Food for thought and water for life
The provision of safe food, clean water and sanitation, and the energy required to supply all three to growing populations has been facilitated, improved and optimised by the parallel advances in chemical engineering.
Not immediately obvious when buying the weekly groceries is the contribution made by chemical engineers, over decades, to increased food yields across the globe through the industrial manufacture of nitrate, phosphate and potassium fertilisers.
Similarly, our easy access to clean water. While citizens of the Victorian era were very aware and indeed grateful for the construction of municipal sanitation and clean water systems, those of us in richer countries are now increasingly concerned with long-term environmental impacts of sewage disposal.
Our daily bread and water are taken for granted in developed societies, but in the world’s poorer countries, these basic commodities are extremely valuable.
Food, water and energy nexus
The food and water industries are faced with the challenge of developing a water-energy-food matrix that can sustainably balance all three.
According to the Food and Agriculture Organisation (FAO) of the United Nations, agriculture is the largest consumer of the world's freshwater resources, and more than a quarter of the energy used globally is expended on food production and supply. Unfortunately, one third of all food produced is lost or wasted. The municipal authorities in many developed countries are now actively engaged in schemes for redistribution of food waste to poorer countries and poorer cross-sections of the industrial societies. However, the long-term sustainability can only be achieved through advanced novel technologies developed via chemical engineering processes. Many innovative chemical process technologies are already being implemented to enable wastewater and biological waste to be recycled, regenerated and re-used
Safety and Sustainability in Food and Water Industry
Consumer safety must always be an overriding priority for food and water provision. When safety is not given priority, consumer confidence is shattered and has lasting consequences. Whether through the neglect of increased levels of pollutants and/or toxic chemicals or via economically motivated adulteration (EMA), such incidents have highlighted the need of consumer risk evaluation through systematic supply chain and process risk management. Chemical engineers provide a vital contribution to the sector through every step of the food production process, from the environmental impact of plant-based foods, regenerative agriculture, and water and energy reduction, through to reducing post-harvest loss and food waste innovation and health and safety at work.
In the context of sustainability, the development of novel ingredients, for example seaweed, hemp, and spirulina all come courtesy of process engineering innovation, as does the development of complex food supply chains and digital technologies such as Industry 4.0.
Managing water, both potable and wastewater, has long been the work of chemical engineering. Critical questions now include the effect of climate change on source water and controlling emissions from treatment plants, a task that appears to be much greater than first thought. The impact of climate change on both the quantity and quality are unknown and difficult to model and predict. Recovering water from waste streams and desalination, and less energy intensive but capacity-limited ultrafiltration and physico-chemical separations of molecular pollutants are critical developments supported by chemical engineers.
Other water management measures that could have an impact include the increasing adoption of water recycling, energy (re)generation and nutrient recovery.
Over the years, regulations for wastewater environmental disposal have tightened for both sewage and industrial wastewater. These tight outlet specifications require high technology processes and larger financial investments.
The knowledge and technologies exist and the upscaling these technologies will be the challenge of the next generation of chemical engineers.
Food production to process technology to biotechnology
Over the last 100 years, chemical and biological engineering have transformed the global food industry to respond to shifting needs, from food preservation to nutritional functionalisation and to the latest therapeutic advances in biomedicine. Engineering applied to food technology value-adds raw materials to create, preserve, package, refrigerate and transport food.
Brewing and its by products provide a worthy example. Brewing produces more than beer and other alcoholic drinks – it is the source of yeast used in bread and vital to bread making involving chemical engineering. Yeast from brewing is also the source of commercial Vitamin-B and creates the much loved (and sometimes maligned) Marmite and Vegemite. Similarly, chocolate and milk are no longer used only in confectionary production for consumption, but also as bio-process intermediates in the production of a very wide-spectrum of natural aromatics, proteins, sugars and natural oils in the cosmetics and pharmaceuticals industries.
Beyond food, fermentation gave rise to penicillin and is now used to ferment human insulin from genetically modified bacteria such as Escherichia coli. This process uses a human gene, which is not only more effective than animal-derived genes, it also avoids the large-scale slaughter of animals, as was the previous practice.
Chemical Engineering for a Sustainable Future
Achieving the sustainable and equitable distribution of food and water resources worldwide will require broad social censuses and government support. When this occurs, great outcomes can happen, as per the City of Milan, Italy (recent winner of an inaugural Earthshot Prize) which has developed a scheme to re-distribute food waste for re-use and regeneration, which could be used as a model by other cities around the world.
Other promising developments from wastewater treatment include digesters that use sewage sludge, waste food and general organic waste in combined or separate digesters to extract energy from waste. The product of the digesters is also used as fertilizer after dewatering and a pelletizer or similar.
Food and water security in a changing climate is a complex problem. With finite resources, but growing populations, we need to apply chemical and biotechnological engineering to produce more food using less land, water and energy. Closed-circuit processes could be part of the solution. Chemical engineers will be critical in developing and implementing a safe, efficient and economic ‘one water cycle’.
Further challenges involve how to shift public perception and responsibility around water use and water sources, how to update old infrastructure in a carbon neutral economy, and the impact of flooding, extreme weather events and sea level rise on water quality in developing countries.
Chemical engineers will play a major role in the realisation of key solutions and have an opportunity to be involved in a policy shift to reassess our food and water systems for a resilient future.