Screening systems offered by Sigma include, but are not limited to:
- Static Screen
- Rotary Screen
- Bar Screen
From the collection sump, the wastewater is fed to the screening system to separate any larger solids and other waste materials. A static or rotary stainless steel screen is housed in a stainless steel screen box. The screens are vee-wire wedge type tangential screens or are bar screens separated at equidistant intervals. The screens have a slot size dependant on the application and range from below 1 mm to greater than 6 mm. The slot width ensures removal of solid bigger than the slot size. The screen box is designed specific to the application and comprises of solids accumulation, compaction and dewatering zones. Cleaning of the screens can be automated as required. The screens are generally self cleaning type with solids entering a collection chute falling into a collection bin. The screens are removable type and can be cleaned with wire brush during routine maintenance. The removal of solids by screening aids in reduction of total solids (TS) and associated biochemical oxygen demand (BOD). The wastewater after separation is sent to further treatment specific to the application.