The Use of Tube Settlers in Water Treatment

desalination, water conservation, waste water management

Water treatment systems use settling tanks unit to allow for sedimentation and settling. The main aim of tube settlers is to minimize the vertical distance that a small floc particle must settle before agglomerating into larger particles.

Water treatment is a major requirement both for raw water for drinking and wastewater management. Both have particles which need to sediment in order to obtain clear water.

Tube settler design involves the use of multiple tubular channels sloping at an angle of 60 degrees and adjacent to each other. This helps in increasing the settling area effectively. Tube settler design reduces the depth significantly compared to the conventional clarifier. This helps in reduction of settling time.

Tube settler collects solids into a compact mass and slides it down the tube channel. When using tube settlers water flow is upward through the tubes and the solids slide down against the current using gravity.

ADVANTAGES OF TUBE SETTLERS

  • They can be applied to new or existing clarifiers of any size
  • Tube settler clarifier increases the rate of operation by 2 to 4 times the normal rate of a conventional clarifier
  • They are available in varying sizes and shapes for fitting in different tanks
  • They are of lightweight because of the material used in manufacturing.
  • Tube settlers enable cutting of coagulant dosage and they maintain lower influent turbidity in the treatment of plant filters.
  • Saving of operating costs in water and electricity because of less filter backwash.
  • New installations can be made smaller because of the increased flow capability.
  • Tube settlers increase flow capacity through the expansion of settling capacity
  • They increase the solid removal rate in the settling tank

TUBE SETTLER’S DISADVANTAGES

  • May have flow distribution issues due to the smaller path of water flow which may cause plugging.
  • The material used for tube settler media may break and move downward into the filter membrane equipment.

TUBE SETTLER SPECIFICATIONS

Tube settlers are specified using

  • Size – it the diameter of the tubing in millimeters
  • Thickness – it defines the wall of the tube settler individual tube.
  • Quantity – it defines the number of tubes per meter square.
  • Weight – it is defined using Kgs per meter square.
  • Specific surface area – expressed as M2 per M3

TUBE SETTLER DESIGN

Tube settlers are designed using PVC, PP or FRP. The design may be the square type or round type tubing. The materials make them lightweight easy to retrofit.

USES OF TUBE SETTLERS

They can be used in the treatment of raw water. The source can either be a river or stagnant water.

Tube settlers save costs of boiling and condensation used to clean water.

Tube settlers are used in the treatment of sewerage water.

TUBE SETTLERS VS PLATE SETTLERS

Plate settlers are more reliable, have low maintenance and are long-lasting. As enhancement used in clarifiers, they decrease the footprint by as much as 50% over basins using tube settlers. Plate settler is made of stainless steel making them last longer than tube settlers.

Plate settlers require low maintenance than tube settlers

Plate settler require smaller basins than tube settlers

Plate settlers need specific installation height although the problem may be overcome by using special plant design.

The initial investment cost of plate settlers is greater than tube settlers

Plate settlers can be built with an enhancement that allows you to walk on during installation and maintenance. The walk-on enhancement enables high-pressure washing without causing damage to the plate settlers.

Influent distribution in plate settlers is blended with basin water and eliminating diving currents, short-circuiting and other differential density anomalies.

Effluent distribution – Plate settler have features that create even draw across the top tube. The mechanism ensures even distribution over the width of the plate settler.

CHOICE BETWEEN TUBE SETTLER AND PLATE SETTLER

The following variables should be considered when making a choice between tube settler and plate settler.

Specific application – it is the type of treatment required e.g. wastewater treatment or the amount of dirt in the raw water.

Space

The geometry of the treatment basin

Expected results

Lifetime costs of maintenance and replacement

Tube settler wastewater treatment ensures maximum clearance of sludge removal. The tubes extend the filter run time and use the minimal chemical to induce sedimentation.

Tube settler tank is used for clarification before getting the effluent. It is attached to the main quiescent zone and separated from the zone by the use of baffle.

Proven over time tube settler are ideal for water treatment especially if the budget is low. When using tube settler the efficiency can be increased by the length and increased no of the tubes in the tank. Currently, there is a tube settler made of stainless steel by some manufacturers. They reduce the shortcoming of PVC tube settler chards from breakages.

Good tube settler media should consider the topography to reduce wastage of resources.

Tube settlers are applicable for varying uses and are portable. They can be used in portable water treatment units.

Water treatment is a requirement for consumable water and when disposing wastewater. There are regulations defining the quality of water released to the environment after use in waste management.

Tube settler help in removing physical particles through sedimentation and do not remove the chemicals contained in the water. 

Tube Settler Vs Tube Clarifier

The difference between tube settler Vs tube clarifier is that a clarifier uses mechanical means when removing solids created by sedimentation while a settler aids in sedimentation. Tube clarifier clears what is created by tube settler.

CONCLUSION

Plate settler and tube settler both are technologies used to enhance sedimentation only. Each has its advantages. Tube settlers are affordable, reliable and effective.

Tube settlers are easy to upgrade because they use lightweight materials and installation procedure is not complicated.

Tube settlers wastewater treatment is an ideal technology for enhancing sedimentation.

 

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