Application of solid-waste derived biochar from Penaeus vannamei mariculture for black-odorous water remediation

Summary

Penaeus vannamei, a premium aquatic protein source, experienced rising global demand accompanied by increasing aquaculture production, yet this growth has concurrently led to the accumulation of solid aquaculture waste. Currently, the treatment of mariculture solid waste remains a pressing challenge due to technical limitations and its inherent high salinity. Coastal eutrophication poses a persistent threat to nations worldwide, necessitating long-term remediation and maintenance of black-odorous water body, with previous studies confirmed biochar's efficacy as an in-situ remediation material. This study pioneered a novel preparation method for biochar(BC) derived from Penaeus vannamei mariculture solid waste; systematically investigated the effects of feedstock mass ratio (shrimp residual feed/feces: shrimp shell = a 1:0, b 4:1, c 2:1, d 1:1) and pyrolysis temperature (500 °C, 700 °C, 900 °C) on the biochar's physicochemical properties and heavy metal removal efficiency, while comprehensively evaluated its remediation performance for coastal black-odorous water. Results demonstrated the shrimp solid-derived BC700c prepared under optimal conditions (2:1, 700 °C) exhibited significantly better physicochemical characteristics and increased significantly (P < 0.05) removal rates for aquatic heavy metals, along with promising removal rate for total nitrogen (33.02 %), total phosphorus (49.09 %), Cu(II) (51.88 %), and Cd(II) (54.41 %) in coastal black-odorous water body. Furthermore, BC700c substantially improved microbial diversity, with the Shannon index increasing by 21.64 %. It promoted the relative abundance of functionally beneficial phyla, particularly Proteobacteria and Actinobacteriota, which helpful to heavy metal and nutrient (N/P) removal. This research provided groundbreaking insights into sustainable aquaculture waste valorization and an innovative technological solution for effective black-odorous water remediation.