A recent article in the Post-Gazette reported on the dedication of the Gladden Abandoned Mine Drainage (AMD) remediation facility and its effect on Millers Run. For as long as I can remember, this stream, running through the heart of South Fayette, has been a bright orange color, and perhaps the most glaring example of the pollution generated by AMD throughout the Chartiers Creek watershed.
My response was to drive to the “mouth of Millers Run” and see for myself. The sight from the bridge carrying Brockwell Street over Millers Run just above the point where it enters Chartiers Creek was astonishing – the creek was crystal clear! This is indeed the result of a modern miracle that I never expected to occur in my lifetime.
All of us who grew up in the Chartiers Valley have been conditioned to believe that our creek is an industrial sewer that will never again be fit for man or beast. When we read accounts of the middle of the nineteenth century, a time when people came here from Pittsburgh to enjoy this lovely stream, we shake our heads in misbelief.
The best description of the contemporary pollution in Chartiers Creek can be found on the Chartiers Greenway website, “chartiersgreenway.net”. Among other things it records the results of extensive sampling done at nine different sources in this area, about eighteen years ago. The most prominent pollutant was iron (Fe). At that time the nine sources added 2,979 pounds of iron to the creek each day. Of this total, Millers Run produced 1,353 pounds, forty five percent of the total. Removing this load is a major contribution to cleaning up Chartiers Creek.
Our region prospered economically because of coal mining; AMD pollution is part of the price society has paid for this prosperity. Abandoned mines are potential reservoirs for underground water. When the surface elevation of these pools exceeds that of the nearby ground surface, the water begins to seep out through discontinuities in the subsurface rocks.
The water in the mine pools dissolves iron sulfate from the mine cavity surfaces, releasing ferrous ions. When the water seeps out of the ground, the ferrous ions are oxidized into ferric ions. These ions then combine with water molecules to form ferric hydroxide, tiny orange colored specks which eventually settle out, miles downstream from the source, waiting to be picked up and washed farther downstream by the next flood.
There are two different approaches to remediating sources of AMD – active and passive. We environmental purists prefer the passive approach, depending upon natural processes to remove the ferric hydroxide particles. An excellent example of this concept is the Wingfield Pines remediation facility, located on the east side of Chartiers Creek in the valley between Bridgeville and Mayview.
Constructed in 2009, this facility uses about twenty acres of land, providing enough area to allow the solids time to settle out in settlement basins. The AMD is delivered in a long, perforated large diameter pipe which sprays it into a large (375’ by 125’) rectangular pond where the oxidation occurs naturally. From this pond the orange colored water flows into the first of four pie-shaped quadrants of a circle with a diameter of 375’.
Seen in a satellite view, this first quadrant is deep orange. It overflows into a second quadrant which is light orange, then a third with only traces of orange color, and finally a fourth which is nearly clear. The fourth quadrant discharges into a large wetland from which crystal clear water enters the creek. The facility handles 1500 gallons per minute of drainage successfully, eliminating eight percent of the total pollution in the creek.
Several of our Pitt Senior Design teams attempted to develop passive solutions for the Millers Run source without success, primarily because of the absence of sufficient level land available for the large ponds required by that approach. Fortunately the South Fayette Conservation Group included pragmatists who were willing to consider an active concept utilizing chemicals and mechanical equipment to treat the drainage in a facility with a small footprint.
The new facility pumps 1500 gallons per minute out of the mine, doses it with hydrogen peroxide to oxidize the ferrous iron to ferric, adds a flocculant to expedite the settling of the particles in a clarifier, and runs the clarified water through a small “polishing” basin before discharging it into Millers Run. The sludge from the clarifier, as much as 690 pounds of iron per day, is pumped back into a deep mine.
The facility cost about thirteen million dollars and is expected to have annual operating expenses of three hundred thousand dollars. Environmental consulting engineering firm Tetra Tech was responsible for design and construction of the facility and will operate it for its first year. Funding for it came from two federal abandoned mine remediation programs.
The net result is that Millers Run has been transformed from an embarrassment to an ecological showpiece. The Fish and Game Commission is actually considering stocking Millers Run and the portion of Chartiers Creek with trout next year.
Now that these two facilities have removed more than half of the pollution in Chartiers Creek, it is time we tackle the rest of the sources, beginning with McLaughlin Run. Perhaps our South Fayette neighbors could give Bridgeville advice on how to solve its problem.
Then we could move to Coal Pit Run, Painters Run, and Scrubgrass Run. The combination of effective remediation technology, intelligent management of the underground pools, and the federal government’s current passion to spend money to improve the environment present a great opportunity to clean up Chartiers Creek forever.
A century and a half ago this region prospered because of a valuable natural resource – bituminous coal. In today’s world clean fresh water is perhaps the most valuable resource. We are blessed with an abundance of fresh water. It is our responsibility to be good stewards and to keep it clean.