Regional Planning - Spring 2016

Lauren Frazier, Yu Jin Hur, Disha Mendhekar

Abstract:

The scope of the semester was to analyze the feasibility and need for an AguaClara plant in India. The team decided to focus on India asa country of potential implementation as India already has AguaClara LLC workers on the ground building connections. The team approached the analysis through large-scale research, gathering data on India’s water sources, demographics, geography, and economy. There are ten ideal characteristics that would suggest a potential site. The team conducted research on India to determine locations with these characteristics. The team also created an optimization model using Matlab to visually display the deliverable in the form of a color-coded map.

High Rate Sedimentation - Fall 2016

Ziwei (Vanessa) Qi, Aimee Owens, Ruizhe He

Abstract:

The Fall 2016 High Rate Sedimentation team investigated the effect of high upflow rates on maintaining a dense floc blanket and functional plate settlers. The team built a small-scale flocculator and tube model of the sedimentation tank in order to simplify the many experiment variation configurations.To analyze variables that effect effluent turbidity at an up- flow velocity of 3 mm/s, which is roughly triple the standard AguaClara rate. Experiment 1 varied length of the tube settlers, Experiment 2 varied length of the floc blanket, and Experiment 3 attempted to increase the density of the floc blanket by adding mass. Experiments have verified that longer tube settlers and longer floc blankets improve sedimentation tank performance.

Countercurrent Stacked Floc Blanket Reactor, Fall 2016

Surya Kumar, Christine Leu, Amlan Sinha, Cindy Dou

Abstract

Floc blankets, which are suspended layers of highly concentrated flocs, have the potential of being a more efficient option for removing arsenic, fluoride, and certain dyes in terms of energy and water consumption than currently employed techniques. For floc formation, a coagulant needs to be added to the water, allowing particles to adsorb to each other when they collide. Previous research has shown that the coagulant, polyaluminum chloride (PACl), has properties that allow arsenic, fluoride, and certain dyes to adsorb to its surface. The first iteration of this research used three floc blankets in series with a counter-current flow of contaminated water and flocs. By feeding flocs from the last reactor into the second, and from the second into the first, the PACl’s surface area can be saturated. To test this theory and apparatus, a dye, Remazol Brilliant Blue R (RBBR), was chosen to be the contaminant due to its less toxic nature and visual component. With this apparatus and contaminant, this semester’s goals were to test dye removal efficiency from water with varying concentrations of clay, PACl, and dye. With a 1:1 ratio of PACl to dye, a dye removal efficiency of roughly 80% was achieved. However, the transportation of flocs from the third reactor to the second and first was not sustainably achieved.

1 L/s Plant Testing – Fall 2016

Yang Pei, Erica Marroquin, Alicia Barrientos, Manuel Queijeiro

Abstract:

The 1 liter per second AguaClara water treatment plant was created in the summer of 2016 for small villages where it was not cost-effective to build full-sized plants. It was the culmination of 10 years of progress in AguaClara and featured new technology, including a crimped pipe flocculator and a free-standing sedimentation tank constructed from corrugated sewer pipe. The Fall 2016 team began the semester with performance checks; the team tested for leakages, dosing apparatus precision, floc blanket formation, and turbidity removal. After the team reached the conclusion of a good performance and shipped it satisfactorily to Honduras, where the work will be continued. The flocculator was re-designed to improve the existing one and test were performed to check that it gave the expected head loss. Finally, it was built.

Sensor Development - Fall 2016

Andrea Pozo, Cheer Tsang, Grace Mitchell, Sidney Lok

Abstract:

The fall semester of 2016 marks the beginning of the Sensor Development subteam to AguaClara, which was created in response to the needs of the Upflow Anaerobic Sludge Blanket (UASB) and Anaerobic Fluidized Bed (AFB) subteams. This semester, the primary goals of this subteam were to develop a gas measurement sensor and a fluidized bed solids concentrator sensor for AguaClara plants. The subteam finalized a method of gas measurement, programmed settings in ProCoDa, and built four final product gas sensors for the AFB subteam. For the fluidized bed solids concentrator sensor, the subteam took measurements of the photosensor output and developed a method to correlate photosensor output to the existing intensity of fluidized solids.

