Filter Flow Control - Spring 2017

Matt Cimini, Alex King, Tanvi Naidu

Abstract:

The objective for the Filter and Treatment Train Flow Control team (FTTFC team) this semester was to design and construct a weir module that would allow the plant operator to easily redirect sucient flow for filter backwash without shutting o↵ other filters’ flow. The goal of the design was to be easily constructible, easy to operate, strong enough to withstand water pressure and require no calculations for plant use. The team designed several removable weir options and ultimately chose a hinged design. The design is similar to a dog door that will be shut during normal flow and open during backwash. The model was fabricated and tested under conditions simulating a 20 L/s plant. The weir module was strong enough to withstand the flow, was easy to construct and was simple to open and close even with the water pressure against it and therefore was a success. There was some significant leakage around the weir flap. Therefore, construction and design should focus on recommendations for watertightness of the flap if this design is to be used in an AguaClara plant in the future.

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.

Floc App - Spring 2017

Christian Rodriguez, 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 fails to provide insight into the specific processes that make up the plant. The earliest reduction in turbidity in an AguaClara plant occurs after the sedimentation tank with a time delay of 30 to 45 minutes. This delay makes feedback control challenging especially when raw water turbidity varies rapidly. The floc size and count app comes in to fill this shortcoming by providing an easyto-use desktop application to measure floc distribution in various parts of the plant. The floc app can measure floc size distribution of the flocculated water to characterize flocculation efficiency. Flocculation residence time is expected to be less than 5 minutes in the next generation of AguaClara plants and this will significantly reduce the feedback time to provide guidance for setting the plant coagulant dose.

Prefab 1 L/S - Fall 2017

Felix Yang, Lilly Mendoza, Ken Rivero-Rivera

Abstract:

The 1 Liter per Second (LPS) Plant testing team is continuing the work done by previous semester's Pre-Fabrication team by attaching the ESTaRS to the 1LPS plant and flocculator. By doing this AguaClara will have a complete 1 LPS Plant running in the lab so that experimental data can be gathered. This data will be used to optimize and improve current designs as well as further iterations of the technology.

Prefab 1L/S - Spring 2017

Sidney Lok, Sung Min Kim, Sean King

Abstract:

The Spring 2017 semester 1 L/s Plant Testing subteam's objectives were to improve upon the previous work done on the design of the 1 L/s pilot plant in Honduras. This semester, the primary goals of the 1 L/s Plant Testing subteam were to complete the 1 L/s plant and to design and fabricate a tapered flocculator. This tapered flocculator design would be used to decide whether tapered flocculation would improve overall water treatment in the 1 L/s plant.

Fluoride Floc Blanket - Spring 2017

Fluoride Auto — 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

String Digester - Fall 2018

Rosalie Krasnoff, Zsofia Szegletes, Madeline Garell, Antonio Martinez

ABSTRACT:

The string digester team’s objective for the Fall 2018 semester was to continue research on designing a new wastewater treatment system to eliminate problems associated with current trickling filters. To improve consistency in wastewater treatment, experiments were conducted using strings to optimize surface area. The long-term goal of this team is to create an efficient wastewater treatment system that will perform secondary and tertiary treatment on domestic wastewater. Initial tests involving different string materials, biofilm growth, and string spacing helped define design parameters for the construction of a functioning string digester.

Sedimentation Tank Hydraulics – Spring 2013

Frances Ciolino, Andrea Fortman, Marlana Hinkley, Marlon Passos

Sand Source and Testing - Fall 2013

Rebecca Schneider and Meghan Furton

Abstract:

The Sand Source and Test Methods sub-team is new to AguaClara this semester. Our main sources of research come from the known SRSF sand constraints, which dictate that no sand should be able to slide through the 0.2 mm slots in the PVC pipe, the sand should be hard and not prone to dissolution in acid, the backwash velocity required to expand the filter bed by 30% should be very close to 11 mm/s, and the sand bed must not have significant stratification after backwash. In addition to the constraints provided by the SRSF, the filter sand used must also satisfy American Water Works Association guidelines (AWWA). We are using American Water Works Association (AWWA) media constrains along with the American Society for Testing and Materials guidelines (ASTM International) to compile a series of test methods for filter sand. We intend to determine which of these constraints apply to the SRSF design. Furthermore, progress towards local sand acquisition is varied between the sites in India and Honduras as of September 2013. In India, sand is currently taken from the Barakar river and the only modifications made are sieving it for correct size on site, using two large rectangular mesh sheets that are shaken by two people. The two sieve sizes currently in use are No. 60 and 30, which correspond to particle sizes of 0.25 mm and 0.5mm respectively. There is also potential access to laboratories in the Universities and NGOs nearby. In Honduras, on the other hand, there is not an established sand mine industry and sand will likely be taken from river beds near the site. Transporting this sand from the river to the site is easy, but testing will be done in the apartments without the use of laboratory equipment that is difficult to transport.

