Technology trains in the framework of the HOlistic Management of Brownfield REgeneration

Transcription

1 The 3 rd International conference on Sustainable Remediation Conference theme: Case Studies Technology trains in the framework of the HOlistic Management of Brownfield REgeneration Oriana Capobianco, Renato Baciocchi, Giulia Costa (Università degli Studi di Roma Tor Vergata - Italy) Martijn Smit (Wageningen University The Netherlands)

2 Background q Cessation of land use has led to the formation of several Brownfields all across Europe. q Greenfields are still being consumed for new construction projects and industrial development q Traditional regeneration techniques are selected following a bottom-up approach aimed only at the clean-up of the Brownfield site. An innovative Brownfield regeneration approach is needed in order to make Brownfields a viable and sustainable alternative to Greenfields in terms of sites to exploit for new housing, commercial or industrial activities.

3 HOMBRE project q Funded by the European Commission under the Seventh Framework Programme q Final aim : achieve «Zero Brownfields Development» q Innovative strategies for Brownfields management are assessed, based on a HOLISTIC APPROACH, which takes into account the overall aspects that influence Brownfield management and regeneration, i.e. social, economic, environmental and urban planning aspects.

4 Land Cycle Management q A site goes through different phases during its life q Generally, Brownfields arise when economic, environmental and/or social costs for continuation of use of an area are higher than its revenues/benefits q A proper management of the site may reintroduce the Brownfield within the Land Cycle. Technology Trains BROWNFIELDS INTERIM USE REINTRODUCTION ABANDONMENT SOCIAL, ENVIRONMENTAL, ECONOMIC ASPECTS CESSATION OF USE PLANNING GREENFIELDS USE Traditional bottom-up approach Selection of one or more best available technologies that can respond to the sitespecific needs Innovative top-down approach Once defined the products/ services needed (OUTPUTS), the available resources (INPUT) can be converted into the desired output by applying proper technologies

5 Technology trains (TT) The role of technology train is to link the available resource at the BF site (INPUT) with the products and services needed in the site or in a broader local/regional context (OUTPUT). INPUTS Available resources Water Soil Industrial residues TECHNOLOGY TRAINS Physical pre-treatments Techniques aimed at reuse OUTPUTS Services/benefits/ products required Construction material Energy Improvement of soil bearing capacity q Three types of technology trains have been elaborated within the HOMBRE project that target the supply of goods and services that are expected to be relevant for the majority of urban use q In addition, environmental services such as supporting services (e.g. bearing capacity of sub-surface) were included.

6 TT for water and energy (TT1) q Aquifer thermal energy storage (ATES) is a system which utilizes inter-seasonal heat storage. This involves the storage of excess energy in summer for use in winter heating applications, and the storage of cooling potential in winter for cooling in summer q The increased groundwater flow and temperature due to the ATES system may accelerate the natural degradation of organic contaminants affecting groundwater. Resource Technology Train Product/service/benefit Groundwater Aquifer Thermal Energy Storage (ATES) systems + Natural Attenuation (NA) Space conditioning Groundwater treatment

7 TT for water and soil (TT2) q The precipitation of calcite may cause an in-situ increase in stiffness and strength of the soil and a decrease in permeability q The CO 2 produced as a result of the CaCl 2 and NaHCO 3 injection Alkaline material CO 2 + organic volatile contaminants Carbonation Gas treatment Gas extraction wells Top soil layer Unsaturated zone Ecogrout reaction may potentially allow the in-situ stripping of volatile organic contaminants (VOCs) from groundwater Evolved CO 2 Stripping of volatile contaminants Saturated zone Contaminant plume q The upward CO 2 flow may stimulate the carbonation of an overlying layer of alkaline material. GW flow direction CaCO 3 precipitation CaCl2 + 2 NaHCO 3 CaCO3 + 2NaCl + CO2 + H2O Resource Technology Train Product/service/benefit Soil Groundwater Alkaline material Ecogrout + Carbonation GW quality improvement Soil reinforcement CO 2 storage Improvement of alkaline material properties

8 TT for building material and soil (TT3) q This TT entails the screening of the contaminated soil in a fine (d < 2 mm) and a coarse (d > 2 mm) size fraction. Contaminated soil (d < 2 mm) q The coarse fraction may be reused directly a the site as filling material q The fine fraction is subjected to a Stabilization/ Solidification and Granulation process to obtain aggregates with suitable physical, mechanical and environmental characteristics to be reused in construction application Aggregates Resource Technology Train Product/service/benefit Excavated material Stabilization/Solidification + Granulation Filling material Aggregates

9 TT3: Case study q The applicability of the TT3 was assessed by applying the S/S granulation process to an industrial soil sampled at the Gruber site, in the National priority site of Terni- Papigno. 3 Samples of industrial soil q The Gruber site was a former wool mill and is located very near to the city center q Currently, the site is abandoned and closed to any kind of use q The Municipality of Terni has approved a requalification project of the site, that will be converted partially to residential use and partially to public services. Most of the outpace will be sealed. Gruber site q It is supposed that during the construction works, the soil shall be excavated.

