|
Mercury
Work Group
Phase II Reports >> Pretreatment Manual
Facilities Loadings
| Pretreatment Manual |
Tech. Identification
Hg Management Guidebook | Mercury Products
Database
For more
information, contact David Eppstein by email at
deppstein@masco.harvard.edu,
or by calling 617-632-2860.
9.0 PRETREATMENT SYSTEM BENCH-SCALE TESTING
If it
has been determined that a pretreatment system is required, a
critical step in the selection and design of the system is
bench-scale testing of the proposed individual unit operations.
Because bench-scale testing can be relatively low in cost, this
type of testing usually precedes the selection, pilot testing,
and design of a proposed pretreatment system. Since the tests
are done with small amounts of wastewater, the test setup is
typically small enough to place and operate on a laboratory
bench, thus the name "bench-scale."
Usually,
the first bench-scale tests are performed to find out if a given
pretreatment technology can reduce the level of targeted
contaminants in specific wastewater samples. This type of
bench-scale testing, called feasibility testing, can be used to
screen pretreatment technologies for their potential to solve a
wastewater discharge quality problem. Whenever possible, the
feasibility tests should be performed on actual wastewater
samples.
Bench-scale
feasibility testing of a proposed wastewater pretreatment system
is typically done with individual pieces of laboratory equipment
used in sequence to replicate the expected unit operations of
the system. At times, the testing is done with several pieces of
laboratory equipment linked together as a scaled-down version of
the proposed continuous system.
After
feasibility of the tested pretreatment technologies has been
demonstrated, further bench-scale testing of the successful
technologies can be used to find expected process operating
conditions. During this effort, the need for and selection of
initial and concluding unit operations in the pretreatment
system can sometimes be determined. In addition, the physical
sizes and chemical dose rates for each unit operation can be
evaluated. This type of testing is often called treatability
testing. Besides the determination of design factors,
treatability test results are often used to develop capital and
operating cost estimates.
Bench-scale
tests are frequently done by technology suppliers at a nominal
price because the suppliers usually wish to cover basic testing
costs. The suppliers could be asked to furnish bench-scale test
results along with recommendations or proposals for treatability
testing and pilot scale testing and with preliminary cost
estimates of a full-scale system.
The
MWRA/MASCO Mercury Work Group, through its Technology
Identification Subgroup of the End-of-Pipe Subcommittee,
recently used bench-scale feasibility testing to evaluate six
different pretreatment technologies for mercury removal. The
feasibility test work was done by vendors using samples of a
clinical laboratory wastewater stream. Refer to the Technology
Identification Subgroup Report for more information on the
Bench-scale Feasibility Testing Project. This report is
available from the MWRA10 or can be accessed on the
Internet at the following Web-site address: http://www.masco.org/mercury.
10Massachusetts
Water Resources Authority, Toxic Reduction and Control
Department, 100 First Avenue, Boston, MA 02129 (617-242-6000
x4900)
RETURN
TO PRETREATMENT MANUAL
TABLE OF CONTENTS
|