Chemical Dose Controller - Spring 2013

Andrea Castro, Kent Chan, Saugat Ghimire

Abstract:

Accurate chemical dosing is an essential part of an AguaClara plant. Proper dosing is required for effective flocculation, sedimentation, filtration and disinfection. Coagulant (Poly Aluminum Chloride or Alum) and disinfectant (Chlorine) are chemicals used for dosing in an AguaClara plant. The linear chemical dose controller (LCDC) automatically maintains a linear relationship between the influent flow to the plant and the chemical dose. The plant operator therefore only adjusts the dose of coagulant based on the turbidity of the influent water. The Spring 2013 team has had two lever-arm assemblies fabricated by Hancock Precision based on the Fall 2012 design with additional improvements, such as having one end rod of the lever arm made up entirely of stainless steel instead of having a stainless steel rod placed over the aluminum rod and substituting anodization of the lever arm with powder coating, as the latter is more resistant to a corrosive environment. One unit has been sent to Honduras and the other is expected to be utilized in India. In addition to this, we have fabricated the manifold system out of PVC, a chemical resistant material. Through application of the orifice equation, we sized the constant head tank float valve orifice. Through application of a statics equation we determined that the 􏰄oat valve size could be reduced, allowing the use of a standard 5-gallon bucket for the constant head tank. We fabricated a constant head tank, suspended by a chain and attached to a turnbuckle, which can be easily adjusted during calibration. We have set up a fully functional unit of the coagulant dosing component of the dose controller in the lab, calibrated the unit, and tested the system at our maximum flow rate to compare how the system behaves compared to the model prediction and were below ten percent error. We created a detailed 3-D drawing in Google SketchUp of the current design of the linear chemical doser system including all appurtenances, in addition to creating a parts list, to facilitate future fabrications and assembly. This will not only be helpful for future groups to better understand the dose controller but also make it easier for the manufacturers to build it in the future. We also came up with ideas for protecting the entrance tank 􏰄oats as water enters the plants at some locations in Honduras, to reduce dosing error.

Chemical Dose Controller - Fall 2014

Zeyu Yao, Saugat Ghimire

Abstract:

The Chemical Dose Controller is an important of component of a AguaClara plant. The CDC delivers the coagulant (Polyaluminum Chloride (PACl) or Aluminum sulfate (Alum)) to the influent water and disinfectant Calcium hypochloride to the effluent filtered water. The Chemical Dose Controller is a simple mechanical response device which maintains a linear relationship between the plant flow and the chemical dose. It consists of a calibrated lever arm which the operator can use to adjust the dose of the chemical based on the turbidity of the influent water. The Fall 2013 team started o􏰂 by putting together three half size doser units for stacked rapid sand􏰃filters constructed in India. All the parts were shipped to India with a detailed instruction manual to aid the assembly. The dosers sent to India contained CPVC ball valves with fluoroelastomer seals that are more resistant to chlorine than the previously used PVC ball valves. The ball valves in all the AguaClara plants will now be replaced with these CPVC ball valves. Similarly, a lock-and lock container will now be used as the Constant Head tank for both chlorine and coagulant suspended with a chain and a turnbuckle for height adjustment. Although the lock-and-lock container degrades when in contact with chlorine, it is locally available and can be easily replaced. In addition to this, the design of a new half-size doser with single arm which only doses chlorine has been completed. A 3D sketch-up file has been created and sent to Hancock Precision for fabrication. This new doser will primarily be used in low 􏰄ow plants in India which only require chlorine delivery.

Laminar Tube Flocculator - Summer 2013

Allan Brooks, Rivu Dey, William Pennock

Abstract:

Over the Summer of 2013, the Tube Flocculator team's overall goal was to further the understanding of floc breakup in order to heighten flocculator performance. Specifically, this was done by examining a single clamp's effect on flocculation, as well as finding the optimal orifice size while using multiple clamps. The effects of the clamps were predicted to increase overall colloid aggregation which would prove beneficial for the next step in AguaClara's process: sedimentation. Based on the results found over this summer, some conclusions can be made. One conclusion based on the end-clamp experiments is that larger orifice sizes display lower mean residual turbidities. Another is that, for a 28-meter-long flocculator, an evenly-spaced sixteen-clamp configuration appears to be better than using no clamps, depending on the clamp size used. The the eight-clamp configuration appears to not be any more effective than a no-clamp control, while a four-clamp configuration appears to show improved flocculator performance for certain clamp sizes. In future work, these findings can be applied to the full scale flocculator in hopes that floc breakup will prove useful for plant performance.

