ESTCP Project #1011, Rhizosphere
Final Report
salt is in the soil from an earlier event, this should be taken into account as well. Within each
site, both vegetated-plus-nutrients and nutrients-alone treatments were fertilized at the same
rates.
3.5.2 Period of Operation. Figure 15 shows both actual treatment times (in days) and
growing degree-day (GDD) normalized data are shown for each of the three sites.
3.5.3 Amount /Treatment Rate of Material to be Treated. Surface areas ranged from a
series of 16 relatively small test plots at each site, ranging from approximately 20 ft by 10 ft at
Annette Island to 20 ft by 75 ft at Campion/Galena. Treatment depth was through the root zone,
or approximately two feet. Cost estimates are based on 10,000 ft2 areas treated to 2 ft, or a total
of 20,000 ft3.
3.5.4. Residuals Handling. Investigation Derived Waste (IDW) was minimal. Typically,
this was generated only from decontamination of trowels and shovels used by the contractors.
All IDW water produced during sampling was collected and put into 55-gallon drums and
sampled as outlined in the Demonstration Plan. At the end of the initial sampling effort, all
drummed IDW was removed from the site and kept in a secured area pending receipt of
laboratory analyses. Upon receipt of analytical results, the IDW was disposed of in an
appropriate manner following all applicable local, state and federal regulations. This water was
found to have no appreciable levels of petroleum in it. For site monitoring, CRREL personnel
merely used soil adjacent to the sampling nodes, but within the test plots, to remove any residual
petroleum contamination on the sample tools. This method works well, if not better, and is
significantly more practical.
3.5.5 Operating Parameters for the Technology. Site setup included initial site
delineation; obtaining time-zero samples; collecting, compositing, preparing and installing soil
socks for later sampling; data-logger setup; and seeding and nutrient additions. Site installation
was conducted during the summer of 1998. At the Barrow site, seeding and fertilizing were not
done until the summer of 1999 due to the brevity of the summer season at Barrow.
One of the concepts associated with using rhizosphere-enhanced treatment is freedom from
utilities and infrastructure. We had either electrical power or battery power at the sites, but this
was merely to operate temperature data loggers; electric power is not required for the operative
processes to proceed. During the demonstrations, a CRREL representative visited the sites
periodically during the growing season to change data storage cans and check on the status of the
sites. We were unable to keep the data loggers, batteries, and associated equipment secure at the
sites.
3.5.6 Experimental Design. Our demonstrations included seeding and fertilizing cold-
tolerant grasses in POL-contaminated soils. At three locations in Alaska, we compared the
treatment effects of nutrient additions on a mix of three plant species and of the interactions of
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