• Save
Flinders University - ATES and contaminated groundwater
Upcoming SlideShare
Loading in...5
×
 

Flinders University - ATES and contaminated groundwater

on

  • 1,013 views

November 25, 2010

November 25, 2010
Flinders University
Adelaide (Australia)

Statistics

Views

Total Views
1,013
Views on SlideShare
1,006
Embed Views
7

Actions

Likes
0
Downloads
0
Comments
0

2 Embeds 7

http://www.linkedin.com 6
https://www.linkedin.com 1

Accessibility

Categories

Upload Details

Uploaded via as Microsoft PowerPoint

Usage Rights

© All Rights Reserved

Report content

Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
  • Full Name Full Name Comment goes here.
    Are you sure you want to
    Your message goes here
    Processing…
Post Comment
Edit your comment

Flinders University - ATES and contaminated groundwater Flinders University - ATES and contaminated groundwater Presentation Transcript

  • EFFECTS OF AQUIFER THERMAL ENERGY STORAGE (ATES) ON MOBILE CONTAMINANTS IN A GROUNDWATER SYSTEM: A MODEL APPROACH Koen Zuurbier (KWR, VU, Deltares), Niels Hartog (Deltares), Johan Valstar (Deltares), Boris van Breukelen (VU), Vincent Post (VU) 26.11.2010, Flinders, Australia
  • 2. Background: ATES and mobile contaminants
    • Aquifer Thermal Energy Storage (ATES):
    • Both heat & cold
    • Use of seasonality
    • Supply by/for buildings
    • Relatively shallow aquifers
    15 - 20 o C 6 - 8 o C
  • 2. Background: ATES and mobile contaminants
    • Aquifer Thermal Energy Storage (ATES):
    • Both heat & cold
    • Use of seasonality
    • Supply by/for buildings
    • Relatively shallow aquifers
  • 2. Background: ATES and mobile contaminants IF Technology Doublet Summer Winter
  • 2. Background: ATES and mobile contaminants ATES ≠ Geothermal Energy! Heat & cold demand Heat demand Building = supply+user Building = user
  • 2. Background: ATES and mobile contaminants BTES (Borehole Thermal Energy Storage): Closed loop systems Horizontal Vertical
  • 2. Background: ATES and mobile contaminants
    • Mobile contaminants:
    • Mainly Chlorinated Hydrocarbons (VOC)
    • Chemical laundries +
    • metal industries
    • Dense Non-Aqueous
    • Phase Liquids (DNAPLs)
    ρ DNAPL > ρ water
    • ATES = sustainable energy
    •  application desired in Greenfields and contaminated Brownfields
    2. Background: ATES and mobile contaminants Risks? Conflict Potential benefits? (source: Sanergy.nl)
  • 2. Background: ATES and mobile contaminants
    • Research Program:
    • ‘ More with Subsurface Energy’
    • Consortium Research Institutes + consultants
    • Field measurements
    • modelling Study (Deltares)
    • Result: guidelines for new policies
  • 2. Background: ATES and mobile contaminants Aim of my study: What effect does ATES have on existing potential contaminant plumes? (focus on PCE, source contaminant)
    • Plume blending in wells + reinjection (larger volume, lower C)
    • Temperature changes (density, visc., degradation?)
    • Increased dissolution of DNAPL (more water obtaining C = max solubility of VOC)
  • 2. Background: ATES and mobile contaminants Aim of my study: What effect does ATES have on existing potential contaminant plumes?
    • Plume blending in wells (larger volume, lower C)
    • Temperature changes (density, visc., degradation ?)
    • Increased dissolution of DNAPL (more water passing, obtaining C = max solubility of VOC)
  • 2. Background: ATES and mobile contaminants
    • Chlorinated hydrocarbons:
    • Degradation follows common sequence
    • Removal of Cl
    Reductive dechlorination VOCl (Wiedemeier, 1999) Source Products following degradation
  • 2. Background: ATES and mobile contaminants
    • Dutch Environmental Protection Act:
    • Target concentrations (S-values): almost background level
    • Intervention concentrations: >100 m 3 requires remediation
  • 2. Background: ATES and mobile contaminants
    • 0 th order:
    •  Constant hydrolyses org. matter = constant degradation rate
    How to describe degradation: C i = concentration component i (kg m -3 ) t = time (s) λ 0 = degradation constant 0 e order (kg m -3 s -1 )
    • 1 st order:
    •  Concentration contaminant
    C i = concentration component i (kg m -3 ) t = time (s) λ 0 = degradation constant 1 e order (s -1 ) C 0 = initial concentration component i (kg m -3 ) Degradation constants ( λ 0 , λ 1 ) vary with redox-conditions and component: Limited degradation of DCE and especially vinylchloride in anoxic environments Larger aquifer volume contaminated = more mass removal!!
