Spectrophotometer, Fall 2015

Bryan Melara Sosa & Michael Stella

Abstract:

The goal of this research was to create a spectrophotometer that would efficiently detect red dye concentration in water. Creating a low cost, inline design that would be implemented at each lab station in the AguaClara lab was a priority. Red dye concentration was measured by fabricating a photo sensitive sensor that measured the voltage of different standards of red dye concentration. Then, various red dye standards were tested to calibrate the sensor of the system. The goal of calibration was to check in real-time the efficacy of the AguaClara system (or part of the system under study) by integrating the spectrophotometer with the team’s Process Controller software.

Ram Pump, Fall 2015

Priya Aggarwal, Juan Guzman, Joshua Levi Ringquist

Abstract

The ram pump used at AguaClara plants uses gravity and hydraulic principles to operate. The surge in pressure of the water due to the closing of the waste valve is used in the ram pump to lift water to a higher elevation. The ram pump is placed below the water treatment plant and it is used to drive the water to the chemical stock tanks and the restrooms located above the plant. Ram pump design parameters, specifically spring components, check valve type, and air chamber size, were tested to determine their effects on ram pump efficiency. Additionally, the pump needed to be reassembled this semester. The team has changed the design to make it more portable to avoid needing to rebuild the pump if it must be moved again. It is much easier to test different parts of the pump when leaks occur or if a part does not work as it is supposed to with the new setup. The team also tested air chambers and different spring lengths this semester.

UASB - Fall 2015

Zoe Maisel, Evan Greenberg, Yi Guo, Mason Minot

Abstract:

The Fall 2015 U​pflow Anaerobic Sludge Blanket (UASB) g​roup has continued the previous work of the AguaClara anaerobic wastewater groups. A literature review of technical journals was conducted to gain familiarity with the current state of anaerobic wastewater treatment technology internationally. The reports from previous wastewater groups were also reviewed to provide insight into the current state of anaerobic wastewater technology within AguaClara. The literature review served to identify common challenges to address during this and next semester including reactor leakage and creating an airtight design, combining a UASB unit with a GSBR unit in an attempt to improve overall treatment capacity, and oxygen stress testing to determine the robustness of the reactor. The beginning of the semester was spent cleaning and removing biomass from reactors, testing for leaks using a bubble solution, and performing a single ­day pressure test in an attempt to approximately quantify the volumetric leakage rate. Two UASB reactors were inoculated and began producing biogas within the first week of operation. COD analysis and gas chromatography were performed to characterize the efficiency of COD treatment and methane production within the reactors.

Whatever it is, the way you tell your story online can make all the difference.

EStaRS - Fall 2015

Skyler Erikson, Lilly Mendoza, Natalie Mottl, Lishan Zhu

Abstract:

The Fall 2015 EStaRS team reworked the lab scale setup of the EStaRS filter to work without a large pool to preserve lab space. The team then finished the orifice inlet implementation that was begun in Spring 2015, and provided an operating procedure for both filtration and backwash to avoid trapping sand in the inlets during the transition. The biggest takeaway from the operating procedure is that orifices can be operated successfully as long as the backwash transition does not create a drastic pressure change. Slowly closing the gate valve on the backwash siphon provides a gradual change and does not trap sand in the inlets. This procedure was the result of numerous inlet cloggings, and thus the team also devised a method for unclogging inlets without disassembling the filter. The team also implemented a pressure sensor to track headloss accumulation through the filter bed in the entrance tank. This pressure sensor was used to measure a clean bed headloss which is very close to the design clean bed headloss.

Modular Designs - Fall 2015

Stephanie Sun

Abstract:

The Fall 2015 Modular Designs task is a continuation of previous efforts to provide AguaClara clients the ability to request individual component designs on the AguaClara website.In Fall 2012, design team member Heidi Rausch began working on creating upper levelMathCAD files that the design tool will use to create individual component designs in addition to the already available full scale plant design. The goal of the Fall 2015 Modular Designs team is to continue working on the modular designs by updating already existing component files as well as creating new upper level files for other parts of the plant.

