Which is better, a cross-flow tank or a radial-flow tank?
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For our company’s wastewater, which contains suspended solids at levels of 3000–5000 PPM, which type of tank is suitable?
A cross-flow type is better. The structure and operating characteristics of cross-flow sedimentation tanks: To ensure that the wastewater flows into the sedimentation tank in a uniform and steady manner, flow rectification measures should be employed in the inlet area. The baffle at the flow outlet is generally 0.1–0.15 m above the water surface of the tank; the immersion depth of the baffle should be no less than 0.25 m, with values of 0.5–1.0 m being typical. The baffle is located 0.5–1.0 m away from the inlet. Outflow device for horizontal flow sedimentation tanks. The outlet weir not only controls the water level in the sedimentation tank but also has a direct impact on the uniform distribution of water flow within it. The overflow rate per unit length along the entire outflow weir in sedimentation tanks should be equal; for primary sedimentation tanks, it is generally 250 m3/m•day, while for secondary sedimentation tanks, it ranges from 130 to 250 m3/m•day. The toothed triangular weir is the most commonly used, and the water surface should be at 1/2 of the tooth height. To adapt to changes in water flow or uneven settlement of structures, an adjustment mechanism that allows the weir plate to move up and down must be installed at the weir opening, in order to keep the outlet weir as level as possible. A baffle should be installed in front of the weir to prevent floating debris, or a scum collection and removal system should be put in place. The baffle should be 0.1–0.15 m above the water surface, 0.3–0.4 m submerged under the water surface, and 0.25–0.5 m away from the outlet.
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A cross-flow design is better; if that doesn’t work, fillers can be added. The cross-flow design used in our company turned out to be too small, but adding fillers worked very well
Of course, a plug flow tank is the best choice – it has many advantages overall, and there’s plenty of information available on it, including knowledge useful for advancing in the field of water treatment.