Fluoride - Spring 2016

August Longo, Pooja Desai, Katie Dao

Abstract:

In many developing countries, high levels of fluoride in groundwater have been found to have chronic effects on bone health. Though some countries intentionally add fluoride to water in order to strengthen teeth, overexposure to fluoride has grown as a problem worldwide. The Fluoride team has been working to solve this very issue, by testing and developing a fluoride removal system fit for AguaClara plants in India and Honduras. In spring 2016, the Fluoride team built on the previous work of the Fluoride and Countercurrent Stacked Floc Blanket Reactor team to create a more optimal and efficient fluoride removal system. In the fall, the Fluoride team worked to understand the efficiency of fluoride removal using polyaluminum chloride (PACl) while the CSFBR team developed a reactor system to remove undesirable soluble particles. This semester, a new system was built consisting of a single floc blanket formed using PACl and clay. In the future, this system will be optimized by changing flow rates and dosages to better understand fluoride treatment and optimize AguaClara plants for fluoride removal.

Fluoride - Fall 2016

Michelle Cheng, August Longo, Briana Vidal

Abstract

The Fluoride subteam seeks to develop and sustainable, inexpensive fluoride removal system for implementation in upcoming AguaClara plants located in India. After earning an EPA Phase II grant for last semester’s fluoride removal reactor, the current subteam hopes to develop a better method of fluoride purification by partnering with the CSFBR subteam and researching the effectiveness of reactors in series versus a single reactor system. At the beginning of the semester, the subteam identified potential issues with floc buildup at the bottom of the apparatus. Thus, a smoothly sloping bottom insert was incorporated into the single system reactor for all comparison experiments. The subteam then analyzed the effectiveness of fluoride removal in a significantly shorter reactor. It was determined that although a shorter reactor would reduce fabrication cost, the lack of sufficient space for floc blanket formation yielded impotable water. After performing a series of side-by-side experiments, some data has been collected to compare functionality between the single reactor system and the CSFBR subteam’s reactor in series, the results are not yet conclusive. In future semesters, more comparable data needs to be collected to draw concrete final conclusion as to which system is more effective.

Humic Acid - Fall 2018

Matthew Lee, Vanessa Qi, Carolyn Wang

Abstract:

The Fall 2018 Humic Acid Team will focus on testing the effluent humic acid concentration changes as coagulant dosage increases for influent humic acid at 5mg/L, 10mg/L and 15mg/L trials. The new AccuView spectrophotometer will be used to measure the flow absorbance and corresponding species concentrations will be calculated from recorded absorbances with Beer's Law. The team expects to develop better understanding of humic acid concentration changes through the overall experimental system and how humic acid particles interact with clay particles inside the sedimentation model. This research will help AguaClara gain more knowledge of how Natural Organic Matter (NOM) interacts with coagulant in water.

Fluoride Automated System - Spring 2019

Fluoride Auto – Dominic Grasso, Melissa Louie, Desiree Sausele, Emily Spiek

Abstract:

The Spring 2019 Fluoride Auto subteam aimed to determine the optimal dosage of polyaluminum chloride (PACl) needed to precipitate fluoride ions out of influent water to meet the World Health Organization’s drinking water standard for fluoride concentration (1.5 mg/L). The team accomplished several fabrication tasks, including lengthening the flocculator used by the Fall 2018 subteam and constructing a new sedimentation tube. The team tested the new apparatus with PACl and red dye to visually determine that it worked properly and that aggregated particles (flocs) were exiting the tube through the floc weir. The team then aimed to run experiments with fluoride but experienced difficulty calibrating the fluoride probe. Upon acquiring a new probe in the future, the team will analyze fluoride removal efficiency using the Langmuir Adsorption Model.

Fluoride - Fall 2019

Fluoride Auto — Sarah Huang, Cindy Jin, Melissa Louie, Emily Yueh

Abstract:

The World Health Organization estimates that globally over one million people face adverse health consequences due to fluoride contamination of drinking water. The current state of fluoride removal technology is not suitable for water treatment plants, and continuous fluoride removal systems do not exist. The Fluoride team aims to develop a cheap and efficient apparatus to reduce ionic fluoride from contaminated water to a safe level. The Fall 2019 team hopes to redesign the flocculation process to optimize the adsorption of fluoride to polyaluminum chloride (PACl) coagulant and the sedimentation process to minimize PACl-fluoride complexes in the effluent, ultimately producing potable water.

Chemical Dose Controller - Spring 2015

Annie Cashon, Christine Leu, Auggie Longo

Abstract:

The Chemical Dose Controller is a device that maintains a constant chemical dose as the plant flow rate changes. After working alongside the foam filtration team in El Carpintero, Honduras this past January, the CDC team has changed the lab set-up to be more reflective of the systems in the field. Specifically, the major head loss element was changed to be vertically-oriented instead of horizontal to decrease the footprint of the CDC system. During the Spring 2015 semester, the CDC team will run a variety of experiments with the new system including head loss testing, determining flow breakpoints, and testing units at stock concentrations. In addition to testing the system through a variety of experiments, several design changes will be looked into this semester. This included tasks such as making the constant head tank from locally available items in Honduras, as well as making the constant head tank chlorine resistant. Finally, the team is compiling a system of equations to convert the CDC system into a modular, packaging item for future shipment. With design changes in mine, a major goal of the CDC team this semester will be to create an assembly manual and parts-list.

