Chemical Dose Controller, Summer 2011

Matthew Higgins

Abstract

Accurate chemical dosing in water treatment plants is imperative to ensure optimal efficiency during flocculation, sedimentation, filtration and disinfection. AguaClara designed the linear chemical dose controller (LCDC) and linear flow controller (LFC) systems to allow plant operators to reliably set and maintain a desired dose of coagulant and disinfectant. A linear relationship between head loss and chemical ow is created by using the major head loss through a small diameter tube to control the flow. To maintain this linear relationship, the systems have been designed to eliminate sources of minor head loss. Our team is actively working to minimize minor head losses through the systems, reduce the systems' maximum percent error and standardize the components and calibration techniques to be used to fabricate the systems in the field.

Structural Design of AguaClara Plants, Summer 2011

Lily Siu

Abstract:

Our main objective we wish to accomplish this summer is to analyze the reinforcement configuration and structural strength of the sedimentation and flocculation tank walls. In the previous semester, the structural design team analyzed the structural capabilities of the columns and walls for the Alauca plant using various assumptions and load cases. The previous team analyzed the walls as closely spaced concrete columns. By modeling the walls as columns the flexural support provided by the horizontal reinforcement is unaccounted for, but it allowed for the use of the same tools and procedures that is used for beam analysis. We seek to attempt to validate the previous team’s calculations as well as suggesting methods to analyze the horizontal reinforcement in order to reduce over-designing. This report is meant to augment the Spring 2011 report.

Sedimentation Tank Hydraulics, Summer 2011

Elana Liskovich, Mahina Wang, Jill Freeman, Yiwen Ng

Abstract:

A floc blanket is a dense fluidized blanket of flocs that helps to reduce effluent turbidity in the sedimentation tank by trapping other flocs. The geometry of the sedimentation tank is crucial in determining the extent of floc resuspension by the jet and hence floc blanket formation. To improve tank bottom geometry, nine experiments were conducted, each testing a different tank bottom geometry. The experiments were run in a 1/2 inch wide tank to model a thin slice of the full scale sedimentation tank. The geometry that resulted in the least sludge accumulation and therefore best floc resuspension was two 60 degree inserts leading to a semicircular trench 10 cm in diameter. We also provided initial designs and calculations for a floc weir to maintain the height of the floc blanket. A preliminary experiment was also conducted to evaluate the feasibility of our initial floc weir design.

Fabrication, 2011 Summer

Abstract

The Fabrication team focused on three main goals for the Summer 2011 semester. Firstly, we worked on developing a system to recharge a cordless power drill without using an electrical wall socket. Our solution was to connect the battery charger directly to a car battery, which may be easily brought to the site. Secondly, we researched more effective ways to remove plugs from hole saws. We determined that the commercially available Lenox speed-slot hole saws would best resolve this problem. Thirdly, we developed, tested, and improved a jig to help facilitate the assembly of plate settler modules.