Demo Plant, Spring 2013

Eric Stucker and Jen Weidman

Abstract

The demo plant team is responsible for design, construction, and troubleshooting of the AguaClara Demo Plant. The successful operation of this plant is crucial in order to demonstrate the inner workings of AguaClara plants to students, faculty, staff, community members, business partners, and potential sponsors. This spring semester, our research team has focused on creating one complete demo plant, and fixing issues with that plant, such as an unreliable flocculator and concerns with differences in head. This work included implementing and testing new fittings for the stacked rapid sand filter, conceptualizing and implementing a more efficient way to facilitate plant assembly and startup to those unfamiliar with it, resolving issues with improper coagulant dosing and head loss differences, and properly documenting all aspects of the plant so that future team members new to AguaClara (like us) would have much less difficulty familiarizing themselves with the Demo Plant.We also measured and adjusted plant ow rates to match historical data and ensure smoother operation of the plant, and labeled tanks to further improve ease of operation of the plant. While we did not achieve our goal of fabricating new plants for future teams to use, we documented all the materials present, as well as those we need, and we provided detailed drawings for future construction.

Village Source to Environment, Spring 2014

Diana Kelterborn, Sarah Levine, Nicholas Parisi, Rachel Whiteheart

Abstract

The newly formed Village Source to Environment Team combines the design of a distribution storage plan and wastewater treatment system for rural villages in India. Current distribution infrastructure consists of an elevated tank that fills and dispenses twice daily, each time supplying half the village’s water needs. This method is inefficient and inconvenient, since villagers can only obtain water when the tank dispenses and must carry it half a kilometer to their homes. This system also makes it impossible to ensure that each family receives their designated share of water. Furthermore, due to limited access to water, villages improvise unsanitary household storage. They obtain all water for washing, drinking and cooking from these open containers, meaning the entire source can be contaminated any time they use it. Our proposed distribution system will 2 pump water directly into villagers’ homes, replacing the elevated storage tank with smaller household tanks. Each tank will connect to a sink for sanitary use on demand. Additionally, the sink’s drain will allow us to eventually integrate a wastewater treatment or irrigation system. Small villages with limited resources often lack sanitary solutions for handling greywater and blackwater; we hope future teams will investigate strategies for treating wastewater for irrigation. Our work builds upon capstone design projects from the Fall 2013 CEE 4540 class that focused on a distribution system for the village of Gufu, India. We revised the distribution design and planned to add household storage tanks, however the distribution system design took the majority of our focus this semester. This new team was formed to facilitate AguaClara’s expansion to India. The local infrastructure, community sizes, and therefore required flow rates, differ significantly from those in Honduras. As a result, the team must take a very different approach to the problem. The Village Source to Environment Team has laid the foundation for distribution design this semester.

Turbulent Tube Flocculator, Spring 2014

Felice Chan, Jonathan Christensen, Stephen Jacobs, Ana Oliveira

Abstract

Since the Summer of 2013, the Turbulent Tube Flocculator team has been developing and optimizing a design for a lab scale turbulent tube occulator to better mimic the processes that occur at full scale plants. From this, a vertical occulator of approximately 1.5 m was constructed with 30 coils of exible tubings connected with pieces of metal pipe. Currently, the team is working on the rest of the experimental setup, which involves pumps, turbidimeters, pinch valves, clay stock, temperature and pressure sensors, Settled Water Turbidity analyzer (SWaT), rapid mix, and Process Controller software. Clay will be added directly to the head tank to keep the suspension stable in absence of coagulant. The coagulant, injected immediately following rapid mix, is responsible for aggregation of suspended particles present in the solution. Experiments will measure turbidity reduction as a function of coagulant dosage.

Turbulent Tube Flocculation, Summer 2014

Shreya Jain, Tanya Peifer, Nadia Shebaro, Luke Zhu

Abstract

Over the summer of 2014, the turbulent tube flocculation team has worked to implement and test a SWaT system for analyzing residual turbidity from the flocculator. The group is also working to implement PID control for the turbulent tube occulator to regulate the amount of clay added to the system. The team made minor physical adjustments to the turbulent occulator through the shortening of tubes and the tube settler position. By the end of the summer research period, the team has established a working occulation system to facilitate experiments done by future teams.

