EP 1110-1-27
27 Jan 00
a. Plant manager -- project level. This person or team operates at the level of the HTRW
remediation project's management level and integrates O&M activities into the overall project goals and
structure. Primary tasks related to well system O&M:
Sets up maintenance action schedules
Follows up to ensure actions are accomplished
Is responsible for data collection and evaluation
Prepares status report of evaluations
Seeks and works with outside expert help as needed.
b. Designated oversight personnel -- operations level. This person or group operates at the
HTRW remediation site level. If a separate O&M Company oversees the regular function of the site's
physical plant, then this group may consist of both the O&M company's management and onsite
personnel. Their work scopes involve:
Assisting in maintenance schedules and making recommendations for modifications based on
site-level experience with individual wells.
Conducting necessary training of pertinent personnel (as necessary with outside expert
assistance).
Being responsible for enforcing maintenance actions and reporting to the plant manager.
4-6. Biological Activity Implications
a. Biological activity importance to O&M. Section 2-9 reviews biological maintenance
monitoring needs. However, HTRW remediation projects are typically designed by personnel
(environmental engineers and hydrogeologists) who typically have a limited background in microbiology.
It is important to understand the purposes for the emphasis on bioassay in maintenance monitoring for it
to be properly implemented.
(1) Production and hydraulic efficiency loss. Historically, the primary factor in well system
production loss on HTRW projects is biological activity (e.g., Leach et al. 1991; Smith 1995; Alford and
Cullimore 1999; ASTM D 5978). Biofouling has been identified as a primary cause of well performance
problems in "clean" water supply for many years (e.g., Borch, Smith, and Noble 1993; Cullimore 1993),
For ground water contaminant plumes, unless the predominant contaminant is biologically recalcitrant
(such as TCE, for example), microbial activity is greatly accelerated and increases the rate of biological
corrosion and clogging.
(2) Effects of "representativeness" of monitoring samples. Biofilms, which serve protection and
scavenging functions for microorganisms that form them, naturally have the effect of attaching and
holding organic molecules and some metals. Consequently, it has been recognized that monitoring well
samples may not always be representative of bulk-formation ground water quality (unpredictable
accuracy). Smith (1995;1996) reviews the limited literature on this subject relevant to monitoring. This
effect and its implications are recognized in ASTM D 5978.
(3) "Unexpected" geochemical changes. Biological activity has the tendency to induce or
accelerate processes that may be unlikely or much slower in an abiotic environment. For example,
biological corrosion occurs in environments considered "encrusting" in Langelier, Ryznar, or similar
indices (Borch, Smith, and Noble 1993). Iron and occasionally manganese clogging accelerates where
metal-precipitating bacteria flourish. Iron, manganese, and sulfur (S00 or SO42-) reduction processes (all
entirely microbial) mobilize large amounts of iron, manganese or sulfide (S2-) into solution. The S2-
4-4
Previous Page
