Trompe The Oldest Technology You Never Heard of

Bruce Leavitt Tim Danehy

Consulting Hydrogeologist BioMost Inc.

Joint Legislative Air and Water Pollution Control and

Conservation

Committee

Environmental Forum

October 21, 2013

Thank You

Over 300 publicly funded of Passive

Systems have been built with hundreds of

stream miles improved

Good Samaritan Act

Growing Greener

Act 13 funding

5,596 miles of stream remain impacted

Mine Discharge

water chemistry and

flow

Mining Facts

4,991 square miles mined

1,941 square miles flooded

1.36 trillion gallons in storage

27.19 billion gallons discharged per year

63.4 % does not go through a treatment plant

37.8 % of the acidity is untreated

40 % of the iron is untreated

97.7 % of the aluminum is untreated

Chartiers Creek Discharges

Coal Run Presto - Sygan

What is a TROMPE?

It is a device that uses falling water to

compress air.

It has No moving parts.

It does Not use electricity.

It is Completely passive.

Principals of Operation

Falling water in a pipe entrains air.

The high velocity water carries the air down the

pipe to an air separation chamber.

Compressed air is separated from the water by

gravity.

The air is collected for use.

The water is discharged.

Trompe Design

TROMPE Design

TROMPES operate in a narrow flow range

Flow is dependent on pipe diameter

Four feet of head is required between inlet

and outlet

Maximum pressure is dependent on the

length of the return pipe

TROMPES can be constructed in parallel or

series to meet flow and air requirements

TROMPES generate about 1 cfm / 25 gpm

3 TROMPES in Series

Trompe History

• Discovered in 17th

century Italy.

• Defining component

of the Catalan Forge

• Developed 1 to 16 oz

pressure

Trompe History Continued

• Rediscovered by Charles

Taylor, Canada

• Ragged Chutes Compressor

delivered 128 psi to the area

mines

• Was in continuous operation

for over 70 years with only

two maintenance shutdowns.

When is Aeration Needed?

When ferrous iron is present and

When the raw water has a low dissolved

oxygen content.

When the raw water has elevated carbon

dioxide.

Effect of Carbon Dioxide

Mine drainage from underground mines

frequently contains excess carbon dioxide.

The effect of this excess carbon dioxide is

to lower the pH of the raw water.

Aeration of mine water will remove the

excess carbon dioxide and could increase

pH (Kirby et al., 2009).

Effect of pH

After Dietz 2008

• The higher the pH the

faster iron is oxidized.

• As iron is oxidized the

pH is lowered

lengthening the time

required for oxidation.

• This increase in

detention time requires

a commensurate

increase in pond size.

Aeration Removes CO2

and Increases pH H+ + HCO3

- ↔ H2O + CO2 (g)

Aeration Test

Aeration needed in the

Anthracite

Curley Raw Water with

Aeration

Ferrous Iron Oxidation

Many mine drainage treatment facilities

require aeration for iron oxidation.

Fe2+ + ¼ O2 + H+ → Fe3+ + ½ H2O

Based on this equation 1 mg of DO will

oxidize 7 mg of ferrous iron.

The time required for this reaction to occur

is dependent on oxygen transfer to the water

and the pH of the water.

Air In

Trompe Aeration

pH Rising

Enhanced Iron Oxidation

North Fork Montour Run

Aeration of Pond 2 at 125 gpm flow

with 3 TROMPES in series

Oxygen Transfer

Oxygen transfer to water is dependent on:

– Air flow

– Bubble size (fine bubbles have more surface

area)

– Depth of aeration (10 feet is recommended)

Disc aeration heads used in sewage

treatment produce fine bubbles.

Periodic cleaning is required.

Curley Results

0%

20%

40%

60%

80%

100%

raw pond 1 pond 2 pond 3

Percent Iron Oxidized

Aerated 1-18 Not Aerated 1-26 Aerated 2-26

Curley Results

0%

20%

40%

60%

80%

100%

raw pond 1 pond 2 pond 3

Percent Iron Settled

Aerated 1-18 Not Aerated 1-26 Aerated 2-26

Single TROMPE Cost

Gallons per

Minute

Approximate

Pipe Cost

Approximate

Installation Cost Total Cost

20 to 100 $3,000 $9,400 $12,400

500 - 1000 $15,700 $16,800 $32,500

500 - 3000 $21,800 $24,268 $46,068

Semi-Active Lime Dissolution

Water powered Lime Dosers.

Long Dissolution Channel.

Lime Buildup in Channel or Ponds.

Carbon Dioxide Reacts to Form Calcite.

Add Pebble Quicklime

MixWell patent pending

Raw water is feed to

the bottom of the

MixWell.

Lime or lime slurry

is added to the

annulus and sinks to

the bottom.

The lime is agitated

by the raw water.

Only small particles

rise to the discharge.

MixWell

Lime Particles from MixWell

A-Mixer patent pending

Compressed Air

supplied by Trompe.

Airlift created in 12

inch pipe.

Circulation in tank

keeps small particles

suspended.

Airlift provides oxygen

for iron oxidation.

Air Lift Mixing

Lime Particles from A-Mixer

Pebble Quicklime

TROMPE Applications

Mine Drainage treatment Active and

Passive

Sewage Treatment

Aquaculture

Lake Aeration

Chemical mixing

Acknowlegement

BioMost, Inc. for providing access to the Curley

site and investing in this new technology.

Tim Danehy who loves the smell of PVC glue at

25°F.

Bryan Page who will willingly wade into any pond

in January.

Cody (Buck) Neely who just loves to help get the

iron out.

Questions?