EP 1110-1-27
27 Jan 00
sufficient for PM monitoring with proper calibration (CEGS 13405). If there is an established
maintenance and calibration schedule for all instruments, accuracy is not sacrificed using onsite,
commercially available instrumentation, and the greater frequency of analysis possible economically
provides more data points to plot trends.
(2) Biofouling microbial component.
(a) Sampling. Pumped grab methods in time-series for BART and turbid sample analysis by
microscopy and biofilm collection on surfaces (sidearm for outflow from wells to collect samples of
biofouling indicative of that occurring in wells).
(b) Analysis. Light microscopy and BART methods (Section 2-8), biofilm mineralogical analysis
(X-ray diffraction for mineralogy and elemental speciation to establish fouling mineral predominant
components).
(c) Recommendation. A combination of time-series pumped sampling and BART analysis and
microscopy for filamentous iron and sulfur bacteria and FeIII-oxide minerals provides a good profile of
biofouling conditions. Routine monitoring can be limited to specific BART analyses selected to best
gauge change and periodic sampling of biofouling solids to gauge changes in type and structure (Sections
5-2 and 5-3 provide a schedule). A one-time mineralogical (XRD) and elemental analysis of solids is
useful to refine preventive maintenance chemical feed choices.
(d) Alternative. Particle counting and turbidity (both of which can be automated) can replace
biofouling sampling in systems with known biofouling characteristics.
(3) Sand content testing. Sand content may be determined by sampling with a Rossum Valve
sampler (Roscoe Moss Company 1992)
(a) At strategic intervals during well development.
(b) Averaging the results of five samples collected at incremental times during a pumping test.
NGWA (1998) provides specific recommendations. A limit of 5 ppm is achievable and optimal criterion
for well redevelopment completeness.
(c) Hydraulic monitoring using methods as described (Section 2-1).
c. Flow meter and other sensor maintenance. To ensure their usefulness in maintenance
monitoring, flow meters, and other sensors must be maintained. An open pipe insert type or nonintrusive
ultrasonic flow meter should be used to limit the effects of encrustation. Units that can be readily removed
should be specified and installed. If used, venturi flow meters (vulnerable to clogging) and sensors
(vulnerable to coating and fouling) should be periodically examined and cleaned as needed. Manual
cleaning using a mild acid detergent and rinse should suffice.
9-8
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