From Bench Trial to Remediation to Results Barry Rakewich, P.Ag., - PowerPoint PPT Presentation

On-Site Treatment of a Dissolved Chromium Plume: From Bench Trial to Remediation to Results Barry Rakewich, P.Ag., EP Kyle Jackson, C.E.T. Nichols Environmental (Canada) Ltd.

Outline  Site History  Phase II ESA  Bench Trial  Remediation Design  On-Site Treatment  ISCR  Results

Site History June to Dec September June and April 2011 2003 July 2009 2011 Phase I ESA Environmental Violations of Phase II ESA Sewer Use Review 29 MWs Completed Bylaw September July to Sep. February September 2012 2012 2012 2012 In Situ Pump and Phase II ESA Bench Trial Chemical Treat Reduction Installation 3 MWs September August 2013 October 2015 September 2012 2017 In Situ End of Pump Initiate Pump Chemical and Treatment Most Recent and Treatment Reduction GW Sampling

Site Layout

Phase II ESA  Completed numerous Phase II ESAs to gain delineation  June 2011 (M11-01 to M11-06)  July/August 2011 (M11-07 to M11-16)  Nov/Dec 2011 (M11-17 to M11-29)  Feb 2012 (M12-30 to M12-32)

Phase II ESA – June 2011

Phase II ESA – July/Aug 2011

Phase II ESA – Nov/Dec 2011

Phase II ESA – Feb 2012

Phase II ESA  Assessment Criteria  Alberta Tier 2 Soil and Groundwater Remediation Guidelines (February 2016)  Site zoned Medium Industrial (IM); also permits commercial land use  Commercial Land Use  Subsoils predominately silty-clay and were confirmed through sieve analyses  Fine-Grained Soils  Surface water retention pond (~1.1 km)  Exclude the protection freshwater aquatic life (FWAL) pathway

Phase II ESA

Phase II ESA  Pre-Treatment Chromium Concentrations Hexavalent Sample ID Sample Date Total Chromium Chromium Alberta Tier 2 Guideline (Commerical Land Use)* --- 0.05 M11-01 Jul-11 0.0638 0.059 M11-02 Aug-11 0.6620 0.149 M11-03 Aug-11 4.15 4.1 M11-05 Aug-11 308 300 M11-14 Nov-11 20.3 19.7 M11-22 Dec-11 70.1 63 BOLD = Applicable Guideline Criteria BOLD = Parameter Exceeds Recommended Guideline Criteria *Alberta Tier 2 Soil and Groundwater Remediation Guidelines (Table 2). February 2016. (All concentrations in mg/L = ppm, unless noted) --- = No value provided in guidelines

Phase II ESA

Bench Trial Ferrous Sulphate (FeSO 4 ) Sodium Metabisulphite (Na 2 S 2 O 5 ) Readily Available Readily Available Solubility - 29.51 g/100 mL (25 °C) Solubility - 67 g/100 mL (25 °C) pH adjustment not required Effectiveness highly pH dependent Presence of iron produces rapid Production of SO 2 by-product can be flocculation an irritant ½ cost of sodium metabisulphite per Highly corrosive when mixed with water

Bench Trial Ferrous Sulphate (FeSO 4 ) Sodium Metabisulphite (Na 2 S 2 O 5 ) 30 mg/L 25 mg/L 99% Reduction of Cr 6+ after 5 mins 53% Reduction of Cr 6+ after 5 mins Rapid flocculation/settling Marginal flocculation/settling

Remediation Design  Pump and Treatment  Focus on high concentration plume  Large diameter bored wells w/submersible pumps installed in ‘hot spots’  Treatment/settling tanks w/secondary containment  Filter pot  discharge to sanitary  In-Situ Chemical Reduction (ISCR)  Focus on low concentration plume and Site boundaries  Entire site surfaced with concrete  Established network of pre-cored injection points  High-pressure direct injections at GW interface

Pump and Treatment

Pump and Treatment

Pump and Treatment Installed 3 – 60 cm diameter recovery wells  Recovery wells consisted of galvanized CSP (resulted in dissolved zinc in GW)  Submersible pumps (3.5 HP) installed into each of the three wells, capable of 5  gpm.

Pump and Treatment On-site treatment plant consisting of two – 20,000 L ASTs  Secondary containment system  Sample ports and filter pot prior to discharge 

Pump and Treatment Groundwater Recovery – Volume in Litres 2012 (September to November) 17,800 2013 (March to November) 119,300 2014 (May to October) 85,000 2015 (May to October) 112,600 Total 334,700 Average Batch Volume = 7,500 L treated with 35 kg of FeSO 4 ~1550 kg of FeSO 4 utilized during treatment process

Pump and Treatment Operation and Maintenance Costs 2012 (installation) $75,000 2012 (operational) $15,000 2013 (operational) $30,000 2014 (operational) $33,000 2015 (operational) $31,000 Total Costs $184,000

Pump and Treatment

ISCR

ISCR Injection Summary – Volume in Litres 15% Ferrous Sulphate September 2012 1,000 August 2013 7,900 July 2015 12,000 Total 20,900

ISCR

Results  Post-Treatment Chromium Concentrations Total Hexavalent % Reduction Sample ID Sample Date Chromium Chromium Hexavalent Chromium Alberta Tier 2 Guideline (Commerical Land Use)* --- 0.05 Jul-11 0.0638 0.059 M11-01 100% Sep-17 0.0306 <0.01 Aug-11 0.6620 0.149 M11-02 100% Apr-17 0.0120 <0.01 Aug-11 4.15 4.1 M11-03 100% Sep-15 0.0055 <0.01 Aug-11 308 300 M11-05 99.99% Sep-17 0.193 0.01 Nov-11 20.3 19.7 M11-14 99.75% Sep-17 17.6 0.05 Dec-11 70.1 63 M11-22 99.83% Sep-17 0.105 0.11 BOLD = Applicable Guideline Criteria BOLD = Parameter Exceeds Recommended Guideline Criteria *Alberta Tier 2 Soil and Groundwater Remediation Guidelines (Table 2). February 2016. (All concentrations in mg/L = ppm, unless noted) --- = No value provided in guidelines

Results

Results

Results

Conclusions  Outcome - success in plume reduction  Learning – do not use galvanized CSP  Learning – Explore pathway elimination  Next Steps…  Confirmatory Soil and GW Sampling in 2018  Risk Management for residual plume  Decommissioning

Questions Barry Rakewich rakewich@nicholsenvironmental.com Kyle Jackson jackson@nicholsenvironmental.com