REMEDIATION AND REUSE OF CONTAMINATED SEDIMENTS: A NEW - - PowerPoint PPT Presentation

REMEDIATION AND REUSE OF CONTAMINATED SEDIMENTS: A NEW PHYSICAL-CHEMICAL PROCESS TO THE POINT

2nd International Workshop: Mechanism and Modelling of Waste/Cement Interactions Le Croisic, October 12-16, 2008 october 2008

• G. Ferrari, A. Careghini, S. Dastoli, L.Bonomo,

L.DePropris, M.Gabellini, S.Saponaro

VOLUME OF SEDIMENT TO BE REMEDIATED 6.000.000 m3

Remediation and Reuse of Contaminated Sediment: a new physical-chemical process to the point

VOLUME OF SEDIMENT TO BE DREDGED 13.000.000 m3

Analytical results of most contaminated sediment selected for this work (600.000 m3)

Compound Concentration (mg/kg d.w.) ISPRA intervention values

• D. Lgs.

152/06 column B Hazardous Substances limits Chromium (total) 91 150 800 1000 Copper 210 75 600 250 000 Nickel 22 63 500 10 000 Lead 51 80 1 000 5 000 Zinc 314 165 1 500 1 000 Arsenic 18 32 50 1 000 Cadmium 1 1 15 1 000 Mercury 200 1 5 500 PCB (total) 3 0,2 5 50 >C12 petroleum hydrocarbons 5 000

• 750

1 000 HCB 0,003 0,005 5 1 000 PAH (total) 5 4 100 1 000 PCDD/F 2,8· 10–4 0,3 · 10–4 1 · 10–4 1 · 10–2 TBT 0,003 0.07

• 2 500

Remediation and Reuse of Contaminated Sediment: a new physical-chemical process to the point

THE OBJECTIVE OF THIS STUDY IS TO EVALUATE THE EFFICIENCY OF A NEW PHYSICAL-CHEMICAL PROCESS FOR THE TREATMENT OF LARGE VOLUME OF CONTAMINATED SEDIMENTS FROM AUGUSTA BAY REUSE OF RESULTING S/S MATERIAL

Remediation and Reuse of Contaminated Sediment: a new physical-chemical process to the point

Ordinary Solidification/Stabilization (S/S) processes aims at encapsulating wastes into a solid cement matrix (Solidification) and decreasing mobility and toxicity of inorganic contaminants (Stabilization) Poor attention has been paid in the past to impart to S/S materials good mechanical properties in a form which could allow their reuse. The reason for this is that, in Italy, S/S process has been normally used to reduce leaching before landfill disposal.

Remediation and Reuse of Contaminated Sediment: a new physical-chemical process to the point

first step: production of a cementitious granular material, based on principles of high performance concrete (HPC) use of superplasticizers and hydrophobic additive to reduce W/C and to improve watertightness Environmental aspect Service life Mechanical properties MAPEI HPSS SYSTEM High Performance Solidification/Stabilization 2 STEPS

Remediation and Reuse of Contaminated Sediment: a new physical-chemical process for the purpose

LOWER W/C AND HIGHER WATERTIGHTNESS MEANS Lower leaching of contaminants HIGHER ENVIRONMENTAL COMPATIBILITY Lower permeability HIGHER DURABILITY Stronger bonds HIGHER MECHANICAL STRENGTH

First step: granulation Formulation:

• Augusta harbour sediment (60%, dry basis)
• Cement (CEM I, 52.5) (21%)
• Additives: Mapeplast ECO 1-A e ECO 1-B (2 %)
• Water (17%)

High shear mixer Rotating plate

Remediation and Reuse of Contaminated Sediment: a new physical-chemical process to the point

W/C = 0.8 W/C+S = 0.2

Remediation and Reuse of Contaminated Sediment: a new physical-chemical process to the point

5 10 15 20 25 30 35 40 <1 1 2 4 5,6 >8

RETAINED FRACTION (%) MESH SIZE (mm)

TYPICAL PARTICLE SIZE DISTRIBUTION OF GRANULAR MATERIAL FROM STEP 1

First step: granulation

Remediation and Reuse of Contaminated Sediment: a new physical-chemical process to the point

INDUSTRIAL PLANT CAPACITY 4m3/h

Remediation and Reuse of Contaminated Sediment: a new physical-chemical process to the point

Second step: thermal vacuum distillation (TDV) of the granular materials from step 1. It is necessary when soil or sediments contain

• rganic/volatile/semivolatile contaminants.

