Online Turbidity Measurement in Potable Water – Non-Contact and Low Maintenance

The measurement of turbidity is based on the Nephelometric method and is enforced according to the “Standard Methods of Examination of Water and Wastewater” / ISO 7027.

As in all optical monitoring procedures, fouling of the optical windows has a considerable influence on accuracy and maintenance.

The monitor AMI Turbiwell from Swan Analytical (Switzerland) is a non-contact turbidimeter with a minimal operating service.

The measuring cell is designed so that the section above contains the heated optical system, and the section below, the non-pressurised measuring chamber, is fitted with a manual or automatic blowdown valve. Because of this, it is possible to easily remove particles of dirt without any disturbance in the process. Air bubbles in the sample water are removed automatically by an overflow system. The optimum sample flow of the measuring instrument is 20 L/h.

The choice of light source is decisive. Instead of a conventional lamp with a limited life expectancy, the AMI Turbiwell has an LED with a life expectancy of approx. 100’000 operating hours and therefore maintains its stability. This makes frequent lamp replacement with complicated calibrations unnecessary.

In order to fulfil the QA standards or national regulations, a quick and simple verification can be carried out with the AMI Turbiwell using secondary standards. For the accuracy and validation of the measurement in operation, the sample current is monitored online with a flow meter control.

Due to its measurement principle, the AMI Turbiwell can be applied to all types of water: for spring water, ground water, tap water and also waste water.