POlluted Site DecontaminatiON - OPEN MARKET CONSULTATION, 7th June 2018, Trieste (Italy) Domen Leštan Neža Finžgar Financed by: Project partners: Contacts: info@envit.si LIFE12 ENV/SI/000969 www.envit.si
ReSoil – fact sheet Pb 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. ReSoil demonstrational plant https://www.youtube.com/watch?v=r50L NFog-Hc&feature=youtu.be Removal of co-contaminating organic pollutants . Compatible with natural attenuation, bio- stimulation etc. Innovative, internationally patented, cost- efficient. 2
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. 3
Technology summary EDTA-based soil-washing efficiently remove Novel knowledge Pb and other toxic metals from soil: O Pb-EDTA chelate 2- 2- 2- O O O Cleansed C C C C soil O CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 O O O Pb H 2 C H 2 C H 2 C O CH 2 CH 2 CH 2 N N N C C C O O O C N N N Pb Pb Pb O O CH 2 O CH 2 O CH 2 H 2 C H 2 C H 2 C O O O C C C O O O C C C Fe -OPb + O O O O O O EDTA, process Pb bound to soil Pb in washing waters recycling solid phases solution Solid wastes enriched Prior knowledge with Pb and other • More than 20-years of research by many groups worldwide. toxic metals • No feasible technological solutions for EDTA recycling, for problems with vast amounts of waste waters, for EDTA environmental persistence and emissions. 4
Technology summary: ReSoil is an ex-situ soil treatment → 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. 5
Technology summary: Innovative aspects and uniqueness 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. � 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, H 2 SO 4 (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 (Fe 0 ) 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. Fe 0 ) 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. 6
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. 7
Technology details: Process material balance Material balance (average based on 10.8 kg of dry waste pilot-scale data) enriched with toxic metals EDTA Contaminated Cleansed 1000 kg soil soil Water 10 kg 200 L 4 kg 6.8 kg 3.9 kg 4.0 kg Fe 0 EDTA Water Lime H 2 SO 4 Waste paper To recycle EDTA To curb To compensate and process waters emissions losses 8
Technology details: Curbing toxic emissions from remediated soil EDTA is characterized by low levels of (A) biodegradability and high levels of environmental persistence. ReSoil patented EDTA recycling and soil rising (A) and patent-pending addition of absorbent (Fe 0 = zero-valent iron) into the soil slurry prevents emissions of residual EDTA and toxic metals (Me) from remediated soils (B) . (B) Treatment & recycling reduces EDTA 20 Remediated soil remediated Residual Pb (mg/kg) and toxic metals (i.e. Pb) concentra- Remediated, Fe 0 amended soil treated 15 tion in downstream process waters. Original (not-remediated) soil original 10 Mixing of Fe 0 into the soil slurry 5 curbs potential emissions of EDTA 0 and toxic metals (i.e. Pb) from 0 7 14 21 28 35 42 49 56 63 70 77 84 91 98 105 remediated soil. Time (days) 9
Technology details: ReSoil preserves soil as a natural resource ReSoil uniquely recycles chelant mainly as Ca-EDTA which is much less soil-aggressive than Na-EDTA. • Insignificant changes in chemical properties (pH, soil organic 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 organic material. Artificial aggregates of remediated soil. 10
Technology details: ReSoil preserves soil as a plant substrate 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. • 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). • Concentration of Pb in edible parts of vegetables cultivated on remediated soil is significantly reduced, often bellow the limit of quantification (by AAS). Original (not-remediated soil) Remediated soil ReSoil remediated soil possess fully restored soil quality and provide ecosystem services including safe food production. 11
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