Plastic Lamella Clarifiers

A honeycomb inclined tube settler is a block of small, six-sided plastic tubes that is fitted into a sedimentation tank to make it clarify water much faster. To understand it, picture ordinary settling: dirty water sits in a tank and the suspended particles slowly sink to the bottom, which takes a long time because they have to fall the whole depth of the tank. The tube settler shortens that fall. The tubes are stacked at a steep angle and packed tightly across the tank, so a particle carried up through a tube only has to sink a centimetre or two to reach the sloping tube wall. Once it touches the wall it is out of the flow, and it slides down the incline back to the sludge blanket at the bottom, while the now-clean water carries on upward and out. Because every tube is doing this at once, the pack behaves like an enormous number of shallow settling tanks stacked into the space of one, so a great deal more water can be clarified in the same tank. That is the whole idea, trade the long fall for many short ones.

It is the principle of shallow settling. How fast a tank can clarify water depends not on its depth but on its settling area, the plan area over which particles have room to land. A deep tank and a shallow tank of the same footprint settle at the same rate; the depth just wastes volume. Inclined tubes exploit this by adding surface. Each tube wall is a settling surface, and packing thousands of tubes into the tank adds up to a settling area many times the tank's own footprint, often ten times or more. More area means more particles caught per minute, so the tank handles a much higher flow before solids start to escape in the overflow. Two details make it work cleanly: the flow inside the narrow tubes is laminar, smooth rather than turbulent, so it does not stir settled particles back up; and the steep incline lets the collected solids slide down on their own instead of clogging the tubes. Add surface, keep the flow gentle, and let gravity clear the tubes, that is why it beats a plain tank.

The honeycomb comes in three common pore sizes and three materials, chosen to match the water and the duty. The pore size, the width across a tube, is offered as 35, 50 and 80 millimetres. Smaller tubes give more settling surface and the sharpest clarification, so the 35 mm size suits clean-water work and fine, light solids; the larger 80 mm passes heavier, stickier or more concentrated sludge without blocking, so it suits dirtier wastewater; 50 mm is the general middle choice. The material is PP, PVC or FRP. PP is the usual, light and chemically resistant choice; PVC is a low-cost option for mild service; FRP is the strongest and best for large, deep packs or hot or aggressive water. Wall thickness rises with the pore size and the material. As a rule: pick the pore size by how dirty the water is, and the material by the chemistry and the load. Tell us the water and the flow and we will specify the pack.

A honeycomb tube settler is used wherever suspended solids have to be settled out of water. In drinking-water plants it clarifies the water after coagulation, before filtration; in wastewater treatment it serves as the settling stage in primary and secondary clarifiers and in tertiary polishing; and it is used in industrial process and effluent water, and in applications like sand and grit removal. One of its biggest attractions is upgrading existing tanks. Because it multiplies the settling area, dropping a tube-settler pack into an old, overloaded sedimentation tank can lift its capacity substantially without building anything new, a cheap way to get more out of an existing works. And for a new plant, designing the settler in from the start means a much smaller tank for a given flow, saving footprint and construction cost. It installs quickly, resists corrosion, and lasts for years. Send us your tank size and flow and we will size the pack.