Turbulent Tube Flocculator, Fall 2014

Felice Chan, Mingze Niu, William Pennock

Abstract

Over the fall semester of 2014, the Turbulent Tube Flocculator Team improved the turbulent tube flocculation apparatus in terms of flow control, turbidity control and general structure. The objective of this improvement was to prepare the apparatus by the end of the semester for experimentation. The team made a number of updates this semester, including building a support structure for SWaT and the effluent line. In addition, two air releases were installed as well as a diffuser system in the constant head tank to eliminate air from the flocculator. In addition to the structural modifications of the apparatus, the team updated the process controller method file for experimentation. The experiments performed on this apparatus will be used to validate the equation derived by Dr. Monroe Weber­Shirk based on the experimental work of Dr. Karen Swetland.

Stock Tank Mixing Team, Spring 2014

Alexandra Cheng and Apoorv Gupta

Abstract

The Stock Tank Mixing team has been charged with the task of designing and fabricating a tool to effectively and efficiently mix stock solutions of coagulant and chlorine. Currently, operators in AguaClara plants utilize a long PVC pipe to mix stock solutions to achieve chemical dissolution, but this method is inefficient and limits the ability of operators to mix large stock tanks. Uniformly mixed stock solutions are required for flocculation and disinfection; this fact is the driving force for creating a mixer to aid the formation of flocs in raw water and improve plant efficiency.

StaRS Backwash Alternative, Fall 2014

Alberto Arnedo, Ainhoa Arribas Llona, Jorge Guevara

Abstract

The current slotted pipes being used in the backwash system of the AguaClara filtration plants have been clogging up with sand, thus posing a problem for the backwash system since the slotted pipes’s purpose is not being fulfilled. Given this issue, the Alternative Backwash without Slotted Pipes subteam will work to find an alternative pipe for the backwash system that will not clog up with sand at any point of backwash or filtration and will be easy to manufacture on site in Honduras and India given the resources available in each respective country. The team has successfully built a STaRS scale model to be used to accurately experiment with alternative pipes for both an inlet and an outlet valve. Through experimentation, it was found that the alternative tubes in the shape of a hollow rectangular prism cut in half lengthwise and placed with the interior facing down did not fill up with sand during the processes of filtration or backwash.Once the pump was turned off, however, the sand would settle underneath the outlet pipe. This led the team to two possible courses of action: the first being that the team could leave the pump running the water at a low flow rate and the second being that the team build a second alternative for the outlet pipe. Both actions would solve the issue of the sand clogging up, but the team pursued the second alternative. The new shape for the alternative was a hollow cylinder with wings that extended out tangentially from the top of the cylinder with a hole in the middle of the cylinder’s bottom. In experimentation, the new alternative outlet pipe worked well for the first trial, but filled up with sand in the subsequent trials. Through more experimentation with the current alternatives, or perhaps new alternatives, future subteams will work to find a solution that will consistently work without filling up with sand.

Fall 2013 Chemical Dose Controller

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 influnt 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 off 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 flouroelastomer seals that are more resistant to cholrine 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 sketchup file has been created and sent to Hancock Precision for fabrication. This new doser will primarily be used in low flow plants in India which only require chlorine delivery

Ram Pump - Fall 2013

Ruben Ghijsen, Madeline Haas, Kelly Huang, Ariel Seidner

Abstract:

AguaClara creates sustainable water treatment plans that are powered entirely from the force of gravity and hydraulic principles, making them completely electric-free. However since plan outlets are located at much lower elevations than the plant itself, this presents difficulties in transporting treated water back into the plant for filling chemical stock tanks and plumbing. The ram pump is an excellent solution because it utilizes the water hammer effect to pump water to a higher elevation than the source water and does not use electricity. Our ram pump is designed to be augmented in an existing plan in San Nicolas, Honduras, where the 750.0 L stock tanks will need to be filled in 3 hours, corresponding to a flow rate of 70.0 mL/s.

