Documents
Members
Spring 2011
Anna Lee
Tiffany Tsang
Yiwen Ng
Summer 2011
Elana Liskovich
Mahina Wang
Jill Freeman
Yiwen Ng
Abstract
The Sedimentation Tank Hydraulics Team performs laboratory research to determine the geometry of the sedimentation tank and the design of the inlet manifold so that a floc blanket forms efficiently. This lowers the turbidity of effluent and is also an indication of uniform flow and the elimination of dead zones. Current modifications to be tested are 1) the insertion of 60˚ incline planes along the perimeter of the tank, 2)manifold diffusers that extend 5 in from the tank bottom that direct downward-flowing jets of flocculated water. It is hypothesized that the diffusers will eliminate non-uniform form with respect to the length of the tank and resuspend flocs that have settled out and were directed to the jets via the incline planes. In order to test these modifications, a tube flocculator and sedimentation tank have been designed so that the upflow velocity in the tank equals the settling velocity, which is dependent on floc size and therefore controlled by parameters of the tube flocculator, as confirmed by previous experiments.
Introduction and Objectives
The current design of sedimentation tanks in Agua Clara plants consists of plate settlers placed above the inlet manifold that catch flocs formed in the flocculator while allowing water to flow past the settlers into exit launders. The flocs then settle out at the bottom of the sedimentation tank and are removed regularly by a sludge drain. Because of non-uniform flow, 1) flocs accumulate unevenly in the tank which causes difficulty in removal, 2) dead zones are created in the tank that lower the efficiency of the system.
We wish to determine the geometry of sedimentation tanks so that uniform flow is achieved and dead zones are eliminated, which would improve the efficiency of the current tank design and decrease the labor needed to maintain a clean tank. Given a particular upflow velocity, under these hydraulic conditions we may also experiment with floc blanket formation, which we believe will provide a second filtration stage for upward flowing flocs in the sedimentation tank and lower the turbidity of the effluent. Flocs may then be drawn off the blanket with a weir, minimizing the effort needed to clean the tank.
Experimental Methods and Results
Spring 2011
Sedimentation Team Research Rationale
Sedimentation Team Research Rationale2
In our Research Rationales, we explained in detail our design procedure and the reasons for such design. It also contains list of potential experiments we will be running this semester.
Sedimentation Team Research Report 1
Detailed report describing the experiments the results from the experiments we ran this semester.
Sedimentation Team Final Research Report
Detailed Final Report, summarizes Spring 2011 semester's sedimentation team work.
Summer 2011
Sedimentation Team Final Research Report
Zipped folder containing Final Research Report in Lyx format, together with attached images.