Stock Tank Mixing

Stock Tank Mixing

The Fall 2013 Stock Tank Mixing team is researching design improvements in the stock tank that will ensure stock solutions are uniformly dense before they are delivered to raw water.

The first Stock Tank team goal is to obtain appropriate hydrometers for usage at plants. Ideally, the hydrometers will be made of polycarbonate or some other shatter-resistant material. Typical AguaClara PACl solution concentrations of 100-200 g/L require a device capable of reading between 1.0-1.2 SG and typical AguaClara chlorine solutions require a device capable of reading between 1.012-1.013 SG. Currently, the $74 Krackeler Scientific 1.000-1.220 polycarbonate hydrometer is being utilized to measure the density of PACl coagulant solution. The team is still researching devices for usage with chlorine; the $33.50 Cole Parmer 1.000-1.050 glass hydrometer with 0.0005 divisions is the tool currently used. Chlorine solutions pose an interesting challenge because they require a much smaller range than typical polycarbonate hydrometers for accurate measurement.

Additionally, the Stock Tank team is working on designing a centrifugal pump to completely mix the stock solutions. Current designs utilize a rotating arm that employs the pressure gradient due to rotation to bring the more dense solution located at the bottom of the tank to the top. Previous teams' designs were modified to a small scale to allow for testing and design evaluation/adjustment. Recent tests show high pump inefficiency due to large amounts of wasted input power due to drag on the rotating arm. Further tests should determine the source of this inefficiency, regardless of if this overall design schematic is pursued. Future design options include tweaking this general design setup or evaluating the possibility of reversing the direction of water flow, using rotating blades, and adding baffles.

Team Members

Apoorv Gupta
Alexandra Cheng

Past Research