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.

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.

Village Supply System - Household – Fall 2014

Pooja Desai, Paula Gomez­Nunez, Mary John

Abstract:

The Fall 2014 Household Infrastructure Team designed a storage tank, sink and a flow regulation system at the household level in a rural Indian village. The ultimate goal of the semester’s designs was to provide equitable flow to each house, to be stored and used in a sanitary environment. The designs determined that a 600L HDPE storage tank at each household is necessary to store a days worth of water to the family, attached to double level sink that provides an upper basin for washing of dishes 1m above the ground and a ground level platform for washing clothes. Tanks are elevated on top of a brick stand that is approximately 1m tall. Inside the tanks, ball cock float valves with an inner diameter of 1⁄2” regulate water flow.

To provide equitable water flow to each household in the village, no matter where the house is located, flow regulation to within 10% of the target household flow, 0.021L/s was forced in our design by adding headloss elements into the distribution system before the storage tanks. Extensive research into pressure regulators as a means of flow regulation was done, but it was determined that they are impractical for villages that have only a few meters of elevation difference. The design expanded further upon previous semesters work with small diameter coiled flexible tubing that greatly restricts flow. Depending on the available tubing diameters, it was found that 1m­6.7m of tubing is required at the household level to force equitable flow throughout the village.

Village Supply System - Distribution Subteam – Fall 2014

Maria Veronica Cordova, Tianchen Yu

Abstract:

The Team Village Supply has three sub teams working on the photovoltaic pump, distribution and household design. The Village Supply­Distribution System Subteam has worked based on last semesters code 2canzzzz’ and improved it so that it has more accurate final results and it can be set continuous, meaning that this code can be updated with any characteristics of other villages. The overall design of the subteam consist in the network of pipes that distribute water coming from the tank to every house in the village. The new code has taken into account the flow variation into each tier of pipes, and thus the result in the sizing of the pipes has changed significantly. As a result we obtain the critical path and the correspondent head loss through the pipes, considering major and minor losses and differences in height elevations. The cost of the total network design including pipes and tees has been calculated with updated costs for the optimal solution.

Village Supply System - PV/Pump – Fall 2014

Qingjing Gong, Anqi Wang, Erika Axe

Abstract:

The PV/Pump Subteam section has worked on how to modify and improve upon the ideas and models already in place for design of pumps in villages for the Fall 2014 Semester; this group is a subset of the entire Village Supply Team in the AguaClara Student Project Team at Cornell University. In general, this subset has worked toward having single electric pumps that send water to the town and lifts water from the well at ground level to an AguaClara facility/distribution system, deliberating types of pumps and pressure requirements for equal distribution, balancing cost and efficiency of pumps, and evaluating the different options for the design of the photovoltaic and pump system. Among the different designs for the photovoltaic and pump system, this section will be looking at two main options. The first option will be to divide the power between the two pumps, create a simple control system for easily maintenance, and to design the photovoltaic system to be able to handle cloudy, winter days. The second option to be looked into will be to divert all the power to the first pump on cloudy days and to allow the control system to automatically divert all of the power to the well pump when the chlorine contact tank isn't full—thereby allowing the second option to be more easily implemented.

Chemical Dose Controller - Fall 2014

Annie Cashon, Jeanette Liu, Christine Leu

Abstract:

The Chemical Dose Controller is a device that maintains a constant chemical dose as the plant flow rate changes. This semester, the Chemical Dose Controller team has started doing research on chlorine compatibility with the constant head tank. Part of this assignment includes exploring alternative CHT designs in hopes of maximizing durability and efficiency while minimizing costs. The team is also considering scaling the CDC system down by looking into the single lever arm design. The team has begun recording these adjustments in a CDC assembly manual for future CDC teams that includes photos and item lists. Finally, the team has reached out to the team in India, in hopes of working out a cost effective and reliable system for future shipments.