Low temperature distillation (max 250 °C) under high vacuum (≤20 mm Hg) No degradation of cement matrix No gas emissions because the process is operating in high vacuum conditions No dust problems because the process is operated on the granular materials MAPEI HPSS SYSTEM High Performance Solidification/Stabilization 2 STEPS

Remediation and Reuse of Contaminated Sediment: a new physical-chemical process to the point

THERMAL VACUUM DISTILLATION EQUIPEMENTS LAB SCALE (LEFT) – PILOT SCALE (RIGHT)

XRD after 24 hours XRD after 28 days FISRST STEP - CEMENT HYDRATION

Remediation and Reuse of Contaminated Sediment: a new physical-chemical process to the point

• no negative effect of sediment on set and hydration rate
• portlandite consumption
• monocarbonate formation

Fine quartz sand mortar W/C = 0.8 ESEM images after 24 hours of hydration

Remediation and Reuse of Contaminated Sediment: a new physical-chemical process to the point

Sediment based granular material W/C = 0.8 FISRST STEP - CEMENT HYDRATION

Remediation and Reuse of Contaminated Sediment: a new physical-chemical process to the point

ESEM images after 7 days of hydration Fine quartz sand mortar W/C = 0.8 Sediment based granular material W/C = 0.8 FISRST STEP - CEMENT HYDRATION

Remediation and Reuse of Contaminated Sediment: a new physical-chemical process to the point

ESEM images after 28 days of hydration Fine quartz sand mortar W/C = 0.8 Sediment based granular material W/C = 0.8 FISRST STEP - CEMENT HYDRATION

SECOND STEP: THERMAL VACUUM DISTILLATION TVD

Evaluation of three different conditions

• 1. Temperature = 150 °C and tresidence = 16 hours;
• 2. Temperature = 200 °C and tresidence = 6 hours;

development process parameters

• 3. Temperature = 250 °C and tresidence = 4 hours.

Remediation and Reuse of Contaminated Sediment: a new physical-chemical process to the point

50 100 150 200 250 300 2 4 6 8 10 12

TIME (HOURS) TEMPERATURE (°C)

SELECTED CONDITIONS: 250 °C FOR 4 HOURS

250 °C, 4 hours 150 °C, 16 hours Results of morphological analysis

Remediation and Reuse of Contaminated Sediment: a new physical-chemical process to the point

SECOND STEP: THERMAL VACUUM DISTILLATION TVD

Results of chemical analysis (1/3)

Mercury

50 100 150 200 250 300 Sediment Step one 150 °C x 16 h 200 °C x 6 h 250 °C x 4 h gravel 1 gravel 2

mg / kg d.w.

C > 12 petroleum hydrocarbons

1000 2000 3000 4000 5000 6000 7000 Sediment Step one 150 °C x 16 h 200 °C x 6 h 250 °C x 4 h gravel 1 gravel 2

mg / kg d.w.

Remediation and Reuse of Contaminated Sediment: a new physical-chemical process to the point

SECOND STEP: THERMAL VACUUM DISTILLATION TVD

Results of chemical analysis (2/3)

PAHs (total)

1 2 3 4 5 6 7 8 9 10 Sediment Step one 150 °C x 16 h 200 °C x 6 h 250 °C x 4 h

mg / kg d.w.

PCBs (total)

1 2 3 4 5 6 Sediment Step one 150 °C x 16 h 200 °C x 6 h 250 °C x 4 h

mg / kg d.w.

Remediation and Reuse of Contaminated Sediment: a new physical-chemical process to the point

SECOND STEP: THERMAL VACUUM DISTILLATION TVD

PCDD/Fs ( WHO-TE index)

50 100 150 200 250 300 350 400 Sediment Step one 150 °C x 16 h 200 °C x 6 h 250 °C x 4 h

ng / kg d.w.

