Our work involved the structural analysis, framework and reinforcement drawings for the circular center-feed clarifier with a scraper sludge removal system as well as all related auxiliary facilities. The tank has a capacity of approximately 3 217m3. The clarifier consists of the tank which has a diameter of 32m. The tank wall is 4m high with a uniform thickness of 0.4m. The base slab is 0.4m thick, with 6.6% slope towards the center. The sludge drain channel is positioned at the top of the tank wall. The channel consists of a 0.2m thick wall and a base slab that is 0.3m thick.
The scope of this project included structural analysis, framework and reinforcement drawings of the Activated Sludge Tank (AST) and all auxiliary facilities. The AST consists of two tanks of approximately 40 × 65m each and 5.6m height. The tank is composed of RC walls supported on a raft foundation slab with thickening under the main walls. The average base slab thickness is 0.4m with four drainage pits in each chamber. Secondary walls in each chamber are 5.6m high with uniform thickness of 0.3m. External tank walls are 5.6m in height, with variable thickness ranging between 0.35m to 0.7m. Other auxiliary facilities on the tank are two service bridges. Their concrete grade was C25/30 with a concrete cover of 5cm.
The center-feed system is located in center of the structure and is supported by 8 concrete 40 × 40cm columns. Other auxiliary facilities along the reservoir are a drainage chamber, a de-sludging chamber and scum chamber. The thicknesses of the walls and chamber base slabs is 0.3m, apart from the base slab of the de-sludging chamber which is 0.4m. At the top of the de-sludging chamber there are gratings and stair access. The grade of the concrete is C25/30 with a concrete cover of 50mm.