Environmental Engineering Reference
In-Depth Information
12.5
WASTE SAMPLING
The principal objective of waste sampling is to obtain waste samples for analyses
and treatability studies. It is important to get a sufficient number of samples and
volume of sample to satisfy the analyses and treatability study requirements. The
sampling guidelines and requirements can be found in several publications.
7-12
The design procedures for selecting field sampling locations, measurements, and
data analyses for S/S treatability studies can follow those used for environmental
monitoring of chemicals.
13,14
•D fine the sampling zones, sampling frames, and variables of interest.
•D fine a general sample collection strategy for each sampling zone.
•
Develop a statistical model and statistical sampling objectives for each
sampling zone.
•
Specify the estimation or testing procedures to be employed and their
desired statistical properties.
•
Select the sampling design parameters to achieve the desired statistical
properties.
There are three basic techniques for obtaining samples: coring, pumping, and
digging. Coring to depths up to 3 m usually uses a pipe or tube with an inside
diameter in the range of 2.5 to 5.0 cm, dependent on the viscosity of the wastes.
Low-viscosity liquids and hard-compacted solids require another sampling method.
For greater depths, or for hard-compacted materials, a drilling rig is used. If the
waste has a low viscosity, a pump can be used to obtain samples. A variety of pumps
can be used as described by Conner.
8
For solid wastes, a backhoe, clamshell, or
dragline can be used to obtain samples at different depths.
The chemical and physical properties of untreated and treated wastes are often
assessed based on the testing of a limited number of samples. Many factors, such
as measurement uncertainty, field heterogeneity, and sample variety, affect the test
results. If the results are variable, the decision should be made based on a statistical
sampling design procedure.
12.6
TREATABILITY STUDIES
The objectives of an S/S treatability study are to provide valuable site-specific
information for the selection and implementation of proper S/S formulation and
process. In addition to the performance specifications discussed in Chapter 11,
treatability studies may also include the following goals:
8
•
Determine the most economical mix design
•
Identify handling characteristics of the waste and binders
•
Determine type of mixing and mixing time
•
Identify interactions between the waste and binder during mixing
•
Determine curing requirements for the S/S waste forms
Search WWH ::
Custom Search