Results of chemical analysis (3/3)

Remediation and Reuse of Contaminated Sediment: a new physical-chemical process to the point

SECOND STEP: THERMAL VACUUM DISTILLATION TVD

Results of leaching test (EN 12457-2)

Mercury

0.2 0.4 0.6 0.8 1 1.2 Step one 150 °C x 16 h 200 °C x 6 h 250 °C x 4 h gravel 1 gravel 2

μg / L

Lead

10 20 30 40 50 60 Step one 150 °C x 16 h 200 °C x 6 h 250 °C x 4 h gravel 1 gravel 2

μg / L

Remediation and Reuse of Contaminated Sediment: a new physical-chemical process to the point

SECOND STEP: THERMAL VACUUM DISTILLATION TVD

Remediation and Reuse of Contaminated Sediment: a new physical-chemical process to the point

Results of leaching test (EN 12457-2) SECOND STEP: THERMAL VACUUM DISTILLATION TVD

Copper

50 100 150 200 250 Step 1 150 °C x 16h 200 °C x 6h 250 °C x 4h μg/L

Nickel

10 20 30 40 50 60 Step 1 150 °C x 16h 200 °C x 6h 250 °C x 4h μg/L

• pH value too high (13) – conditioning step in water
• Chlorides
• Selenium

Identified problems:

Remediation and Reuse of Contaminated Sediment: a new physical-chemical process to the point

BEFORE VTD AFTER VTD (250 °C FOR 4 HOURS) AFTER REHYDRATION CONDITIONING STEP IN WATER FOR 7 DAYS

Remediation and Reuse of Contaminated Sediment: a new physical-chemical process to the point

5 10 15 20 25 30 35 40 EFFUSIVE ROCKS LIMESTONE MIXED AGGREGATE SILTY LIMESTONE BLAST FURNACE SLAG

ACV (%) TYPE OF AGGREGATE

MAPEI HPSS SYSTEM

CONCLUSIONS (1/2)

Remediation and Reuse of Contaminated Sediment: a new physical-chemical process to the point

MAPEI HPSS TREATMENT WAS EFFECTIVE IN STABILIZING INORGANIC AND REMOVING VOC AND SVOC WHEN APPLIED TO MARINE SEDIMENT OF THE AUGUSTA HARBOUR (SICILY) 1. HYDRATION RATE WAS NOT AFFECTED BY THE SEDIMENT, BUT CHEMICAL INTERACTION BETWEEN CEMENT AND SEDIMENT WERE EVIDENT (PORTLANDITE CONSUMPTION, MONOCARBONATE FORMATION AND MORPHOLOGICAL MODIFICATION OF THE HYDRATED MATRIX) 2. THERMAL TREATMENT OF HYDRATED GRANULAR PRODUCTS HAD A POSITIVE EFFECT IN REDUCING THE LEACHING OF COPPER, NICKEL AND COBALT 3. 4. THERMAL TREATMENT OF HYDRATED GRANULAR PRODUCTS DECOMPOSED AFt AND AFm PHASES BUT REHYDRATION IN WATER PROMOTE THEIR REFORMATION

Remediation and Reuse of Contaminated Sediment: a new physical-chemical process to the point

5.

CONCLUSIONS (2/2)

Pollutants mass balance a.

FUTURE DEVELOPMENTS

More complete tests for physical and mechanical properties and durability (total porosity, Los Angeles, Micro-Devall, alkali-silica reaction, freezing-thawing) will be performed b. pH dependent leaching tests and leaching column test c. Speciation of mercury d. THERMAL TREATMENT OF HYDRATED GRANULAR PRODUCTS AT 250 °C DID NOT CAUSE THE DEGRADATION OF THE CEMENT MATRIX AND THE RESULTING PRODUCTS SHOWED GOOD MECHANICAL PROPERTIES FOR REUSE OPTION

Thank you for your attention!!!

Remediation and Reuse of Contaminated Sediment: a new physical-chemical process to the point