SIGRIST-PHOTOMETER AG, with its roots and headquarters in Ennetbürgen in Switzerland, has been developing, manufacturing and marketing high-quality optical measuring instruments for use in the fields of water treatment, food industry, industrial processes as well as traffic and environment since 1946. The company is one of the technology and quality leaders and sells its products in more than 80 countries. With great commitment, its 85 employees contribute to the sustainable positive development of the company and its value-based culture.


  • True non-contact measurement in free-fall stream (models WTM, WTM A, HT)
  • Dual beam measurement in optimized cell (model P)
  • Re-calibration with secondary standard (fully automatic at model WTM A)
  • Lowest stray light levels
  • Virtually maintenance free
  • Convenient operation via touch screen
  • Graphical display of trends and/or values
  • Visualization of measured values over the past month



The AquaScat measures turbidity of potable water according to IEC 27027 using 90+° scattered light detection in a free-falling water stream. This contactless design eliminates window foiling and minimizes servicing to a minimum. Calibration check is performed with a calibration unit that is either mounted to perform the check or that is already built in (depending on variant).


  • Turbidity measurement in raw water
  • Monitoring of flocculation and dosage of flocculants
  • Filtration monitoring of filter performance and back-wash control
  • Turbidity measurement in treated and final waters
  • Turbidity monitoring of water in storage and distribution networks
  • Turbidity measurement in process and waste waters


  • Potable Water Treatment Works
  • Waste water treatment
  • Industrial water production



The ColorPlus measures the colour/absorbance online at up to three different wavelengths in the UV and visible range, also combined. Turbidity can be compensated at the same time by selecting an appropriate wavelength. The modular design of the instrument enables to cover various applications by selecting the most suitable measuring cell. In many cases, a standard housing like e.g. Varivent® is used.

Alternatively, custom-specific flow cells in different materials and designs are available. For inspecting the instrument, checking units on the basis of reference filters can easily be inserted. Operation is done intuitive using the intelligent control system SICON via touch screen technology and colour display. Values, graphs, alarm and status messages can be presented. An internal data logger allows recalling and displaying measured data from the last 32 days. A variety of analogue and digital interfaces allows smooth system integration and control.


The instrument is used for monitoring oil traces in raw, surface, process and waste water. As a result of the non-contact free-fall measurement, there are no reading falsifications arising from window soiling and there is an extremely low need for maintenance. The instrument’s factory setting is calibrated with 16 EPA-PAH standard.

The OilGuard 2 W can be recalibrated by the customer with a secondary standard (solid reference) which allows an exact recalibration without 16 EPA-PAH. The ingenious instrument design of the OilGuard 2W in combination with the high quality of its optical components minimizes the effect of interferences. Thus, even the smallest traces of oil, as well as larger amounts, can be precisely detected. The instrument can be adapted to various types of oil to meet customer requirements. Checking the instrument is easy with corresponding solutions.


Measuring system for Scrubber wash water monitoring

More and more goods are transported by sea on a global scale and cruise liners are also enjoying an increase in popularity. For economic reasons, many ship operators choose heavy fuel oil as a propellant. The International Maritime Organization (IMO) has issued guidelines for limiting pollutant emissions of heavy fuel oil powered ships. In order to continue operation with highly sulphurous heavy fuel oil, the ships are refitted with scrubbers. 

The certified measuring system ScrubberGuard reliably and continuously measures the parameters of the scrubber wash water, such as turbidity, oil-in-water, pH and temperature in accordance with the guidelines for exhaust gas treatment systems MEPC.259 (68).



Delivering high quality drinking water is a permanent challenge. Technical innovations are needed now to guarantee safe, healthy and clean water – today and for future generations.

Watch our video to see how BactoSense developed by bNovate Technologies SA will help you to guarantee that your water is safe to drink.

What does Bactosense do ?

  • Precisely Counts the number of microbial cells in water
  • Monitors the microbiological evolution in water and alerts as soon as limits are exceeded.

Application fields 

  • Drinking water
  • Pharma and cosmetics
  • Dairy industry
  • Bottled water
  • Sterility testing
  • Brewery / wine



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