Treatment of industrial wastewater from explosives manufacturing: Technologies, legal requirements - Case study

Wastewater from explosives manufacturing poses significant treatment challenges due to extreme pollutant concentrations and complex contaminant matrices. This work addresses wastewater-related problems at an initiating explosives production facility, where lead azide, lead styphnate, and pyrotechnic compositions are manufactured. The pollutant concentrations substantially exceed regulatory limits: lead reaching up to 653 mg/L (exceedance factor >1300), nitrates up to 3840 mg/L (exceedance 128 × ), sodium up to 4490 mg/L, and COD up to 9700 mg/L. The batch-based nature of production results in significant temporal and spatial variability in wastewater quality, with discharge intervals ranging from days to over 150 days depending on the production schedule. Additionally, the diversity of pollutants-heavy metals, nitrates, and organic compound requires fundamentally different treatment approaches (reduction vs. oxidation), complicating process design. BOD₅/COD ratio 0 and high lead concentration exclude biological treatment. Regulatory requirements were analyzed, including Polish legislation, EU directives, BAT reference documents, and HELCOM recommendations. Despite extensive research on industrial wastewater treatment, comprehensive case studies using real wastewater from European explosives facilities remain scarce, with most of the literature focusing on synthetic wastewater. A critical review of applicable treatment methods is provided, including precipitation, coagulation, advanced oxidation processes, nano zero-valent iron, electroreduction, ion exchange, adsorption, and membrane filtration. The results indicate that hybrid multi-stage treatment configurations are essential to achieve the required 99% removal efficiency, with retention tanks being a key element for load equalization.