OPTIMISATION AND UPGRADING OF A PLANT FROM 100 l s[sup(–1)] TO 250 l s[sup(–1)]

From the flocculator, the water flows to three settling basins by way of a manifold 1.00 m wide by 0.80 m deep, entering each basin through two gates 0.30 m wide and 0.70 m deep. The three settling basins are 6.75 m wide and 23.70 m long. The depth varies from 3.60 m at the entrance to 4.20 m at the sludge drain and up to 3.00 m at the outlet. There is a permeable baffle at the entrance with four rows of 0.10 m square ports. Each row of each settling tank has eight parts. Settled water is collected in three channels 3.75 m long, located one at each side of the basin and one in the middle as shown in Figure 8.1.