How to get rid of industrial waste: feed it to bacteria

A spin-out company is pioneering the use of bacteria that literally eat the toxic by-products of high-tech engineering.

Professor William Pope, Microbial’s Chief Executive Officer, with untreated metal working fluid (left) and metal working fluid after treatment with MicrocycleTM (right)

Professor William Pope, Microbial’s Chief Executive Officer, with untreated metal working fluid (left) and metal working fluid after treatment with MicrocycleTM (right)

Microbial Solutions Ltd has developed a clever solution to the disposal of ultra-high toxicity fluids, a serious issue for high-tech metal working companies such as those that manufacture aircraft and cars. Extremely precise engineering is required to create something like an aeroplane’s wing or a modern fuel efficient engine, and the interface between the metal and the machine cutting it has to be constantly lubricated with a carefully emulsified mixture of high-grade oils and water. The fluid carries away metal swarf, facilitates the most accurate cut possible, and absorbs heat which could otherwise damage the product and the tool.

There is a problem, however: bacteria love these oil and water mixtures. They are warm and full of hydrocarbons which the bacteria feed on, providing a perfect breeding ground. Under normal working conditions the fluids can rapidly become so contaminated with bacteria that they have to be replaced. This is expensive, and therefore the lubricating fluids contain biocides to make them as toxic as possible, resulting in fluids that last much longer, give better machining performance and save companies money.

In the long run, though, even these fluids become unusable, and this creates another problem: a highly toxic waste product that has to be disposed of. Expensive and energy-intensive chemical methods can be used to break up the fluids, but these will not remove all the toxic components. The poisonous sludge left behind also has to be disposed of – incinerated, or in some parts of the world buried in landfill, where it will slowly break down anaerobically, but at the cost of releasing the greenhouse gases methane and CO2 into the atmosphere. The disposal process can cost companies hundreds of thousands of pounds a year.

It was research by Chris van der Gast, a DPhil student affiliated to the Department of Engineering Science and working at the NERC Centre for Ecology and Hydrology (CEH), which began to address this problem. In conjunction with Professor Ian Thompson (then at the CEH, but now at Oxford University), Chris investigated whether bacteria could be employed to deal with the poisonous waste. It seems counterintuitive to use bacteria to consume something that has deliberately been treated with biocides, but in fact almost anything can be eaten by bacteria – it is just a question of finding the right ones.

After a careful worldwide search of the hundreds of bacteria that survive naturally in metal working fluids, five were selected, and this mix of bacteria was able to create a self-sustaining system. At ambient temperature and pressure, with no need for high energy inputs, the bacteria gradually consume the toxic fluids (including the waste oil), producing small amounts of carbon dioxide. Toxicity, carbon and nutrient balancing keeps bacterial growth at a stable level and prevents algal bloom. The grey water left over at the end of the process can be recycled or released directly into the sewers, and the system has proved capable of running for years at a time without the need to add more bacteria.

The research led to the spin-out of Microbial Solutions in 2008. Industry was quick to see the potential of the company’s patented MicrocycleTM bacterial treatment, since it helped them to meet increasingly stringent targets for reduction of pollution, landfill waste and greenhouse gas emissions, as well as saving them considerable amounts of money. The technology has been trialled by British Aerospace and the Ford Motor Company, with highly successful results; Microbial Solutions has won Technology Awards from both companies, as well as a UK Award for Environmental Excellence, and the future of its innovative bioreactors looks extremely promising. Meanwhile, further research into the innovative uses of bacteria in environmental engineering is continuing in the Department of Engineering Science.

Peter Fish, Systems Estates Manager for British Aerospace, said: ‘Microbial Solutions reactor solves a number of problems at once: it can save costs and also helps us meet our environmental obligations. We have a site of special scientific interest near our Brough plant, and we have to be very careful when transporting, treating, or disposing of waste. Being able to remove the toxins from metal working fluids so effectively is a huge benefit. We’re very pleased the trial has worked so well and look forward to continuing our excellent working relationship with the Microbial Solutions team.’

