Environmental Engineering Reference
In-Depth Information
Key factors in trickling filter operation include the following:
hydraulic loading rate
gpd
ft
Flow (including recirculation) (gpd)
=
2
2
MediaTop Surface (ft )
organic loading rate
lb/day
1000 ft
BODinfilter (lb/day)
Media
=
3
3
Volume (1000 ft )
recirculation ratio
RecirculationFlow(MGD)
Average Influ
Ratio
=
entFlow(MGD)
7.3.5.2 Operator Considerations
Trickling filter operation requires routine observations, meter read-
ings, process control sampling and testing, and process control calcula-
tions. Comparison of daily results with expected normal ranges is the
key to identifying problems and appropriate corrective actions.
•
Slime—
The operator checks the thickness of slime to ensure that it
is thin and uniform (normal) or thick and heavy (indicates organic
overload); the operator is also concerned with ensuring that exces-
sive recirculation is not taking place and checks slime toxicity (if
any). The operator is also concerned about the color of the slime:
green slime is normal, dark green/black slime indicates organic
overload, and other colors may indicate industrial waste or chem-
ical additive contamination. The operator should check the sub-
surface growth of the slime to ensure that it is normal (thin and
translucent). If growth is thick and dark, organic overload condi-
tions are indicated. Distributor arm operation is a system function
important to slime formation, and it must be checked regularly for
proper operation; for example, the distribution of slime should be
even and uniform. Striped conditions indicate clogged orifices or
nozzles.
•
flow—
Flow distribution must be checked to ensure uniformity. If
nonuniform, the arms are not level or the orifices are plugged. Flow
drainage is also important. Drainage should be uniform and rapid.
If not, ponding may occur from media breakdown or debris on the
surface.
•
distributor—
Movement of the distributor is critical to proper opera-
tion of the trickling filter. Movement should be uniform and smooth.
Chattering, noisy operation may indicate bearing failure. The dis-
tributor seal must be checked to ensure that there is no leakage.
