up-front orders of magnitude reduction and accelerated bio-destruction using a dispersive injectable reagent Webinar: “Case studies and first EU projects” broadcast live on 3 November 2015 To watch the webinar recording visit regenesis.com/gb/webinars/
115
Embed
up-front orders of magnitude reduction and accelerated bio ... · up-front orders of magnitude reduction and accelerated bio-destruction using a dispersive injectable reagent Webinar:
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
up-front orders of magnitude reduction and accelerated bio-destruction using a dispersive injectable reagent
Webinar: “Case studies and first EU projects”broadcast live on 3 November 2015
To watch the webinar recording visit regenesis.com/gb/webinars/
Principal technology features • Rapid reduc5on of groundwater concentra5ons • Mul%ple order of magnitude concentra%on reduc%ons in days / weeks
• Accelera5on of contaminant biodegrada5on • Elimina%on of low-‐concentra%on performance tailing • Ability to secure stringent clean-‐up targets
• Wide subsurface dispersion • Efficient fieldwork • Ability to address areas of restricted access, deep plumes etc.
• Long-‐term efficacy • The reagent is not consumed – it regenerates in situ
• A highly dispersive, injectable sorbent and microbial growth matrix
• Sorbent • Rapid drop in dissolved-‐phase contaminant concentra%on • Immediate risk-‐reduc%on
• Microbial growth matrix • Accelerated bio-‐destruc%on of sorbed mass • Ability to secure clean-‐up to much lower targets
What it is
• A highly dispersive, injectable sorbent and microbial growth matrix
• Sorbent • Rapid drop in dissolved-‐phase contaminant concentra%on • Immediate risk-‐reduc%on
• Microbial growth matrix • Accelerated bio-‐destruc%on of sorbed mass • Ability to secure clean-‐up to much lower targets
What it is
How does this work?
Bio Basics: Availability and Threshold Concentrations
• Bacteria live on surfaces – biofilms • Think ‘sink plug-hole slime’ or ‘dental plaque’ rather than ‘tadpoles’
• They have to wait for their growth substrate (food) to come to them – they do not hunt• They must therefore either sit on / in the food source (rotting vegetables)
• Or wait for it to dissolve and come to them in solution (groundwater bioremediation)
• As the plume is progressively cleaned up, the contaminant concentration drops• The rate that substrate comes to the bacteria reduces
• The rate that bacteria can therefore degrade it reduces – first order kinetics / half-life degradation
• Furthermore, below a certain concentration, the rate can slow dramatically• Threshold concentrations (Smin) for microbial growth – sufficient energy for activity – ‘starvation’ boundary
• The threshold is variable but typically in the low µg/L range – therefore not relevant for every site
• This step change slow-down is in addition to first-order diminishing returns
6,000 µg/L removed in first week
3,000 µg/L removed in second week
1,500 µg/L removed in third week
750 µg/L removed in fourth week 12.5% of initial weekly mass removal
6,000 µg/L removed in first week
3,000 µg/L removed in second week
1,500 µg/L removed in third week
750 µg/L removed in fourth week 12.5% of initial weekly mass removal
What if this (linear) rate could continue at this lower concentration….?
So this is the general idea – although the top end is accelerated too
• Colloidal ac%vated carbon (1 – 2 µm) • Size of a bacterium – suspends as ‘liquid’ • Huge surface area – extremely fast sorp%on
• Proprietary an%-‐clumping / distribu%on suppor%ng surface treatment (patent applied for) • Core innova%on • Enables wide-‐area, low-‐pressure distribu%on through the soil matrix without clogging
• Low-‐solubility / controlled availability matrix nutrients • Support in-‐matrix contaminant biodegrada%on • Does not impact groundwater / eutrophica%on
– Treatment 1: with PlumeStop (live)– Treatment 2: with PlumeStop (sterile)– Treatment 3: no PlumeStop (sterile)– Treatment 4: no PlumeStop (live)
• Sampled destructively in triplicate– Days 1, 7, 14, 21, 28
• Water concentration monitored by head-space analysis• Total benzene mass monitored by whole-system extraction
PlumeStop™: post-sorption biodegradation
Rapid sorption in both PlumeStop treatments <1 day Ongoing drop in live PlumeStop and live soil control ∴ likely to be bio But could it be a sorption artifact?
