Flocculator Design and Construction

Design Objectives

The goal The design objective of the flocculator is flocculator is to create the largest flocs possible without causing shear-induced floc breakup. Its hydraulic  The flocculator's hydraulic residence time is to be on the order of 5 minutes. The flocculator should preferably be compatible with the existing flow control module and sedimentation tank.

Theoretical Design

Determining Amount of Mixing and Maximum Shear

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The new flocculator has 31 channels and is about 35 cm long. The corrugated plastic dictates that each channel will be 0.7 cm by cm x 1 cm. The clearance between the end of each baffle and the water surface or flocculator floor is 2.5 cm. The plant flow is 100 mL/min and the height of the water in the last channel is 25 cm, in order for the new flocculator to be compatible with the existing sedimentation tank. The height of the water in the first channel is about 26 cm and the headroom is set to be 2 cm. The flocculator is therefore 28 cm tall. The maximum shear in the flocculator is 45 /s and the total mixing is 5300. The residence time is about 5.4 minutes. The flocculator is compatible with the existing sedimentation tank, but is incompatible with the existing flow control module due to the downward flow direction of the first channel.

An ISO A1 construction drawing was also created for the flocculator and a similar drawing was released for construction.

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Clear corrugated plastic, with 0.7 cm by cm x 1 cm channels, was chosen to be used to build for building the flow channels due to its lightweight and ease of construction. The bottom of the flocculator was made from a 1 inch a 1" diameter acrylic rod. Stands The supporting stands for the flocculator was made out of acrylic of 6" x 2.25" x 0.5" acrylic slabs.

Construction Process

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The stands for the flocculator were made by drilling 1 inch holes in thin acrylic " holes at the center of the acrylic slabs. A screw hole was then tapped from the top of each stand to allow a thumb screw to be inserted to keep the flocculator from rotating around the acrylic rod bottom.

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