EP 1110-1-27
27 Jan 00
Table 5-2 Troubleshooting New Site Data Needs
Parameter
Potential Problems
Fe and Mn (total, Fe2+/Fe3+, Fe minerals,
Indications of clogging potential, presence of
Mn4+/Mn2+, Mn minerals and complexes)
biofouling, Eh shifts. Fe transformations are the
sometimes other metals such as Al. Select based
most common among redox-sensitive metals in
on presumed geochemistry.
the environment. Mn is less common but locally
important.
S (total, S2-/SO42-, S minerals and complexes) as
Indications of corrosion and clogging potential,
suspected due to site geochemistry.
presence of biofouling, Eh shifts.
pH.
Indication of acidity/basicity and likelihood of
corrosion and/or mineral encrustation. Combined
with Eh to determine likely metallic mineral states
present.
Indication of TDS content and a component of
corrosivity assessment.
Major ions.
Carbonate minerals, F, Ca, Mg, Na, Cl determine
the types of encrusting minerals that may be
present and are used in saturation indices. One
surrogate for many cations is total hardness.
Sand/silt content (v/v, w/v).
Indication of success of
development/redevelopment, potential for
abrasion and clogging.
Biofouling parameters.
See Chapter 2 Section 9: Select appropriate
methods to permit a complete but convenient
assessment of biofouling mechanisms present.
b. Note on monitoring levels of effort. Choices should be made on the basis of long-term site life-
cycle cost-effectiveness. The cost comparison should be between the cost to perform the appropriate
maintenance vs. the cost of having the well system or the remediation project to fail to function properly
with possible replacement of numerous wells. If specific experience with particular contaminant or site
conditions permit a much reduced level of effort without impairing performance, this is acceptable.
However, history indicates that
Maintenance monitoring is cost-effective compared to the alternatives.
Decisions made to minimize prevention and maintenance monitoring based on short-term
experience may be regretted later as deteriorating phenomena result in performance
degradation.
(1) It may actually reduce operational problems if certain monitoring is intensified, at least on
certain critical wells. For example:
Test pumps at least annually.
Conduct graphical analyses of pumping tests monthly, instead of quarterly, for wells in which
rapid decline or fluctuation of specific capacity is noted.
Conduct physicochemical analyses at least monthly on wells which exhibit highly variable
water quality.
Add turbidity or (better yet) particle counting, using automated, in-stream sensors, to detect
upswings in particulate sloughing that often accompanies enhanced biofouling.
Add microscopy of samples from biofilm flow cells (Smith, 1992) to visually observe
5-3
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