The co-occurrence of organohalides and heavy metals constitutes a pervasive environmental challenge in anthropogenically impacted settings such as industrial complexes, electroplating facilities, and e-waste recycling sites. Owing to their persistence, toxicity, and chemical recalcitrance, these co-contaminants pose substantial ecological and human health risks while markedly increasing the complexity of remediation. Conventional physicochemical treatments are frequently insufficient to address their combined presence, especially given the synergistic inhibitory interactions that undermine removal efficiencies. As a result, microbially mediated synergistic bioremediation has garnered considerable attention as a sustainable alternative capable of achieving concurrent detoxification. Within these systems, organohalide-respiring bacteria (OHRB) play a key role by transforming organohalides into non-halogenated products that are more readily subjected to biotoxicity reduction. In parallel, sulfate-reducing bacteria (SRB) facilitate heavy metal immobilization through sulfide-mediated precipitation while simultaneously supplying electron donors (e.g., acetate, hydrogen) that sustain OHRB metabolism. These intertwined carbon–sulfur metabolic networks support the formation of stable, functionally complementary microbial consortia, enhance dehalogenation kinetics, and alleviate heavy metal toxicity. This review integrates current advances in understanding the occurrence, ecological impacts, and microbial mechanisms governing the co-remediation of organohalide–heavy metal contamination. Special emphasis is placed on characterizing the functional roles, metabolic coordination, and syntrophic interactions among key microbial guilds. Collectively, these insights provide a mechanistic foundation for the rational design of targeted, efficient, and ecologically robust synergistic bioremediation strategies for complex co-contaminated environments.

Mariculture wastewater often contains emerging contaminants and elevated chloride concentrations, posing significant treatment challenges. This study developed and assessed a novel process that integrates hydrodynamic cavitation with calcium peroxide for the removal of the antibiotic tetracycline. The hydrodynamic cavitation/calcium peroxide system exhibited superior tetracycline degradation across a wider pH range compared to the homogeneous Fenton-like system, achieving over 92% removal at pH 3 with a synergistic coefficient of 9.40, while maintaining 61% efficiency under neutral conditions. Additionally, it achieved a chemical oxygen demand removal rate of 50.73% from actual mariculture wastewater, surpassing the performance of the homogeneous Fenton-like system. This approach also significantly reduced the formation of toxic disinfection by-products. The concentrations of trihalomethanes (0.29 μg/L), dichloroacetic acid (1.38 μg/L), and trichloroacetic acid (0.41 μg/L) were lower than those produced by the homogeneous Fenton-like system, resulting in an effluent with a markedly reduced toxicity-weighted concentration. Liquid chromatography-mass spectrometry analysis did not identify any stable large-molecule chlorine-containing intermediate products. Coupled with experiments on the hydrodynamic cavitation degradation of dichloroacetic acid, these findings suggest that the extreme conditions generated by hydrodynamic cavitation can effectively disrupt the C–Cl bond, thereby preventing the accumulation of chlorine-containing by-products. This study establishes the hydrodynamic cavitation/calcium peroxide system as an efficient and environmentally safe technology for the treatment of antibiotic-contaminated high-salinity wastewater.