Experimental Study on Enhanced Fenton Technology Coupled with Biological Processes for the Treatment of Explosives Production Wastewater

This study developed a combined zero-valent iron (ZVI) enhanced Fenton + upflow anaerobic sludge blanket (UASB) + biological aerated filter (BAF) process for treating high-strength explosives wastewater (rawCOD ≈ 52,000 mg/L; B/C = 0.011). The optimized ZVI-Fenton pretreatment achieved 78–80% COD removal, significantly reducing COD to ∼ 15,000 mg/L. Crucially, it enhanced biodegradability, raising the B/C ratio to 0.238 and increasing the 48 h median effective concentration (EC50) from 3.8% (highly toxic) to 38% (moderately toxic). The subsequent stable UASB–BAF biological stage further purified the effluent. The integrated process demonstrated an overall COD removal efficiency of 84–85%, elevated the final B/C to 0.63, and produced low/non-toxic effluent with an EC50 > 80%. This coupled process effectively overcomes the challenge of high toxicity and poor biodegradability via “rapid detoxification followed by deep purification,” exhibiting advantages like lower reagent consumption and less iron-sludge generation, confirming its strong potential for industrial application.