Dose Controller for AguaClara Water Treatment PlantsEPA Grant Number: SU834338
Title: Dose Controller for AguaClara Water Treatment Plants
Investigators: Weber-Shirk, Monroe
Current Investigators: Weber-Shirk, Monroe , Swetland, Karen A. , Patel, Akta , Johnson, Dale , Ko, Harrison , Curtis, Kayti
Institution: Cornell University
EPA Project Officer: Page, Angela
Project Period: August 15, 2009 through August 14, 2010
Project Amount: $10,000
RFA: P3 Awards: A National Student Design Competition for Sustainability Focusing on People, Prosperity and the Planet (2009) RFA Text | Recipients Lists
Research Category: Pollution Prevention/Sustainable Development , P3 Challenge Area - Water , P3 Awards , Sustainability
Our objective is to design a Chemical Dose Controller (CDC) that can automatically adjust the head loss (and flow) in response to changes in municipal water treatment plant flow rate. Plant chemical dosing is determined based on plant inflow and turbidity, which changes greatly with storms and rainfall. The CDC will eliminate the need for plant operators to adjust the chemical feed systems when the plant flow rate changes. This will simplify plant operation and reduce the opportunities for error. With a CDC in place the water treatment plant will be able to increase the chemicals being dosed as soon as the plant flow rate increases, or a decrease in dosing as flow rate decreases. This automated response to plant flow rate is expected to improve plant performance. Rapid flow changes due to clogging or repair of the intake will no longer cause a treatment upset due to incorrect chemical dosing. The CDC will also eliminate the need for the operator to use a plant operating table or to do math in order to set the chemical feed flow rate. Instead the operator will directly set the desired dose and the chemical dose controller will take care of the rest.
Our designs are developed based on a combination of fundamental fluid mechanics and ongoing feedback from AguaClara water treatment plants in Honduras. The AguaClara team has already invented a gravity-powered flow controller that delivers a constant flow rate and that is adjusted simply by raising or lowering a flexible tube. Although the AguaClara design process is sophisticated, the resulting designs are simple and use components that can easily be repaired and replaced by plant operators. We will extend this approach to the CDC and will create designs that work over a broad range of flow rates.
The expected results include a proven design for a gravity powered dose controller that works for calcium hypochlorite or aluminum sulfate solutions. The dose controller will be coupled with plant flow rate measuring systems that have compatible relationships between flow rate and head loss. The dose controller design will be documented on the AguaClara wiki and will include detailed design specifications and AutoCAD drawings.