Quality Assurance/Quality Control (QA/QC) for Waste Stabilization/Solidification - Stabilization and Solidification of Hazardous, Radioactive, and Mixed Wastes - page 332

1. Use of different techniques to examine archived samples to provide the

basis for implementing the remedy and quality assurance plan

2. Testing of treated wastes in leachate columns or field lysimeters period-

ically for performance criteria

3. Examination of groundwater from collection stations to evaluate the per-

formance of the constructed waste forms

The treated wastes disposed of at the site may exhibit different properties from
those of archived samples. In a field demonstration project, differences in properties
were noted between the cores of solidified wastes taken in the field and those cast
at the site but cured in the laboratory. 30,31 These differences were attributed to
different curing and exposure conditions.
Also, whenever the early indicators point to failure, public health and the envi-
ronment may be at risk. The remediation of the failure may need much more effort
and cost much more than the original treatment process.
Subject to approval, the mix design may be changed based on the characteristics
of the material being treated. An additional field demonstration may be required
prior to implementation of the new mix design.
Most of the problems related to quality control have been due to inadequate
specifications, misunderstanding of the required specifications, or an inadequate
number of samples tested for statistical evaluation. 29 Therefore, a good QA/QC plan,
which includes monitoring materials quality, equipment calibration, personnel
requirements, real-time testing, pilot cell demonstration, and early failure indication,
will help avoid these problems.

12.11 SUMMARY

This chapter discusses the basic QA/QC principles and their applications for S/S
processes. To assure that these S/S goals are achieved, quality QA/QC plans are
indispensable parts of the treatment process. QA/QC testing of both physical and
chemical properties of raw materials and treated wastes provides important feedback
used to decide whether or not the formulation and mixing process needs adjustment.
Enough testing should be conducted to provide valid information. The frequency of
post-treatment testing has also been subject to approval by local regulatory agencies
and has varied from project to project. To ensure formulation of the treated waste
within an acceptable range, quality control charts can be developed for daily operations
after a series of tests on the treated wastes.

REFERENCES

1. State of California Department of Transportation, Quality Control Quality Assurance

Manual For Asphalt Concrete Production and Placement, June 2002.

2. USACE, Guide Specifications for Military Construction: Solidification/Stabilization

of Contaminated Materials, CEGS 02445, Washington, D.C., 1994.