SORBENT DEVELOPMENT FOR MERCURY CONTROL. Final topical report including semiannual for January 1, 1998 through June 30, 1998.

The US Environmental Protection Agency (EPA) draft Mercury Study Report to Congress (1) estimated anthropogenic mercury emissions to be 253 tons/yr in the US, with the majority (216 tons/yr) from combustion sources. The three main combustion sources listed were coal (72 tons/yr), medical waste incinerators (65 tons/yr), and municipal waste combustors (64 tons/yr). The emissions from both medical waste incinerators and municipal waste combustors were recently regulated, which, together with the reduction of mercury in consumer products such as batteries and fluorescent lights, has already reduced the emissions from these sources, as stated in the final EPA Mercury Report to Congress (2). EPA now estimates total point-source mercury emissions to be 158 tons/yr, with coal remaining at 72 tons/yr, while medical waste incinerators are down to 16 tons/yr and municipal waste combustors are at 30 tons/yr. Coal is now the primary source of anthropogenic mercury emissions in the US, accounting for 46%. In addition, the use of coal in the US has been increasing every year and passed the 1-billion-ton-per-year mark for the first time in 1997 (3). At the current rate of increase, coal consumption would reach 1.4 billion tons annually by the year 2020. On a worldwide basis, the projected increase in coal usage over the next two decades in China, India, and Indonesia will dwarf the current US coal consumption level. Therefore, in the US coal will be the dominant source of mercury emissions and worldwide coal may be the cause of significantly increased mercury emissions unless an effective control strategy is implemented. However, much uncertainty remains over the most technically sound and cost-effective approach for reducing mercury emissions from coal-fired boilers, and a number of critical research needs will have to be met to develop better control (2)