Chemical Dose Controller

Overview

The Chemical Dose Controller is a critical piece of the AguaClara technology which couples the plant flow rate with the flow rate of the coagulant or disinfectant stock solution. The result is a semi-automated system in which the plant operator only needs to set a dose for the chemical and it will be administered automatically as the plant flow rate varies. The device has evolved steadily with major advances every year. The ability to accurately and predictably control the alum and chlorine dosages without electricity sets AguaClara technology apart from other water treatment technologies. Our Dose Controller technology that couples plant flow rate and chemical dose is novel.

Figure 1: General Schematic of Chemical Dose Controller

The Non-Linear CDC makes it possible for an operator to set the chemical dose without referring to any tables. This could be a significant advantage. The disadvantage is that this design is more complex and thus we will need to work this carefully to ensure that the CDC technology is sustainable.

Current Research Team

Fall 2010 CDC Development

• Our goals are 1)To become familiar with the current apparatus, design parameters and constraints. 2) To design a Nonlinear Chemical Dose Controller that can be scaled up or down depending on an input plant flow rate. Also, we would like to improve the design so that it will incorporate the different chemicals used in the plant in addition to alum such as chlorine.3)To create appropriate databases for the materials used (i.e.: float valves, frame, tubing). Additionally, we will be further investigating frame and component materials that are compatible with the chemicals and can be found locally.

Past Research Teams

Academic Year 2009/2010 Nonlinear Chemical Doser

• Redesigning a chemical doser with a precise nonlinear chemical dose response to changes in plant flow while also minimizing aeration in an attempt in prevent surface foams.

Summer 2009 Research: Surface Foam Formation

• Trying to model the surface foam formation that takes place at the end of rapid mix in current plants and come up with a retrofit design that will minimize air entrainment.

Linear Chemical Dose Controller

• The linear dose controller uses major losses to adjust chemical doses to the plant as raw water flow rates change.

Nonlinear Chemical Dose Controller Fall08-Summer09

• Major losses cannot be used to adjust chemical flow rates when flow in the dosing tube is turbulent. Therefore, a chemical doser with a precise nonlinear chemical dose response to changes in plant flow is being designed.

Rapid Mix Chamber Design Program

• The design of the entrance tank for high flow rate plants such as Gracias.

Summer 2010 CDC Research

• Validate the Nonlinear Chemical Doser by measuring both precision and accuracy to determine the best manufacturing techniques, document surface tension issues and to determine if material selection plays a role in accuracy or precision.
• Investigation of various materials and determine the most appropriate components to use.