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.

Arsenic Sensor - Spring 2017

Kevin Juan, Dylan Vu, Kelly Stefanski

Abstract:

Final research report was not available for this team, so the final presentation is linked instead. If you know where this research report can be found please reach out the RIDE Committee, so this can be updated.

Fluoride - Fall 2017

August Longo, Victoria Zhang, Michelle Cheng

Abstract:

The Fluoride subteam seeksto dvelop a sustainavble, inexpensive fluoride removal system for implementation in upcoming AguaClara plants located in India. After earning an EPA Phase II grant for the Spring 2016 fluoride remocal reactor, the subteam continued to improve fluoride purification by testing lab-scale systems consisting of either a single reactor or two reactors in series. During the experimentation process, clay was incorporated into the influent stream to abate PACl buildup at the bottom of the reactors. As the subteam seeks to transplant their system to India, it is currently working to optimize fluoride removal by minimizing use of resources. Thus, the team is currently trying to eliminate the use of clay and lower PACl dosages by increasing upflow velocity and further redesigning its reactor. Initial tests suggested insufficient fluoride removal for potable effluent, but the team is looking to repeat its previous experiments using the summer 2017 High Rate Sedimentation subteam’s reactor design

Fluoride - Summer 2018

Ching Pang, Kevin Sarmiento, Cheer Tsang

Abstract:

Fluoride is a major contaminant in drinking water in many parts of India. The fluoride team's overarching goal is to create low cost, compact, and sustainable solutions to fluoride contamination in drinking water. The Summer 2018 team aims to continue and expand upon the work of previous teams by running experiments with both the pump-controlled system and the gravity powered system. The goal for the summer is to optimize the amount of coagulant needed to reduce the effluent fluoride concentration to 1 mg/L, as per the fluoride standard in India and design an easily adjustable gravity powered system. In addition, the team aims to develop a simple user guide for the fluoride probe in order to maximize future teams' efficiency.

Fluoride Auto - Fall 2018

Fluoride Automated System

Tigran Mehrabyan, Janak Shah, Samba Sowe

Abstract:

The Fluoride Auto subteam seeks to develop a sustainable, inexpensive fluoride removal system for implementation in upcoming AguaClara plants in India. Using the apparatus developed in previous semesters, the team continued running experiments testing how various concentrations of PACl affect fluoride removal. The team then analyzed the variability of the Langmuir isotherm generated by the summer 2018 Fluoride team. This analysis factored into the overarching goal of developing a model to predict an optimal coagulant dosage given both influent and target effluent fluoride concentrations.

Humic Acid, Kaolin, Floc/Sed Model - Spring 2019

Matthew Lee, Walter Guardado, Carolyn Wang

Abstract:

This semester, samples of HA at 5 mg/L, 10 mg/L and 15 mg/L and concentrations of clay at 10 NTU, 100 NTU and 100 NTU are tested separately to find the respective absorbances. The individual absorbances recorded are used to compare with the mixture of different concentrations of clay and HA to find the additive aspects of the mixture. The results of these tests will investigate how absorbance and spectrophotometry can be used to quantify the concentrations of humic acid and clay in water mixtures. A mathematical model that relates the concentrations of clay and humic acid to the stream's absorbance and turbidity will be developed. This model will increase the capabilities of AguaClara plants and technology in measuring the dirtiness of nearby water sources. The model will also give insight on how efficient and effective current processes are in removing humic acid from water

Humic Acid, Floc/Sed Model - Fall 2019

Lawrence Li, Maya Shanti, Carolyn Wang

Abstract:

The Fall 2019 Humic acid subteam seeks explore the relationship between optimal coagulant dosages and effluent absorbance. Past teams have tested optimal concentration for removing HA. Based on previous work, the optimal coagulant concentration appears naround 1.5 mg/L. For this semester, the team plans to test more coagulant concentrations and humic acid concentration and find the optimal dosage to lower the absorbance of the effluence. The AccuView spectrophotometer will be used to measure the effluent absorbance and measure the efficiency of removing color. The concentrations of HA and coagulant is set based on the data collected from water plants.

Fluoride Removal - Summer 2019

Fluoride Auto - Cindy Jin, Melissa Louie, Mike Rees

Abstract:

The Summer 2019 Fluoride team investigated issues related to the Automated and Gravity systems, with the goal of determining ideal conditions for removing fluoride. Initial qualitative tests prompted fabrication changes, such as an increase in the plate settler angle in the sedimentation tube. Jar testing was also done to examine if a floc blanket is needed for fluoride removal. Several changes in the sedimentation tube were tested to develop an optimal system for fluoride removal. Fluoride concentrations were measured with an ion electrode to determine removal efficiency and to continue developing the Langmuir Adsorption Isotherm model.