Caution: Be aware of the potential for combustible
materials entering with the wastewater. Provide proper
ventilation and equipment to prevent explosive conditions.
Screenings may freeze to the sides and bottom of
containers; prevent this from happening if at all possible.
Grinders may bind because of ice if they are not run often
enough. Consider operating the grinders continually or often
enough to prevent ice buildup. Covering channels with rigid
insulating materials may contain enough heat from the wastewater
within the channel to prevent ice buildup on the grinder. Gear
oil viscosity will be affected by freezing weather. Follow the
manufacturer's recommendations for cold weather maintenance.
Condensation will also occur in the gear boxes of this equipment,
adversely affecting the gear oil. Check the oil routinely (twice
monthly) in the winter.
Grit Removal Processes. Operation of grit-
handling facilities may be very difficult during extremely cold
weather. The grit that is collected and transported will freeze
easily in the equipment used to clean and move it to the holding
container. Temporary enclosures may assist in keeping the
process warm. If this process is to be enclosed, choose the
materials carefully to prevent dangerous or explosive conditions.
Heat-tracing the metal equipment may help prevent ice buildup.
Heat-tracing involves wrapping an electrified wire loop around
the equipment. Running warm water across cleaning areas may also
prevent freezing, depending upon local conditions.
Flow Measurement. Freezing weather conditions may
cause the stilling well of flow measurement devices to freeze.
A solution of mineral oil, or a small amount of antifreeze or a
salt solution, will keep this stilling well liquid. Under low-
flow conditions, some of this antifreeze will drain out and may
need to be replenished periodically. Other remedies are to
enclose the area with rigid insulating board or plywood and to
use a light bulb for heat. Enclosing float wires will prevent
them from freezing.
A layer of frost may coat ultrasonic sensors inside the
cone on the sensor head. Use a thin layer of petroleum jelly on
the face of the detector to prevent this problem. Note that the
sensor should be recalibrated after the jelly is applied.
In systems that have an air bubbler system to measure
the level of water, condensate may become trapped within the air
line and it may freeze. Heat-tracing the air line will prevent
freezing and condensate problems. Dry air will also help prevent