A Socio-Environmental Model for Recovering Expanded Polystyrene Waste as a Building Material in Colombia

Abstract

Expanded polystyrene (EPS) is a voluminous, low-density waste that is rarely recovered in Colombia, although its use as a lightweight aggregate is well documented. This study designed and validated a socio-environmental management model for transforming post-consumer EPS into a building material in Sogamoso (Boyacá, Colombia). A qualitative, exploratory action-research design was used. The diagnosis combined documentary analysis with four semi-structured interviews and two open-ended questionnaires answered by six actors from the public-institutional, waste-management and construction sectors; a demonstrative block with EPS occupying 25% of the mould volume was produced in ten trials, and the model was validated with representatives of the same sectors. Three independent sources agreed that EPS is not collected because it is paid by weight and has no buyer; no local entity knows its volume, and it hinders compaction in collection trucks. The barrier operates at two points: the waste has no buyer, and a new product must overcome the preference for clay brick. The model evolved through three versions; the cooperative proposed in the second, the only component not derived from the actors, was the only one rejected. The final model combines volume-based payment to waste pickers, a special-waste collection channel within the municipal waste plan, a private transformation company and voluntary public training. The block (about 900 g; ≈952 kg/m³) demonstrates production feasibility only; mechanical, acoustic, durability and fire performance must be verified against applicable standards before any construction use. Recovering EPS in intermediate cities appears to be mainly a governance and market problem.