Turbidity meter TUD-211

Water quality measurement equipmentTurbidity meter

Turbidity is a very important index to know the pollution degree of water.

Product Features

In recent years, environmental pollution caused by industrial wastewater and household wastewater are on the rise and a wide range of areas requires measurement of turbidity including rivers, lakes and seas as well as water and sewage treatment plants.

  • This is a direct immersion type measuring instrument for continuous metering process.
  • This turbidity meter is little affected by the color of solution. In addition, the detection surface of the turbidity meter is protected from adhesion of green algae.
  • Maintenance is easy.

Turbidity meter for water and sewer services

Highly sensitive turbidity meter

Our highly sensitive turbidity meter is a consecutive water quality meter suitable for low-turbidity management of filtrate water and water supply at water purification. In addition, our turbidity meter is effective for responding to the interim guidance stipulated by the Ministry of Health, Labour and Welfare.
Low turbidity at 0.1 degrees can be measured with accuracy and longterm stability by adopting a side-way scattering system in which laser source is used as the measurement method.
Unlike the particulate counter system, converting the number of particles into turbidity and strict control of flow rate of water sample are not required, providing high sensitivity while remaining faithful to original measurement principles.

  • This turbidity meter is little affected by chromaticity.
  • Consecutive and highly accurate measurement is possible.
  • Adjustment of zero point and span is easy, thus quality control is ensured.
  • Side-way scattering system is unaffected by flow fluctuation and accuracy of measurement is not affected by flow fluctuation, thus measurement of flow rate of sample water is not required.
  • If longterm consecutive measurement is carried out, iron and manganese may adhere. However, a simple structure is adopted for the light-emitting part and light-receiving part and thus customers can maintain turbidity meters easily.
Item Highly sensitive turbidity meter
Type LTB-1000
Measuring object Turbidity of filtrate water at water and sewage services
Measuring method Laser light side-way scattering system
Display resolution 0.001 degrees (NTU)
Measuring range 0 to 2 degrees
Measurement accuracy Repeatability Within ± 3%F.S.
Linearity Within ± 3%F.S.
Output signal DC4 to 20 mA (Maximum load resistance: 600 Ω)
Switching among 4 modes (0 to 0.25, 0 to 0.5, 0 to 1 and 0 to 2 (degrees))
Contact output Classification Turbidity anomaly x 2, discontinuance of water sample and during maintenance
Sample water condition Temperature 0 to 40°C (no freezing)
Pressure/withstanding pressure 0.02-0.3MPa
Flow rate Approx. 0.2L/min
Surrounding environmental condition Temperature 0 to 40°C (inside installation)
Humidity 85%RH or less
Calibration method Zero point Laser light source turned OFF
Span Formazin reference solution
Power source AC100V 50/60Hz
Electric power consumption 10VA or less
External dimensions W400×H1500×D400 mm (if the stand table is used)
Mass Transformer part Approx. 5 kg
Detector part Approx. 1 kg

Measurement accuracy

Measurement principle

Side-way scattering system in which luminous flux emitted from the laser light source is reflected on turbidity in water sample and turbidity is detected with reflected and scattered light and luminous flux and photocell in the perpendicular direction. Output of scattered light is extracted from the photo cell as the turbidity signal

Turbidity meter for sewer service

Turbidity meter

Our turbidity meter can be used for consecutive process by directly immersing the detection part into the water sample.

  • Zero calibration can be performed accurately and easily with no water.
  • Near-infrared light is used for measurement light, thus there is no fluctuation of output caused by coloring of water sample. In addition, for the same reason, the detection surface of the turbidity meter is protected from adhesion of green algae.
  • Square-wave light emitting system extracts alternating-current component from the received light, thus measurement can be done even in places with abundant natural light.
  • Near-infrared light emitting diode is used as the light emitting source and intensity of emitting light is controlled with the feedback circuit, thus stable output can be obtained without aging deterioration even at temperature changes.
Item Turbidity meter
Type TUD-211
Measuring object Turbidity of water
Measuring method 90 degrees light scattering type
Maximum scale 2 to 200 degrees (FTU*) (Setting is available in steps of one degree of FS.)
Measuring range Minimum range: 0 to 2 degrees, Maximum range: 0 to 200 degrees
Measurement accuracy Repeatability Within 1%
Linearity Within 2% Within 3% for temperature below 5°C
Temperature of measurement liquid 0 to 40°C (no freezing)
Output signal DC4 to 20 mA (maximum load resistance: 600 Ω, isolated output)
Contact output Classification (Upper and lower limit alarm, during maintenance, abnormality of meter and cleaning command)
Capacity AV100V 0.5A、DC24V 0.5A
Surrounding environmental condition Temperature 0 to 45°C
Humidity 90%RH or less
Power source AC100V±10% 50/60 Hz Single phase Approx. 10 VA
Mass Transformer part Approx. 7 kg
Detector part Approx. 7 kg

