napl site remediation (hmvt)
DESCRIPTION
TRANSCRIPT
In-Situ Remediaton
Removal of 1.500 m3 LNAPL
Jack van RossumRonny Hilhorst
Hannover Milieu- en Veiligheidstechniek
SPE ViennaFebruary 23th, 2011
Contents Presentation SPE
• Introduction HMVT• Case: LNAPL removal in the Port of Antwerp
– Site information– Soil & Pollution
• Shallow LNAPL– Tender– Remediation approach and system– Remediation Equipment– Water and air treatment– Results
• Deep LNAPL– Remediation approach– Results & costs
HMVT: Experts in-situ soil remediation
HMVT
• Experts in in-situ soil remediation, water and air treatment
• Excavation, extraction, biological and chemical techniques
• Since 1988
• 45 Employees
• Offices in the Netherlands and Belgium
• Member of Antea group
• Advise, Design, Pilot & Bench scale testing
• Contracting, Operation & Maintenance
• Risk based contracting
Brief description location
Site information
Oil and chemicals storage terminal in the port of Antwerp
• Storage tanks
• Pumping stations
• Contractors village and other buildings
• Underground and above ground pipelines
• Roads and railways
• Contamination caused by leakage at pumping station (naphta) and a storage tank (diesel)
Site LNAPL
Brief description soil
Site information: Soil
• Ground level has been raised up to 4 – 6 meters with sandy
material for port constructions
• Original clayey soil is still present (5 – 7 mbgl)
• Groundwater level 2,5 mbgl
• Groundwater level fluctuates ca 1 meter between summer and winter
• Debris of former village on clay layer
Brief description contamination
Contamination
Contamination: LNAPL of naptha & diesel
• Estimated LNAPL about 1.000 m³
• Area with LNAPL about 23.000 m²
• Thickness LNAPL > 1 meter
• Hugh contamination of soil and groundwater
• Shallow and deep LNAPL
Surface area LNAPL
Cross section LNAPL
Brief description tender
Tender
• Limited tendering started in 1999
• Two principals
• Open tender, consultants did not know a good remediation
approach (Design & Construct)
• Air and groundwater treatment must be able to treat also other
gas and water of the customer
• Existing buildings and equipment must remain in function
• High demands on safety (ATEX) and operation
• Design, negotiations and safety aspects took 1,5 year
Design Remediation System:
• Multi Phase Extraction:
• 950 MPE-filters, two levels (2,5 – 3,5 and 3,5 – 4,5 mbgl),
• Soil vapor and groundwater extraction:
• 25 combined filters for soil vapor- and groundwater extraction (6 mbgl),
• Deep groundwater extraction:
• 3 deepwells (15 mbgl),
• Airsparging:
• 43 injection filters (6 mbgl),
• about 35 km underground tubing!
Remediation system
Remediation system
Combined filter
MPE shallow
MPE deep Airspargi
ng
Original clay
Design Remediation Equipment:
• Multi Phase Extraction
• 4 MFE-units, capacity 200 Nm3/hr, knock out pot to separate extracted water, LNAPL and soil vapor,
•Groundwater extraction
•Shallow: 2 Piston pumps, total capacity 10 m3/hr,
• Deep: 3 Piston pumps, total capacity 7,5 m3/hr,
•Soil vapor extraction
•Blower, capacity 450 Nm3/hr with knock out pot,
•Airsparging
•1 Compressor, capacity 200 Nm3/hr
• All installations ATEX
Remediation Equipment
Remediaton Equipment
Water treatment
Water and product treatment system:
• Capacity 25 m³/hr,
• 2 Oil/water separators in sequence,
• 1 Product tank,
• 3 Stripping towers in sequence,
• 2 Rotating biological contactors,
• 1 Activated carbon vessel,
• Sediment pond,
• Discharge pump to public sewer system,
• Water treatment also used for other water.
Water treatment
Air treatment
Air treatment unit (6.500 m3/hr):
•Incinerator, capacity 100 kg product per hour,
•Flow variable between 3.000 en 6.500 m3/hr,
•Oxidation at a temperature of 720 degrees Celsius, gas-fired,
•Heat exchanger to reduce gas consumption,
•Treatment air from:
•MPE
•Soil vapor extraction
•2 Stripping towers
Air treatment
Results and costs
Results product removal
• Period 2001 – 2006:
• 700 tons gas phase (MPE and SVE) incinerator
• 310 tons liquid phase (oil; mainly MPE)
• 80% oil layer removed (surface)
• Period 2006 – 2008:
• 225 tons gas phase
• 95% oil layer removed (surface)
• In 2008 focus changed from LNAPL removal to stimulation of biological degradation (airsparging and SVE),
• Total costs from start till 2008 (LNAPL removal):
• € 29,-/m3 contaminated soil or
• € 3,-/liter removed product.
Deep LNAPL removal
Hier 2e dwarsdoorsnede van Marco invoegen
Remediation approach deep LNAPL
Tender and remediation approach
• Residual deep oil layer: 1.200 m2, 5 – 7 mbgl
• All obstacles will be removed new tanks
• HMVT made an overview and cost estimate for all possible remediation approaches
• Based on this overview the client decided to excavate the deep oil layer
• Based on the cost estimate the 2 responsible principals made a deal about the costs
• HMVT made a detailed design, including an alternative sheet pile
Results and costs
Results product removal
• Sheet pile: 190 m1 / till 10 mbgl
• Groundwater extraction:
• Deep and shallow, total 50 m3/hr
• Treatment in existing and extra water treatment
• Excavation:
• Excavation 15.100 m3 ground,
• 4.122 tons polluted ground treated
• The work was performed within the timetable
• Cost saving: € 130.000 for the client
Deep LNAPL removal