Question Time: Food & Water

Experts discuss how chemical engineering can help achieve food and water supply security

IN the sixth webinar of IChemE’s Centenary series, the topic of conversation was Chemical Engineering for Sustainable Food and Water – Feast or Famine? Panellists considered the complex challenges posed by the food, water, and energy nexus, and the role that chemical engineers can play in achieving security.

It’s all connected

Highlighting challenges that chemical engineers need to help address, Rachel Gomes presented on key issues within food, water, and energy. Gomes is a Professor in Chemical and Environmental Engineering at the University of Nottingham, UK, with research activities into intelligent resource use in process environments.

She explained the food, energy, and water (FEW) nexus, saying that there is “strong interconnectivity between the issues of FEW, and the key idea behind the nexus is that each resource affects the other”. Gomes said that as pressure on the nexus grows, the need to better understand the interdependencies between the resources “becomes paramount”.

“Chemical, biochemical, environmental process engineers play a major role in delivering sustainable solutions for food, for energy, and for water, and the nexus,” she said. This role is not only in offering understanding of the connectivity between FEW but also in developing practical solutions, which requires systems thinking and generating engineered systems solutions to meet desired targets.

She introduced the concept of FEW2 “where FEW resources become more”. This can be achieved by recognising and using waste to manage the nexus.

Gomes used an example in Mexico of existing work in this area. For more than 100 years, raw wastewater has been used for agricultural irrigation in Tula Valley, in Mexico. She said in the last 10 years, the Atotonilco wastewater treatment plant came online, which can treat wastewater from a population equivalent of 12m people, and a portion of this is used for agricultural irrigation.

Hugh Thomas said that “treated wastewater itself is a valuable resource in terms of irrigation”. He said that agriculture typically accounts for the “biggest slice” of water demand, though usage varies across the globe. In Europe, he said 44% of freshwater abstraction is used for agriculture. Thomas is a Technical Director and Disciplinary Lead for Water Treatment and Supply at consultancy Atkins.

Gomes said: “there’s also opportunities to translate expertise and capabilities between different sectors.” She highlighted utility Severn Trent’s initiative to produce as much electricity as it could from renewable sources to reduce the need to import electricity. In 2010, the company was constructing what was to be the UK’s first energy-crop anaerobic digestion (AD) plant, after recognising synergies between AD of sewage sludge and energy crops, and that biomethane from both processes can power combined heat and power plants.

“The answers to a lot of questions that policymakers pose come from chemical engineers, because we understand the food-energy- water nexus”

Severn Trent has since expanded within the UK AD sector. Currently, Severn Trent Green Power is one of the largest food waste recyclers in the UK, receiving about one quarter of UK collected food waste and about 12% of commercial collected food waste at its facilities.

However, Gomes stressed that it is important to remember that solutions are context dependent, “so we need to engineer solutions that understand the context or are adaptable to context”.

Where chemical engineers come in

Gomes said that chemical engineers can contribute systems thinking and technologies that support not just addressing a particular point or issue within sectors or resources, but also consider them in a wider context, such as ensuring energy efficiency and reuse of spent resources for energy generation. She discussed modelling and analytics to support systems thinking and interactions. She said machine learning and artificial intelligence models could be used to “fit and predict” resource use, reuse, and interactions. She added that modelling and analytics tools could be adapted for variable waste streams, different sectors, and sites.

She also discussed cloud manufacturing which can facilitate industrial symbiosis. She said the cloud manufacturing model is the concept of sharing manufacturing capabilities, and resources, and the cloud platform can make intelligent decisions to provide the most sustainable, robust manufacturing routes.

Viknesh Murugappan said that in Malaysia it is common practice to look at energy recovery and industrial symbiosis. Murugappan is an Associate Professor at Swinburne University of Technology Sarawak Campus, and is focused on optimisation of energy systems and supply chains.

He said in the palm oil industry there is a lot of application of industrial symbiosis. “You see palm oil mills connected to a biogas capture system, which treats waste and generates biogas, and that produces electricity,” he said, and added that co-located palm oil refineries are also seen, which would be producing refined products.

Thomas highlighted that treating water, wastewater, and biosolids is a series of chemical, physical, and biological processes designed and optimised by chemical engineers. “And the same is true with resource recovery, and the circular economy”. He said rather than thinking of wastewater treatment as a disposal and environmental management exercise, it is an opportunity for resource recovery and capturing benefit and closing the loop.

He said there are many other opportunities available from wastewater, some of which are well-established – such as AD for the release of biogas for energy – and are being optimised by chemical engineers in the water sector. Other roles he discussed for chemical engineers in water include ensuring resilient and high-quality water supply, while contending with issues of climate change, population distribution, and limited resources.

Murugappan discussed an “unconventional” role that chemical engineers can play in the future. He said: “it would be nice to have chemical engineers working as policymakers as well, or joining the policymaking team” where they could provide chemical engineering knowhow and give a better perspective into developing policy.

Thomas agreed, and said that some of his most rewarding work has been in the policy and strategy space. He added: “It’s my firm belief that the answers to a lot of questions that policymakers pose come from chemical engineers, because we understand the food-energy-water nexus, we understand the carbon emissions associated with electrical energy, the opportunities around resource recovery. If we aren’t feeding that to policymakers and strategists, or if we aren’t at the table, then I think that’s a missed opportunity. And the likelihood of unintended consequences, or maybe going down blind alleys, is significantly higher.”

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Watch the recording: https://bit.ly/3C8IUty