Sensors – pH, ORP, Conductivity, Turbidity, Dissolved Oxygen

Organics, solids and nitrate are some of the most important components of natural surface water, wastewater and recycled water. Typically, the detection and measurement of these components has relied on labour intensive manual sampling followed by time consuming laboratory procedures and the use of a multiplicity of expensive online instruments.

The AQUALABO STAC changes the game.  It is an affordable compact on-line UV absorbance analyser, capable of monitoring TOC, BOD, COD, TSS and Nitrate, using an innovative and patented technology.The STAC records the spectral profile of the sample, providing a true numerical picture of the water quality, and can also detect undesirable substances such as pesticides and aromatic hydrocarbons.

The presence of algae in surface waters is a potential threat to the quality and ecology of the water system. Therefore, the monitoring and control  of the algae types and concentrations is very important.

The ALGcontrol offers online monitoring of different algae types by continuously measuring the chlorophyll fluorescence of different algae classes in real time. Compared to time-consuming sample preparations and counting by microscope, the on-line fluorescence monitoring provides quick determination of the chlorophyll content in for example lakes, rivers and reservoirs.

The ALGcontrol makes use of fluorescence excitation. This means that when chlorophyll molecules absorb light, a fraction of the energy absorbed is re-emitted as fluorescence. Due to the fact that algae of the same class contains a similar quantity and quality of pigments, their fluorescence excitation spectrum (with a fixed emission wavelength at 680nm) is significant. Thus, it is possible to differentiate classes of algae by their fluorescence excitation spectrum.

Traditional chemical analysis, alone, is not enough to get a complete view of water quality.  Biomonitoring of behavioral responses and stress levels, experienced by living organisms, is important as it can be used for assessing toxicity as a first line of defence in managing the use of source waters.

The most important drivers for on-line biomonitoring systems are:

1. Traditional analyses are only possible for a small number of the dangerous chemical substances, even with the latest highly sophisticated instruments.
2. It is estimated that only about 5% of the existing toxic chemicals in water can be analysed by on-line monitors.
3. Concentrations of many products are lower then the detection limits.
4. Results of traditional, chemical analyses give no information regarding the toxicity of the combined effects of mixtures

The iTOXcontrol uses a decrease in luminescence of the Vibrio Fischeri bacteria as an endpoint effect to measure the toxicity of water samples. The acute test with this bacteria species is one of the best known ecotoxicity tests and has been used in ecotoxicological research since the 1980’s.  It is internationally standardized and accredited (ISO 11348 Determination of the inhibition effect of water samples on the light emission of Vibrio fischeri).

The iTOXcontrol can be Integrated with different optional sensors like a UV-VIS sensor or Algae sensor (for Chlorophyll-a and blue-green algae) which creates a combined system for Early Warning and Water Quality Monitoring .

Work on with Phil

1. digital comm and then optical technology