Fluidized Bed Flocculator -Spring 2014

Felice Chan, Jonathan Christensen, Stephen Jacobs, Ana Oliveira

Abstract:

Novel methods of water treatment, that do not use electricity and only require basic construction materials, are in demand worldwide in remote regions without established centralized water treatment. Gravity-driven unit processes must be developed for these water treatment facilities. Current hydraulic flocculators use baffles with dimensions on the order of meters to generate turbulence and achieve particle aggregation. An alternative approach is to use sand grains, rather than large solid sheets, as flocculator baffles. A fluidized sand bed flocculator occupies much less plan view area, but generates much more head loss. Implementation will depend on a balance of the cost of land and materials against the available hydraulic head.

Floc Probe - Fall 2014

Surya Kumar, Larry Ge

Abstract:

The sedimentation tanks at AguaClara sustainable drinking water treatment plants are performing well, but they can perform better. When floc settles it becomes sludge. If there is sludge buildup in a sedimentation tank, a host of problems follow: uneven water flow through the sedimentation tank, impaired performance, anaerobic digestion, and methane production. However, if a sedimentation tank can be designed to prevent any flocs from settling, then the drinking water treatment process will never have to be stopped, and the sedimentation tanks will never have to be cleaned. AguaClara is investigating the creation/use of a “Floc Probe” to better understand floc behavior and achieve this improved tank design. The research tool will be used to survey currently functioning sedimentation tanks in Honduras to identify where sludge is building up. Sonar has been found to be a potential solution. Sonar can detect substances of varying densities as well as record at what depth the substance was found. This technology can therefore distinguish between flocs and sludge, and can also recognize the amount of sludge buildup.

Fabrication - Fall 2014

Carl Talsma, Sara Sanz, Adrian Cobo

Abstract:

Make a hydraulic working scale model of the SRSF weir system for two filters to demonstrate how the weir system is used to set the flow to the filter during backwash. The hydraulics of this system are sufficiently complicated that explaining how it works is difficult and thus we need a working model for demonstration.

No final report was available for this team for this semester. The final presentation is linked below.

Enclosed Stacked Rapid Sand Filter - Spring 2014

Dhaval Mehta, Ariel Seidner, Sarah Sinclair, Lishan Zhu

Abstract:

The Low Flow Stacked Rapid Sand Filter (LFSRSF) is a scaled-down version of the AguaClara Stacked Rapid Sand Filter (SRSF). Similar in theory of operation to the SRSF, the LFSRSF is optimized to treat smaller flow rates of 0.8 L/s. The current LFSRSF design in India uses multiple valves to switch from filtration to backwash; the LFSRSF research subteam at Cornell seeks to reduce the number of valves by designing a filter that uses hydraulic controls. In detailing the teams work this semester, this report seeks to accomplish three main goals: to document the design process for such a filter, to document the fabrication process to facilitate easy technology-transfer to India, and to document filter performance as tested to date.

This semester, the team calculated appropriate design specifications for slotted manifold, trunks, plumbing systems and sand for the filter, as well as created a unique flexible-tubing derived sand drain. The team completed all fabrication, and also set up a water-recycle and leak containment system to support testing, as well as a pressure sensor array to test ow-distribution between sand layers. The team then solved multiple water- and air-leak issues. Ultimately, the team was successful in ensuring that the LFSRSF backwashes easily, efficiently and whenever an operator may so desire.

Teams working on the project further must tackle three major issues: the current filter cannot handle backwash flow rates greater than around 0.6 L/s, its entrance and exit tanks need to be raised, and the filter also faces significant challenges of larger-than-expected head loss during backwash. Once these issues are solved, the hydraulically-controlled LFSRSF shall be truly ready to be deployed in the field

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

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.

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.

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 1L/S - Summer 2016

Juan Guzman, Josiah Hinterberger, Juan Mantilla Quintero, Erica Marroquin, Disha Mendhekar, Ibrahym Sabha, Claudia Vesga Rodríguez, Victoria Zhang, Monroe Weber-Shirk

Abstract:

Conventional water treatment technology often have fixed costs too high for small communities with demands less than 5 L/s. The goal for the 2016 AguaClara summer program was to design scaled-down processes and fabricate an inexpensive 1 L/s plant. This pilot plant employs conventional flocculation, sedimentation, filtration, and disinfection methods, but accomplishes each step using innovative materials and methods to maximize space efficiency and minimize cost.

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.