Sustainable chromium ore processing residue (COPR) waste treatment with black soldier fly larvae (BSFL)

Chromium elements are prevalent in daily life, and millions of tonnes of Chromium Ore Processing Residue (COPR) remain untreated in China, posing significant environmental risks. In search of a cost-effective and environmentally friendly treatment method, this study investigated the potential of black soldier fly larvae (BSFL) as a biological treatment for COPR. Experiments were conducted using BSFL to treat 100 % COPR and a mixture of 50 % COPR with 50 % wheat bran. Post-treatment analysis using ICP-MS, X-ray diffraction (XRD), and scanning electron microscopy revealed a significant reduction of approximately 43 % in COPR dry mass and a decrease in total hexavalent chromium content from 5636 ppm to 563 ppm. The optimal treatment conditions involved mixing 50 % COPR with 50 % wheat bran. The results suggest that BSFL can serve as a sustainable and economically viable biological treatment for hazardous waste such as COPR, offering potential benefits for both the environment and the economy. Further research is needed to explore the mechanisms and effects of BSFL on hazardous waste treatment. • BSFL treatment reduces COPR waste by 43 %. • Innovative biological solution for China's environmental threat. • BSFL as a green alternative to traditional waste disposal methods. • Potential for widespread application in hazardous waste management. • Cost-effective and environmentally friendly COPR remediation strategy.