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Injection Wells: Digging Deep for Wastewater Solutions

Early last year, the Miami-Dade Water and Sewer Department (MDWASD) announced their plans to dive into a project that invests in the future of wastewater disposal. The majority of treated wastewater, which is about 300 million gallons daily in Miami-Dade County alone, currently feeds right back into the middle of the Atlantic Ocean via outfall pipes. As the population continues to grow, this task is getting more difficult to keep up with financially.

Wastewater, or effluent, is the result after water has been used—to flush, wash, etc. in any capacity whether personal, industrial, commercial, or other use. Efforts are now being focused on cutting costs and continuing to safely dispose of this effluent. This utility has been tasked with finding an alternative within the next nine years. By 2025, the state will prohibit the use of the ocean as a dumpsite.  The MDWASD has now turned to digging into the Earth to build injection wells to dispose of waste, thousands of feet below any drinking reserve.

Although injection wells currently exist, including 21 others belonging to the county, their current depths are usually no more than 3,500 feet. The South District Wastewater Treatment Plant is a testament to this with the next goal being the implementation of this method at the Central District Waste Water Treatment Plant.

Because upward seeping of effluent through leaking wells has been an issue in the past, a much deeper goal has been set with the hope that a new horizon may be reached. Even when the injection wells have leaked before, contamination has never occurred; these instances have made valuable lessons for additional preventative measures to be taken into consideration.

The largest water utility in Florida is now attempting to dig the deepest injection well in the state, estimated to be about 10,000 feet deep located on Virginia Key.

Using a very hefty 120,000 pound drill, intricate research, and her team at her disposal, lead geologist on the project, Virginia Walsh, is exploring just how far we can get away with digging to ensure plenty of distance from the surface and our aquifers in order to allow the geological elements to aid in the breakdown of remaining effluent.

There are, of course, potential dangers and concerns related to this venture. These injection wells seem to bare similarity to the sensitive topic of fracking, which also involves drilling into rock deep into the earth, for natural gas inside rather than allowing an avenue for wastewater. The controversy lies in the potential to contaminate the groundwater and aquifers around it. Other areas, such as Los Angeles, that have implemented injection wells have had instances where wastewater has surfaced. There is also the concern that it can cause vibrations in the earth.

According to the Miami Herald, this project is an estimated $635 million out of a $5.2 billion effort to revamp the sewage system.

There’s a long road ahead, and its outcome will determine if others like it are pursued. Walsh’s research shows this method is cost effective; she feels it is much safer in the long run and is very hopeful for where it will go.

By Aura Altamiranda

0 0 1339 20 May, 2016 Green, News May 20, 2016

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