Domen Letan Nea Fingar Financed by: Project partners: Contacts: - - PowerPoint PPT Presentation

Financed by:

LIFE12 ENV/SI/000969

Project partners:

POlluted Site DecontaminatiON - OPEN MARKET CONSULTATION, 7th June 2018, Trieste (Italy)

Domen Leštan Neža Finžgar Contacts: info@envit.si www.envit.si

Efficiently removes Pb and other toxic metals from soil and sediment; immobilize As. Closed-cycle operation. Recycles EDTA and reuses process waters in closed process loop. No waste-water is generated. Emission free. No emissions of EDTA chelates from remediated soil.

• Sustainable. Preserves soil as a functional natural

resource offering all ecosystem services. Removal of co-contaminating organic pollutants. Compatible with natural attenuation, bio- stimulation etc. Innovative, internationally patented, cost- efficient.

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ReSoil – fact sheet

Pb

ReSoil demonstrational plant

https://www.youtube.com/watch?v=r50L NFog-Hc&feature=youtu.be

Problem to solve

Only a fraction of soils contaminated with Pb and other toxic metals is treated due to the lack of efficient and environmentally sustainable technologies.

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Technology summary

EDTA-based soil-washing efficiently remove Pb and other toxic metals from soil:

Pb-EDTA chelate Pb bound to soil solid phases

C O H2C N H2C C CH2 O O C CH2 N CH2 C O O CH2 O O O

Pb

2- C O H2C N H2C C CH2 O O C CH2 N CH2 C O O CH2 O O O

Pb

2- C O H2C N H2C C CH2 O O C CH2 N CH2 C O O CH2 O O O

Pb

2-

C O O O C O Pb

Fe -OPb+

Pb in washing solution EDTA, process waters recycling Solid wastes enriched with Pb and other toxic metals Cleansed soil

Prior knowledge

• More than 20-years of research by many groups worldwide.
• No feasible technological solutions for EDTA recycling, for

problems with vast amounts of waste waters, for EDTA environmental persistence and emissions.

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Novel knowledge

→ Soil excavation and transportation to remediation plant (off or on site). → Soil extraction with EDTA solution. → Separation of solid and liquid phase. → Recycling of process solutions and EDTA in a closed loop. → Return of remediated soil.

Technology summary: ReSoil is an ex-situ soil treatment

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Technology summary: Innovative aspects and uniqueness

Up to 75- and 95% of Pb and co-contaminating metals (i.e. Pb, Zn, Cd, Cu) are

removed from contaminated calcareous and acidic soils.

Recycles EDTA and process waters using inexpensive and waste materials as auxiliary

reagents: lime, waste polysaccharides, H2SO4 (patent family EP 3153246B).

Closed-loop operation ensures for effective soil washing and rinsing, no liquid

wastes are generated (patent family US 9108233B2).

Produces only solid wastes: up to 1.5% (wt.). Produces no emissions. Uses zero-valent Fe (Fe0) to prevent leaching of EDTA and EDTA chelates with toxic

metals from remediated soil (patent application GB 1720126.0).

Enables effective immobilization of EDTA-resistant co-contaminants, i.e. oxy-anion

forming As, by addition of immobilizators (i.e. Fe0) into the soil slurry.

Recycles EDTA mainly in soil-friendly Ca-EDTA form. Preserves remediated soil as a

natural resource, i.e. for safe food production in urban agriculture.

Low operation and remediation cost.

ReSoil is the single available remediation option which efficiently removes Pb and other toxic metals from contaminated soils and preserves soil as a natural resource.

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Technology summary: Technology readiness level

• ReSoil technology prototype is currently demonstrated in operational

environment; capacity: 6.000 kg of soil day-1

• Technology Readiness Level: TRL 7 (EU, NASA).
• Technology uses commonly used process equipment.

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Material balance (average based on pilot-scale data)

Technology details: Process material balance

1000 kg EDTA Water Contaminated soil Cleansed soil

4 kg EDTA 6.8 kg Lime 3.9 kg H2SO4 200 L Water 4.0 kg Waste paper 10.8 kg of dry waste enriched with toxic metals To compensate losses To recycle EDTA and process waters To curb emissions 10 kg Fe0

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EDTA is characterized by low levels of biodegradability and high levels of environmental persistence. ReSoil patented EDTA recycling and soil rising (A) and patent-pending addition of absorbent (Fe0 = zero-valent iron) into the soil slurry prevents emissions of residual EDTA and toxic metals (Me) from remediated soils (B).

Technology details: Curbing toxic emissions from remediated soil

(A)

Treatment & recycling reduces EDTA and toxic metals (i.e. Pb) concentra- tion in downstream process waters. Mixing of Fe0 into the soil slurry curbs potential emissions of EDTA and toxic metals (i.e. Pb) from remediated soil.

5 10 15 20 7 14 21 28 35 42 49 56 63 70 77 84 91 98 105 Residual Pb (mg/kg) Time (days) remediated treated

• riginal

Remediated soil Remediated, Fe0 amended soil Original (not-remediated) soil

(B)

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ReSoil uniquely recycles chelant mainly as Ca-EDTA which is much less soil-aggressive than Na-EDTA.

• Insignificant changes in chemical properties (pH, soil
• rganic matter, soil N, P, Fe, Ca content) of

remediated soil.

• Minor changes in soil texture and soil-water

properties (mainly due to loss of soil structure and disaggregation of soil silt into clayish fractions).

• Transitional changes in soil biological properties (soil

enzyme activities, microbial abundance and structure of population).

• No effect on the rate of mineralization of model
• rganic material.

Technology details: ReSoil preserves soil as a natural resource

Artificial aggregates of remediated soil.

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• We observed no or minor (and transitional)

effects of remediation on visual plant growth, biomass, and physiological processes (photosynthesis, stomatal conductance and evapotranspiration of water).

Technology details: ReSoil preserves soil as a plant substrate

Original (not-remediated soil) Remediated soil Plants possess a basal tolerance to toxic non-essential metals: biomass yield on metal-contaminated soil is not affected. EDTA is nonspecific chelant and could reduce concentration of bio-available micronutrients essential for plant growth.

• Concentration of Pb in edible parts
• f vegetables cultivated on

remediated soil is significantly reduced, often bellow the limit of quantification (by AAS).

ReSoil remediated soil possess fully restored soil quality and provide ecosystem services including safe food production.

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