10 Application of TT3 at lab scale Materials Passing (%) Q1: D< 2mm: 49 % wt. 40 Q2: D< 2mm: 48 % wt. 20 Q3: D< 2mm: 95 % wt. 0 0,01 0, Sieve size (mm) Conc. (mg/kg) ,1 Major elements f oc Sample Q1 Fe, Al, Ca 1.2 % wt. 0,01 As Be Cd Co Cr Cu Hg Ni Pb Sb Sn V Zn Fairly low contamination by metals Sample Q2 Sample Q3 Fe, Al, Ca Fe, Al, Ca < 0.05 % wt. < 0.05 % wt. Italian regulatory limits for residential use (It. LD 152/06) Limits exceeded

11 Application of TT3 at lab scale Methods STAGE 1: preliminary screening tests on natural soil AIM: investigate the effects of the operating conditions and mixture formulations on the physical and mechanical properties of the product CEMENT AIR DRIED SOIL WATER (+ additive) Changed parameters 24 rpm Water content (W/S ) Additive content (A/C) Cement type (CEM 42.5R, CEM 52.5R) Cement content (C/S) cm 30 cm Additive type (sulfonate-based (A1), acrylic-based (A2) superplasticizers) STAGE 2: tests on industrial soil AIM: analyze the influence of the combined S/S G process on the properties of the obtained aggregates and evaluate its applicability to treat a metal - contaminated Brownfield soil CHARACTERIZATION Physical properties Mechanical properties Environmental properties

12 Application of TT3 at lab scale Results of the preliminary tests (Stage 1) Changed conditions Main results Selected conditions Cement type Aggregates showing a mechanical resistance comparable to that of natural gravel were obtained by employing CEM 52.5 R Cement 52.5 R Cement content Cement/solid ratios higher than 30 % wt. and lower than 25 % wt. resulted in a significant decrease of the mechanical resistance of the aggregates 30 % wt. Additive type The use of both additives allowed to obtain finer and weaker aggregates No additive Additive content No effects of additive content on the aggregates size and strength was noted No additive

13 Application of TT3 at lab scale Results of the tests on the industrial soil (Stage 2) Physical properties (Particle Size Distribution ASTM D422) Mechanical properties (Aggregate Crushing Value BS ) % wt Untreated soil Granules from Q1 Granules from Q2 Granules from Q3 ACV (% wt.) Blast furnace slag Mixed gravel d<2 mm 2<d<4 mm 4<d<10 mm 10<d<25 mm UNTREATED SOIL GRANULES 0 Granules from Q1 Granules from Q2 Granules from Q3 D mm D 50 = 5-8 mm ACV Granules strength Selected operating conditions: 30 % CEM 52.5, no additives, optimum water content Selected operating conditions: 30 % CEM 52.5, no additives, optimum water content

14 Application of TT3 at lab scale Results of the tests on the industrial soil (Stage 2) Environmental properties (Leaching behaviour EN ) Limits for groundwater quality (It. LD 152/06) Limits for reuse in simplified procedure (It. MD 186/06) Concentrations lower than the instrumental quantification limit q Leaching of most metals for both untreated soil and produced aggregates was lower than the instrumental quantification limits q Exception: Ba, Cu, Cr 10 Untreated Q1 Granules from Q1 10 Untreated Q2 Granules from Q2 10 Untreated Q3 Granules from Q3 Conc. (mg/l) 1 0,1 0,01 1 0,1 0,01 1 0,1 0,01 0,001 Ba Cu Cr 0,001 Ba Cu Cr 0,001 Ba Cu Cr Factors influencing Ba, Cu and Cr release: q Characteristics of the cement q Increased ph q Contamination degree of the starting material (e.g. Cu for sample Q1)

15 Assessment of the applicability of the process: Operating windows Characteristics of the mixture Cement Need of high clinker containing cement (CEM 52.5 R) Optimum range: 25 30% wt. Texture A fine and heterogeneous soil texture provides better results Characteristics of the soil Contamination level Leaching targets may not be achieved if a soil with relevant concentrations of metals is used f oc High f oc (> 1 %wt.) may interfere with the process

16 Assessment of the applicability of the process: TT3 vs Dig&Dump Traditional endpoints q Protection of groundwater resources by minimizing the leaching of contaminants (GW); q Protection of human health by reducing the exposure to fine particles (HH); q Physical/mechanical properties of the material for civil engineering applications (PM). Sustainability endpoints q Greenhouse gas emissions (GHG); q Land consumption (L); q Consumption of abiotic resources (AR) Starting soil conditions Future site conditions Potential of achieving the traditional endpoint Potential of achieving sustainability endpoints Technology Low foc Low contamination Fine texture Sealed Unsealed GW HH P/M GHG AR L TT3 X X X X - High High High X X X - X High Average High Average High High - - X X - Average Average Average Samples Q2 and Q3 - - X - X Low / Average Low / Average - X X X - Average High - X X - X Low Low X X - X - Average High X X - - X Average Low Average Low / Average Low / Average Low / Average Low / Average D&D * * * * * High High High Low / Average Low Low

17 Conclusions q Within the HOMBRE project, technology trains are proposed as a tool to exploit the resources present at Brownfield (BF) sites in order to achieve products and/or services for the site itself and/or the surrounding land; q With reference to the issue of managing large volumes of excavated soil arising from regeneration activities, the coupling of Stabilization/Solidification and granulation technologies (TT3) may provide aggregates to be reused as construction material; q The application of TT3 to the Gruber soil allowed to obtain aggregates with suitable physical, mechanical and environmental properties for reuse (samples Q2 and Q3) ; q The performance of TT3 (samples Q2 and Q3) in terms of Traditional endpoints may be comparable to that of traditionally applied techniques (D&D) q Compared to standard solutions, the proposed technology train may provide a higher performance in terms of sustainability endpoints.

18 Thank you for your attention! Oriana Capobianco