Grit Removal Innovative Technologies (GRIT) Team
Introduction
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The current design of the AguaClara entrance tank was created after difficulties with grit clogging the flocculator at Agalteca and Marcala. The solution to the grit problem was to make a large entrance tank that is effectively a horizontal flow sedimentation tank, which would settle out larger "grit" particles. The entrance tank could be made smaller by making a more effective grit removal system that uses plate settlers that double as flocculator baffles. This section of entrance tank could be integrated into the first channel of the flocculator. By Because of past problems involving grit clogging flocculators, the GRIT team explored grit removal design using plate settlers before flocculation, deciding on an iteration of design called the Channel GRU. It decreases the plant’s plan view area by reducing the size of the entrance tank or integrating it into the flocculator, the plan view size of the overall plant will decrease. This means a decrease in plant construction costs, ensures even flow distribution using creative plate-to-floor geometry, and incorporates chemical dosing and rapid mix after grit removal. This design has been sent to Honduras for construction. |
Current Research
The current AguaClara plant design requires a large entrance tank to settle out grit particles prior to the flocculator. Grit removal by horizontal flow sedimentation prevents the settling of these large particles in the flocculator (a phenomenon that has been observed in several AguaClara plants to negatively affect plant flow and operation). The purpose of the Grit Removal Innovative Technologies (GRIT) team is to redesign the current grit settling system by introducing plate settlers prior to the flocculation unit. In doing so, the plan-view area needed to settle out grit will be greatly reduced, decreasing construction costs and overall AguaClara plant size. This paper outlines the GRIT team’s process exploring plate settler design options that act either as sedimentation units only, or as combined flocculation and sedimentation units.
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With about a month left of the semester, the team was asked to design a grit removal system for a potential plant to be built in San Juan Guarita. The plant would be integrating various new technologies into its 4 L/s design, along with grit removal. We decided on utilizing the last iteration of our design, the Channel GRU, for this plant design after considering all the pros and cons of each iteration. The resulting design was coded into the design code, and AutoCAD representations of the entire plant, including the Channel GRU, were drawn.
Figure 3.a.i. A zoomed-in view of the GRU, which is elevated above the rest of the flocculator channel (to the right). The red pipe is the pipe stop, the blue pipe on the left is the water inlet, and the blue pipe on the right is the LFOM.
Figure 3.a.ii. The zoomed-out version of the entire flocculator channel, including the GRU, for scale. This length is the same length as the sedimentation tank (hidden).
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