Ram Pump - Fall 2014

Abigail Brown, Annie Ding, Pablo Nistal, Kadambari Suri

Abstract:

The Fall 2014 ram pump team is working on expanding and improving upon the work of previous ram pump teams, which includes fabricating and implementing a working ram pump design in a plant in Honduras. The team has completed literature research, fabrication of the ram pump designs to be tested, basic experimentation, and data collection. The literature review has determined that while experimentation done on ram pump components like the spring check valve indicate that these parts will last for decades, the non-ideal conditions of the use of the spring valves in AguaClara plants means that more experimentation is needed to determine how long the valves will last while in use in AguaClara plants. Additionally, the team has found other points of wear within the valve during testing this semester. Ideas for potential improved designs have resulted in the fabrication of air chambers of varying sizes and drive pipes of different lengths and diameters. The most efficient pump model was determined by taking data for different models with varying numbers of weights on pressure within the system and flow rates at various head loss values. The team found that the optimal system for the ram pump is to use as few weights as possible without causing the ram pump to stop, along with either one of the two tested outlet possibilities, and as large an air chamber as desired or available. However, this system does not result in an adequate output flow rate, due to losses within the system. More work still remains to be done - the team is currently working on a vertical system alternative which may eliminate the need for a horizontal drive pipe and may reduce the number of losses within the system that is affecting the output flow for the system currently in use.

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

Distribution System Contamination Prevention, Fall 2014

Alicia Peters, Chen Weier, David Gold, Lucia Garcia-Iturri Gallego

Abstract

Contamination of treated water in the distribution system has the potential to negate the improvements to water quality provided by an AguaClara plant. Intermittent distribution systems may create the conditions for the mechanisms which cause this contamination to occur. The most likely mechanisms of distribution system contamination are pipeline intrusion, cross contamination and inadequate household storage. Through proper operator training, effective regulation and installation of secure storage facilities and backflow prevention valves, these mechanisms can be prevented and safe water delivered to all AguaClara households.

EStaRS, Fall 2014

Sarah Bolander, Skyler Erickson, Subhani Katugampala, Mary Millard, Savannah Wing

Abstract

The ultimate goal of the EStaRS (Enclosed Stacked Rapid Sand) Filter team was to develop an appropriate configuration for the stacked rapid sand filter system that could be implemented to treat groundwater in India. The stacked rapid sand filter is an excellent choice for treating water near the city of Ranchi, India, as the primary water source there is groundwater. The low turbidity of groundwater means that the full AguaClara treatment process is not required and filtration with dosing will suffice. After testing the current apparatus, the goal was to improve the design so that modular EStaRS filters can be run in parallel efficiently and sand bed fluidization can be detected. This team set up a system to allow for extended backwash times, proposed a weir design to run multiple EStaRS Filters in parallel, and set up a manometer system to analyze bed fluidization during backwash.

Foam Filtration - Fall 2014

Kristin Chu, Marlana Hinkley, Ethan Keller, Valerie Pietsch

Research report not available. Research presentation attached below.

Small Scale Plant Model, Fall 2014

Serena Takada and Nick Cassab-Gheta

Abstract

During the fall semester of 2014, the Small Scale Plant Model Team worked on repairing the current small scale plant model and began using AutoCAD to 3D print a small scale model of AguaClara plants. The purpose of using AutoCAD to print models of AguaClara plants, rather than using Rhinoceros 5, is to automate as much of the printing process as possible. The team evaluated multiple methods of converting a solid in AutoCAD to a meshed solid. In addition, the team looked into alternative printers that would be more compatible to printing using AutoCAD. Eventually, the team hopes to develop a system where anyone can request an STL file containing the design of the most up to date design of an AguaClara plant at any flow rate. Upon request, this STL file should be sent to any 3D print shop to be printed.

StaRS Backwash, Fall 2014

Vicki Chou, Nick Farino, Chenhao Qi, Rui Zhang

Abstract

The goal of StaRS Backwash is to determine the sand grain sizes and distribution for the most efficient and effective backwash in the stacked rapid sand filters. The proper fluidization velocity for efficient backwash must first be determined. An expansion ratio of 1.3 is the current standard for the sand bed during fluidization. A sand size ratio below 1.5 is suggested for minimal segregation during backwash. The team ran experiments with sands sized by sieve combinations of 20­40 and 30­40 at different backwash velocities to test for segregation. Through the experiments, the team found that the 20­40 sized grains always segregated at all backwash velocities, but the 30­40 sand, which is under the 1.5 sand size ratio, did not segregate below backwash velocities of 15 mm/s. Current AguaClara plants use a backwash velocity of 11 mm/s, so using 30­40 sand would be a good option because it should not segregate according to the data collected.

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.

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.

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.