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Electrical Utilities: Hydroelectric

Reliable Oil & Solids Separation for Turbines, Powerhouses & Dam Infrastructure

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

Overview

Hydroelectric facilities generate some of the most challenging oily-water streams in the utility sector. Turbine hall drainage, lube-oil leaks from bearings and governors, powerhouse washdowns, gate machinery lubrication, and runoff from spillway or intake structures all flow into sumps and pits that were often built decades ago.

Many plants still rely on original concrete pits, skimmer trenches, outdated poorly designed CPI units, or improvised oil-skim boxes that were never designed for today’s flow variability or solids loading. When grit, silt, vegetation, rust scale, or turbine fines enter the system, these old separators quickly foul. The result is unstable hydraulics, solids accumulation, sheens bypassing during high flows, and growing regulatory scrutiny at NPDES-regulated outfalls.

Mercer breaks that cycle.
Our Multi-Pack™ coalescer and Compliance Master™ separator technology provide predictable oil capture, automated removal, and stable performance, even under the surge conditions common in hydro plants. With sealed covers, automated solids evacuation cycles, and corrosion-resistant construction, Mercer systems restore reliability to drainage handling and protect downstream waterways.

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INDUSTRY CHALLENGES

Solutions Across the Power Generation Landscape

Hydroelectric

Treat turbine-bay drainage, gatehouse leaks, and powerhouse oily runoff while minimizing solids carry-through and protecting waterways.

Natural Gas

Handle lube-oil leakage, compressor drainage, turbine washdowns, and sump water in highly variable flow conditions.

Coal

Remove oils and fines from coal pile runoff, conveyor/washdown water, and process-area drainage before it enters surface water or NPDES outfalls.

Nuclear

Manage controlled-area drainage, turbine lubricants, transformer leaks, and regulated wastewater streams with predictable, documented performance.

Petroleum-Fired Generation

Capture fuel-oil spills, boiler house drainage, tank farm runoff, and oily sumps — automatically and with sealed emissions control.

Renewables

Support wind, solar, and battery storage sites with containment and drainage solutions for transformer bays, inverter pads, and maintenance hubs.

Solution

Mercer’s Solution

Mercer systems replace skim pits, outdated CPI units, and failing vaults with predictable, automated, enhanced-gravity separation engineered specifically for variable-flow, solids-rich hydro environments

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 zclear 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.

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APPLICATION AREAS

Typical Hydroelectric Applications

Turbine Bay Drainage & Lube-Oil Leakage

Capture bearing and governor oil, sheen, and particulate before they reach the sump or powerhouse outfall.

Draft Tube & Tailrace Sump Water

Stabilize performance even with high solids, silt, or algae loadings.

Gatehouse & Intake Equipment Rooms

Treat lubricating oil drainage from hoists, mechanical equipment, and spillway gate actuators.

Powerhouse Floor Drains & Washdowns

Prevent sheens from bypassing during cleaning or maintenance operations.

Dam Spillway & Spill Gate Drainage

Manage hydrocarbon-laden runoff during spill events or seasonal high-flow periods.

Stormwater Around Turbine & Generator Areas

Handle intermittent flows with consistent oil removal and solids evacuation.

SYSTEM PERFORMANCE

Common Hydroelectric Challenges

Aging Drainage Infrastructure

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.

Grit, Silt & Turbine Fines

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.

Shock Loads & Variable Flows

Turbine starts/stops, washdowns, or seasonal runoff create rapid surges that overwhelm old separators and send sheens to the outfall.

Oil Layer Collapse & Solids-Induced Sinking

Lube-oil that sits too long mixes with fines and rapidly sinks, becoming bottom sludge that rarely gets removed until a full outage.

NPDES Compliance Pressure

Regulators increasingly monitor sheen control and hydrocarbon discharge limits at hydro outfalls. Legacy systems can’t document or sustain performance.

Open Pits = Vapor & Odor Issues

Uncovered oily pits contribute to odor, aerosol, and operator-exposure concerns — now a rising priority in utilities.

99.9%

Oil Removal Rate

75%

Space Reduction

25+

Year Lifespan

Performance Highlights

MERCER ADVANTAGE

The Mercer Difference

Built for Harsh, Wet, Solids-Heavy Environments

Hydro plants demand robust designs that tolerate the grit and debris CPI systems can’t handle.

Automated, Safer Operations

No manual skimming. No hand-digging sludge. No confined-space entry.

Predictable Compliance Performance

Stable separation for sheen control, NPDES outfalls, and environmental audits.

Emission & Odor Containment

Sealed lids prevent vapor escape and protect operators, a growing requirement across utilities.

Long-Term Lifecycle Value

Reduced hauling, fewer shutdowns, and less maintenance deliver measurable ROI.

Transform Your Hydropower Drainage Management

Free testing. Guaranteed performance.

Cleaner water. Fewer cleanouts. Automated, reliable performance.

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Frequently Asked Questions

Q.

Can Mercer systems handle the grit and silt common in hydro plants?

A.

 Yes — automated purge valves and controlled-flow geometry prevent blinding and maintain consistent rise paths.

Q.

Can these separators retrofit into existing hydro pits?

A.

 Often yes. Multi-Pack™ modules can drop into many existing vaults, improving performance without major civil work.

Q.

How do systems handle high-flow events or washdowns?

A.

Enhanced-gravity designs maintain performance during surges that overwhelm CPI and skim-pit systems.

Q.

Do sealed covers help with odor and vapor control?

A.

Yes. Airtight lids prevent vapor seepage and keep debris and insects out of the separator.

Q.

Is daily operator involvement required?

A.

No. Automated oil removal, timed purge cycles, and SCADA connectivity reduce operator workload dramatically.

Q.

Are systems suitable for remote or unmanned hydro stations?

A.

Yes. Alarms, telemetry, and automation make them ideal for lightly staffed sites.