Evaluation of Environmental Impact and Social Return on Investment (SROI) from Fly Ash Utilization as Fertilizer at PT PLN Nusantara Power UPK Tarahan

Abstract

This study evaluates the environmental, social, and economic impacts of utilizing fly ash in organic fertilizer production. As part of Corporate Social Responsibility (CSR) program at PT PLN Nusantara Power UP Tarahan. Fly ash, by-product of coal combustion, is used to enhance soil quality while reducing industrial waste. This study employed mixed-methods research design to assess plant growth, soil quality, and community-level outcomes. The quantitative methods (field experiments and laboratory testing), followed by statistical analysis using one way ANOVA and Fisher’s LSD test. Qualitative methods, including surveys and interviews, were used. The incorporation of 10% fly ash into organic fertilizer significantly improved soil nutrients and plant growth. Soil nitrogen content increased to 0.70%, available phosphorus rose to 363.50 ppm, potassium (K₂O) reached 394.85 mg/100g, and the Cation Exchange Capacity (CEC) improved to 24.05 cmol/kg. Environmental valuation indicated notable savings from reduced waste disposal and pollution prevention. The Social Return on Investment (SROI) ratio exceeded 1. This is indicating that every unit of investment generated greater value in social and environmental benefits. These findings support the financial viability and long-term sustainability of the program, emphasizing its positive impact on both the environment and local communities.