combined sewer overflow (CSO) turbidity meter

- Usage application: Improvement of combined sewer system

  1. (1)Organic contamination concentration of overflow can be measured in real time when it is raining.
  2. (2)Effects of formulation of combined sewer system and past measures can be measured and this measurement can be used for evaluation and review.
  3. (3)It is possible to grasp the situation of turbidity load outflow when it is raining. This advantage contributes to formulation of effective operation methods at pumping stations and wastewater treatment plants.

Combined sewer overflow (CSO) turbidity meter is a sensor allowing organic contamination concentration of overflow when it is raining to be measured automatically and consecutively. It is possible to grasp the influence of environment on the existing facilities by measuring the turbidity load concentration in the pipeline. This advantage contributes to formulation and evaluation of measures for improvement of combined sewer systems. The combined sewer overflow (CSO) turbidity meter is jointly developed with Tokyo Metropolitan Government Bureau of Sewage and Tokyo Metropolitan Sewerage Service Corporation.

  • This meter is equipped with a globular float allowing it to respond to sudden flow, including first flush when it is raining and the water level fluctuating rapidly at the outlet of rainwater.
  • If the water level is low on sunny days or there is no contaminated water, the detection part is stored in the cleaning solution in the detector. If the water level increases when it is raining, the detection part automatically protrudes for measurement.
  • A light emitting diode is adopted for the light source, thus operational life is semipermanent. In addition, intensity of scattered light is measured, thus structure is simple and maintenance is easy.
Item combined sewer overflow (CSO) turbidity meter
Measuring object Turbidity of water at pump station and rainwater outlet of sewer pipe
Measuring method Light scattering system
Measuring range 0 to 150 mgCOD/L or more with CODMn conversion
Measurement accuracy Repeatability Correlation coefficient R2 between CODMn measurement value and analysis value = 0.8 or more
Structure Transformer part Movable structure that protrudes when the water level is above a certain level and is stored within the body of detector filled with cleaning chemical liquid when the water level falls below a certain level
Detector part Movable and floating structure equipped with a float that rises according to rise of water level when it is raining; measurement of turbidity is possible near the overflow portion in the overflow weir (The float is pluggable according to the installation situation.)

Combined sewer overflow (CSO) turbidity meter Correlation of measured values

Example of installation of rainwater outlet

Combined sewer overflow (CSO) turbidity meter and water level indicator are installed within the trunk flow passage.
The detector rises with the float according to rise of water level and the detection part protrudes near the overflow and performs measurement. The measured value can be monitored as a real time trend on Web via the monitoring system utilizing the mobile phone network.

Background of development

Combined sewer systems in which polluted water and rainwater are collected with the same pipe have the issue of combined sewer overflow (CSO) when it is raining. The regulation value of BOD (Biological Oxygen Demand) concentration for CSO is enhanced to 40 mg/L from the 2014 fiscal year (currently, 70 mg/L) (from the 2024 fiscal year for the public sewerage system with 1500 ha or more of treatment area) due to partial revision of sewage enforcement order while formation of comfortable waterfront space is requested. For the Tokyo metropolitan area in which 80% or more of the treatment area adopts the combined sewer system, enforcement of more effective measures for improving the combined sewer system is required. Thus, we jointly developed the combined sewer system with the Tokyo Metropolitan Government Bureau of Sewage and Tokyo Metropolitan Sewerage Service Corporation as one countermeasure.