOXAutomated pH Adjustment

Mobile: 50‐350gpmFixed: Up to 5,000gpm

WAVEIONICSElectrocoagulation

Mobile: 50‐1,000gpmFixed: Up to 5,000gpm

ROADSIDE ACISTChemical Treatment SystemMobile: 300‐1,000gpmFixed: Up to 5,000gpm

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Evaluating a Construction Project

• Things to Consider: Discharge Location

• Regulations• Permits• Discharge Limits

Site Characteristics• Soil Type• Rainfall Patterns• Schedule

BMPs• Planning• SWPPP

Budget

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Discharge Location

Drives ALL Permitting & Treatment

Surface Water

Dept. of Ecology City/County

Settleable Solids, pHAuthorization, Minor, Major

SS/CSO

KCIW/Local Sewer District City/County

Turbidity, pHAdministrative Order

Detention, pH Adjustment, Mechanical Filtration, Active Treatment, GAC 

Detention, pH Adjustment, Mechanical Filtration, GAC

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Discharge to Surface Water

NPDES (aka Construction Stormwater General Permit or CSWGP)• Applicability

• Construction Sites disturbing ≥ 1 acre and will discharge stormwater offsite

• Sites under an acre that are part of a common plan (residential)• Other sites that may discharge to sensitive areas or have contamination

• Requirements• Must comply with permit limits for Turbidity (<25) and pH (6.5‐8.5)• Must have a site‐specific Stormwater Pollution Prevention Plan (SWPPP)• Must have a CESCL perform site inspection weekly and take water quality readings

• Additional sampling/treatment required if site has contaminantsPROPOSED UPDATES for JAN 1st:• More information required for Contaminated sites• Contaminated sites will use AKART – Active Treatment• Drilled shaft water (no drilling fluids) can be infiltrated• SWPPP Elements (preserving topsoil/LID)

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Discharge to Sanitary Sewer/CSO

King County Industrial Waste Discharge Authorization and/or Local Approval• Applicability

• Sites discharging to a Combined Sewer• Construction Sites disturbing < 1 acre and will discharge stormwater offsite• Alternate discharge for sites that may discharge to sensitive areas or have contamination

• Requirements• Must comply with permit limits for Maximum Daily Volume, Settleable Solids(<7mg/L) and pH (5.5‐12)

• Must take Field Measurements (min Flow/Volume, Settleable Solids, pH) every day that discharge occurs

• Additional sampling/treatment required if site has contaminants• Must submit monthly reports and pay per gallon fee.

Current review time for KCIW permit is at least 4 weeks, double if complex or contaminated site.

City of Seattle may hold grading permit until SSPTD is obtained.

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Local Authority

• Local Jurisdictions (City/County)– May require specific plans for work during the wet season 

• Review SWPPP, site plans, geotech, may have formal application pkg

– May have more stringent discharge requirements than the State– Allow time for review and approval (4 weeks min)– Administrative fees associated with some approvals

City of Redmond – Wet Weather Plan City of Bellevue – Turbidity Monitoring PlanCity of Seattle – Drainage Side Sewer Permit $, Dry Season Grading ExtensionCity of Tacoma – Special Authorization to Discharge (SAD) $King County – Wet Season PlanSnohomish – Enhanced TESC Review

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• Surface Water– Turbidity 

• 25 ntu benchmark• 250 enforcement level

– pH • 6.5 – 8.5

– Other as receiving water or past site activity dictates

• Sanitary Sewer/CSO– Settleable Solids

• <7 mg/L

– pH• 5.0 – 11.0

– Other as receiving water or past site activity dictates

Discharge Limits

2000 1000 500 100 5

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Site Characteristics

• Identify Site Characteristics1. Rainfall – how much runoff should we 

plan on?2. Soil Type (i.e. Particle Size!) 3. Schedule – what time of year will the 

work take place?4. Contamination Onsite

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Rainfall

• 1” rain on 1 acre of impervious surface = 27,000 gallons• Site Size = 2 acres• 1” Storm = Detention Required = 3 tanks (18,000 gallons each)• 2.5” Storm = Detention Required = 8 tanks (135,000 gallons)

Confidential & Proprietary

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Soil Type

10000 Gravel 0.016 sec2000 0.4 sec1000 1.7 sec600 Coarse Sand 4.6 sec300 Silt Fence, Ponds 19.0 sec200 Bioswales 42.0 sec150 1.25 min100 Fine Sand 2.8 min60 Passive filtration 7.8 min25 Pressurized SF 2.2 hrs15 Bag Filters 6.2 hrs10 Silt 14.0 hrs5 Active Treatment 56.0 hrs3 CESF/EC 155.3 hrs

