OPERATOR AND UNIT MAINTENANCE MANUAL
(INCLUDING REPAIR PARTS AND SPECIAL TOOLS LIST)
FOR WATER QUALITY ANALYSIS SET: PURIFICATION (WQAS-P)
DESCRIPTION AND USE OF CONTROLS AND INDICATORS FOR TURBIDITY METER
With the Turbidity Meter, turbidity measurements can be performed with high precision in the field as well as in the
laboratory. the turbidity meter is a hand-held, microprocessor-based, battery operated instrument used to determine the
turbidity of water and waste-water. The meter covers a 0-1000 FTU range in two scales: 0.00 to 50.00 FTU and 50 to
1000 FTU. The auto-ranging feature of the instrument sets the appropriate range for the measurement.
The Turbidity Meter, has been designed according to the ISO 7027 International Standard, consequently the turbidity
measurement unit is the FTU. FTU is identical to the other internationally recognized unit: NTU.
The Turbidity Meter is a portable turbidity meter with the ⊂ ∈ mark, in compliance with the European directives EN
50081-1 and EN 50082-1, ensuring low emission values and accurate measurements in presence of electromagnetic
The meter is housed in a rugged and lightweight case, with an easy-to-read LCD. To save battery-life, the instrument is
equipped with an automatic shut-off feature which is activated after 4-minutes of non-use.
The meter is very simple to use. All operations can be carried out with only four keys and trouble-shooting functions can
be performed with displayed error code guides. An exclusive positive-locking system guarantees that the cuvette is
firmly placed in the cell. The keypad is water-resistant and can be wiped with a moist cloth for quick cleanups.
The one-point calibration at 10 FTU* can be easily performed using the available standard. In addition, theTurbidity
Meter is the first portable turbidity meter that allows storage of the last calibration date and to retrieve it at the user's
A 10 FTU* calibration point was chosen because it is the value that best fits the water turbidity measurements in
different applications, from drinking water to wastewater treatment.
*1 FTU = 1 NTU
The primary standard is a AMCO-AEPA-1 to avoid all formazine-related problems. Formazine is a very toxic, unstable
substance, which requires particular care; its standards have to be prepared only a few minutes before performing the
calibration, and cannot be reused because of their short life. These standards are extremely stable, can be reused, and last
up to six months, if free from contamination. The Turbidity Meter can be used with both standards.
RULES OF OPERATION
The Turbidity Meter has been designed to perform measurements according to the ISO 7027 International Standard.
The instrument functions by passing a beam of infrared light through a vial containing the sample being measured.
A sensor, positioned at 90 with respect to the direction of light, detects the amount of light scattered by the undissolved
particles present in the sample. The microprocessor converts such readings into FTU* values.
As noted above, FTU unit is equal to the NTU unit.
However, there are other known measurement units for
turbidity; Jackson Turbidity Unit (JTU) based on the old
method of Jackson's candle, and Silica Unit (mg/L of SiO2).
For reference, the conversion table between these
*1 FTU = 1 NTU
measurement units is shown.