This study assessed volatile organic compound (VOC) emission characteristics from
wastewater treatment plants (WWTPs) in five Taiwanese industrial districts engaged
in numerous manufacturing processes, including petrochemical, science-based industry
(primarily semiconductors, photo-electronics, electronic products and biological technology),
as well as multiple manufacturing processes (primarily pharmaceuticals and paint manufacturing).
The most aqueous hydrocarbons dissolved in the wastewater of Taiwanese WWTPs were
acetone, acrylonitrile, methylene chloride, and chloroform for the petrochemical districts;
acetone, chloroform, and toluene for the science-based districts; and chlorinated
and aromatic hydrocarbons for the multiple industrial districts. The aqueous pollutants
in the united WWTPs were closely related to the characteristics of the manufacturing
plants in the districts. To effectively prevent VOC emissions from the primary treatment
section of petrochemical WWTPs, the updated regulations governing VOC emissions were
issued by the Taiwanese Environmental Protection Administration in September 2005,
legally mandating a seal cover system incorporating venting and air purification equipment.
Cost analysis indicates that incinerators with regenerative heat recovery are optimal
for treating high VOC concentrations, exceeding 10,000 ppm as CH(4), from the oil
separation basins. However, the emission concentrations, ranging from 100 to 1,000
ppm as CH(4) from the other primary treatment facilities and bio-treatment stages,
should be collected and then injected into the biological oxidation basins via existing
or new blowers. The additional capital and operating costs required to treat the VOC
emissions of 1,000 ppm as CH(4) from primary treatment facilities are less than USD
0.1 for per m(3) wastewater treatment capacity.