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Flow Equalization Basin Safety
Safety programs set forth by the employer in accordance with all federal, state, and local regulations will be followed by employees. Check with your immediate supervisor if you are unsure of the safety requirements necessary to perform duties in this process area.
General Safety Precautions
  • Use safety lockout procedures for valves, slide gates, local disconnects, and mechanical equipment before working on any pumps.
  • Use lockout procedures when performing maintenance on any electrical or mechanical equipment prior to servicing.
  • Use extreme caution to avoid falls during entry and exit from drained basins. Grating and handrails may become slippery when wet due to condensation.
  • Practice meticulous personal hygiene when work requires contact with raw sewage.
  • Keep access hatches closed when not in use.
Process Specific Safety Precautions
Atmospheric Hazards

Wastewater treatment personnel are exposed to numerous hazards on a routine basis. With good work practices and a little common sense, wastewater operations and maintenance personnel can minimize the effects of these hazards. Proper personal hygiene is the first step in minimizing these hazards.

The following atmospheric hazards must be taken into account before entering any wet well:
  • Oxygen-deficient atmospheres: The atmosphere in a confined space may lack sufficient oxygen. If the oxygen level is less than 19.5%, a worker must not enter the space without proper ventilation or approved self contained breathing apparatus (SCBA).
  • Flammable atmosphere: The drained basin could contain flammable liquids and / or gases that may be entrained in the raw sewage. Care must be taken to eliminate all sources of ignition from the area. No smoking is allowed in a confined space.
  • Toxic atmosphere: Gases and vapors may be entrained in the collection system. These gases may be released in the drained basin, causing a toxic atmosphere.
  • Noise: If this hazard is suspected, proper ear protection is required.
  • Engulfment: All equalization transfer pumps, sluice gates and valves must be locked out to eliminate an engulfment hazard.
  • Falling objects: When personnel open a drained basin for maintenance, ensure all tools and materials are removed from the edge.
  • Slick or wet surfaces: The drained basin floor may contain slime or other slippery material. All surfaces must be hosed down completely to minimize this hazard. In addition, proper footwear must be used.

Wastewater personnel are obligated to understand and follow all confined space requirements set forth by the City of Wenatchee.

Mechanical Concerns

  • Be careful when manually removing debris from the drained basin to avoid being cut by sharp objects.
  • Lockout the equipment before performing any maintenance on it.
  • If a wet well is isolated by closing the inlet and outlet gates, the gate actuators must be locked out before any work is done in the wet well.
  • The drained basin may be classified as a confined space.  Follow the Confined Space Entry policy before entering.
  • The basin walkways can be wet and slippery, exercise caution to avoid slipping.
  • Check that all machine guards are in place before starting equipment.
Related Safety Programs and/or Polices

Refer to the plant confined space safety policy.
Refer to the plant policy for operating the gas detector.


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Last Updated: 9/16/2013 11:45:45 AM
Version 4.0.1