Case Studies: Full-Scale Operations and Delivery Systems - Stabilization and Solidification of Hazardous, Radioactive, and Mixed Wastes - page 346

example of S/S from earlier projects. Such examples establish the success and
longevity of S/S as a reliable waste treatment technology.

13.4.1 C ASE S TUDY #1: L EAD -C ONTAMINATED S OIL AT A F ORMER
B ATTERY P ROCESSING S ITE 4

13.4.1.1 Background and Purpose

This site had been utilized for various industrial purposes since the mid-1800s.
Metals in the site soil — lead, cadmium, arsenic, and antimony — were believed
to have been generated by a former battery processing operation. Remedial action
was required not only to clean up an area contaminated with these metals, but also
to allow both the soil and the site to be used as part of a new park. Lead was the
primary contaminant of concern. 4

13.4.1.2 Treatability Studies

Previous analyses by an engineering company of samples from the site had shown
that the soil typically contained about 18,000 mg/kg of lead, and lesser amounts of
arsenic, cadmium, and antimony (see Table 13.1). While arsenic, cadmium, and
antimony leach resistance met regulatory criteria, the TCLP extract lead concentra-
tion was 41.0 mg/L, more than 8 times the limit. The results of the treatability study
are summarized in Table 13.1. Leachability testing was done using the standard
USEPA SW-846 Toxicity Characteristic Leaching Test (TCLP). A liquid chemical
additive in a portland cement-based system built additional early strength and helped
stabilize lead. The additive also reduced the amount of cement required, thereby
lowering the volume increase and the chemical costs for treatment.

TABLE 13.1
Treatability Study Results for Case Study #1

TCLP Extract Concentration
(mg/L)

Total Concentration
(mg/kg)

Before
Treatment

After
Treatment

TC
Limit a Contaminant

Antimony 170 0.9 < 1 15.0 b

Arsenic 160 0.6 0.01 5.0

Cadmium 11.0 1.0 < 0.02 1.0

Lead 18,000 41.0 < 0.4 5.0

a Toxicity Characteristic limit.
b No TC limit defined. The California Soluble Threshold Limit Concentration
(STLC) test requirement applied to this project.