When should I measure turbidity online versus in the lab?

Document ID

Document ID CO170

Published Date

Published Date 27/02/2019
Question
When should I measure turbidity online versus in the lab?
Summary
Briefly outlines online versus lab turbidity measurement
Answer
Sometimes it is essential to monitor turbidity continuously.  Continuous monitoring of drinking water effluent confirms compliance and also provides immediate notification of process upsets.  Continuous monitoring of wastewater treatment systems provides real-time process optimisation data.  Whenever immediate turbidity results are required, either for compliance or process control, a process turbidity analyser is the best solution.
  
 In addition to delivering continuous analyses, process turbidity analysers are simple, accurate, and low maintenance.  Process analysers eliminate grab sampling and analyst errors.  Proper sampling, sample preparation, and cell handling are critical for accurate laboratory turbidity measurements where sample settling, cell orientation, and glass cell imperfections can have significant effects.  Properly maintained and calibrated process turbidity analysers avoid all of these potential issues.  Maintenance and calibration of Hach process turbidity analysers are simple procedures facilitated by automated cleaning routines and Hach StablCal turbidity standards.

 Process turbidity analysers may be used in conjunction with laboratory measurements for verification or calibration.  Recent advances in turbidimetric technology in Hach TU5 instruments ensure that process/laboratory verification measurements are closer than ever.  Process turbidity analysers may also be correlated to gravimetric total suspended solids (TSS) measurements for creation of a turbidity/TSS correlation, or to total iron colorimetric measurements for creation of a turbidity/iron corrosion correlation.