Small Scale Plant Model, Spring 2015

Ed Cheng and Jenny (Ruoyu) Yin

Abstract:

The Small Scale Plant Model Team of Spring 2015 worked to design a clear and portable model of the AguaClara water treatment plant. The current small scale plant model is cumbersome to travel with and difficult to understand for those unfamiliar with AguaClara technologies. After repairing the previous model, the team identified promoting education and awareness the primary purposes of the new model. Representing the water treatment plant in a clear and critical way will be the main objective of the Small Scale Model Team. After a semester of material testing and prototypes, the new small scale model will be completed over summer and fall 2015.

Water Technology Treatment Selection Guide - Spring 2015

Andrew Mullen and Sarah Sinclair

Abstract:

The Water Treatment Technology Selection Guide (WTTSG) team seeks to implement a webtool capable of providing recommendations regarding the efficacy and appropriateness of various water treatment options. This tool must be dynamic, responding appropriately to user input, and robust cross-­culturally, recognizing cultural and language barriers. It must also adhere to principles of human-­centered design, remaining accessible to populations with various degrees of skill while engendering a positive user experience. The current WTTSG team has continued the work of previous teams in creating a functional and attractive website. Significant strides were made this semester in passing data between pages of the site, the design and implementation of the results page, the construction of the administration panel, and the collection and population of data in the site. The site is now equipped to calculate regressions, provide automatic translations and log user input, and has been deployed on a MySQL-­enabled server. Future challenges include the tackling logistics of providing the best recommendation possible, while continuing to make the website’s recommendations scalable to new languages and technologies.

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

Fabrication - Spring 2015

Stephen Galdi, Natalie Mottl

Abstract:

The team’s task is to test, troubleshoot, and complete the scale model of the weir system developed by last semester’s team. By the end of the semester, the team will create as et­up and video that accurately portrays the behavior of the water through the full scale weir system. The Fabrication Team aims to create a plant that is easier to operate, troubleshoot, and build.

EStaRS - Spring 2015

Sarah Bolander, Skyler Erickson, Liza Johnson, Subhani Katugampala, Lilly Mendoza

Abstract:

The Spring 2015 EStaRS team built upon the work of previous semesters to optimize the original filter design as well as to develop alternative strategies to sections of the filtering process. Over the course of the semester, the team altered the process for attaching the filter cap in order to prevent future cases of blow­off, adjusted the system for controlling water level height during backwash, and ran tests on filtration efficiency. While at the beginning of the spring semester the team’s goals also included developing a method of testing and recognizing bed fluidization within the filter, looking into a method of running multiple filters in parallel, and setting parameters for backwash duration and frequency, the team changed directions and concerned itself with the implementation of a new filter injection system to combat the problems associated with using slotted pipes.

Floc Hopper Probe, Spring 2015

Steve Love and Garret Jancich

Abstract

The Fabrication Team’s purpose is to address current issues or areas of improvement in AguaClara plants. This semester, the team’s tasks included designing and fabricating a probe for monitoring sludge accumulation in the floc hopper. The floc hopper probe team created an operational tool for peering into the floc hopper in order to know when to drain it. The team also began work for developing the research capabilities of the probe. This would be achieved by taking image data via borescope snake camera and translating it into meaningful turbidity/DOM readings.

Large Capacity Float Valve, Spring 2015

Kwabena Nimo

Abstract

The goal of this team is to develop a large capacity float valve to regulate flow from a storage tank to the entrance tank. This system will be put in place for smaller plants, so that they may still be operated at design flow rate during droughts. This subteam aims to create a plant that is easier to operate, troubleshoot, and build.

Dissolved Organic Matter Sensor, Spring 2015

Andres Larraza

Abstract

The Fabrication Subteam was created to address problem that arose in the AguaClara plants that are in operation. The Dissolved Organic Matter (DOM) sensor is a project that was created because in the plants in Honduras. DOM is a contaminant in the water that is present naturally due to leaves and other matter in the rivers being decomposed. The DOM in the water was affecting the required amount of coagulant needed to properly flocculate particulates in raw water by requiring more coagulant. The problem was that there was DOM present and we could not measure it properly. This semester, the objectives for the team are to have a working model that can use the RGB(red, green, and blue) values detected by the Arduino board to calculate the concentration of DOM in the water.. This is a first attempt that AguaClara is conducting

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 includes 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 is compiling a system of equations to convert the CDC system into a modular, packaging item for future shipment. With design changes in mind, a major goal of the CDC team this semester will be to create an assembly manual and parts­list.

