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.

UASB, Fall 2016

Andrew Kim, Yang Chen, Evan Greenberg

Abstract

To lower the amount of wastewater discharged into natural bodiesof water, low-cost, energy-efficient treatment technologies are needed indeveloping countries. The AguaClara team has developed lab-scale UASBreactors to evaluate the degree of treatment and energy recovery from”black water” (concentrated wastewater from toilets). Specifically, theobjectives this semester were to improve the current laboratory set-upand equipment, adjust the wastewater stock recipe to prevent cloggingin influent lines, and determine the residence time and maximum organicloading rate for the reactors. Ultimately the set-up changes were effectiveand a sufficient wastewater stock recipe was developed. Tracer tests foundthe residence time of each reactor to be approximately three hours, butthe maximum organic loading rate has yet to be characterized.

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.

Milli-Sedimentation Fall 2016

Jillian Whiting, Tianyi Wang, Janak Shah

Abstract

The goal of the milli-sedimentation team was to find and explore the boundaries between sedimentation and filtration which could be used to reduce the size and residence time of AguaClara plants. The technology was designed using coffee straws that are sized between the spacing of plate settlers (10 mm) and the porosity of filter material (0.1 mm). The size of the plant would be on the scale of a small town or village, less than 1000 residents, replacing what the foam filter did in El Carpintero. One of the biggest challenges for the semester after building the sedimentation-filtration system was attempting to clean the apparatus, as this determined the feasibility of the design.

CSFBR - Fall 2016

Jacqueline Dokko, Javier Espada Fraile

Abstract

The countercurrent stacked floc blanket reactor is a system for removing suspended solids or dissolved dyes by coagulating them into larger lumps of particles referred to as flocs using opposing currents to run clean water one way and floc-ridden water the other way. Using two standardized reactors, dye and coagulant concentrations, and flow rates, the team worked towards determining whether multiple reactors in a series is more efficient than a single, long reactor. With the known mechanism and the result of the previous research, this semester’s goal was to intensify dye removal by modifying the design of the reactor, system flow path and flow rates. For the future, the flocculator will be modified to be longer allowing larger flocs to form, increasing efficiency of the system as a whole since the discrepancy in flocculator size prevented comparable performance between the single reactor system and the system of reactors in series.

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.

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.

Ram Pump - Fall 2016

Javier Paternain Martinez, Christopher Galantino, Luna Oiwa

Abstract

The purpose of the Ram Pump team is to design and develop a properly functioning hydraulic ram pump, or hydram, for implementation in AguaClara plants. The hydram can be used to deliver water from below the facility back to the top for utilization in chemical stock tanks or to collect water at higher elevations for alternative uses. The team’s goal for this semester is to find a practical method for measuring the pump’s flow rate and efficiency, to determine the effects of adding distribution piping to the bottom of the apparatus, and implement method to solve issues as they arise.

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.

Enclosed Stacked Rapid Sand Filtration (EStaRS) - Fall 2016

Susan McGrattan, Victoria Zhang, Elizabeth Johnson, Mikel Aurteneche

Abstract:

The EStaRS team’s goals for this semester were to design a new EStaRS filter that was compatible with the recently built 1 L/s plant. The 1 L/s plant’s sedimentation exit elevation provided a height constraint of 6 feet and required a scaled-down version of the existing EStaRS filter. The team first worked to gain a complete understanding of the EStaRS filter design and operation using experiences and observations recorded by previous teams. MathCAS calculations from the AguaClara design server were adjusted for the new design and AutoCAD drawings were created to provide a completed design that was ready for fabrication.

Floc App - Fall 2016

Christian Rodrigues, Anthony Verghese, Deniz Yilmazer

Abstract:

Turbidity measurements provide the primary source of performance monitoring at many water treatment plants. Turbidity provides an excellent way to measure overall plant performance, but it does not provide insight into why the water treatment plants are performing well or poorly. The floc size and count app team’s aim is to create and easy-to-use desktop application that would measure floc size distribution and potentially provide insight as to why a plant is performing well or not. The app will be written in LabVIEW and made available for easy use as a stand alone executable application. The aim for this semester is for the team members to finish the LabVIEW program, integrate the program with a camera system, and have other teams test the camera system and software. By the end of the semester, we hope to have a functional prototype than can be tested by other AguaClara Teams in their experiments.