Fluoride - Spring 2018

Philip Akpan, Tigran Mehrabyan, Desiree Sausele, and Victoria Zhang

Abstract

The Fluoride subteam seeks to develop a sustainable, inexpensive fluoride removal system for implementation in upcoming AguaClara plants located in India. Using the apparatus developed by previous semesters, the team continued running experiments testing how various concentrations of PACl affect fluoride removal. However, complications with the ability to measure fluoride concentrations required the team to shift its goals to designing a lab scale, gravity-powered system. The team finalized a design and completed construction of the new, electricity-free apparatus. The team plans to run experiments to test its fluoride removal capabilities after ensuring that there are no remaining water leaks.

Fluoride - Spring 2017

August Longo, Briana Li-Vidal, Michelle Cheng, Victoria Zhang

Abstract

The Fluoride subteam seeks to develop a sustainable, 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 removal reactor, the subteam seeks to improve fluoride purification by testing lab-scale systems to compare a single reactor with reactors in series. At the beginning of this semester, the subteam identified potential issues with floc buildup at the bottom of the reactor. Thus, a sloped plane bottom geometry was incorporated into the reactor system to encourage recirculation of the flocs. Additionally, experiments with high concentrations of PACl resulted in clogging of the apparatus due to PACl buildup. Clay was incorporated into the influent stream to abate this PACl buildup. Initial testing of fluoride removal with the updated one and two reactor systems provided results that seem to indicate slightly better fluoride removal efficiency with two reactors, but more data collected by future testing is required to make a concrete conclusion.

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.

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 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.

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.