Case Studies: Full-Scale Operations and Delivery Systems - Stabilization and Solidification of Hazardous, Radioactive, and Mixed Wastes - page 354

TABLE 13.6
Physical Properties of the Untreated and S/S Treated Soils - Case Study #2

Sample
Depth
(m)

Water
Content
(wt%) a

Bulk
Density
(kg/l)

Compressive
Strength
(kPa)

Hydraulic
Conductivity b
(cm/sec)

Sample
Description

0.3 - 0.6 20.5 c - - -

Untreated Control Core 1.2 - 1.5 16.9 c 2.15 - 8.08 × 10 -8

2.4 - 2.7 18.4 c 1.75 - -

3.9 - 4.2 16.5 c - - 8.09 × 10 -8

0.3 - 0.6 19 1.73 c 5200 d 8.88 × 10 -6

Treated Core 1.2 - 1.5 23.5 1.66 c 3500 -

2.4 - 2.7 19 1.72 2600 -

3.9 - 4.2 13.6 2.00 c 390 7.75 × 10 -6

a Loss on drying at 60°C.
b All values represent the average of six measurements. Data reported at 25°C per ASTM D5084.
Permeant fluid: 0.001 M CaSO 4 solution.
c Average for two samples.
d Sample taken at the 1-m depth.

strength with depth was due to the degree of grouting that varies with depth, which
was confirmed by visual inspection. The pH of the treated soil reflected the high pH
(12.5) of the grout, ranging from 10 to 11, with the deepest soil having the lowest
pH. The VOCs in the TCLP extract were mostly undetected, except for 0.08 mg/L
TCE at the 1.5-m depth (still below the regulatory limit of 0.5 mg/L).
In spite of a number of physical and mechanical problems encountered during
shakedown, and difficulties in controlling the rate of grout delivery at different
depths, the results were generally good with respect to achieving the regulatory
requirements of the project. In addition, the operation demonstrated that the mechan-
ical system used in this project was effective in limiting the evolution of VOCs from
the contaminated soil during treatment.

13.4.3 C ASE S TUDY #3: S OLIDIFICATION OF L IQUID W ASTE

C ONTAMINATED WITH A NTIMONY

13.4.3.1 Background and Purpose

This project took place nearly 30 years ago and is a good example of cement-based
S/S technology that has stood the test of time. 1 Its chemistry, delivery system, and
operation are just as pertinent today as they were 30 years ago. The waste treated
at this site in the New Orleans area originated at a chemical plant in West Virginia.
It had been routinely transported to New Orleans, tanked temporarily, and then
ocean-dumped when that technology was still permitted. When ocean dumping was
stopped, 4,000,000 gallons remained in storage tanks. One requirement of the project
was that all 4,000,000 gallons had to be contained on-site after solidification, until
the state could test it. Treatment and compliance testing verified the treated waste