Measures to prevent emissions of PCDDs/DFs and co-planar PCBs from crematories in Japan

In this study, PCDDs/DFs and co-planar PCBs concentrations in flue gases fr om 17 crematories and in fly ashes and bottom ashes (mainly bone) from seve ral crematories were measured to grasp the present state of PCDDs/DFs emiss ions from crematories. The effects of several factors were discussed to pre vent PCDDs/DFs emissions from crematories. Total concentration (normalized by 12% O-2) of PCDDs/DFs was ranged from 4.9 to 1200 ng/m(3) N, and toxic e quivalent concentration was ranged from 0.064 to 24 ng TEQ/m(3) N. As the r esults obtained in this research, the following measures to reduce PCDDs/DF s emission are recommended for existing crematories: (1) keeping the temper ature at 800 degreesC in main/secondary chambers during a whole cremation, and (2) lowering the temperature in the dust collector. For newly installed crematories, following measures to prevent PCDDs/DFs emission including th e measures for existing ones are recommended: (1) connecting one secondary chamber to one main chamber, (2) installing the high efficiency dust collec tor and reducing dust concentration to less than 0.01 g/m(3) N, and (3) ins talling the sampling point for monitoring of PCDDs/DFs. (C) 2001 Elsevier S cience Ltd. All rights reserved.