In-Situ TROLL 9500 Operators Manual - Manual (Page 65)

58
Multi-Parameter
Water Quality TROLL ®
TROLL 9500 Operator’s Manual 0095110 rev. 007 01/09
10 MONITORING WATER QUALITY: OVERVIEW
WHY MONITOR WATER QUALITY?
At a time of increasing demands on the finite natural resources of our
planet, public organizations and private individuals alike have become
acutely aware of the responsibility to maintain the quality of the earth’s
air and water supplies.
Recent rapid advances in knowledge and technology have made it
possible to deliver accurate, timely, and reliable data on processes
we cannot necessarily examine visually. New-generation sensors for
in-situ measurement of surface waters and groundwater can be an
efficient alternative to time- and labor-intensive programs of field sam-
pling and transportation to a laboratory for analysis, or can supple-
ment such programs. If it is possible to collect, interpret, and respond
in a timely fashion to accurate information about water supplies and
water quality, we can design better systems for protection of those
supplies.
Monitoring water-quality parameters can reveal much about the
presence and movement of natural and unnatural components of
water—the presence of harmful bacteria, potential pollution sources,
depletion of nutrient requirements for aquatic life, salt-water intrusion
into fresh water bodies, changes in water level or temperature that
can alert observers to the onset of an “event” that can adversely affect
the quality of the resource.
Monitoring water quality in surface and groundwater resources may
be required by Federal, state, or local regulations. Digital records of
monitoring can document compliance with guidelines and standards
mandated by regulatory bodies.
Profiling and logging water-quality data can provide timely information
on continually changing conditions—profiling to provide instantaneous
real-time feedback, logging to track trends and demonstrate compli-
ance.
THE SENSORS
The Multi-Parameter TROLL 9500 takes advantage of new technolo-
gies to monitor water-quality parameters in-situ with high accuracy.
Each sensor has been manufactured to our rigid specifications and is
designed to operate with the entire suite of sensors and with the MP
TROLL 9500 electronics. These “smart” sensors retain serial number
identification and calibration information, and are detected and identi-
fied by the instrument. A sensor may be calibrated in any MP TROLL
9500 and moved to another port that accepts the sensor type, or used
in another MP TROLL 9500, without recalibration. The most accurate
results will be obtained when a sensor is calibrated and operated in
the same MP TROLL 9500.
The water quality sensors available for the Multi-Parameter TROLL
9500 may be classed in two general types:
BASIC SENSOR SET
s
Dissolved Solids, Resistivity)
The pH sensor is a Single ISEs (ion-selective electrode). The Combi-
nation pH/ORP sensor is a Multiple ISE.
The Basic sensors can be factory-calibrated and pre-installed in the
MP TROLL 9500. They are ready for use right out of the box with a
brief Quick Cal. However, for best results, if your software supports
it, we recommend that you perform a traditional two-point calibration
for pH and DO, and a specific range calibration for conductivity as
described in sections 11-13 below. The accuracy that can be achieved
from the instrument is proportional to the time and care you put into
calibration.