Original research funded by the Natural Environment Research Council

Visit the Microbial Solutions website

This is one of the Oxford University research impact case studies

Nick Hankins appointed editor-in-chief of new Elsevier water journal

Dr Nick Hankins of the Department of Engineering Science has been appointed as editor-in-chief of the Journal of Water Process Engineering.

The Journal of Water Process Engineering is a new journal which will publish refereed, high-quality research papers with significant novelty and impact in all areas of the engineering of water and wastewater processing. The journal will particularly focus on contributions involving environmentally, economically and socially sustainable technology for water treatment.

The first issue of the Journal of Water Process Engineering, comprising of invited papers, will be published towards the end of March 2014. Dr Hankins will co-edit the journal with  Professor Abdul Wahab Mohammed  of the Universiti Kebangsaan, Malaysia.

Ian Thompson wins grant to develop new hybrid technology to combat water pollution

Prof. Ian Thompson, Department of Engineering Science, has been awarded funds from the Science & Technology Facilities Council (STFC) to develop a hybrid technology for treating recalcitrant water contaminants using electron beams.

The project is one of seven aimed at solving environmental challenges that have been awarded a total of £1.5M under the Challenge Led Applied Systems Programme (CLASP). The projects plan to produce tangible results in a 3-5 year period and bring STFC researchers together with other academic disciplines and industry through new collaborations to solve real environmental challenges.

See the full list of successful projects

Thames Water Sponsored DPhil Studentship 2012-2015

Reduction of algal loading onto water treatment works

A three-year funded DPhil studentship is available from October 2012, in the Department of Engineering Science at the University of Oxford.

We are seeking a highly-motivated researcher for this exciting opportunity to develop research expertise in the design and operation of novel, biological pre-filters for potable water treatment works. Such skills are in great demand within the water industry, in universities and in consultancy companies. The ideal candidate will hold an undergraduate degree in a biological science such as zoology or botany, or an applied engineering or environmental science. The candidate must possess good communication and inter-personal skills, be numerate, and should have experience of, or enthusiasm for, engaging with industry on problems of an intellectually demanding and highly practical nature.

Thames Water have identified peaks in chemical demand associated with algal blooms as a current cause of seasonal increases in the costs of potable water treatment; a goal has been set to minimise the impact of algal blooms and thus reduce treatment costs at Farmoor stage 2 reservoir in Oxfordshire. It is proposed to install a combined physical and biological barrier, consisting of a combination of submerged booms and floating reed beds, in order to reduce the algal biomass exiting into the treatment process. The project will investigate and evaluate how well the installation meets its goals over a three year period via an intensive field- and lab-based protocol; this would involve quantifying and monitoring the ecology of the reed-bed installation and associated booms and filters, measuring their effects on hydrochemical flow pathways, monitoring the impact of the installation on algal populations, and quantifying the impact on the downstream water-works operation and wash water treatment and disposal. The ultimate goal would be the development of a successful final design for installation on other suitable reservoirs.

The student would be integrated into the Thames Water organization at Farmoor, with smaller scale lab-based work being executed at Oxford University Begbroke Science Park and at the Thames Water Innovation Centre, Kempton Park. She/he would be supervised jointly by academic staff at Oxford University and by staff at Thames Water.

The studentship covers university fees at the UK/EU student level, College fees, and a tax-free stipend for three years: £14,400 in the first year, with annual increments. It is available to all applicants, but non-UK/EU students would need to provide the difference in university fees. The deadline for applications is July 24, 2012. Interviews will take place during the week commencing the 6th of August. Applicants should send a CV, a covering letter explaining what they can bring to this challenging project, and reference letters from two academic referees to: Dr Nick Hankins, Department of Engineering Science, The University of Oxford, Parks Road, Oxford OX1 3PJ (to whom informal enquiries may be addressed).

Applicants should hold a full, clean driving licence. The successful candidate would be expected to work over deep water, and gain the necessary boat handling qualifications.