How did humans pressurize air before electricity? Meet the trompe – the oldest technology you’ve never heard of. Dating back to the 17th century, trompes harness the power of falling water to generate cool, dry pressurized air that can be used in forges and mines. Trompes feature a simple design with no moving parts and require no electricity – just running water and an elevation drop! Air is mixed into the water as it falls down a pipe to a lower air separation chamber, where the bubbles rise back out of the water and are collected before the water itself discharges.

Canadian Charles Taylor rediscovered the technology and built the world’s largest trompe on the Montreal River in 1910. Featuring a 345 ft drop, the Ragged Chutes Compressor generated 128 psi, approximately 5,000 horsepower, and a spectacular 200 ft geyser! Not only do trompes work well, but they also work reliably – Ragged Chutes was in continuous operation for over 70 years with only two planned maintenance shutdowns.

The late hydrogeologist Bruce Leavitt first saw Ragged Chutes from the window of a tour bus and realized decades later that the same technology could be used in the remediation of acid mine drainage. Aeration of mine water can remove excess carbon dioxide, raise the pH to more neutral levels, restore dissolved oxygen, and remove ferrous iron by oxidizing it to an insoluble form that can then precipitate out of solution.

REMC specializes in such treatment of mine drainage and has extensive experience in the installation of both passive and active aeration systems. Few technologies, however, can match the simple elegance and low maintenance costs of the trompe.

Image sources (clockwise, from top left): Practical Engineering, Bruce Leavitt, Cobalt Silver Heritage Trail, ASME Milwaukee