Description
The CBU is a comprehensive combined unit designed for the preliminary treatment of wastewater before it enters a wastewater treatment plant. This unit efficiently performs three key operations: screening, grit removal, and grease removal.
In the screening process, wastewater passes through a screen that eliminates larger particles. This screen, which can be a spiral screen (TSS or SSS type) or a rotary drum screen (TR type), also washes and compacts the screenings before their discharge. The efficiency of this process is influenced by the screen’s perforation and its capture rate. Additionally, the screen tank can include a by-pass tank with a manual screen, and the screen basket or drum can be made from either perforated plate or wedge wire.
Following the screening section, the wastewater proceeds to the settling tank for grit sedimentation. A specially designed baffle in this tank ensures a laminar flow and helps to equalize temperature differences, thereby enhancing the sedimentation process. The settled grit accumulates in a pit and is then removed by an inclined screw conveyor, known as a grit classifier, which can optionally include a washing system.
For the removal of suspended particles such as oil, grease, and other substances, the unit employs a system of paddles made from stainless steel wire. The settling tank is equipped with an air blower to further facilitate the separation of organic matter and the settlement of grit. Larger units may be fitted with two blowers for increased efficiency.
The CBU unit can be manufactured in stainless steel (grade 304 or 316), with the spiral component available in either carbon steel or stainless steel, or a combination of these materials. In cases where grease removal is not necessary, the unit is modified to exclude the paddle system and is referred to as the CBU2.
The CBU offers flexible treatment options, capable of performing various combinations of processes:
- Screening, grit, and grease removal.
- Screening and grit removal.
- Grit removal only.
- Grease and grit removal (without screening).
To meet specific operational requirements, the unit can be equipped with a control panel upon request, available in either electromechanical or PLC-controlled formats.