Ovivo® Plow Blade Scraper Clarifier

The Ovivo® plow blade scraper clarifier is designed mainly for municipal wastewater treatment applications. It features grit and sludge removal via rake blades and efficient scum removal. This model can be used for primary or secondary clarification processes and is available in bridge or column supported clarifier designs.
  • Efficient removal of sludge solids
  • Standard plow blade sludge collection
  • Column supported clarifier
  • Low maintenance
  • Low operator attention

The Ovivo® plow blade mechanism uses the fundamental principal of gravity separation of solids from liquid to produce a clarified overflow water and sludge. The sludge accumulates at the bottom of the clarifier and is then scraped and removed via diagonal plow blades attached to the rake arms, while the underflow is removed by means of a sump located near the bottom center of the tank.    The plow blade clarifier can be used for both primary and secondary clarification.

This simple, yet effective design provides trouble-free and quick installation. The variety of options available and Ovivo’s clarification experts will help you select the right equipment for your specific application.

  • Over 80 years of industry experience to ensure the best clarifier packages for specific applications
  • Ovivo’s EWT™ world-renowned, long lasting drive units
  • Low installation, operation and maintenance costs
  • Diameters from 30 feet up to 250 feet
  • Superior Aftermarket support and customer service

Ovivo circular clarifiers have been used for clarification for over 80 years. They present consistent and reliable results for numerous applications throughout the industry. The column-supported clarifier design can be used in light, medium or heavy applications. The Ovivo cast-iron, oil lubricated drives are best choice for long life, low maintenance, dependable equipment in the harsh atmosphere of wastewater and industrial applications.

Ovivo provides exceptional experience in clarification coupled with a robust mechanism design.  The clarifier mechanism is typically supplied with a half diameter bridge and platform (although full-span bridges are available), ensuring easy access to the cast-iron drive for lubrication and maintenance. Our engineers can retrofit existing units with the new components to boost current plant operations and our exceptional aftermarket team will work diligently to provide any replacement items needed in a timely manner, reducing possible down time due to upgrades or improvements.

  • Clarifier sizes: 20’ to 250’ diameter
  • Drive design: cast iron base, time tested strip liner bearing, solid deep gear, oil bath lubrication, up to 35 years of service
  • Drive torque capacity: 9,000 ft-lbs to 1,000,000 ft-lbs AGMA 20 years continuous torque
  • Rotation speed: 8 to 14 fpm, variable speed available
  • Available mechanism fabrication materials: A36 steel, hot dip galvanized steel, 304 & 316 stainless steel
  • Scum skimming design: conventional scum box, full trough skimmer, rotating pipe skimmer
  • Tank configuration: accommodate existing and new tank, steep to flat tank bottom, shallow or deep side water depth

Mixed liquor enters the clarifier through a center column, passes into the Energy Dissipating Inlet (or optional EquaFlo 360™ EDI) through the column ports.  The Energy Dissipating Inlet reduces the flow velocity prior to entering the mechanism feedwell.  Within the feedwell, the influent velocity receives its final reduction allowing solids to settle. 

The Energy Dissipating Inlet (EDI) dissipates the kinetic energy of the influent mixed liquor flow. Evenly spaced scoops or vanes create a controlled and quiescent discharge of the mixed liquor into the flocculating feedwell to enhance flow distribution and flocculation.  For a high efficiency energy dissipating inlet see Ovivo’s EquaFlo 360™ EDI.

The flocculating feedwell promotes flocculation of the mixed liquor suspended solids. It allows for a gradual redirection of the flow velocity into the clarifier and the sedimentation of the flocs creating a sludge blanket at the bottom of the tank.

An Ovivo cast-iron, oil-lubricated drive mechanism mounted on the center column supports and rotates a center cage with truss arms. Each arm supports plow-type or diagonal scraper blades.

The blades transport the sludge accumulated at the bottom of the clarifier toward a sump located at the center of the tank. The sludge is then withdrawn from the sump periodically. Scum is removed from the surface with a scum skimming system. The skimming system consists of two full radius skimming arm assemblies connected to the center cage and cantilevered from the rotating feedwell and a full radius scum collection trough anchored to the concrete tank wall. The scum is skimmed into the trough and then flushed out of the clarifier twice per revolution with maximum efficiency.

Oviov’s cast-iron, oil lubricated drives are equipped with bearings, worms and pinion mounted on a precisely machined surface. In every drive a high quality solid pinion maintains alignment and gives better resistance to bending and deflection under loads. Mating parts are machined to precise tolerances to assure precise fit and alignment. Every drive part is fully restrained (top and bottom) with no overhung loads. Main bearings are fully restrained into base. Worm gear reducer, single solid pinion, single solid worm / worm shaft and main gear all meet the latest AGMA (American Gear Manufacturers’ Association) standards.

Each drive is equipped with an overload control device activated by thrust from the worm shaft. This drive control includes a clear plastic enclosure and a weatherproof enclosure of epoxy coated aluminum construction with electro-mechanical switches.

What life expectancy can I expect from the Ovivo clarifier drive?

Ovivo (Formerly Eimco Water Technologies) clarifier drives typically last more than 30 years. We have even seen some clarifiers running with drives that were more than 35 years old!

During winter In the Northern United States we experience icing problems with our clarifier’s conventional scum collection system and have to lock out the skimmer.   If we don’t lock out the skimmer it is bent during heavy icing conditions.   Is there a better solution?

Ovivo’s “Full Trough Skimmer” is a full radius (the space between the feedwell and the scum baffle) scum box and scum skimmer system.  The skimmer system is neoprene curtain hanging from a rotating cantilever support beam.  With two skimmer arms, the entire clarification surface between the feedwell and scum box is swept into the radial scum box twice per mechanism revolution.  Because the neoprene wiper merely hangs from the cantilevered support, the skimmer will safely travel over any ice which has formed on the liquid surface.

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