The sedimentation process in both water and wastewater treatment is a physical process which relies on gravity to settle and remove suspended solids. Advanced solids settling processes typically utilize lamella, commonly referred to as tube settlers or plate settlers, to reduce the vertical distance solids particles must fall until hitting a “settling surface”. Higher flow rates, better effluent quality, and more compact sedimentation basins can all be achieved with both types of lamella sedimentation equipment. Although both operate on the same principles of solids settling and can be used as basis of design in many cases, there are several notable differences between the two technologies.
Characteristics of Tube Settlers and Plate Settlers
Tube settlers utilize multiple adjacent tubular channels that are sloped at a nominal 60° angle and combine to form an increased effective settling area. The size and shape of the tubular channels vary by manufacturer. Brentwood’s tube settler design features a trapezoidal shape created by thermoforming PVC sheets. You can learn more about our design process by reading our Thermoformed vs. Extruded Tube Settlers blog.
In contrast, plate settlers use a series of inclined plates, typically constructed of steel, which are spaced two to three inches apart from each other on a 55° to 60° angle to form an increased effective settling area. As a result of these design differences, typical design parameters for these two types differ.
Comparing Design Parameters
It is important to note that there is a difference in application rate (flow rate/coverage area, expressed in gpm/ft2) between tube settlers and plate settlers as a result of different effective settling area terms used, despite settling principles being similar for the two technologies. To provide a more direct comparison, the application rates of tube settlers can be converted to an equivalent “plate” application rate by taking into account the projected surface area of tubes:
As illustrated in the above table, the equivalent maximum “plate” application rates of Brentwood tube settlers are in the same range as a generic plate settler, which has an average application rate of 0.30. IFR6041 tube settlers are the most comparable to plate settlers in regard to coverage area because settler length is similar. However, Brentwood’s other tube settler modules are capable of treating required flow just as effectively with appropriate coverage area. Tube settlers also eliminate cross-flow and eddy currents, which makes flow hydraulics more stable and efficient.
In addition to varying design approaches, there are other advantages and disadvantages to consider when comparing tube settlers or plate settlers for your application:
Tube Settlers
Advantages:
Lightweight PVC results in easy installation and does not require heavy lifting equipment
Lower capital cost due to materials of construction
Applicable in shallow tanks with underflow velocity concerns
Twenty to twenty-five year service life, provided proper maintenance is performed
Only PVC tube settlers are replaced at the end of their useful life typically supporting structures and effluent troughs can remain
Tube settlers are strong enough to walk on top of for proper maintenance
Highly customizable to accommodate varying basin configurations
Disadvantages:
Maximum module vertical height is 41 inches, resulting in a maximum application rate of 3.5 gpm/ft2
PVC must be protected from extensive UV exposure. Brentwood tube settlers do contain UV inhibitors. AccuGrid protective surface grating is also available for additional UV protection.
Plate Settlers
Advantages:
Less limitation on depth
Longer lifespan due to material of construction
Disadvantages:
Two to three times higher capital cost
Higher installation cost due to required heavy lifting equipment
Deeper basin requirements to accommodate underflow velocities
Risk of corrosion in certain environments (certain industrial wastewater applications)
Polyhedral Hollow Ball packing is made from heat resistant and chemical corrosion resistant plastics, and the application temperature in media ranges from 60 to 150 degrees.
Plastic Polyhedral Hollow Ball (PP, PE, PVC, CPVC, RPP ) is also called plastic multi-aspect hollow ball, polyhedral hollow ball packing composed of two hemispheres which will form into a ball. And each hemisphere consists of a number of half fan-shaped leaves, the upper and lower leaves in a staggered arrangement. The design concept is advanced and the structure is reasonable. Plastic Polyhedral hollow balls have the virtue of light weight, wide free space, small wind resistance, and good surface hydrophilic, big full wet surface area and convenient filling in the equipment and sound usage effect.
Plastic polyhedral Hollow Ball can be used in sewage treatment, desulfurization of CO2 in power plant, desulfuration and purified water tower packing. Plastic multi-aspect hollow ball is a new type of high-efficiency tower packing applied in water treatment equipment.
Pall rings are the most frequently used form of random packaging. They are made of metal and plastic. They also have different applications. Our experts will give you the most beneficial info about pall rings through this blog at Linquip. To find more, read on.
As said above, pall Rings are a random ring-type packaging with a well-established success background and a globally distributed base. They try to increase the use of packaging by disrupting the flow by providing an increased number of edges while reducing the volume of the ring packing medium itself. Pall rings have identical cylindrical dimensions but have window rows that improve the surface area size. They are ideal for low-pressure drops and applications with high power. They have randomness and relatively high liquid retention that promotes high absorption, especially if the reaction rate is slow. Pall rings’ cross structure makes them mechanically robust and ideal for deeply packed beds.
Pall ring is applied in a variety of areas, including:
Different Separation and Absorption
Absorption and Stripping Services
Steam Stripping
Quench Towers
Direct Contact Cooling
Reaction Towers
Distillation Columns
Tower Packing
Random packaging has been used for over 50 years to boost the efficiency of a tower.
In comparison with high-performance packing, plastic pall rings are less sensitive to liquid distribution quality and have a higher hold-up and residence time. Although plastic pall rings do not have “high performance” characteristics, they are