Novel wastewater treatment targets molecules

A novel, integrated treatment service uses a smart dispenser to simultaneously multiply, preserve and dose the number of microorganisms necessary for the bioremediation of industrial waste water.

A novel, integrated treatment service uses a smart dispenser to multiply, preserve and dose the number of microorganisms necessary for the bioremediation of industrial wastewater.

The different composition of contaminants in wastewaters makes them difficult to remove. That is because each contaminant needs a special treatment that can be expensive and inefficient. This puts pressure on companies as they struggle to meet the strict requirements of EU legislation on pollutants discharged in water. An established bioremediation technique uses bacterial ingredients to break down hazardous molecules into something more benign. The EU-supported RIBATI project carries the idea one step further by creating an integrated system that makes the process more accurate. It also requires less technical know-how to apply and is more effective.

Bioremediation of recalcitrant molecules in wastewater

RIBATI’s host, the Spanish company Amapex Environment, screened several strains of Bacillus subtilis and Pseudomonas before finally isolating a strain that met their bioremediation requirements.

“Properly fed, we found we could produce many enzymes that work outside the bacteria, known as exoenzymes. These break down certain recalcitrant molecules present in industrial wastewater,” explains Joaquim Canadell, CEO of Amapex Environment.

When put into an anaerobic environment, these microorganisms metabolise nitrogen. This means that the ammonium-based contaminants, often present in wastewater, can be broken down through this metabolic process.

Automating the system to remove human error

The team worked on what ingredients the microorganism needed to grow at the right rate and produce the necessary exoenzymes for a year. They had to work out a system that could supply the bacteria with the right blend of nutrients. They also had to monitor the rate at which the microorganisms were multiplying.

“We found an exponential factor of 3 was the sweet spot. This made the treatment system cheap enough to be cost-effective for industry,” says Canadell. Once Amapex had established the right nutrients, they then had to work out how to dose the wastewater at the right time with the right quantity of bacteria.

He adds: “In collaboration with an external engineering company, we developed a smart dosing unit (SDU). It would simultaneously multiplies, preserves and doses the number of microorganisms necessary to treat the wastewater.”

Smart by name and smart by nature

The SDU monitors the bacterial concentration while it is multiplying. Depending on the concentration of effluents of the water to be treated, it is programmed to dose more or less of the bacteria accordingly. To verify all is working as it should, clients can then collect and send data to Amapex. They conduct maintenance and carry out any adjustments that might be needed.

A variety of industries can benefit from the innovation

The RIBATI project’s SDU has been tested in various sectors, such as the textile, tanning, chemical and metalworking industries. It has proven effective on contaminants such as oils and fats, paraffin and hydrocarbon derivatives, and lactic acid.

Biologically based wastewater treatment currently requires very long times since the bacteria must reproduce and multiply before they can then colonise the tank.

“Isolated and preserved bacteria,” notes Canadell, “are expensive and slow growing. The quantity of bacteria required to start metabolising effluents is so large that either a huge amount needs to be introduced, which is then economically unfeasible, or the user has to wait while they multiply adequately. Normally this will take over a month, which is not feasible given the time pressures users face.”

The SDU Amapex has developed the time and the cost by sensing how much of the bacteria is needed on a contextual basis and by identifying the best way to ‘feed’ the most efficient strains.

From wastewater to biogas

Due to the huge amount of water used in the dyeing and finishing processes, the textile industry increasingly needs to employ strategies that allow it to recycle part of the water used and produced. It is this sector that Amapex intends to focus on over the coming years. But they are not stopping at wastewater decontamination. The team has also tested the process to optimise biogas production in anaerobic digestion plants.

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