OHIO UNIVERSITY
Russ College of Engineering & Technology
Department of Mechanical Engineering
DESIGN OF A WATER PURIFICATION SYSTEM
A Water Purification Solution Utilizing Ultraviolet Light for
Village of Konalai in Southern India
Ohio University Mechanical Engineering Senior Design 2010
Team Biological Filtration Technology
AUTHORS: Seth Beachy, David Gallagher, Ben Barkley & Jamison Swope
,
ABSTRACT:
Ohio University mechanical engineering senior design team Bio Filtration
Technology has designed a water purification system for the village of Konalai in India.
Konalai’s 1800 residents suffer from water related illness due to poor drinking water
quality. BFT has designed a water purification system to augment the village’s water
distribution system. The system utilizes sediment filtration supplemented with ultraviolet
light to effectively filter and sterilize contaminated well water as it is pumped to the
village reservoir. The goal of the project was to meet the needs of the village and provide
a long term water treatment solution. The purpose of this report is to present an overview
of the entire project including: the design solution, project cost, construction, and
maintenance information, testing and evaluation results and future field testing plans.
SOLUTION:
The goal of our design process was to meet Konalai’s needs as defined through
contact and communication with the village and BFT’s internal review processes. The
needs are prioritized in the table below in order of decreasing importance.
BFT received information concerning the village from contacts in India including water
quality test results. This indicated an excess of fecal coliforms and fluoride present in the
well water supply being pumped to the village.
The team looked at a wide range of design possibilities including slow sand
filtration, open and closed channel ultraviolet light sterilization, reverse osmosis and
point of intake filtration and from each generated multiple concepts for evaluation. Each
of the generated concepts were ranked and scored using metrics that related how well
each fulfilled the village’s needs. An ultraviolet light system with pre filtration was
chosen for development. The design goals of having a pre packaged stand alone system
that was compact and shippable shaped the developed of the prototype. The design
consists of two high flow reusable polyester filters in series; a 50 micron followed by a
20 micron. The filtered water enters an ultraviolet sterilization chamber with electronic
controller. The design was verified through experimental testing and finalized for
shipping and installation in Konalai.
Pressure gauge
UV chamber
controller
Service hose
75 psi pressure
relief valve
UV chamber
50 micron
reusable filter
UV chamber
bulb ballast
The final design is a packaged solution that can be reproduced and installed in
needy locations. The system can be connected to existing water lines from a pump as in
Konalai, standard water lines or gravity fed water lines such as from a large tank or
reservoir. The purification system is transferable to many locations when they have
several conditions present. These include most importantly access to reliable electricity, a
moderately level and protected area for installation, personnel available for maintenance
and an availability to obtain replacement parts.
Safety and backup features are incorporated into the system design. A pressure
relief valve prevents over pressuring of the system and the UV controller has a built in
audio failure alarm and visual port to check bulb operation. A pressure gauge has been
included to monitor pressure increases due to sediment build up in the filters and assist in
determining when cleaning or replacement is needed. A service hose is operated at the
entrance valve to bypass the filters and UV chamber to supply water directly from the
20 micron
reusable filter
pump for spray cleaning of the filters or as an emergency bypass. In the event of a failure
of a component, the system can function as passive water piping until a repair or
replacement is available. Flow can be maintained to the reservoir at previous levels and
the village will not be in a worse situation than it is currently in the system fails. The
service hose would also be able to supply emergency water in the event that the village
piping or reservoir fails or cleaning of each would be necessary.
COST:
A chart of the total project manufacturing costs including labor is given below.
These estimates are based on US labor rates.
The total cost of manufacturing was $1181. A majority of this cost is incurred in the UV
and filtration hardware. The fixed cost associated with just material expenses is $950.
Some goals that our design achieved were providing a simple yet effective stand alone
purification system of minimal weight and size (to reduce shipping cost) and an easily
serviceable system due to the use of commercially available parts and simple construction
methods. The images below show in detail the color coding assembly method and simple
bolted frame.
Some of the materials and construction methods used in the design could be
reduced if the purification system were to be built locally. Steel instead of aluminum
could be used for the frame since shipping costs would not be an issue, and direct piping
adaptors could be installed instead of the flexible connections and multiple adaptors that
were required for our system since the team never received feedback concerning the
exact layout of the Konalai pump house or the pipe diameters and locations. Employing
local labor would reduce the total project cost since most locations would have
significantly lower labor rates than the United States. Excluding piping, a complete list of
material costs, vendors and part numbers is given below
It is important to note that the design can be scaled to meet specific water volume needs
of a population. This system was designed to take advantage of the pre existing pump and
closed piping in place in Konalai. Selecting a Sterilight® UV chamber model to match
desired water flow and assessing the availability of electricity are the most crucial
decisions to make when installing a new system for service.
