This is the most common unit and can be provided in various options as below :

• Conventional Circular Clarifier with Central drive is provided with a central rake drive mechanism supported on a bridge which can either be half bridge or full bridge depending upon the Clarifier tank size or plant requirement. This is the most basic unit and is available in sizes upto 60 M diameter & above.
• Conventional Circular Clarifier with peripheral drive is provided with a rake drive which travels on the peripheral tank wall driving the bridge which is pivoted at the centre and is carried on an adequately sized bearing supported on the centre pier. The rake arm is attached to the moving bridge which can either be half bridge or full bridge depending upon the process requirement mostly dictated by the sludge generation. In view of the moving bridge, the power supply is provided through a slip ring assembly mounted at the centre of the bridge sourcing power supply by the electrical cable laid through the centre pier.
• Clariflocculators with concentric flocculator zones can be provided in both the above options.
• Circular Clarifier with Tow Bro header which is mechanically similar to the central driven conventional circular Clarifier except that sludge withdrawal is achieved hydraulically through a hollow tube forming part of the rake assembly. This arrangement has following benefits :
  • Rapid Sludge removal ensures fresher sludge with less chance of septicity.
  • Maximum solid concentration as the header design ensures gentle action ensuring minimum disturbance for the settled sludge. This results in reduced sludge pumping cost.
  • Uniform sludge removal across the diameter of tank bottom in one revolution and hence less chances of sludge accumulation.

The Tow Bro header design can be retrofitted in the existing tank to improve its performance without any major modifications in the Clarifier Scrapper mechanism.

• Circular Clarifier with Rim-Flow arrangement is the peripheral feed and peripheral overflow unit where both these sections are placed on the periphery of the Clarifier tank top in such a way that the construction costs are minimized by combining these two sections into a single structure. These units are mainly used in Secondary and Final Clarifier applications involving biological treatment as they offer increased overflow rates due to greater hydraulic efficiency. This is achieved by reduced short circuiting due to intelligently placed feed and effluent launders ensuring that the water current passes through the longest path from feed to exit point and utilize the full tank volume. The deflector plate mounted below the feed orifices and the influent skirt baffle play an important role in this operation by uniform and gentle distribution of the feed stream into the tank. The increased overflow rate reduces the footprint by atleast one third compared to the conventional Clarifier units.
• Circular Clarifier with Rim-Flow Tow-Bro arrangement can be provided combining the benefits of Rim-Flow and Tow-Bro options into one unit.