back to case studies 
Difficult Pumping Applications from
Blackhawk Environmental Company
In the realm of contaminated site remediation and source
recovery, coal tar has reigned as one of the most stubborn
substances to remove in quantity from the subsurface. Time
and again, this thick, sticky, viscous liquid with the consistency
of molasses has thwarted efforts to remove it from below ground
areas at the 30-acre Calhoun Park Area Superfund Site in the
burgeoning, historic harbor district of Charleston, SC. That
is, until persistence and the decision to use the Blackhawk
Piston Pump to do the cleanup paid off.
To understand more about the sticky nature of the situation
and its solution, some background history is in order. Coal
tar is often much of what is left of a former manufactured
gas plant (MGP) associated with the Gaslight Era from 1830
to 1950, when coal gas, a different type of gas than the natural
gas we know, was used first for lighting, then for cooking
purposes.
No longer in use today, coal gas was created by heating or
“cooking” coal in large, air-tight ovens at an
MGP. This process generated substantial amounts of coal
tar as a byproduct as the gas cooled in the piping and the
large gas holders. As the availability of electricity
and natural gas increased, MGPs became obsolete. The aboveground
facilities of many were abandoned and later demolished, and
the coal tar residues below the surface were left to be forgotten
until another time.
The Calhoun Park Area Site, where a MGP operated from 1855
to 1957, is such a site. Assessed for remediation in the early
1990s, EPA-mandated removal of the coal tar by South Carolina
Electric & Gas (SCE&G), the principal subsidiary of
SCANA, an $8 billion (assets) energy-based holding company
serving customers in North Carolina, South Carolina, and Georgia. Fieldwork,
which began in 1998, was limited when it came to the removal
of the coal tar from portions of the site inaccessible to
excavation. Several pumps were field tested and couldn’t
handle the job; even a belt skimmer arrangement was unable
to recover more than a few gallons
“The turning point came when our contractor, Management
and Technical Resources (MTR), put the Blackhawk Anchor Electric
Piston Pump to work in March of 2001. Unlike the other pumps
we tried, the Anchor Piston Pump continues to remove coal
tar from the former gas holder. Despite a pumping distance
of 32 feet from below grade to the ground surface, it requires
very little maintenance,” said Thomas Effinger, who
manages SCANA’s MGP remediation program. “Seeing
that the Anchor Piston Pump was working very well, SCANA and
MTR decided to bring in two Blackhawk Trident Pneumatic Piston
Pumps, which are being used to remove coal tar from 15 to
20 feet below the ground surface, to help complete the job
in other areas of the site. The results are pretty impressive
. . . we currently recover approximately 100 gallons of coal
tar per week and have removed a total of 3,000 gallons over
the last six months.
Effinger continued, “Sure we’ve hit a snag or
two here and there, but with coal tar recovery, who doesn’t?
The folks at Blackhawk have worked well with MTR, to fix problems
and get us back up and running. We’ll keep pumping until
we can’t recover any more — the good news is that
at this point in time, the recovery rate will only decrease
due to all the coal tar being removed and the job nearing
completion.”
Blackhawk Environmental’s Anchor Electric and Trident
Pneumatic Piston Pumps feature the pump inlet at the bottom
of the pump, so that the pump acts like a syringe, extracting
product from the bottom of the well with every stroke for
highly reliable and consistent pumping. Liquid is pulled into
the pump intake, and the pump operates consistently whether
the pumping action is clean or dirty. The positive displacement
action resists slowdown or stoppage even in the most sticky
or oily situations. The pump drive mechanism is positioned
on top of the wellhead enabling the operator to see whether
the pump is running or not.
“There are very few moving pump parts in the well to
cause problems. Blackhawk Piston Pumps have the controls on
the top, so they are very easy to install, inspect, trouble
shoot, and maintain. No other pump that we tried can compare
to this positive displacement pump when it comes to the effective,
recovery of a thick, oily liquid, like coal tar,” said
Effinger. “We’re very pleased.”
SCANA Corporation is headquartered in Columbia, SC. Its businesses
include regulated electric and natural gas utility operations,
telecommunications and other non-regulated energy-related
businesses. SCANA’s subsidiaries serve nearly 547,000
electric customers in South Carolina and more than one million
natural gas customers in South Carolina, North Carolina,
and Georgia.
Blackhawk Environmental Co. specializes in manufacturing
quality pumps and controls for demanding pumping applications.
Blackhawk pumps can be powered pneumatically or electrically
and can work in hazardous or potentially hazardous environments.
For more than a decade, Blackhawk pumps have been successfully
operating in a wide range of pumping applications across the
United States. Blackhawk’s pumps are custom manufactured
in a variety of sizes and designs depending on the application.
Download PDF (99KB)
back to case studies
 |
To
view these files, you will need the free Adobe Acrobat
Reader program. If you do not have this program, you
can
download it from here. |
|