PlumeStop™: post-sorption biodegradation
Total system extract – soil and water No net loss in either sterile system, with or without PlumeStop Both non-sterile systems show benzene reduction Degradation significantly faster in the PlumeStop system
Howard et al (1991) “Handbook of Environmental Degrada:on Rates.” Lewis Publishers Inc. ISBN 0-‐87371-‐358-‐3
What if this (linear) rate could continue at this lower concentration….?
So this is the general idea – although the top end is accelerated too
–performance –
chlorinated solvents – post-sorption degradation – lines of evidence
Background• Groundwater bioremediation progress
– Typically monitored in the dissolved phase
– Lines of evidence approach – multiple parameters
• PlumeStop™ - sorption precedes degradation– Contaminant and daughter products drop to below detection limits
– What verification lines of evidence for degradation remain open?
• Case study example – Geochemical and microbial diagnostic lines of evidence
California Site
• Pilot test – single well• Former dry cleaners• Modest µg/L PCE residue
PCE immediately ⬇︎ to ND (<5µg/L) Micro parameters increase post-app then decrease after ~two months
225%
541%676%
(init. ND)3,000 x
(no methanogenesis)
< MQL (5 µg/L; 0.5µg/L) through 7 consecu%ve sampling rounds – 451 days (15 months) and coun%ng…
Data Summary• >99% (two OOM) PCE concentration reduction within 14 days
– 550 µg/L to non-detect (<5 µg/L)
• Optimal dehalorespiration conditions established– Redox from +254 mV to -150 mV (±30 mV) ‘sweet spot’
– Competing electron acceptors depleted
• Post-inoculation microbial trends– Increase then decrease in dechlorination species and enzymes
– Consistent with solvent metabolism and depletion
Specifics• DHC enzyme activity – provides strong indicator of degradation
– Increase in tceA reductase and vinyl chloride reductase post-application
– TCE and VC remain below detection limits in groundwater (<5µg/L)
• Dechlorination species proliferate post-application– Dehalococcoides spp., Dehalobacter spp., Dehalogenimonas spp. ⬆︎⬆– Reasonable to assume they are growing on H2(aq) and solvent
• Geochemical status favourable for dehalorespiration– but not favourable for competing methanogenesis
– therefore optimal for bioremediation performance and efficiency
Conclusions
• PlumeStop™ - depletion of GW solvents to n/d within 19 days
• Lines of evidence for post-sorption degradation secured
• All data obtainable from groundwater samples alone
• Former Filling Sta%on • BTEX residues • Pilot Applica%on • Tight forma5on • 2.75 – 4.5 mbgl
• Clay with Sand (ca. 3.53x10-‐7 cm/sec)
• Seepage Velocity Zero • ORC-‐Advanced®, PlumeStop™
<0.5 µg/L >98.3% reduc%on
Case Study- Inner-City Development / Time Pressure -
Downtown Chicago
• Neighborhood of McCormick Place – Central Chicago – New Sports Stadium – New Hotel Complex
• Solvent residues • Tight 5me window • High cost implica5ons of delay • Key remedia5on requirement: FAST
Case Study: Inner City Development – Time Pressure
Case Study: Inner City Development – Time Pressure
• Why the 5ght 5me window? – Weren’t the solvent residues known?
