Environmental Assessment of Wastewater Treatment Plants in Developing Countries Using LCA: A Case Study in Perú

Abstract

Treating municipal wastewater is essential to safeguarding both ecosystem integrity and public health. Although wastewater treatment plants (WWTPs) significantly improve effluent quality, they also incur collateral environmental burdens. In this investigation, a “gate to gate" Life Cycle Assessment (LCA) was conducted to analyze the environmental performance of two major WWTPs in Arequipa: La Escalerilla (Plant A, activated sludge) and La Enlozada (Plant B, trickling filters). The analysis was conducted using OpenLCA and the ReCiPe Midpoint (H) 2016 impact assessment method, with a functional unit defined as 1 m³ of treated effluent. Energy consumption emerges as the primary driver for the climate change (GWP100), fossil depletion (FDP), and human toxicity (HTPinf) impact categories, accounting for approximately 75% to 85% of the total effects. Plant A, which requires 0.59 kWh/m³ of electricity, achieves superior nutrient removal reflected in a freshwater eutrophication potential of 1.92 × 10⁻⁶ kg P-eq/m³, and exhibits marginally higher CO₂-eq emissions (GWP100) (1.17 × 10⁻¹ kg CO₂-eq/m³). Conversely, Plant B consumes only 0.34 kWh/m³, resulting in a slightly lower GWP100 (1.14 × 10⁻¹ kg CO₂-eq/m³) and a significantly greater reduction in fossil depletion potential (FDP) (2.56 × 10⁻² kg oil-eq/m³ vs. Plant A's 4.75 × 10⁻² kg oil-eq/m³), although it exhibits an elevated eutrophication potential of 4.10 × 10⁻⁶ kg P-eq/m³. Both plants meet discharge standards. This study shows that treatment technologies must balance efficiency and sustainability, with energy use being critical. As Peruvian LCA research is scarce, these results offer key insights for future policies.