Ram Pump, Spring 2015

Pablo Nistal, Kadambari Suri, Larissa Sakiyama, Priya Aggarwal

Abstract

The Ram Pump sub­team was charged with designing and optimizing a pump to

elevate a small amount of water in the plants to fill chemical stock tanks and to provide

bathroom services. A common testing issue has been low effluent flow rate compared to what

is expected at the plant. The Spring 2015 ram pump team has designed a new ramp pump

system which allows users of the ram pump to adjust the size of the spring in the ram pump to

provide for maximum efficiency. The team is working on testing each part of the system,

seeing what can be fixed and changed, and then implementing those changes. The team has

found that ultimately springs of varying spring constants and lengths provide similar flow

rates. The team has also found that an air chamber greatly improves the flow rate of the

system and bigger air chambers provide better flow rate than smaller ones.

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.

Laminar Tube Flocculator - Spring 2015

Luyan Sun, Tanvi Naidu, Kevin Shao

Abstract:

Research on the Laminar Tube Flocculator in Spring 2015 aimed to validate the results obtained by Karen Swetland with the FReTA system and to further investigate factors that affect the overall turbidity removal. The past semester’s team worked to test the new residual turbidity monitoring system, SWaT, in comparison to the FReTA system and to verify that the new system can obtain similar results to those obtained with the old system. However, the actual coagulant tubing size used in the previous SWaT experiment was different from that in the pump control method file. Because of the incorrect input in tubing size, the PACl dosages were not accurate. The Spring 2015 research derived correction factors that would make the previous date usable. Then experiments were conducted in the SWaT system to finish verifying Karen Swetland’s results. Future works includes experiments to determine if there is an optimal floc size which is small enough to combine with small clay particles yet large enough to be separated in the sedimentation tank. Also, future teams should study how dissolved organic matter (DOM) affects the performance of the flocculator and sedimentation tank. These findings will improve the performance of the flocculator and make it more effective for use in water supply.

Grit Removal Innovation Technologies - Spring 2015

Annie Ding, Mary Millard

Abstract:

The current AguaClara plant design requires a large entrance tank to settle out grit particles prior to the flocculator. Grit removal by horizontal flow sedimentation prevents the settling of these larger particles in the flocculator (a phenomenon that has been observed in several AguaClara plants to negatively affect plant flow and operation). The purpose of the Grit Removal Innovation Technologies (GRIT) team is to redesign the current grit settling system by introducing plate settlers prior to the flocculation unit. In doing so, the plan-view area needed to settle out the grit will be greatly reduced, decreasing construction costs and overall AguaClara plant size. This paper outline the GRIT team’s process exploring plate settler design options that act either as sedimentation units only, or as combined flocculation and sedimentation units.

There is no other literature on the topic of designing such grit removal systems, and not all of the relevant parameters are well understood. The team’s design process has therefore been based on a series of reasonable assumptions and equations currently used in flocculator and sedimentation tank design. Many constraints (detailed in this report) were found to impact the design of the grit removal unit, including grit particle “roll-up” effect, optimal head loss, optimal unit length. In addition to the design of the grit removal unit itself, this team explored the corresponding designs of rapid mix, linear flow orifice meter (LFOM) placement, and coagulant dosing, in order to create a fully integrated system.

