Technical data

1.3
WATER MANAGEMENT
Because soil microorganisms inhabit and are only active within thin films of water, the soil
water content is maintained at an optimal condition for their growth. Soil water moisture
content is monitored on-site using an oven as needed. Initial and monthly moisture
measurements will be performed in accordance with Table 1.1.
The target soil moisture
content is approximately 60 to 80 percent of the field holding capacity corresponding to
between 10 and 15 percent moisture on a weight basis. The percent moisture can vary
depending on the material being treated. Table 1.3 shows the data sheet used to calculate
the percent moisture. Because the driest soil conditions will occur at or near the surface,
soil samples should be obtained from 0 to 4 inches. Soil at this depth is subject to the
greatest drying. Six sample locations are selected, one from each quadrant, and composited
into three samples prior to analysis.
Stormwater and leachate which is collected in the biocell sump is pumped into the 20,000-
gallon holding tank adjacent to the facility. Water is applied to the biocell for moisture
control as necessary from this tank using a centrifugal pump and a sprinkler system.
Moisture monitoring results from the biocell quadrants are used to determine recycle .rates.
In case of excess stormwater and leachate, the water is transferred to the water treatment
plant located adjacent to the facility.
1.4 SOIL MIXING AND AERATION
Following the initial application of fertilizer, soil will be thoroughly mixed to distribute hot
spots of contamination and reduce soil particle size.
Once the soil fertility and moisture
regimes are optimized, the factor limiting growth of soil microorganisms is usually oxygen
Oxygen is supplied by conventional tilling methods, which thoroughly mixes and loosens
the soil.
A conventional farm tractor with tiller attachment is used for this purpose.
Several overlapping passes of the equipment will be performed longitudinally in rows in the
north-south direction. The entire biocell will be tilled to the full depth of the
contaminated soil immediately following initial moisture and nutrient additions and
turned twice per month during the operation and maintenance period or as needed.
1.5 SAMPLING AND ANALYSIS
Collection and analysis of soil samples will be performed at three different times for each
batch of petroleum contaminated soil. They are as follows:
* Initial characterization of incoming soils
0 During the O&M period for performance monitoring
l At the completion of treatment for confirmation sampling
O&M Manual 1-4
OHM/%6032