Gravity separation is a function of available surface area for separation. The Tilted plate interceptor offered by Paramount with technology acquired from M/s. PWT, Holland provides an extensive reduction in surface area requirement of a separator by introducing multi layer separation wherein area required is reduced considerably depending upon a number of such layers. It is feasible to achieve almost complete removal of all the particles which would not have normally be achieved by a single large surface separator. This is possible because of a considerable increase in the surface area of the unit, within the same depth. In most of the cases, the plates are installed at an angle of 45° or more and thus the separated material can be collected and removed by gravity.

As corrugated plate packs are predominantly used, the tilted plate pack type separators are widely known as Corrugated plate interceptor or simply as CPI separators. However, a TPI (Tilted plate interceptor) may use a corrugated type plate pack or simply plain parallel plate packs. Hence, TPI separator or Lamella separator is a generic terminology used in such type of separators.

The salient features of a TPI/ CPI separator are:

• A double slotted baffle located at the inlet of the CPI/ TPI separator evenly distributes incoming effluent water at the entrance of the plate pack separator.
• In the plate pack of the CPI/ TPI separator, the droplets of the lighter liquid are intercepted and coalesce into large droplets. They leave the pack rapidly countercurrent upwards against the liquid flow to the surface.
• Suspended solids having settling properties, if present in the aqueous phase is similarly separated in the plate pack of CPI/ TPI separator and then slides down to the sludge compartment.
• The treated clear lighter phase liquid or treated effluent (as in oil in water separators) from the CPI/ TPI separator leaves the plate pack at the bottom and gets discharged over a weir arrangement and to the outlet nozzle.

TPI/ CPIs can be supplied in modules of up to five plate pack per basin. Paramount has specialized in the design of TPI/ CPI separator installation in both RCC (Reinforced cement concrete) and steel basins. The selection of the basin of the TPI/ CPI separator is advised to the client based on the basic requirement, adaptability, time and economy criteria envisaged in the treatment process installed.