CONSTRUCTION AND MAINTENANCE:
On-site installation of the purification system was simplified by the use of a color
coding plan and pre assembled components. 1” standard piping and metric connectors
have been used throughout. A detailed parts list is given in the picture based owners’
manual that was developed for the final design. The manual includes installation and
operation procedures as well as maintenance and troubleshooting methods.
Pre assembled
components
Flexible
connectors
Maintenance of the design is minimal. A weekly inspection and cleaning of the
polyester filters and UV chamber is required. Various components of the system have a
finite life and require eventual replacement. The filters are designed to be replaced at
least yearly, the UV bulb after 9,000 hours of operation (3 years of operation at Konalai)
and the o-rings and piping fixtures on an as needed basis. Yearly maintenance and
operation cost can be estimated from replacement component cost and electric usage but
are designed to be under $100 excluding replacement of a housing or chamber. Proper
handling, operation and storage of the design is critical to maintaining its service life. The
purification system is designed and adaptable to be a pre packaged unit for purchase and
quick installation.
TESTING AND EVALUATION:
Several experiments were performed to evaluate the impact and effectiveness of
the prototype design. The effect of adding flow restrictive filters was analyzed by
performing a pressure and volumetric flow change experiment. An experimental lab was
built using a ¾ horsepower centrifugal pump and pressure transducers. It was determined
that the pressure drop across both filters was less that 4 psi with a nominal value of 36 psi
at a flow rate of 30 GPM. Konalai’s current pumping schedule of 6 hours per day to fill
their reservoir will have to be extended as is necessary to account for flow reduction.
The sterilization effectiveness of the prototype was analyzed by performing a
before and after E. coli (a fecal coliform) standard plate count. A super saturated E. coli
solution was added to a control pre-filtration water tank. The E. coli filled water was then
pumped through the prototype and collected. This process was performed with two prefiltration water sources: de-chlorinated tap water and high turbidity river water both
saturated E. coli additions. The resulting collection samples were then plated using
standard dilutions methods on the selective media Eosin Methylene blue agar (EMB).
This quantitative analysis proved the system to be over 99.999% effective at eliminating
E. coli from both the tap and river water sources at a flow rate of 30 GPM.
Though the system was validated in addressing the fecal coliform contamination
in Konalai’s water, no viable cost effective solution could be designed to control the
excess fluoride. Even highly developed areas face the same problem of being able to
efficiently eliminating excess fluoride and its presence in drinking water is not an
immediate health concern.
FIELD TESTING PLANS:
As of the time of this report, the shipping and subsequent installation of the
purification system in Konalai is under way. The contact in India will be receiving the
disassembled unit and will install it in the village with the help of an engineering student
from Bishop Heber College. The team hopes to receive feedback over the next year as to
how the system is improving the health of residents, problems and concerns with the
design including failures and maintenance issues and the performance life of the various
components. If the system is proven to be an effective solution for Konalai, a yearly
budget for planned maintenance will be developed.
Receiving field performance results from multiple installed units will best enable
the purification system to be analyzed. Feedback and data received from communities
where a purification system has been installed will enable the long term capabilities and
performance issues to be evaluated. The impact potential the design has on improving the
health of so many people warrants further study and investment.
•
Solar Power Feasibility
The scope of the design did not include adapting and testing the system to operate
on solar power. However, we have included a study of the feasibility of using solar power
to operate the purification system to demonstrate the possibility of enhancing the system
in areas without access to electricity. The efficiency of using solar power would be
maximized if a purification system were installed in a solar energy rich region of the
world such as southern India.
The 12SQ-PA Sterilight® model operates on an AC source ranging from 100-240
Volts at 50-60 Hz. The unit has a 48W draw and operates at 0.6 Amps. The wattage
required is fairly low and could be supplied by panels as small as the BP Solar 350 which
is commercially available for around $450. Solar panels of this size are designed to
produce lower DC voltages so the use of a step up transformer and inverter ($75) would
be needed to power the UV controller. An energy storage system is also required to
insure continuous powering of the UV system when the pump is in operation regardless
of the weather conditions. A single 12V car battery at 90Ah appears to be a sufficient
backup source. Additional work would be necessary to design and implement the solar
option and determine an accurate cost estimate, but it is technically feasible and the
additional cost would likely be less than $1000
CONCLUSIONS:
The final water purification design satisfies the needs of Konalai. The designed
purification system provides a low cost long term solution that is maintainable by the
local residents. Ultraviolet water purification technology in couple with local planning
and cooperation is a strong water quality solution for underdeveloped or rural areas
because of its adaptability and low cost per amount of purified water. Our system is
adaptable to help populations where a reliable electrical source is present and the local
population is able to install, maintain and service a system as required. Water distribution
systems that utilize all manners of closed piping are viable candidates for the installation
of a purification system. Given the local availability to purchase and obtain the system
components, a purification unit can be easily manufactured and installed by the local
population.