Over the course of the Spring 2015 semester, the GRIT team has developed three potential grit removal designs, created visual mock-ups of each, and even sent a detailed design of the best iteration to Honduras for implementation in a small-scale plant. The first iteration, a combined grit removal and flocculator system, integrated grit removal capabilities into the flocculator baffles, but it was rules out early in our design process due to the potential loss of coagulant to grit (as coagulant would be dosed before grit would be removed), inefficient use of space, and construction and cleaning impracticalities. The second and third iterations were both based on the idea of creating a tightly packed series of plate settlers (we call this a Grit Removal Unit, or GRU), analogous to the ones used in current sedimentation tank design, used before the flocculation process and designed to settle out grit specifically. The second iteration placed this GRU inside the entrance tank, while the third iteration placed it within the first flocculator channel. After analyzing space need, flexibility of design, and capacity for rapid mix/coagulant dosing integration, the third iteration was chosen as the optimal grit removal design and is well on its way to being constructed in Honduras!

Foam Filtration Pore Size - Spring 2015

Lotta Van Leeuwen, Tianchen Yu, Caroline Caglioni

Abstract:

Abstract unavailable for this team for this semester.

Please note, the final report is not available for this team for this semester and the Final Presentation is linked instead.

Foam Filtration - Spring 2015

Marlana Hinkley, Alena Hutchinson, Ethan Keller, Alicia Peters

Abstract:

The primary goal of foam filtration is to design a low cost, locally sourced, easy to operate water filtration system. Throughout the semester, backwash cleaning efficiency experiments were performed on the small-scale filter, designed in Fall 2014 to hydraulically model the full scale filter implemented in El Carpintero. The objective of these experiments was to determine an empirical relationship between backwash pore velocity and the percent mass removal of the particles from the foam during the cleaning cycle. Experimentation with different pore sizes revealed a new mechanism for filtration: the foam acts as a sedimentation tank, providing a large surface area for the flocs to settle. This is contrary to the initial hypothesis that coagulant-covered flocs stuck to the inside of the pore walls, and that a large shear force would be required to remove the flocs during backwash. Evidently, there is still much to be understood with regards to the mechanisms behind filtration and backwash. 

Apart from work in the laboratory, the team continues to analyze data collected from experiments performed on the full-scale filter in El Carpintero by AguaClara engineer, Walker Grimshaw, to understand the discrepancies between performance in the laboratory and in the field. 

Much of the semester was spent preparing for the EPA P3 Conference held on April 10th and 11th in Washington, DC. The team fabricated a small scale model of the technology, prepared a technical report, and created a poster display for the competition, and received an Honorable Mention for its efforts in creating an “Off-Grid Solution to Drinking Water Treatment.”

High Rate Sedimentation - Fall 2015

Oge Anyene, Larry Ge, Yuqi Yu

Abstract:

The Fall 2015 High Rate Sedimentation team aims to design a new sedimentation tank that will allow the tank upflow velocity to be significantly increased (by a factor or 2 to 10), without sacrificing particle removal performance (no increase in effluent turbidity). The motivating factors behind this velocity increase would be to decrease the plan view area of the sedimentation tanks, leading to smaller plants and lower the construction costs and to decrease the overall hydraulic retention time of the plant. One of the primary objectives of the new sedimentation tank will be to maintain a consistent floc blanket (i.e. one that allows for excess floc drainage into a floc hopper) similar to the ones found in current AguaClara plants, even with the increased upflow velocity. In order to achieve this goal our proposed design will feature two sets of plate settlers, one set near the bottom of the tank that will be suspended within the floc blanket, and one above them to capture finer particles. To test the feasibility of such a design, several small-scale experiments will be run in the lab. Such experiments will prove to demonstrate whether or not it is possible to maintain a fluidize bed within plate settlers and what the bulk flow of flocs will look like for a floc blanket maintained within plate settlers.

StaRS Filter Theory - Spring 2015

Theresa Chu, Nick Coyle, Alexandra Schwab

Abstract:

The Stacked Rapid Sand Filter Theory team designed and built an apparatus to induce clogging and test the head loss across a slotted pipe, which allows the water to flow directly into the filter without sand leaving the filter. Experiments were run with high turbidity and coagulant doses to clog the slotted pipe and determine which influent conditions led to clogging and high head loss. Slotted pipes as an injection system for the stacked rapid sand filters have proven to be problematic due to clogging. Results show that floc build up of coagulant clay increased head loss and clogged the slots.