Prefab 1L/S - Summer 2016

Juan Guzman, Josiah Hinterberger, Juan Mantilla Quintero, Erica Marroquin, Disha Mendhekar, Ibrahym Sabha, Claudia Vesga Rodríguez, Victoria Zhang, Monroe Weber-Shirk

Abstract:

Conventional water treatment technology often have fixed costs too high for small communities with demands less than 5 L/s. The goal for the 2016 AguaClara summer program was to design scaled-down processes and fabricate an inexpensive 1 L/s plant. This pilot plant employs conventional flocculation, sedimentation, filtration, and disinfection methods, but accomplishes each step using innovative materials and methods to maximize space efficiency and minimize cost.

Prefab 1 L/S - Fall 2016

David Herrera, Yinghan Hua, Sung Min Kim, Sean King, Felix Yang

Abstract:

Since January 2016, the Pre-Fabrication team has been experimenting with the creation of a 1 L/s water treatment plant. The Spring 2016 team successfully created a small scale version of the sedimentation tank and the Summer 2016 team fabricated a full scale plant. This full-scale plant will be shipped to Honduras in December 2016, and the goal of the Fall 2016 team is to construct an additional 1 L/s plant with a focus on streamlining and improving the production methods and accuracy. The team will focus most heavily on improving the methods of the flocculator and determining the structural integrity of the plant to confirm the validity of its design approach.

Prefab 1 L/s - Spring 2016

Kimberly Buhl, Claire DeVoe, Meryl Kruskopf, and Felix Yang

Abstract:

The goal of the Prefabrication 1 L/s team was to research, test, and provide fabrication methods to be used when constructing the 1 L/s plant design in Honduras. The team worked on an approximate 1/10th flow rate scale model to design novel geometries for a low-flow flocculator and sedimentation tank while implementing known AguaClara fluid mechanic techniques. The cost per capita associated with these plants was calcu- lated to be much lower than plants built using traditional construction methods. Recommendations on design and fabrication methods were re- layed to future teams working on full-scale plant production.

StaRS Filter Theory - Fall 2016

Theresa Chu, Jonathan Harris, Lucinda Li, William Pennock

Abstract

Dynamic models of stacked rapid sand filtration has proved elusive in accounting for the diminishing pore space and increasing head loss. Empirical data has shown that head loss increases linearly over time despite filter breakthrough. Dirty filter bed head loss shows that minor losses add to head loss over time. A new model for dynamic filtration is proposed, which models captured particles as embedded rings of flocs in the filter bed. Particle removal through filtration is described with an active filtration zone of empty pores filling up with particles. This zone moves throughout the layer of sand until there is no available pore space and surface area for particles to attach.

StaRS Filter Theory - Spring 2016

Theresa Chu, Lucinda Li, Jonathan Harris

Abstract

A mathematical model describing sand filtration would promote the understanding of stacked rapid sand filter performance. Variables affecting filter performance include coagulant dosage, influent turbidity, and sand filtration depth. The collected data from a model filter informed a mathematical model explaining the effect of coagulant mass on the filter’s effluent turbidity, head loss, and failure time. Experiment runs demonstrated that increasing coagulant dosage led to an increase in head loss and decrease in time until filter failure as well as vary effluent turbidity. Head loss curves for the various PACl dosages had the same trend after filter failure and converged to the same value after a 24 hour run time.

Chemical Dose Controller - Fall 2016

Cynthia Chan, Anna Doyle, Ashish Sangai

Abstract:

The Linear Chemical Dose Controller (CDC) system was designed to maintain a constant chemical dose to the treatment train as the plant flow rate and influent turbidity change. Past CDC teams worked on improving the the design of the Constant Head Tank (CHT), and making the CDC system modular. This semester the CDC team redesigned the CHTs so that all four tanks were connected to each other, and so that the calibration columns were attached to the CHT module. Additionally, the team recreated and modified the modulat CDC system designed in past semesters to address the goals of being fully chemical resistant, compact, and simple in operation and maintenance. The new CHT will be demonstrated and eventually implemented in Honduras.

Fabrication: Constant Head Tank - Spring 2016

Anna Doyle, Valerie Shao, Serena Takada

Abstract:

The main problem with the plastic Tupperware Constant Head Tank (CHT) containers currently used in the the AguaClara water treatment plants is that they are not chlorine resistant so they have to be replaced frequently. This issues was addressed by the fabrication team this semester. New CHTs were designed, fabricated ,and evaluated to determine the best to be implemented at AguaClara treatment plants. The first design was fabricated from clear PVC sheets and constructed using PVC welding; the second was constructed out of a PVC pipe and cap. The two designed were then compared in terms of ease of construction, functionality, and costs. Based on this analysis and the recommendations from the AguaClara engineers, the second design was determined to be the best and will be implemented in future AguaClara water treatment plants.