Laminar Tube Flocculator - Spring 2013

Margaret L. Fleming, Patience Ruijia L

Full Scale Floc Breakup - Spring 2013

David Buck and Meg Fitzgerald

Abstract:

The objective of this research was to design a floc break up device to test the concept of floc break up at full-scale and improve flocculation performance of the AguaClara plant located in Atima, Honduras. Recent research suggests that using 􏰅ow constrictions to break up flocs improves performance and reduces settled water turbidity. Using this hypothesis, we designed a device to cause floc break up. We used a perforated plastic sheet which constricts 􏰅ow and creates many jets, which dissipate energy and break flocs. The proposed design for the prototype for Atima includes 21 orifices and an orifice diameter of 5.1 cm (2􏰃), which results in approximately 9.3 mm of head loss per device and 40% open area. We also determined that the devices should be optimally placed in the flocculator so that water flows upward through them. We plan to attach the devices between the baffles and walls of the flocculator with foam blocks. Our design can be fabricated in Honduras with locally sourced materials, so although the fabrication will require local labor, it does not rely on shipping materials from the United States. We will send our design to Drew Hart in Honduras who will fabricate the perforated plates and test them at full scale.

Foam Filtration - Spring 2013

Jenny Guan, Monica Kuroki, Lishan Zhu

Abstract:

Originally, the foam filtration system was designed to provide clean water to small-scale communities. The system was also designed to provide water in emergency situations such as a refugee camps. The system was ideally powered by gravity and the optimal filtration rate was made to be 3 L/min. For the Spring 2013 semester, the foam filtration team began fabricating a new system and recording the process of the new system. The previous filtration system was designed and shipped to Honduras in January 2013. The current design focuses on pieces readily acquired in-country. This allows feasible construction in Honduras and, potentially, other developing countries. Products such as 8020 steel, clear PVC piping and flexible tubing have been removed from the design because they cannot be easily found outside of the US. The foam filtration team this semester is also working on making the design more compact for easy transportation. Additionally, the foam filtration team designed a new compact stand of PVC piping to hold the filtration system. The team included a larger collection tank to allow for the incorporation of a linear dosing system.

Foam Filtration - Fall 2013

Skyler Erickson, Melissa Shinbein, Jeffrey Suen, Kadambari Suri

Water Treatment Technology Selection Guide – Spring 2014

Subhani Katugampala, Neelesh Bagga

Abstract:

This is the final research report of the Water Treatment Technology Selection Guide Team for Spring 2014. Our goal this semester was to design a selection guide that provides a clear rubric for evaluating and comparing water treatment technologies. A major part of this involved developing the framework and decision-making methodology for such a decision-support system. Current technology selection guides tend to focus on providing information on treatment technologies based on contaminant removal requirements, while ignoring the realities of resource-constraints and skill-constraints of communities, and without considering sustainable engineering practices. An expert guidance tool is needed to empower water supply professionals to make better decisions and to learn the constraints determine which technologies are appropriate.

Water Treatment Technology Selection Guide – Fall 2014

Yao Lu, Larissa Sakiyama, and Sarah Sinclair

Abstract:

The Water Treatment Technology Selection Guide Team seeks to build an attractive and functional web application that will allow parties interested in the construction of an AguaClara plant to compare various available treatment technologies and receive an estimate of plant costs. This semester’s team was tasked with integrating plant cost calculator (PCC) and water treatment technology selection guide (WTTSG) tools, improving the regression equations which provide cost estimates to the PCC, and synthesizing and incorporating information about various treatment plants into the application. The team worked to completely overhaul previous semesters’ web development work in order to pursue a design that embodies UI/UX (User Interface/User Experience) principles. The new tool is highly interactive with a sleek, modern design, and is in the process of being deployed live as part of AguaClara’s web presence. The team has developed several regression equations useful for cost estimation, engaged in research related to plant cost and available treatment technologies, and made significant progress in the implementation of the WTTSG tool over the course of the semester.

Plant Cost Calculator – Spring 2014

Andrew Bales, Chris Mills, Derrik Yee

Abstract:

AguaClara designs low-cost water treatment facilities and desired a tool to estimate and present the capital and operational costs of an AguaClara plant. The goal of the Plant Cost Calculator team is to create such a tool to provide an accurate estimate of the costs associated with construct- ing and operating an AguaClara water treatment plant. The objective of the calculator is to allow users to easily obtain accurate design and operational cost estimates that can be compared to alternative water treatment options, and to make users better aware of the factors that contribute to the final plant cost. At the end of our first semester, the plant cost calculator team has completed the back-end for a working and easy-to-use calculator based in part on data from existing plants in Honduras. Future objectives will include developing a more attractive front-end interface, closer collaboration with WTTSG, and integrating India plant costs into the data used for prediction.