C2. Technical and financial assessment. Replicability and up-scale
ASSESSMENT OF UP-SCALABILITY AND REPLICABILITY OF LIFE ECO-SANDFILL SFS VALORISATION SOLUTION
After an initial assessment of barriers and drivers for industrialisation of the proposed solution of recovering reclaimed SFS as secondary aggregate in construction sector, made by the consortium, gathering the perspectives of the foundry and the construction company on technical, economic, logistics, market and regulatory issues, and considering the later experience during the demos, issues raised and results of performance tests, a SWOT analysis was conducted to summarise all the considerations from the consortium for the reclaimed SFS utilisation in the construction and foundry sectors.
According to the SWOT analysis performed and the results at lab-scale, some main conclusions arose regarding technical construction performance, and their impact in their market potential:
- Technical issues: Due to the variability of this by-product, it would be important to ensure the quality standardisation and labelling of SFS, in order to obtain a reliable and valuable by-product as aggregate for construction and clear the reliability doubts of stakeholders when substituting traditional natural sand.
- Logistic issues: Due to the high quantities of sand needed for construction works, big stocks of SFS should be available when the construction sites require them. It might be helpful a waste management company with space and additional media (silos, hoppers, tank discharges, etc.) for sand storage and transportation.
- Administrative issues: It should be necessary to develop a regulatory framework to promote the use of (reclaimed) SFS in construction sector, since there is still a certain reluctance to their utilisation among construction stakeholders, even though authorisation by Environmental Authorities may be granted.
ECONOMIC ASSESSMENT (LCC)
A life cycle costing assessment (LCC) has been conducted, following the methodology described in standard ISO 15686-5:2017 “Building and constructed assets - Service life planning - Part 5: Life-cycle costing”. The economic impacts of the LIFE ECO-SANDFILL reclaiming process have been assessed and compared with those of the thermally reclaimed SFS and those of the production of virgin sand. Four main cost categories have been considered: investment costs, manpower costs, energy costs and waste management costs.
The results show that obtaining reclaimed SFS through the LIFE ECO-SANDFILL mechanical process (operating conditions: batch=60 kg, rotation speed = 2235 rpm, residence time = 60 s) has lower costs than thermal reclamation, regardless of the hours spent on reclaiming operation per day. The more time the reclaiming operation is performed per day, the lower the cost per tonne of SFS reclaimed. Thus, costs can drop from almost 60 €/t when spending just 1 hour per day reclaiming SFS, to 10.20 €/t when reclaiming operation runs for 8 h/day.
When comparing costs of SFS reclaimed in the prototype with prices of virgin sand, results vary depending on the sector:
- In the construction sector the price of virgin sand varies between 6 and 17 €/t (transport costs to worksite not included).
- The price of virgin foundry sand is around 60 €/t delivered at foundry. Therefore, depending on mode of transport and distance between supplier and foundry, reclaimed SFS could be an economically viable alternative. For road transport, the maximum distribution distance to ensure minimally profitable commercialisation of reclaimed sand has been estimated at 45 km (for reclamation unit operating 8 h/day).
