On the decanter discharge, before entering into the treatment plant, a Primary screen may be required. This will be determined during testing of the effluent and depends significantly on the performance of the decanter.
The primary screen removes bulk solids (>3mm) to prevent settling in the balance tank as well as abrasion of the Membrane Bioreactor (MBR) membranes. The solid screenings are normally collected in a skip bin for disposal. The screened water flows into a pit, where it is transferred into the balance tank/pond.