Page 166 - Wastewater Solids Incineration Systems

Emission Control and Monitoring 133

Thus, particulate matter can be any solid or liquid material—excluding water,
which is not chemically bonded—that is measured by the method 5 particulate test
method (40 CFR, Part 60, Appendix A, Method 5) (1991b). Although small amounts
of liquids may be present, particulate matter, or total suspended particulate (TSP)
mostly consists of incinerator ash. Total suspended particulate is primarily a mixture
of minerals and oxides of several elements: silicon, aluminum, calcium, iron, magne-
sium, and phosphorus. Although most particulate matter can cause respiratory harm,
the much smaller quantity of metals causes the greatest toxic and health effects.
Particulate matter is commonly classified by size and by filterability. For
instance, PM has a mean diameter equal to or less than 10 μm. U.S. EPA Test
10
Method 201 or 201A determines this classification. The text consists of extracting a
gas sample at a constant flow rate through an in-stack sizing device such as a
cyclone or cascade impactor. Because particulate matter larger than 10 μm is rela-
tively easy to capture, it is generally assumed that all controlled emissions from an
incinerator are PM . A newly determined size distinction is PM , which refers to
10 2.5
the small fraction of particulate matter that has a mean diameter of 2.5 μm or
smaller. The designation of PM is significant because smaller particulates are
2.5
respired more deeply into the lungs and can have significant health effects. U.S. EPA
is evaluating the health effects of PM and may impose emission criteria for large
2.5
combustion sources, including incinerators.
Particulate matter is also classified as having a filterable portion and a non-fil-
terable (or condensable) portion. Although these terms are often used in a general
sense, they can take on specific meaning when applied to a particular test proce-
dure. For example, U.S. EPA Test Method 5 (40 CFR, 60, Appendix A, Method 5) for
the Determination of Particulate Emissions from Stationary Sources is typically used
to determine particulate matter from incinerators (U.S. EPA, 1991b). The test
involves withdrawing a hot, wet sample of flue gas through a glass fiber, 0.3-μm
filter maintained at 121°C (250°F). The mass of particulate captured on the filter is
the filterable particulate matter. Following the heated filter, the sample is drawn
through a series of four impingers (condensers) in an ice bath that are used to con-
dense out the water vapor in the sample so that the moisture content of the flue gas
can be determined. The impingers, however, also will capture any condensable
matter in the flue gas. U.S. EPA and most states regulate only the filterable fraction
of the particulate catch (front half). Some states, however, require sampling of both
the filterable and condensable portions and regulate the total combined catch (front
and back halves). Including the condensable fraction can more than double the total