Why Does My Ejector Pit Smell?
If your ejector pit smells like rotten eggs or sewage backing into the lower levels of your building, the cause is almost always a combination of biofilm growth inside the pit, hydrogen sulfide gas escaping through the cover, and a vent line that cannot move air fast enough to keep the headspace under negative pressure.
The four causes we see most often
1) A thick organic film coating the pit walls and float switches that releases sulfur compounds as it decomposes. 2) Dried-out check valves or flapper seals that let sewer gas migrate up the discharge line. 3) Vent stacks that are blocked, undersized, or terminated too close to fresh-air intakes. 4) Pump cycles that are too short to fully evacuate solids, leaving a sludge layer that keeps regenerating odor between cycles.
Why bleach and enzymes don't work long-term
Bleach flash-oxidizes the surface of the biofilm but leaves the anchored layer intact, so the smell returns within days. Enzymes are designed for grease, not sulfur-reducing bacteria, and most enzyme products are inactivated by the chlorine residual in city water. Encapsulation chemistry binds the odor molecules at the source and keeps working between dosings.
What actually fixes it
A metered dosing pump that injects an encapsulant on a timed cycle, paired with a one-time mechanical cleaning of the pit walls and floats. We pair the dosing with a vent audit so the headspace stays negative and any residual gas exits above the roofline instead of into the lobby.
Frequently asked questions
- How fast will the smell go away?
- Most buildings see a noticeable drop within 48 hours of the first dosing cycle and full resolution inside two weeks once the legacy biofilm is dissolved.
- Will I need to shut down the pit?
- No. Cleaning and dosing happen with the pumps running on their normal cycle.
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