• Access restric5ons – historic buildings – Precluded early start
• Problem was moved aside
Case Study: Inner City Development – Time Pressure • PCE and TCE residues – up to 7,440 µg/L • Sand forma%on over clay
– Treatment area 300 m x 500 m – (1,000’ x 1,600’) – Treatment Zone 3 – 7 mbgl -‐ (10’ – 22’)
• Enhanced bio: HRC®, BDI® – Sufficient to address the contamina%on
• PlumeStop™ – Rapid risk reduc%on and bio process accelera%on – Take the bio process out of the groundwater phase
• 19 days’ fieldwork on site (Chicago winter) – 138 direct-‐push injec%ons – no resident equipment
96.9% reduc%on Total VOC
96.5% reduc%on Total VOC 92.3% ∑ VOC MCL 567 µg/L
TCE MCL 242 µg/L (site works / access restric%ons – no groundwater data)
96.9% reduc%on Total VOC
96.5% reduc%on Total VOC
Compositional changes consistent with biodegradation
92.3% ∑ VOC MCL 567 µg/L
TCE MCL 242 µg/L (site works / access restric%ons – no groundwater data)
83% reduc%on Total VOC
84% reduc%on Total VOC
Compositional changes consistent with biodegradation
79%
TCE MCL 242 µg/L
∑ VOC MCL 567 µg/L
(site works / access restric%ons – no groundwater data)
Chicago Site -‐ Status • Rapid reduc%on in groundwater contamina%on
– 80 – 97% from first sampling interval (total solvents)
• Bio condi%ons established (redox, TOC, microbial numbers) – Parent/daughter compound ra%o shivs (dissolved phase) – (consistent with biodegrada%on)
• ∑VOC targets met – from first sampling round (through all rounds) • TCE targets met – from second sampling round (and degrading fast) • Comple%on report submiwed (June 2015) • No further ac%on required
“Effective foc” – activated carbon sorption >> organic carbon sorption Plots show factor of 50 – 100 x The factor estimated for TCE is significantly higher
-‐ preliminary data -‐ PCE: 100% capture in all samples (2,800 µg/L)
Bologna Centrale: Status
• Field Pilot – real-‐world prac%cality – Method of applica%on ☑︎ – Placement valida%on ☑︎
• First field sampling data imminent – (not quite in %me for webinar)
• Full scale applica5on approved – Scheduled for January 2016
Europe Status
Europe Status
• Eight further projects scheduled in next 4 – 5 months – United Kingdom – Belgium – Italy
• 30 further projects in design phase • Wide interest everywhere
– Ireland to Poland – Scandinavia to Mediterranean
• Wide regulatory acceptance
- usage indicators -
1. When time is critical
2. To secure stringent clean-up targets
3. For passive control of migrating contamination
4. As a long–term means of addressing matrix back-diffusion
PlumeStop™ – product usage indicators
PlumeStop™ – product usage indicators
1. When time is critical
The fastest groundwater remediation technology available today?
• Immediate risk reduction secured through sorption(especially fast due to high relative surface area and wide dispersion)
• Long-term destruction secured through in-matrix biodegradation(accelerated degradation achieving bio-regeneration of sorption sites)
PlumeStop™ – product usage indicators
2. For securing stringent clean-up targets
• Low µg/L targets are challenging for all technologies
• Bio typically performs comparatively well, but at very low concentrations, substrate availability becomes insufficient to support microbial activity
• PlumeStop accumulates low-level contaminants into the bio-matrix until concentrations become sufficient within the matrix to support an active microflora while keeping contaminants out of the groundwater
PlumeStop™ – product usage indicators
3. Passive control of migrating diffuse contamination
Used in barrier formation to capture diffuse contaminants
• Concentration of contaminants in matrix for locally intensive treatment
• Tighter capture zone than bio-barriers alone(especially valuable where space is limited and/or groundwater is fast-flowing)
• Faster destruction rates and greater timing tolerance between (bio) amendment applications – if still needed
PlumeStop™ – product usage indicators
4. A long–term means of addressing matrix back-diffusion (i.e. diffusion-driven rebound)
• PlumeStop maintains a concentration gradient out of the immobile porosity
• Mobile porosity contaminant conc. remains low due to capture by PlumeStop
• Sorption sites regenerate due to accelerated in-matrix biodegradation
• The product is not consumed and remains functional – theoretically for decades
Contaminant diffuses out of
immobile porosity
Biodegrada%on accelerated within the matrix
Mobile-‐porosity concentra%ons
decline / remain low
Sorp%on sites are regenerated
GW contaminants par%%on into the
PlumeStop
Back-‐diffusion gradient
created / sustained
Bacteria and substrate are concentrated
together
- close -
PlumeStop – positioning within Regenesis product range
• Used to further increase bioremediation performance