Environmental Engineering Reference
In-Depth Information
12.11 Summary ..................................................................................................... 332
References.............................................................................................................. 332
12.1
INTRODUCTION
The formulae developed for S/S treatment of hazardous wastes in the laboratory
may behave differently in the field due to the variation in composition of the waste,
the accuracy of the weighing system, and the type of mixing and placing processes.
Typical goals for S/S treatment of wastes include:
•
Contaminant mobility (leachate) reduction
•
Support strength
•
Environmental durability
•
Low hydraulic conductivity
To assure that these goals are achieved, quality assurance/quality control
(QA/QC) plans are indispensable parts of the treatment process. Test results provide
important feedback used to decide whether or not the formulation and mixing process
need adjustment. Past experience and sound judgment are important in evaluating
test results and assessing their significance in controlling the treatment process.
The performance of treated waste forms may behave differently in the field due
to the variation in composition of a waste, the accuracy of the additive dosage, and
the type of mixing and placing processes. A good QA/QC plan helps ensure that
the treated waste meets the specified criteria for utilization or disposal. A QC plan
should address the control and documentation of raw materials, mixing and place-
ment, and post-treatment testing based on the laboratory and field feasibility studies.
Although S/S technology has been identified as a best demonstrated available
technology and is the most frequently selected treatment technology for controlling
the source of environmental contamination at Comprehensive Environmental Response
Compensation, and Liability Act (CERCLA) remediation sites, few published docu-
ments can be found on QA/QC of S/S operations. However, ready-mix concrete and
construction industries have very comprehensive QA/QC documents to ensure the
quality of construction.
1
Parts of these documents can be extrapolated, modified, and
adopted for S/S operations. This chapter discusses the basic principles of QA/QC
and summarizes existing guidelines for laboratory feasibility studies and field oper-
ations for S/S of waste or remediation of contaminated sites.
12.2
GENERAL PRINCIPLES OF QA/QC
12.2.1
Q
UALITY
A
SSURANCE
QA is defined as those planned and systematic operations conducted to ensure that
the operation or product meets specifications. QA encompasses the project engineer
or chemist's oversight of the contractor's quality control plan; review of inspector,
sampler, tester, and laboratory qualifications; verifying the results of quality control
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