Environmentally sound destruction of hexachlorobutadiene during waste incineration in commercial- and pilot-scale rotary kilns

Abstract

Hexachlorobutadiene (HCBD) is a persistent organic pollutant (POP) that is banned in many countries. To investigate the destruction of HCBD in industrial waste, we conducted incineration tests at a commercial-scale incineration plant equipped with a 130-t/day rotary kiln and at a pilot-scale plant with approximately 2-kg/h of feeding rate. At the commercial-scale plant, waste oil containing 37% by weight of HCBD was co-incinerated at 1058 °C together with the solid and liquid industrial wastes that the plant normally processes. The concentrations of HCBD in the bottom ash (0.25 ng/g-dry), effluent slurry (2.8 ng/L), and stack gas (8.2 ng/m3N) were comparable with those obtained when only the usual industrial waste was incinerated. A destruction efficiency of 99.999996% was obtained from the co-incineration test, with negligible discharge of chlorinated dioxins and furans. At the pilot-scale plant, refuse-derived fuel spiked with HCBD was incinerated. It was found that both decomposition and unintentional generation of HCBD occurred simultaneously in the primary combustion chamber; however, the decomposition rate exceeded the generation rate to afford a destruction efficiency of 99.99993%. Together, these results indicate that HCBD contained in industrial waste can be efficiently destroyed in best available technology (BAT) rotary kiln waste incinerators.