Mercer’s enhanced-gravity separators bring automated, compliance-ready performance to hydroelectric drainage systems, from turbine bays and draft tube sumps to gatehouse mechanical rooms and powerhouse floor drains.
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INDUSTRY INSIGHT
Electrical utilities face some of the most complicated oily-water challenges of any industrial sector. Transformer leaks, lube-oil drainage, turbine washdowns, fuel-handling runoff, stormwater, coal pile leachate, and equipment-bay containment all produce oily wastewater that must be captured, treated, and kept out of the environment.
Many facilities still rely on outdated concrete vaults, undersized skim pits, CPI units, slotted-pipe “skimmers,” or makeshift trenches originally installed decades ago. These systems clog, blind, and overflow — especially when solids, emulsions, or fuel-oil sheens enter the mix. The result is unpredictable discharge quality, heavy maintenance, and regulatory exposure.
Mercer eliminates that cycle.
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INDUSTRY CHALLENGES
Many hydro stations still operate with 40- to 80-year-old pits that were never designed for modern environmental requirements. Undersized weirs, plugged slots, and uneven floors disrupt separation and cause short-circuiting.
Lube-oil that sits too long mixes with fines and rapidly sinks, becoming bottom sludge that rarely gets removed until a full outage.
Unlike refinery or pipeline sites, hydro plants deal with riverborne debris — sand, silt, leaves, algae, and fines. These rapidly blind CPI media, clog slotted pipes, and bury skim trenches.
Regulators increasingly monitor sheen control and hydrocarbon discharge limits at hydro outfalls. Legacy systems can’t document or sustain performance.
Turbine starts/stops, washdowns, or seasonal runoff create rapid surges that overwhelm old separators and send sheens to the outfall.
Uncovered oily pits contribute to odor, aerosol, and operator-exposure concerns — now a rising priority in utilities.
Solution
Hydropower facilities demand separators that work in tight powerhouse footprints and fluctuate with turbine loading. Mercer’s enhanced-gravity design meets those requirements without the chronic blinding and headloss issues seen in tight-packed coalescers. Wide-gap plates maintain clear rise paths even in grit-heavy sump conditions, and the compact footprint replaces the massive concrete pits traditionally used for oil collection in turbine halls — delivering reliable separation without adding complexity to plant operations.
Electromechanical skimmers remove oil the moment it rises, preventing collapse, sinking, and re-suspension. Decanting stages consistently produce <1% BS&W recovered product.
Hopper-bottom designs with multiple automated sludge valves prevent solids accumulation, ending the cycle of buried trenches and hand-dug pits.
Controlled-velocity flow geometry preserves rise paths even during turbine washdowns or storm events that would overwhelm CPI units.
Airtight covers eliminate vapor seepage, keep debris out, and maintain clean hydraulics. Coatings resist river sediment abrasion and mechanical-room chemical exposure.
Multi-Pack™ modules can drop into existing pits or concrete vaults, upgrading performance without shutting down major station operations.
APPLICATION AREAS
SYSTEM PERFORMANCE
MERCER ADVANTAGE
Power plants demand predictable performance and Mercer delivers systems that remain stable regardless of load, solids, or weather.
Enhanced-gravity separation that exceeds the 150-micron limitation of open-weir devices.
No confined-space skimming, no manual desludging, no “fishing for oil.”
Extend maintenance intervals, eliminate sludge buildup, and reduce hauling frequency.
Repeatable performance for SPCC, NPDES, and state discharge requirements.
Sealed lids and vapor-control packages tackle VOC/odor issues and operator exposure, a growing mandate in utility operations.
Mercer systems capture 3× smaller droplets, maintain stable hydraulics, prevent media blinding, and automate oil/solids removal.
Yes. Multi-Pack™ modules drop into many existing structures, turning non-compliant pits into automated separators.
Enhanced-gravity designs maintain performance even under shock loads, unlike CPI tanks that flood or short-circuit.
Absolutely. They capture dielectric oils efficiently and can integrate with substation containment plans.
Airtight covers, vapor-capture options, and sealed skimming prevent VOC/odor release and improve plant safety.
No. Mercer’s controlled-flow geometry and plate spacing resist blinding and maintain clean rise paths.
