Agriculture Reference
In-Depth Information
secondary combustor, as well as, an off-gas cleaning system that contains a quencher, a
semi-dry scrubber and a fabric filter. There is another pyrolysis furnace (5 tons/day) in this
factory, and its exhaust gas is emitted through the same stack as the incinerator. So the stack
position is defined as this MWI location. The height of this stack is 35 m, and it is still lower
than the near hills (Fig.1).
2
nd
Combustor
2
nd
Combustor
Rotary Kiln
Rotary Kiln
Quencher
Quencher
Fig. 1. Outside view and internal view of the medical waste incinerators.
2.2 Soil sampling method
Twelve soil samples for each year were collected in the vicinity of the MWI as shown in
Fig.2. The exact sampling points were determined and recorded within 10 m of accuracy by
a handheld GPS device (Meridian Color, Thales Navigation, USA), then transformed each
point into the Geographic Information System (GIS) software packages of Google Earth
(2003).
Fig. 2. Soil sample sites around the studied MWI.
The background sample (SB) was collected in a farmland southeast of the stack, 2400 m
away. The local climate is featuring distinct seasons, typical to a subtropical weather
condition. The seasonal wind is from the southeast direction in summer and northwest in
winter. The sampling sites are mainly distributed in southeast and northwest. The MWI is
built in a valley area, so that the choice of sampling sites must consider the site-condition.
As some sites were frequently cultivated by farmer, the sampling was carried out by
inserting a cylindrical steel corer (24cm × 4cm, length × internal diameter, Eijkelkamp,
