What Is A Sedimentation Tank? Types Of Sedimentation Tanks?
What Is A Sedimentation Tank?
Sedimentation tanks are large, rectangular tanks with sloping sides. They are used to treat raw water before it enters the distribution system. Water flows through the sedimentation tank and separates suspended solids and other unwanted materials (fines).
Sedimentation tanks can also remove heavy metals and other pollutants from water that has already been treated by conventional processes such as filtration or chlorination.
What Are Various Types Of Sedimentation Tanks?
There are several different types of sedimentation tanks with varying shapes and sizes, as well as methods of operation that affect how quickly they can process their contents. The following list provides some information about each type of sedimentation tank:
- Horizontal flow tanks.
Horizontal flow tanks are widely used in the industry as they have many benefits. These include:
– Easy installation and maintenance
– Less space required for installation compared to vertical flow tanks
– A simple design that allows easy access to the bottom of the tank for cleaning purposes.
A horizontal flow sedimentation tank consists of an outer and inner shell, separated by baffles or partitions that act as barriers between each stage of treatment (settling).
Water enters through an opening at one end of this vessel and flows horizontally through it until reaching its destination point, where it exits via another opening on its opposite side.
To calculate how much space is needed to install such a structure, we must first understand how sedimentation works inside them!
- Radial flow tanks.
Radial flow tanks are circular vessels divided into three concentric zones. In these tanks, sludge is pumped from the centre to the outer zone while the liquid is pumped from the outer zone to the centre.
This concentrates sludge in an annular space between two concentric plates or discs that rotate together with shafts rotating at different speeds.
- Inclined settling.
Inclined settling is a process that uses gravity to help settle suspended solids in water. The tank is filled with water and sludge and left alone for some time so that the heavier particles can sink to the bottom and form layers. This process is called sedimentation.
Sedimentation tanks are used in many industries, including agriculture, food processing, and pharmaceuticals; however, they are most commonly used in municipal wastewater treatment plants (WWTPs). Inclined settling tanks use gravity drainage techniques where liquid flows down an incline toward an outlet pipe at one end of your storage vessel. At the same time, solid material stays behind due to its greater density than liquids or gases in the same space.
- Ballasted sedimentation.
Ballasted sedimentation. In this type of sedimentation, the solid particles settle by gravity. The settling velocity of a particle is proportional to its density and the square root of its radius:
V = k r^2 where V = settling velocity (m/s), k = constant (2 for most materials), and r = radius (m).
- Floc blanket sedimentation.
Floc blanket sedimentation is a process similar to ballasted sedimentation. In this case, however, the floc blanket is used instead of sand to remove solids from water.
The floc blanket is a porous membrane that attaches itself to suspended particles in the water and removes them through filtration.
Floc blankets are typically made out of cellulose fibers or synthetic materials such as polyvinyl alcohol (PVA), which can withstand high temperatures without deteriorating.
- Sirofloc® Process.
This patented process uses negatively charged polyelectrolytes to reduce suspended solids and colloids in water. It attracts positively charged particles such as colloidal silica, calcium carbonate, magnesium hydroxide, and other minerals found in water.
The positively charged particles are then removed from the water through flocculation (clumping together into larger particles), followed by adsorption onto the negatively charged polyelectrolyte resin beads.