There are several benefits, which is why the Spillceptor features a two-chamber design:
- Improved water-quality outcomes
- Ability to handle large spills at full flow
- Greater hydrocarbon removal
- Coalescer protection as silt is retained in the first chamber
In a two-chamber design, the first chamber extracts 90–95% of the hydrocarbons. The second stage ‘polishes’ the water with the help of a coalescer. The coalescer attracts microscopic globules of oil that are too small to rise up and be caught in the first chamber and ‘sticks’ them to itself. Once enough of these globules have accumulated, the combined net buoyancy will cause them to detach from the coalescer and rise to the top of the second chamber where they are caught. This method ensures a very high degree of separation with outlet qualities typically less than 5ppm.
While single-chamber full retention separators are still available, these devices pose risks to both on-site compliance and the environment.
In single-chamber units, the first chamber is combined with the coalescer chamber. Because there is no dedicated coalescing chamber, separation may fail or only partially complete under high flow. The result is that oil remains in the blend and water leaving the unit is more likely contaminated.
Units with this design are more prone to non-compliant discharge during adverse weather events and under high flow because silt can accumulate in the same chamber as the coalescer.