PRESERVING FRANKLIN’S MOST VITAL RESOURCES

Welcome to the Franklin Water Purification Demonstration Facility

ENTER

Membrane filtration

Franklin’s multi-barrier approach

These water purification steps are designed to work together to remove smaller and smaller physical, chemical, and microbial contaminants, resulting in purified water that can supplement our current water resources.

Ultraviolet light/ Advanced oxidation

Granular activated carbon

Franklin Water Purification Demonstration Facility

Biofiltration

Purified water for river and reservoir augmentation

Ozonation

The process of removing biological toxins, chemicals, suspended gases and solids, and other contaminants, in order to produce purified water for specified uses. 

Franklin Water Purification Demonstration Facility

These water purification steps are designed to work together to remove smaller and smaller physical, chemical, and microbial contaminants, resulting in purified water that can supplement our current water resources. EndFragment

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Membrane filtration The source water enters this tank and then high-pressure pumps pull water through the hollow fiber membranes, leaving contaminants behind.  The fibers have very fine pores that can only be seen with advanced microscopes.  Contaminants (such as particles, bacteria, and protozoa) are trapped and filtered out, while water passes through the membrane pores to the next step.

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Contaminants

Hollow fiber membrane

Pores

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STEP

We are testing ultrafiltration, where the pore size is as small as 0.02 - 0.05 microns, which is 100x more narrow than a human hair!

Biofiltration Water flows through a filter of active carbon granules infused with millions of beneficial, living bacteria, and then through a layer of sand. The living bacteria breaks down organic compounds and contaminants of emerging concern (CECs). This step also reduces nitrogen in the water, which helps to protect the water quality of our river and reservoir.

The layer of sand at the bottom of the columns removes any nonactive or microbial particles, similar to how a conventional filter works.

Biologically activated carbon granules

Sand

Living bacteria

Granular activated carbon

Pores adsorb chemicals

Water flows through a canister filled with carbon granules. The granules are "activated," which creates numerous small pores and surface area to adsorb chemicals in the water. This step uses a physical-chemical process to remove CECs such as PFAS (per- and poly-fluoroalkyl substances) and disinfection byproducts from the water.

Granular activated charcoal

A handful of granular activated carbon has the surface area equivalent to a football field!

Destroys 99.9%

UV lamp

Hydrogen peroxide

Ultraviolet light with advanced oxidation

The hydrogen peroxide reacts with the light to form powerfully reactive molecules that destroy microconstituents in the water including pharmaceuticals and personal care products.

The vessels in this step are fitted with ultraviolet (UV) lamps, which produce rays similar to extremely concentrated sunlight. A powerful disinfectant, such as hydrogen peroxide, is injected upstream of the UV vessels. The UV light also destroys 99.9999 percent of protozoa, bacteria, and viruses present, leaving only purified water.

Increasing the amount of water we can reclaim and reuse

Supplementing water levels in our drinking water reservoir.

This process produces purified water, which is safe for adding to our water supply cycle. Goals for using water purification technology include:

Mouse over or touch icons for more information about goals.

Expanding recreational use of the Harpeth River.

Enhancing the ecological health of the Harpeth River.

Purified water

Atomic oxygen (O1)

Ozone is efficient in breaking down organics, chemicals, and contaminants such as coliform, bacteria, and protozoa, and also makes large organic molecules into more readily available organic "food" for the next process

O1

Micro-organism

3 oxygen atoms

Atmospheric oxygen (O2)

Ozone's high oxidation breaks down the cell membrane of common microorganisms, killing the pathogens.

Ozone (O3)

THE PLAYERS

O3

The free oxygen atoms combine with other oxygen molecules to form ozone. 

MAKING OZONE

HOW OZONE KILLS

Ozonation Oxygen molecules (O2) from the air are comprised of 2 oxygen atoms (O1). When subjected to high electrical voltage, the atoms split apart, mixing with other oxygen molecules to form ozone (O3). The ozone gas is infused into the water to destroy microorganisms. The ozone is consumed and converted to dissolved oxygen prior to the next step.

O2

Ozone

2 oxygen atoms

MAKING OZONE

HOW OZONE KILLS

High voltage splits oxygen molecule into 2 oxygen atoms.

THE PLAYERS

Step 1: Membrane Filtration

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Step 2: Ozonation

Step 3: Biofiltration

Step 4: Granular Activated Carbon

Step 5: Ultraviolet Light With Advanced Oxidation

Testing and Monitoring