The ultra high rate solids contact clarifier (UHRSCC) is a compact, efficient and low cost clarifier for surface water and wastewater clarification. The UHRSCC design combines technology of solid contact clarifier and plate clarifier. As a result the unit gives improved performance at increased rise rate. The unique design of UHRSCC offers all the advantages of solid contact and plate clarifier and limitations of individual technology is eliminated.

The INDION UHRSCC unit is a true solids contact clarifier that combines mixing, flocculation and sedimentation in a single basin. Raw water and chemicals mix with previously formed sludge then pass through distinct zones within the basin for reaction, flocculation, separation, sludge removal and clarification. All occur in a single treatment basin for maximum treated water production in minimal space. With all the advantages shown above, the best choice in solid contact clarifiers is the INDION UHRSCC.

The INDION UHRSCC unit excels in treating surface and ground water in such applications as turbidity removal, iron and manganese removal, colour removal, etc.

Success of solids contact clarification results from bringing raw water and treatment chemicals into intimate contact with previously formed precipitates. These precipitates help accelerate the chemical reaction and serve as a “seed” (deposit point) for newly-formed precipitates. This helps to maximize the treatment chemical efficiency and create large heavy sludge particles that settle rapidly.


Mixing zone

Raw water and chemicals are intimately mixed in the draft tube in the presence of previously formed sludge recirculated from the bottom of the basin. A high efficiency impeller re-circulates the sludge into the reaction-flocculation zone.

Reaction-flocculation zone

The reaction-flocculation zone also called detention hood receives the total mixed flow from the mixing zone. Flocculation is accelerated here by the intimate contact between reacting chemicals and re-circulating precipitated solids on which the newly forming material is deposited. Part of the flow, equal to the raw water rate, is then discharged into the separation (clarification) zone, and the remaining flow is recirculated into the mixing zone.

Clarification zone

The large area under the edge of the detention hood ensures even distribution and low velocity entrance to the clarification zone. The water enters the outer clarification zone with a dense and bigger size of particles, which settles rapidly. Hence it is not necessary to maintain a suspended deep bed of precipitate (sludge) in the settling zone as required for sludge blanket solid contact type of clarifier.

The settling area of the clarification zone is greatly enhanced by inclined lamella plates installed near the top surface of the clarification zone that ultimately reduces the unit size, handles more flow and gives better quality. The overflow from the clarification zone is collected from both the sides of the plates through adjustable overflow weirs. This ensures equal distribution of flow among the plates and eliminates uneven loading.

Sludge removal and recirculation

A portion of the sludge in the recirculation settles to the bottom of the basin. This settled sludge is moved to the center of the basin by a slowly rotating scraper. The scrapped sludge falls into the sludge hopper where sludge thickening pickets concentrate the sludge and reduces the blow down.

The sludge is automatically or manually removed at regular intervals. The remainder of the sludge is recirculated through the draft tube and used to increase the solids content in the flocculation zone and enhance flocculation formation.



  • Combined technology of solid contact clarifier and plate type clarifier.
  • Reaction, flocculation, separation, sludge removal, and clarification occur in a single treatment basin.
  • Minimal space requirement.
  • Intimate and prolonged contact with large quantities of previously formed solids.
  • Positive uniform recirculation of solids independent of feed flow.
  • Lamella plates in the clarification zone.
  • Entire bottom of UHRSCC unit is used for settling and collection of dense precipitates.
  • Slowly moving multi-blade sludge scraper arms carry the settled precipitates into a sludge hopper at the center of the unit.
  • Continuous removal of heavy precipitated sludge from the bottom of the unit.
  • Thickening pickets concentrate the settled sludge, which is then removed as a highly concentrated slurry.
  • Simple to operate.
  • Minimum operator attention required.


  • Impoved performance at very high flow rates.
  • Improved performance at very high flow rates.
  • Rapid chemical reaction.
  • Complete chemical reaction.
  • Dense, easily settled precipitates.
  • Minimum chemical requirement.
  • Thorough contact with solids.
  • Sudden flow fluctuation does not affect the performance.
  • Uniform results obtained regardless of feed suspended solid fluctuation.
  • Minimum energy consumed.
  • Utilization of complete area.
  • Handles higher flow rate.
  • Reduces the overall size of the equipment hence the cost.
  • Gives better outlet quality.
  • Effective solid handling and sludge removal.
  • Maximum consistency of sludge.
  • Minimum amount of water lost through sludge blowdown.
  • Maximum solids concentration for subsequent dewatering steps.


  • Clarification of surface water
  • Removal of colloidal silica
  • Colour removal
  • White water recycling
  • Primary treatment of wastewater
  • Removal of heavy metals in the chemical and automobile industries

In conclusion, the INDION UHRSCC unit stands out as a compact, efficient, and cost-effective solution for the clarification of surface water and wastewater. By seamlessly combining the technology of solid contact clarifiers and plate clarifiers, it offers a wide range of features and advantages, from improved performance at high flow rates to minimal space requirements and energy-efficient operations. This versatile system is highly effective in addressing various water treatment challenges, including turbidity removal, iron and manganese removal, color removal, and more. With its innovative design and robust performance, the INDION UHRSCC unit proves to be the optimal choice for industries and municipalities seeking reliable and efficient water clarification solutions. Whether it’s enhancing water quality or optimizing wastewater treatment processes, the UHRSCC unit is a game-changer in the field of water and wastewater treatment.

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