Organic Matter Measuring Device

Online continuous detection of organic matter in water.

Eco-friendly, simple-to-use technologies obtain clear results

Excess organic matter is the primary pollutant of aquatic ecosystems, its source often in effluents from municipal or industrial wastewater treatment processes and livestock activities.

Organic matter discharged into the natural environment alters the level of organisms that live in watercourses by decreasing the levels of dissolved oxygen, for example.

ADASA has developed a series of solutions to support the collection of reliable, rapid and continuous data to help determine the source of polluting discharges, vital to regulatory bodies and facilities likely to cause spillages.

We simplify the monitoring of organic matter as much as possible without sacrificing the speed and precision of the results.

Facilities at risk of spillages need to monitor the inflow and outflow of organic matter in order to:

Adapt treatment to the incoming organic matter – an excess reduces process efficiency.
Ensure that treatment processes are working optimally.
Guarantee effluents comply with the corresponding regulations to avoid environmental damage.

The most common parameters to quantify in organic loads in water are:

BOD (biologically oxidisable organic matter)
COD (chemically oxidisable matter)
TOC (total organic carbon)

Biologically oxidizable organic matter detector

BOD (Biologically Oxidisable Organic Matter)

BOD measures the amount of oxygen consumed by the microbiological oxidation of organic matter present in water, under controlled conditions, and is a difficult technique to automate. This parameter best reflects the impact of organic matter in a natural environment, and its capacity for self-purification, but it takes five days to obtain a result. The presence of solvents, chlorine or disinfectants negatively affects the development of the test, too.

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At ADASA, we have developed BOD-306, a system to measure BOD5 within 90 minutes. Our system is not affected by microbial activity inhibitors and is eco-friendly – we do not use toxic reagents or generate harmful waste.

COD (Chemically Oxidisable Matter)

COD measures the amount of dissolved oxygen consumed by chemical oxidation of organic matter and oxidisable mineral salts, whether biodegradable or not, present in water.

The relation between the values of BOD and COD inform us about the type of discharge:

Inorganic (from industrial wastewater) if BOD/COD ratio is <0.2,
Organic (from urban wastewater, livestock remains, food industries and more) if this quotient is >0.6.

Aautomatic COD analysers provide measurements within two hours. The presence of chlorides impairs their performance, and they use different chemical oxidants such as potassium dichromate and permanganate.

TOC (Total Organic Carbon)

For TOC measurement, the sample is oxidised to carbon dioxide. This oxidation can be carried out by chemical agents (persulfate), by combustion (with the help of a catalyst) or by exposure to heat or ionising radiation (UV). The carbon dioxide produced is measured with a non-dispersive infrared detector or by measuring conductivity. Online TOC analysers present a greater instrumental complexity, which translates into greater difficulty in handling and usually a higher operating cost, e.g. high price of spare parts.

We have developed a compact and easily integrated module for the measurement of UV absorption at 254nm, one of the most widely-used techniques for these purposes.

This module includes a quartz cell, through which the sample is continuously circulated, and an optical assembly of LED technology to compensate for the interference caused by turbidity. Our solution can include turbidity measurement, according to ISO 7027.

These techniques offer high sensitivity and simple instrumentation, making them ideal tools for process control, and these eco-friendly technologies do not require reagents or generate waste.

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