Unit allows continuous TMF disposal

Oxfordshire-based group Microbial Solutions has launched the latest version of its bioreactor for continuous disposal of toxic metalworking fluids (MWFs).

The latest design incorporates modular continuous flow capabilities and builds on the company's existing microcycle technology, which has recently undergone trials at BAE Systems' Brough facility.

The technology is aimed at replacing MWF clean-up systems, such as vacuum evaporation and ultra filtration, which are energy intensive and produce oily waste residues.

Will Pope, chief executive of Microbial Solutions, said: 'Overall we think our bioreactors are around 50 per cent of the cost of the classical competition in terms of energy efficiency. Unlike the other systems, we don’t have to heat up to great temperatures or use huge pressures.'

The system works by treating MWFs in a bioreactor that carries a selection of bacterial cultures. When mixed with the MWFs, the bacteria are able to reduce the toxic levels of the fluids by up to 98 per cent.

Since trialling the system with BAE, the company has adapted the design to allow for continuous flow and treatment of MWFs on a modular basis.

Pope added: ‘In our original bioreactor, we put a certain amount of MWF in and left it for a period of time. That’s fine, but of course it involves operator time – you've got to fill it up, leave it for a while, check its position and then you release it and refill.

'The advantage of the new continuous flow bioreactor is you simply plug it in and leave it. You pump the MWF at a determined rate at one end, and at the other end, treated effluent runs out. That’s a huge gain in terms of operator time.’

The bioreactors can also change size to suit requirements. This is done using a cell system, whereby each cell works independently to treat certain amounts of MWFs. The amount of cells can be increased or reduced depending on the amount of fluid that needs treating.

Pope said: 'The biological principle is the same, so there is no new risk involved in the technology of how the bugs metabolise the toxic MWF. However, mechanically what we’ve been able to do is adjust the flow rates and retention times in the tanks so that the bioreaction is completed in the right period of time to give the output performance.'

The company has a seven-tonne unit installed in its workshop, which is the largest bioreactor it has operated. According to Pope, the group is in the process of setting up another bioreactor at a large automotive manufacturer at 10 times the size. This is due to be operational early next year.

Ellie Zolfagharifard