Environmental Engineering Reference
In-Depth Information
Figure 6.27
Low solids reactor 1.
and 12.7 cm in diameter. The screws rotate at variable speed in
U
-shaped
troughs constructed within a rectangular metal housing measuring 1.93 m ×
0.79 m × 0.56 m. The screws simply slide on the wear- and chemical-resistant
lining. Each screw is operated by a 0.75-hp motor equipped with a gear control
having a gear ratio of 40. Electrical inverter controllers (Baldor 15H) regulate
individual screw speed and rotation. The side troughs are inclined, making
a 4˚ angle with the bottom of the reactor. The middle trough is also inclined
at the same angle but in the opposite direction of the side troughs. The middle
screw rotates at twice the speed of the side screws in order to transport the
material back to the lower end of the side screws for continuous mixing.
The shaftless screw reactor significantly reduces the dewatering costs
associated with low solids slurries. The shaftless screw reactor enhances the
treatment efficiency by reducing the mass transfer limitations in high solids
slurries and increases the soil microbial activity by facilitating the addition
of nutrient amendments in high solids slurries, thereby reducing the treat-
ment time and cost.
The high solids reactor shown in Figure 6.29 simulates the contaminant
treatment in
in situ
land farming. The reactor consists of a galvanized
