Copyright © Françoise Herrmann
Contrary to the COVID19-related pause that also paused relatively big polluters, such as air and automobile traffic, the environmental damage caused by industrial wastewaters, for example, has hardly paused. The good news, however, is that the following invention aims to make a small dent, specifically in mining wastewaters, also called Acid Mine Drainage (AMD).
In a tradition that extends as far back as 300,000 years to prehistoric cave art, pottery and body paint, natural earth-based iron-rich oxides (e.g.; ochre) have been used as color pigments (Hirst, 2019). To date iron oxide is still used to make color pigment in a wide variety of paint and cosmetics applications. When heated, iron oxide changes color, producing yellow, red to purple pigments depending on the thermal treatment. Each year, 240 tons of iron oxide are used in the US, mostly imported from China (Dilawar, 2020).
Iron that has oxidized in various ways, inside some 23,000 old abandoned coal mines in the US, also leaks out as contaminated mining wastewaters. Mining wastewater, specifically contaminated with iron-oxide, produces red-orange streams and brown water, which kills all aquatic life, destroys plant life, and corrodes bridges. This sort of pollution, called Acid Mine Drainage (AMD), also contaminates watersheds and drinking water. Transported via streams into rivers and oceans, iron oxide in turn becomes an added source of marine and waterway contamination.
In 2015, for example, the Animas River in Colorado (shown in the picture) was contaminated with an estimated three million US gallons of contaminated mine water. The (orange) contaminated mine water, containing metals such as cadmium, lead, iron, copper and zinc, as well as acid such as arsenic, poured out of an old gold mine, at a rate of 500 to 700 USgal/min. Sadly, the accident occurred when the mine wastewater plug was destroyed during an Environmental Protection Agency-led effort to drain a contaminated pond, just at the entrance of the Gold King Mine (DiStasio, 2015).
In the US, coal mines are mostly found in the Appalachians, regrouping West Virginia, Kentucky and Pennsylvania, further extending to Ohio, Alabama and Virginia. Treatment of coal mine wastewater —at the expense of the mine operators for active coal mines; local and state authorities for abandoned coal mines— has variously consisted in applying expensive and lengthy processes such as alkalization (neutralizing the acid contaminants), removing the sources of contamination, collecting discharged wastewaters into ponds for settling and treatment, diverting streams to treatment facilities, and re-introducing fauna and flora into the contaminated areas. However, for the case of some abandoned coal mines (i.e.; no longer regulated), wastewater has continued to runoff into streams, often untreated, simply because of insufficient local and public funds. Cognizant of this situation, a grassroots coalition of artists, academic researchers and community organizers, backed by the non-profit group Rural Action, is in the process of changing the direction, processes and goals of the treatment of iron oxide-contaminated wastewater, escaping from flooded and abandoned coal mines at various rates, or accumulating as a disaster-waiting-to-happen anew, somewhat comparable to the 2015 Animas River spill.
Indeed the artist-environmentalist-activist, research and community coalition group intends to initially extract an estimated 1000 tons of granular iron oxide pouring into a creek called the Sunday Creek, for the purposes of making pigment for artist paint. The creek runs through the town of Millfield Ohio, previously called Truetown, where an underground mine discharges all the iron oxide. Plans exist for the model treatment facility, built on location, to in turn scale-up to other locations, where iron oxide is a major water contaminant. Plans that are anticipated to result in the creation of jobs, decontaminated water, and the production of pigments for artist supplies that might be sold to offset the costs of water purification. Artist supplies sold to artists like John Sabraw, art professor, environmentalist and activist, who became an important player in the whole grassroots process, when he realized that the pollution he witnessed in Ohio Rivers was caused by iron oxide, the raw material for the paint pigments on his artist palette (Dilawar, 2020).
The new treatment processes are recited in the 2018 US utility patent application US20180134597A1, titled System and method for actively treating mining wastewater for pigment production. The wastewater treatment is different from prior art processes in that it directly results in the production of a useful end product, i.e.; paint pigment for artists. The wastewater treatment is also different in that the oxidation process both emulates and greatly speeds up the slow process of passive oxidation, actually observed in the abandoned mines. Using iron-oxidizing micro-organisms (i.e.; bacteria), the invention treatment activates a process that naturally occurs over a long period of time, implementing it in just a few hours.
The invention processes are best described succinctly in the patent application abstract included below. The patent application Figure 1 block process diagram is also included, as it specifically indicates the very swift timeframe of the wastewater treatment processes invoked for remediation, oxidation, and extraction of iron oxide from sludge for production of art supply paint pigments.
Systems and methods for actively treating mining wastewater, such as acid mine drainage, using a mixed culture of iron oxidizing bacteria, in a manner that results in both remediation of the water and the production of a useful end product. Exemplary systems and methods employ a reaction vessel where the bacteria can oxidize the iron in the mining wastewater for some amount of time, and a settling tank into which reacted water may be transferred and retained to permit iron oxyhydroxide contained in the water to settle as iron oxyhydroxide sludge. The iron oxyhydroxide sludge may be dried to produce iron oxyhydroxide solids that can be employed in the manufacture of a usable pigment .[Abstract US20180134597A1]
References
Dilawar, A. (Sept. 4, 2020) An Ohio Artist and Activist is Turning Acid Mine Pollution Into Paint. Time.com https://time.com/5881219/pollution-into-paint-john-sabraw/
DiStasio, C. (8-25-2015) 30,000 mines leaking toxic waste into US Water. Inhabitat.
Hirst, K, (July 3, 2019) Ochre the oldest known pigment in the world. ThoughtCo.
Rural Action (website) https://ruralaction.org/
John Sabraw (website) https://www.johnsabraw.com/
Tuffnel, S. (Sept. 5, 2017) Acid Drainage: The global environmental crisis that you have never heard of. The Conversation.com
https://theconversation.com/acid-drainage-the-global-environmental-crisis-youve-never-heard-of-83515
https://theconversation.com/acid-drainage-the-global-environmental-crisis-youve-never-heard-of-83515
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