Chemical Dose Controller - Fall 2015

Serena Takada

Abstract

This semester, the Chemical Dose Controller (CDC) Team improved the AguaClara Automated Design Algorithm by updating the CDC drawing file to reflect recent updates in the CDC system design. Updating the CDC drawing code will allow clients and team members to obtain an accurate design of the current AguaClara plant designs using the AguaClara Design Tool. When 1 the existing CDC drawing code was implemented with the most uptodate drawing at the beginning of the semester, AutoCAD outputted the design illustrated in Figure 2. As shown in Figure 2, with the existing code, the CDC system is located inside of the Flocculator even though it should be mounted on the outside wall of the Flocculator. This was the starting point of the challenge. By the end of the semester, the CDC dosing system and lever arm were mounted against the Entrance Tank and Flocculator wall.

Floc Hopper Probe, Fall 2015

Miguel Castellanos, John Lopez

Abstract

The floc hopper probe team aims to create a fully functional floc hopper probe design for future visits to Honduras and elsewhere. Currently, very little information is know about the location or condition of the floc blanket in the floc hopper. This year’s research should lead to a better understanding of the events preceding sedimentation as well as more details on the location of the floc blanket inside the hopper. An experimental setup was created to test different floc hopper probe designs and observe which one gave accurate readings. This year’s team contributions include: a final design of the floc hopper probe and an assembling manual for the current probe design. The team has tackled the problem in the lab and now field testing is required for further improvement of design.

Flocculator Efficiency, Fall 2015

Mallika Bariya, Tanvi Naidu, Chae Young (Flora) Eun

Abstract

The Fall 2015 Flocculator Efficiency subteam worked on designing, developing, and testing a flocculator model that optimizes the vertical­flow flocculator used in AguaClara water treatment plants. The team addressed the accumulation of low­shear regions of water above the top of the lower flocculator baffles, a phenomenon that creates a “dead” region in which collision potential for the creation of flocs is very low. Dead zone formation occurs due to a decrease in fluid velocity as water transitions from the bottom of the flocculator to the top and as it flows over the lower baffles. The team hypothesized that compressing the water flow would increase the fluid velocity and, as a result, allow the water to flow at a higher trajectory over the lower baffles and reduce the formation of dead spaces. Furthermore, the addition of an extra contraction and expansion would create more turbulence in the region above the lower baffle and increase collision potential. This issue was addressed by installing obstacles in the form of slit pipes at the tops of the lower baffles. Test results with these features showed that the obstacles were able to compress the flow and consequently increase the fluid velocity and turbulence in the ‘dead zone’ region. The team measured and observed the results of this design feature by testing the model through flow visualizations using a red dye tracer. Among the variables tested, the best desired effect was observed with a restriction of 78% of channel width, for both laminar flow and potentially turbulent flow (Re= 3000). With a 60% restriction, the formation of a circulating region was observed, although this eventually cleared up. There is a need for further research on how the geometry of the obstacle might be impacting this phenomenon.

Granular Sequencing Batch Reactor (GSBR) - Fall 2015

Amiel Middlemann, Nisarg Gohil, and Andrea Whalen

Abstract:

The AguaClara Wastewater team returned in Fall 2015 with two teams investigating both anaerobic and aerobic wastewater treatment reactors. The GSBR (Granular Sequencing Batch Reactor) team worked to expand knowledge about this potentially innovative and sustainable wastewater treatment technology. The goal of the Fall 2015 semester was to investigate potential improvements to reactor operation that would improve nitrogen removal. Furthermore, the team was interested in the stability of granular sludge under lower aeration requirements. One continuously operating reactor was inherited by the GSBR team at the start of the semester, which had been inoculated during the summer 2015 by visiting student researchers from Brazil. Lastly, the team considered the feasibility of this technology in implementation.

Results from monitoring ammonium and nitrate concentrations through several cycles of operation indicated that improvements to nitrogen removal did not result from operational changes that were installed. Conclusions from the semester included a decreased nitrification efficiency under lower aeration supply. However, granule stability and chemical oxygen demand (COD) removal remained under lower airflow conditions.

StaRS Filter Theory - Fall 2015

Isha Chaknalwar, Theresa Chu, Michelle Lee

Abstract:

Modeling the physics of particle capture in stacked rapid sand filters allows for greater understanding and further innovation in filtration. A two-layer sand filter will be built to measure filtration performance parameters of effluent turbidity, head loss, and time until turbidity breakthrough or excessively high head loss. Sand filtration should be effective in removing small flocs, so flocculated influent water with coagulant and clay will enter the filter to simulate filtration and clogging.