This project investigates the Dioxin amount in emission water from the following industries and special businesses: common waste incineration, business waste incineration, vinyl chloride production, pulp manufacture, final waste disposal sites, alumina alloy manufacture, zinc reclamation, lactam production, acytylene manufacture, eto-chloro-propane manufacture, and sewage systems from public and industrial zones. On-site survey of 52 plants were conducted, with 42 tested and inspected, within examined production wastewater and emission water, wastewater from wet washing process of exhaust gas from waste incinerators contains highest Dioxin contents, with concentration range of 61.1 to 24,295 pg I-TEQ/L. Emission water from this industry also contains relatively high concentration of Dioxin, between 4.54~42.3 pg I-TEQ/L, with a range of 0.054~9.82 pg I-TEQ/L after treatment. Other industries producing next highest Dioxin concentration include vinyl chloride production, pulp manufacture, and alumina smelting production. Dioxin concentration from wastewater or mixed pools is between 0.211~71.6 pg I-TEQ/L, and from controlled emission water between 0.211~71.6 pg I-TEQ/L. For other industries, the Dioxin concentration in raw wastewater, mixed pool wastewater, or emission water is less than 10 pg I-TEQ/L. Integrating inspection data from this project with other data from EPA database, research projects information, and operating volume and wastewater amount from specific businesses/plants special businesses/plants surveyed by this project, a complete Dioxin emission checklist in Taiwan is established. The estimated wastewater Dioxin emission is 0.435 g I-TEQ/year. Comparing to 101.9 g I-TEQ/year of air Dioxin emission in 2005, the ratio is 0.43/99.57. This is comparable to Japan’s ratio of 0.55/99.45 in 2005, which is from wastewater Dioxin emission of 1.84 g I-TEQ/year to air emission of 323~348 g I-TEQ/year. The tested data from this project indicates that waste incinerators, pulp manufacture, vinyl chloride manufacture, and alumina smelting, are the industries that have great potential of emitting high Dioxin pollution in the emission water. This project advises measures to be taken for risk prevention management, and to postulate control standards of Dioxin in emission water with reference to the emission standards of USA and Japan. The drafted emission control standard by this program for specific industries/plants of waste incinerators, pulp manufacture, vinyl chloride production, and alumina smelting, is 10 pg I-TEQ/L. For new plants, the emission standard of Dioxin shall be 5 pg I-TEQ/L. This project is the first time for Water Protection Division to establish a complete checklist of domestic water Dioxin emissions. When integrated with data from Air Protection Division, a complete checklist of Dioxin emissions is derived. This makes us next only to Japan in the world having domestic Dioxin emission factors from complete inspection data to estimate Dioxin emission amount domestically, providing a valuable reference to the world. This program suggests the water Dioxin emission checklist be updated each year, and continue to combine with air emission list to establish annual emission amount, such that the reduction of Dioxin effect can be fully demonstrated by actual data.

dioxins, wastewater, inventory