Clarification is one of the widely used and oldest methods of wastewater treatment, according to Ashton Tucker Water Treatment. Clarifiers, also called sedimentation tanks, in wastewater treatment work on a principle of gravity.
Heavy suspended solids in wastewater settle at the bottom and end up in the center well by scraper blades for collection. There are different types of clarifiers available from online shops. The ideal water treatment clarifier for you depends on your intended function and space availability. Here are the three main designs of water clarifiers.
A circular clarifier design consists of a large influent well, deep scraper blades, adjustable skimmers and cast iron drive housings. The influent well is at least 10 feet in diameter. The influent enters your clarifier not from one end but rather from the center. Circular clarifiers are sensitive to hydraulic load and temperature fluctuations since their flow pattern is entirely dependent on inlet hydraulics.
Rectangular clarifiers have their inlet and outlet at opposite ends. A typical rectangular clarifier has a 4:1 length to width ratio. The traveling cycle time in this design depends on the solid characteristics and type of wastewater. Rectangular clarifier designs are mostly used in industrial and municipal settings as they require an ample space.
This design consists of inclined plates ate 55- to 65-degree angles. Water travels upwards, and the solids settle at the bottom. A lamella design has high efficiency due to its extensive surface area and needs a small space for installation. The design is common in industrial settings as biological growth from organic waste reduces the clarifier’s efficiency.
In most cases, the natural settling of sediments in a clarifier gets an improvement by adding a polyelectrolyte and coagulant. The coagulant is useful in neutralizing the charges and agglomerating the sediments forming Microfloc. The polyelectrolyte binds the Microfloc in long chains making them heavy enough to settle at the clarifier’s bottom.