  • 2. Background: ATES and mobile contaminants How to describe degradation: Monod kinetics: combination of 0 th and 1 st -order Not modelled (yet) At high C At low C
  • 3. Methods: modelling tools No integral modelling code available Flow: MODFLOW Transport: MT3DMS Density/Viscosity + SEAWAT (V4) Reactions: PHT3D (V2) (PHREEQC) Plume blending: Multi-Node-Well Package (MODFLOW) (total discharge  discharge per model layer) (mixing concentrations in well) Compilation
  • 4. Case study ‘Uithof’
    • Desire for realistic configurations: ATES ‘Uithof’
    • Discharge data
    • Geohydrology (layers + heads)
    • No contamination…
     added (in model only)
  • 4. Case study ‘Uithof’ You are here Temp injection = 8 o C / 16 o C Temp background = 10,5 o C Imbalance: net 1.2 % to K1
  • 4. Case study ‘Uithof’ You are here Temp injection = 8 o C / 16 o C Temp background = 10,5 o C Imbalance: net 1.2 % to K1 N.B.: Start installation in last week of November (week 1)
  • 4. Case study ‘Uithof’ 2.8 m 50 m 56 m 41 m Vertical Cross-section 39 m 1760 m 135 m Holocene cover Aquif. 1A Sandy clay Aquif. 1B Aquitard Aquif. 2 DNAPL Holocene cover Aquif. 1A Sandy clay Aquif. 1B Aquitard Aquif. 2
  • 4. Case study ‘Uithof’ Scenario’s Here: degradation using 0 th –order (1.1*10 -9 mol L -1 d -1 ) ? x x x All factors present S-4 Increasing mass in aquifer, large volume contaminated x x Degradation absent S-3 Initial increase in volume, followed by decrease (increased degr.+blending) x x DNAPL absent S-2 Contaminated plume in +/- original size x Reference: No DNAPL, no ATES S-1 Predicted effect DNAPL ATES Degr. Characteristics Scenario
  • 5. Results
    • 630 l PCE at base of aquifer 1
    • Plume developement by lateral background flow
    • Dispersion ( λ = 1m) causing mixing + broadening of plume
    Future ATES warm bubble t = 40 yr: Initial plume Conc. requiring remediation (I)
  • 5. Results
    • 630 l PCE at base of aquifer 1
    • Plume developement by lateral background flow
    • Dispersion ( λ = 1m) causing mixing + broadening of plume
    Future ATES warm bubble PCE, base of aquifer 1 t = 40 yr: Initial plume Conc. requiring remediation (I)
  • 5. Results
    • Scenario 1 (no DNAPL, no ATES):
    • small decrease contaminated volume
    • small decrease mass in aquifer
    • Scenario 2 (no DNAPL, but addition of ATES)
    • initial increase contaminated volume, drop in concentrations
    • after 19 yr: small volume of contaminated groundwater left
    • quick removal of mass PCE
  • 5. Results
    • Scenario 1 & 2:
    Mainly remaining in aquitard
  • 5. Results
  • 5. Results
    • Scenario 3 (DNAPL+ATES)
    • Major spreading of PCE
    • in aquifer 1
    S I
  • t = 19 jaar
  • 5. Results
    • Scenario 3:
    • >50% of DNAPL
    • in solution in 19 yr
  • 5. Results
  • 5. Results
    • Scenario 4 (ATES, DNAPL and Degradation)
    • Limited volume
    • contaminated
    • Degradation after
    • reinjection
    S I
  • 5. Results
    • Scenario 4:
    • > again >50% of DNAPL
    • in solution in 19 yr, but
    • a smaller contaminated
    • volume
  • 5. Results
    • Scenario 4:
    • Eventually buffering
    • of mass PCE due
    • to degradation in
    • a large aquifer
    • volume
    • Dependency λ
  • 6. Discussion
    • Important factors:
    • DNAPL (yes/no, where?)
    • Local hydro(geo)logical system (blending)
    • How to descbribe degradation, what rates, temp. effects?
  • 6. Discussion
    • Important factors:
    • DNAPL (yes/no, where?)
    • Local hydro(geo)logical system (blending)
    • How to descbribe degradation, what rates, temp. effects?
  • 6. Discussion
    • Degradation 1 st order: hard to get concentration below desired S-value:
  • 6. Discussion
    • Model optimalisation?
    • computer time
    • monod kinetics
    • temp. dependent degradation
    • mixing of redox-zones?  effects on degradation
  • 7. Conclusions
    • Important new insights on effects of ATES!
    • Positive effects ATES dissolved plume + 0 th order (expected)
    • Negative effects ATES when DNAPL near well (unexpected/not considered)
    • Blending of plume depends on local conditions (3-D modelling required)
    • Work ≠ finished (especially considering to degradation)