Alpes Lasers develops ultrafast sensor to tackle toxic wastewater

Harmful wastewater is created when, for example, crude oil is refined

A new laser-based sensor for detecting minute traces of toxic substances in wastewater is currently in development by a consortium of European scientists, led by Swiss company Alpes Lasers.

Researchers from Alpes Lasers have teamed up with a group of oil industry partners and academic institutes to create an ultrafast sensor that can detect “the tiniest concentrations” of oil and suspended solids in water.

The detection rate is improved using AI and machine learning; this new laser-based system will continuously monitor water in a live setting, with no need for sampling or preparation. Using hyperspectral imaging, the sensor will detect microscopic pathogens that are indistinguishable using conventional imaging methods, say the Alpes scientists.

Harmful wastewater by-products are created particularly when, for example, naturally-occurring crude oil is, processed, distilled and refined to make new fuels such as diesel, kerosene, and liquefied petroleum.

Producing cooling water, process water, stormwater, and sanitary sewage waters, oil refineries have sought to reduce the number of dangerous by-products by monitoring the wastewaters at critical stages in their refining processes.

”The new light-based analyser will help reduce the release of pollutants into the environment during oil refining while simultaneously optimising core processes in water extraction from crude oil by 10%,” say the Alpes scientists.

Frequency combs
Aiming to give Europe a global competitive lead in oil refining, the European consortium Hydroptics is developing the most sensitive and one of the first water analysers to use quantum cascade laser frequency combs. These are novel laser sources that provide equidistant, coherently-linked optical modes in the mid-IR range, currently deployed in spectroscopy applications due to their special properties.

Hydroptics is developing the most sensitive water analyzer to use QCL frequency combs

Project coordinator, Dr Antoine Muller commented, “The Hydroptics project is creating a highly accurate oil-in-water analyser based on mid-infrared sources and spectroscopy techniques. Our highly sensitive analyser will optimize several critical stages in oil production as well as control downstream processing routines for final mineral oil product development.

“Frequency Comb Quantum Cascade Laser source will enable scientists to rapidly measure the area of the absorption peak related to deformation vibration of the methyl groups.”

At present, QCLs can be used to measure the oil content in water. However, this requires a reference sample that can take several hours to prepare and deliver a result. But, the new Hydroptics device can deliver measurements in minutes.

Continuously monitored
Project coordinator Dr Sargis Hakobyan said, “Our scientists at Hydroptics are using two lasers to continuously monitor the oil-in-water content for long periods, which is not possible with current techniques that use a single laser. We are also developing machine learning techniques to collect and analyse data to refine the extraction process.”

The EU is the second-largest producer of petroleum products in the world after the United States, with a crude refining capacity of about 15 million barrels per day, representing 16% of total global capacity.

Hakobyan added, “Our novel, ultrasensitive oil-in-water on-line analyser will mean Europe will gain a significant industrial lead. Hydroptics will enable Europe’s oil industry to have a better yield with less waste, to have a by-product we can re-use while having a positive environmental impact.”

The consortium expects to have a prototype ready by 2023. Dr Muller said, “We expect to test a working prototype that will be installed in an oil refinery business with our two partners in Austria and Turkey in a love setting. All parts of the prototype will be verified by each corresponding partners labs.”