Real Tech’s innovative new meters use ultraviolet (UV) and visible (VIS) LEDs for measurement. Many compounds absorb light in the UV-VIS spectrum, including organic compounds. Absorbance data from multiple preselected wavelengths are used for measurement of organic compounds with an additional reference wavelength used to compensate for interferences (i.e., particles).  

Absorbance data from the selected wavelengths is related to concentration using reference laboratory samples to develop a correlation or calibration model for BOD, COD, TOC, DOC, TSS, or colour. The calibration model is what is used by the meter to translate the absorbance data into meaningful concentration data for the given parameter that is easily interpreted and familiar to the user. Each meter comes ready with several starter calibrations pre-programmed. 

A starter calibration is a model developed using water quality data collected from various similar sites and sampling locations.  

Over the past decade, Real Tech has built an extensive library of calibrations from our experience with UV-VIS instrumentation. Therefore, each meter comes ready with several starter calibrations pre-loaded for operation right out of the box. The meter is available in several different models, so users can select a model based on their desired measurement parameters and industry. The starter calibrations pre-loaded on that meter will match to get you off to the best start possible. 

Since the meter uses calibrations to estimate BOD, COD, TOC etc., Liquid Ai Data Management PC Software was developed to empower users with the ability to manage these calibrations independently. The easy-to-use desktop program allows you to upload saved results directly from your meter to the program, input matching laboratory results and compare your meter samples to the lab result. The laboratory results can be used to improve existing calibrations for your site-specific conditions or even develop new calibrations. From there, any new or improved calibrations can be sent back to the meter for use next time you’re sampling.  

While the pre-loaded starter calibrations may provide satisfactory results, Real Tech recommends site-specific improvements whenever possible.  

Since correlations between absorbance and traditional BOD, COD or TOC vary depending on the type of organic compounds that are making up these aggregate parameters, it is important that the meter utilizes a calibration model that matches the site-specific water characteristics to ensure the most accurate results.  

The software also gives the user the flexibility to create new calibration models for any sampling location in their plant. 

No, results from the meter would not be acceptable for compliance reporting, as those regulations are generally associated with standard laboratory methods, such as BOD5. 

The meters were designed as a process control tool, giving operators a rapid estimation of BOD and COD in the field in seconds. However, when lab samples are sent for compliance, the results can be used to improve the meters calibration over time. 

In some cases, sites are sending multiple samples to the lab daily. Not for compliance, but rather to try and gain insights about their process. In these situations, our clients have found  

These would not be NCDENR acceptable, as I believe those regulations are specific to BOD5 the 5-day laboratory standard test method. This tool is geared more towards process control, providing instant results to help with estimating what your BOD or COD loading would be in a real-time fashion. Our clients find this gives them the ability to catch events much sooner and then be able to adjust in response. 

LIQUID AI CUSTOM CALIBRATION ENABLED  

Real Tech’s BOD/COD Meter comes ready with several starter calibrations pre-programmed onto the meter. Access to additional starter calibration models can be obtained by connecting via USB to a PC with Real Tech’s Liquid Ai Data Management PC Software Program. In addition to starter calibration models, site-specific calibration models can be created and loaded onto the BOD/COD meter using the software. In the field, measurements can be taken using any of the calibration models previously loaded onto the BOD/COD meter. Users can also build upon their site-specific calibrations over time to further increase the accuracy and robustness of measurements for any given monitoring sit