Polychlorinated dibenzo-p-dioxins and dibenzo-furans (PCDD/Fs) are notorious pollutants classified as persistent organic pollutants (POPs), which even at trace levels can bio-accumulate in the environment and have negative effects on organisms. Due to their adverse health effects, countries around the globe have introduced stringent emission standards to reduce the formation of PCDD/Fs. Using data in the literature over the past two decades (2001 to 2023), this review discussed the PCDD/F emissions from incineration facilities, E-waste recycling, iron sintering, secondary metal smelting plants, and crematories. But the review only focused on pollutants and remediation strategies from the incineration processes. There are two heterogeneous mechanism pathways that lead to the formation of PCDD/Fs, firstly, the De novo phase, using macromolecules of carbon or polycyclic aromatic hydrocarbons to begin the synthesis, and secondly, the condensation reaction beginning with the rearrangement of the molecular structure of the precursor compound. On the remediation strategies, adsorption injections were the most preferred method; however, recent studies reported other strategies such as catalytic filtration systems, an electron beam system, and good combustion practices. This review concluded that a lot has been done to manage and prevent PCDD/F formation efficiently to the level which no longer poses a hazard to human health and the environment. Graphical abstract

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Incineration is any procedure, technique or method that transforms waste to flue gases and by-products by means of oxidation. Although the recommended way of treating healthcare risk waste is through incineration, the utilization of incinerators is still disputable. The fundamental problem for incinerators in the Republic of South Africa started with the new amended Section 21 of the National Environmental Management Act: Air Quality Act known as NEMA: AQA 39 of 2004 that requires stack emissions to be reduced by almost 50%. Since the promulgation of the standard, incineration facilities have not been complying with the emissions standard. This study was conducted to investigate the optimum hydrated lime [Ca(OH)2] dosage required to reduce acid gas emissions to the required level. The dosage rate was then raised and kept between 2.5 and 3.5 kg/h. This technology was able to achieve a high removal efficiency of 97% for HCl, 86% for HF, 83% for NO, 87% for SO2 and 74% for NO2. The optimum emissions removal temperature for HCl was between 1190°C and 1200°C, 1020°C for SO2 and NO2, and between 1120°C and 1200°C for NO2. The optimum Ca(OH)2 dosage for maximum NO removal was 3.1 kg/h, HF was 2.9 kg/h, SO2 was 2.8 kg/h, NOx was 2.8 kg/h and HCl was 3.2 kg/h.