Diamond Grinding Use in NC

Ken Pace, P.E.

October 29, 2014

Overview

• Regulations and Permits

• Hydrodemolition and Diamond Grinding

• Evolution

• Current Process for Disposal

• Lessons Learned

• Expectations

2

Rules Governing Handling and Disposal

• Hazardous Waste (12.5 pH)

• Industrial Waste as defined in Statutes:

“any liquid, solid, gaseous, or other waste substance or

a combination thereof resulting from any process of

industry, manufacture, trade

or business, or from the

development of any natural

resource.”

3

NCDOT Concrete Management

Slurry Disposal

• Bridge Hydrodemolition Projects

• Durham Freeway Pavement Rehabilitation

• Western Wake Freeway

• Other Notable Projects:

• I-485 / I-85 Project

• Goldsboro Bypass

• Fortify Project

4

Hydrodemolition

5

• Large Number of Projects

• No Release into Environment

• Older Material

• Cannot Recycle Water

• Smaller Particle Size

5

Concrete Grinding

6

• Increasing Number of Projects

• Large Volumes of Material

• New Concrete

• Can Recycle Water

• Larger Particle Size

6

Disposal Options for Hydrodemolition Slurry

7

1. Waste Water Treatment Plant or Other Permitted Facility

2. July 2011 Statewide Permit – Issued “Bridge Hydrodemolition Conjunctive Reclaimed Water Utilization”

Stringent Performance Standards

– Separate Liquids/Solids

– Solids(Residuals) Disposal

– Land Application with Effluent Limitations

– Setbacks from Wells and Surface Waters

– Extensive Sampling, Monitoring and Reporting Requirements

– Annual Reporting for Waste Water (Sampling Results, Volumes, Land Application Areas, )

– Record Keeping for Residuals (Haulers, Date Material Hauled, Estimated Volumes, Disposal Locations)

Disposal Options for Hydrodemolition Slurry

8

• Sampling Requirements Corrosivity, Ignitability, Reactivity and

Toxicity Characteristic Leaching Procedure (TCLP)

Initial Disposal Options for Diamond

Grinding Slurry

9

1. Waste Water Treatment Plant or Other Permitted

Facility

2. Dewater and Haul Solids

to Landfill

3. July 2012 “Western

Wake Freeway Project

Land Application of

Diamond Grinding Slurry”

10

Project Specific Performance Standards

– Land Application of Slurry at Agronomic Rates (Dewatering Not Required)

– Operation and Maintenance Plan

– Mark Land Application Areas on Project or Off-Site

– Could not apply on slopes and ditches

– Setbacks from Wells, Surface Waters, Ditches, Bedrock Outcrops (15 ft.)

– Sampling, Monitoring and Reporting Requirements TCLP for Initial Application

– Ceiling Concentrations and Monthly Average Concentrations for Heavy Metals (Arsenic, Cadmium, Copper, Lead, Mercury, Molybdenum, Nickel, Selenium, Zinc)

– Annual Reporting for Waste Water (Sampling Results, Volumes, Land Application Areas)

2012 “Western Wake Freeway Project Land

Application of Diamond Grinding Slurry” Permit

Current Concrete Slurry Permit

11

• 2013 Land Application Permit for Hydrodemoliton and Diamond Grinding Slurry

• June 2014 Permit Modification

• Performance Standards Less Restrictive

– Slurry Can Be Applied on Land with Less Than 50% Groundcover without Incorporation or Injection within 24 Hours

– TCLP Analysis Requirement Removed

– Bi-monthly Sampling Removed and Monitoring Parameters Reduced (Calcium Carbonate Equivalence (CCE), Percent Solids, pH Each Truckload or Storage Unit/Tank, Soil Sampling)

Disposal Options for Slurry

Current Land Application Permit − (Agronomic Rates, Waste Disposal Plan, Maintenance Plan, Landowner

Agreements, Operations Checklist, Inspection Logs, etc.)

Alternative Daily Cover in Municipal Landfill − (Solid Waste-Paint Filter Test, Non-Hazardous, DWM Approval, Meet

RCRA Regulatory Limits for Metals)

Beneficial Fill − (Inert Debris, Paint Filter Test, Non-Hazardous, Meet RCRA Regulatory

Limits for Metals, No Ground Water Impacts)

− Location OK for Long Term Disposal?

12

Lessons Learned

Communication Is Important

Provide Updates to Regulatory Agencies

Not Waste Disposal but Beneficial Product

13

When Bidding and Performing Work

Read Contract Specifications

Have A Waste Disposal Plan

Include Disposal Costs into Bid

Communicate Expectations to

Subcontractors

14

When Bidding and Performing Work

Adhere to Permits Conditions,

Regulations, Project Specifications

15

When Bidding and Performing Work

No Release to Environment

16