University of Houston – Mechanical Engineering Capstone Project

Background

Clean water is essential to all communities, but some do not have the necessary development or infrastructure to provide clean water appropriately. The solutions that are available to tackle these shortcomings are very expensive and are not suitable for small scale usage. The Solar Powered Water Filtration and Purification Device is aimed at providing a system that can filter and purify water from an external freshwater source and produce clean drinking water for an individual or family, for less than a $1000.

Project Scheduling

The following figures are Gantt charts detailing the schedule assigned in order to complete the device.

Design Concepts

The overall design can be broken down into two main systems, the filtration system and power supply. In order to produce clean drinking water from an external freshwater source, there must be a reduction of total contaminants and particulates that exist in nature. The EPA details possible contaminants and allowable quantities for each listed in the following url: https://www.epa.gov/ground-water-and-drinking-water/national-primary-drinking-water-regulations.

The filtration system needs to be capable of eliminating harmful contaminants fully, such as bacteria, and reduce all contaminants in the filtered water to a regulated range of 30-400 ppm (parts per million) as defined by the EPA for clean drinking water. To accomplish this, the filtration system will be utilizing three type of filters: sediment, carbon, and UV light. Sediment filters are designed to prevent particulates from contaminating the filtered water up to the sizing of the filter pores. Carbon filters eliminate some chemicals, but mainly chlorine, while also reducing the odor of the filtered water and improving the taste. The UV light filter is designed on an allowable flow rate for filtered water to pass through, exposing the water to UV light, which eliminates bacteria. In order to propel water through the filtration system, a submersible electric water pump rated at 11 gpm is utilized. In total, two 5-micron sediment filters, two 5-micron carbon filters, a 2 gpm UV light filter, and an 11 gpm pump comprise the designed filtration system.

The power supply system needs to be able to keep the device operational in varying weather conditions while also being able to keep the pump and UV light filter functioning properly to prevent potential contaminants remaining in the filtered water. To do this, a rechargeable 12V battery is connected to a DC to AC converter where the pump and UV light filter can be plugged into using normal electrical sockets. To keep the battery charged, a 20W solar panel is used in conjunction with a solar charge controller to prevent overcharging the battery and monitoring all transmitted voltages.

Both the filtration and power supply systems need to be contained effectively in a lightweight and portable frame that can withstand varying environments and situations. The frame is constructed from one inch diameter PVC piping and quarter inch thick plywood to comprise the bottom and top.

CAD

The following figures represent the final design of the device where blue colored components denote the filtration system, red colored components represent power supply, and white represents the frame.

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From the figures above, water enters via the pump which rests outside of the frame, propelling water through the series of sediment, carbon, and UV light filters to form an outlet on the other side of the device where filtered water can the be collected.

Prototype Fabrication

The following figures represent the fabricated prototype based on the CAD developed by the team.

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These figures show the completion of the frame with most of the components placed on the device. The dimensions of the prototype are 23″ x 21″ x 18″ and with every component in place, weighs 42.2 lbs.

Prototype Testing

The following figures represent the device during testing at a local river.

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As seen above, a five gallon bucket was used to collect river water to provide a contained environment for the submersible pump while normal water bottles were used to collect water samples.

Testing Results

The following figure represents the collected samples from the river, after filtration through the device, and then faucet water used as a control.

From left to right, the samples are from the faucet, after filtration through the device, and from the river water directly.

Utilizing an electronic water tester, the follow results were tabulated for the samples pictured above.

From this table, there is roughly a 10% decrease in ppm for the filtered water compared to the river water itself. This decrease is enough to be within the EPA recommended range, but compared to water from a faucet, the ppm remains significantly higher.

Utilizing a testing kit to examine 10 contaminants, the following table was created.

From the results in the table above, only two tests were higher than EPA standards. These tests include the pH and Hardness of the filtered water.

Budget Breakdown

The initial budget Team 26 planned for was $1000. The following table shows all expenditures relating the device.

From the table above, the team ended up over $500 under the planned budget.

Conclusions

The Solar Powered Water Filtration and Purification Device showed roughly a 10% reduction in contaminants after filtration, higher than EPA recommendations on tests for pH and hardness, and was under budget by over $500. From the water sample tests, the team cannot be certain whether safe clean drinking water was produced through filtration from the device due to the limited amount of contaminants tested. However, the device showed it was capable in eliminating major contaminants like bacteria and a quantifiable reduction in total ppm. To further improve on the device, Team 26 recommends higher rated filters for further ppm reduction and more contaminant tests.

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Team 26 consists of three seniors in the Mechanical Engineering department at the University of Houston: Zach Gallagher, Luis Diez, and Andrew Ibarra.