Before pouring slag into the structure, it was necessary to
sieve the material to > ¼”. This was
done on a large scale at a gravel quarry next door to the steel mill located in
Ft. Smith, Arkansas. A liner was placed
on the bottom of the structure before dumping the sieved material into it. A liner was also placed on the outflow side of
the structure (i.e. “apron”) in order to channel all of the treated water into
the flume for monitoring purposes.
The sides of this outflow apron were constructed with
railroad ties. In the above picture they
are covered with the liner.
The perforated drainage pipes were placed at the floor of
the structure (on top of the liner) before covering it with the sieved
slag. Note that these drainage pipes
channel water to the outlet of the structure, which is comprised of expanded
metal. Between 35 and 40 tons of slag
was dumped into the structure use a skid steer:
After the drainage pipes were covered with slag and the
structure was nearly filled up, we installed the inflow manifold pipes. These
perforated pipes located just barely below the surface serve to evenly
distribute runoff water throughout the surface of the structure:
We ran out of sieved slag near the end, so we had to sieve
around 10 tons of slag to produce 6 more tons of >1/4” slag. I’m pretty irritated in the picture below because
the concrete vibrator that was used to screen the material kept breaking all of
our U-bolts:
Eventually we ran out of U-bolts and we cleaned out the
local hardware store for U-bolts. At
that point we had to sieve it the old fashioned way. The guy on the right is Stan Roberts, a
salesman from Automatic Engineering, the distributor for ISCO auto samplers in
Oklahoma. Stan was supposed to stop by to
help with programming…..hahaha, but we put him to good use since we were not
yet ready for programming. That is a
good salesman right there. Steps out of
the office and does some “hands on” work with no complaints.
During the installation, we forgot to stabilize the
downstream “gate”. After it was filled
with slag, the metal started to bow. Note
that the wood in the picture below was temporary. It was removed after the slag was treated
in-situ.
We managed to remove the bow in the metal gate using a
come-along and 40 feet of chain. After we
pulled it back, we stabilized it by pounding several ½” rebar into metal
sleeves welded to the gate. I wish I had
a picture of that process because it was pretty awesome. Again, the slag was treated in-situ. The samplers were set up (which is what we called
Stan for!) and were placed in their own respective buildings:
We rolled out some erosion control mats and seeded uphill of
the structure. Trimmed the excess
liner. We also built a new suction head
for the samplers to be able to handle a very shallow depth of water.
At this point we are ready to collect samples! Just offhand, I hope that we can have a field
day presentation in January. We will
continue to update this blog with results.