1.5 26.0 days1 Clay 58.0 days

0.1 16 yrs0.01 Colloidal Particles 1600 yrs

Soil Type Time Required to

Settle 3ft

Particle Diameter (microns)

SS/CSO-Settleable Solids

Surface Water-Turbidity

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BMPs

• Source Control (i.e. Prevention)• Plastic Covering• Mulch• Hydroseeding• Nets & Blankets• Soil Roughening• Terracing• Construction Schedule• Check Dams / Straw Wattles• Outlet Protection• Stabilization Construction Entrances / Exits

GOAL = Cover Soils / Slow Velocity!Performance not dependent on particle size

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BMPs

• Runoff Control (i.e. Treatment)1. Detention Ponds / Vaults / Tanks2. Bioswales3. Silt Fencing4. Filter Bags5. Sand Filters6. Active Treatment

Confidential & Proprietary

GOAL = Remove soil particles from waterPerformance #1‐5 dependent on particle size

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Chitosan Enhanced Sand Filtration (CESF)

Electrocoagulation (EC)

Approval Level GULD GULD

Consumable Liquid Chitosan EC Cells

Labor On‐Site Labor When Operating

Automated Operator with Alerts

Contaminants Turbidity Only Turbidity, Metals, Emulsified Oils

Active pH Range 7 to 8 5 to 12

Active NTU Range 0 to 600 0 to 4,000+

Rental Cost (300 gpm) $195 to 225 / day $250 to 310 / day

Active Treatment BMPs

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SchedulePermitsActivitiesSeasonal

BMPsDischarge Limits

Civil PlansContingencies

BudgetMaterialsEquipment

Labor

SiteSoil Type

TopographyProximity to Sensitive Areas

Stormwater Pollution Prevention 

Plan

Construction SWPPP

Confidential & Proprietary

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Case Study: Surface Water 7.7 Acres – Direct Discharge to Lake Washington

“The Geotechnical Engineering Design Study for Southport Hotel prepared by Hart Crowser (April 18, 2014) lists site soils as a combination of sand, silt, and clays at various depths. The depth to, and thickness of, the soil layers vary greatly throughout the site.”

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Case Study 

• Initial Action• Site had 140,000 gallons of existing storage 

in a detention vault• Site runoff for 1” storm = 208,000 gallons• 208,000 – 140,000 = 68,000• Divide by 8 hr shift = 8,500 gallons• Divide by minutes = ~140gpm

Influent Turbidity(NTU)

Effluent Turbidity(NTU)

Effective Particle Size Removal

125 48 63 microns

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Case Study 

• Intermediate Action• Site could not meet turbidity benchmark• Added sand filter – still only reduced 

turbidity down to 40 NTU• Submitted sample for particle size 

distribution

Influent Turbidity(NTU)

Effluent Turbidity(NTU)

Effective Particle Size Removal

48 45 25 microns

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Case Study

• Final Action• Particle Size Distributions indicated           

very small particles• Implemented WaveIonics

electrocoagulation system

Influent Turbidity(NTU)

Effluent Turbidity(NTU)

Effective Particle Size Removal

175 5 0.01 microns

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10000 Gravel 0.016 sec2000 0.4 sec1000 1.7 sec600 Coarse Sand 4.6 sec300 Silt Fence, Ponds 19.0 sec200 Bioswales 42.0 sec150 1.25 min100 Fine Sand 2.8 min60 Passive filtration 7.8 min25 Pressurized SF 2.2 hrs15 Bag Filters 6.2 hrs10 Silt 14.0 hrs5 Active Treatment 56.0 hrs3 CESF/EC 155.3 hrs

1.5 26.0 days1 Clay 58.0 days

0.1 16 yrs0.01 Colloidal Particles 1600 yrs

Soil Type Time Required to

Settle 3ft

Particle Diameter (microns)

Project Planning Quick List• Know the Site

• Discharge Location / Limits• Site Characteristics 

• Rainfall• Schedule• Soil Type 

• Regulatory Requirements • Get Permits

• Identify BMPs to Treat Turbidity/SS & Contaminants if present

• Implement BMPs

• Work the Plan!• Monitor• Report• Maintain & Adapt

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6300 Merrill Creek ParkwaySuite C‐100Everett, WA 98203

For more information please contact:Liisa Doty,National Construction Accounts Managerliisa@watertectonics.comMobile (206) 371‐1693

www.watertectonics.com

Thank you!