Transition to zero pollution

By Priyanka Kumar a PhD student in the Department of Chemical Engineering and a member of the second Transition to Zero Pollution PhD cohort and the  Science and Solutions for a Changing Planet DTP

As the urgency to phase-out fossil fuels from the energy sector increases, biorefineries, which convert sustainably grown biomass into a variety of chemicals, biomaterials and advanced biofuels are being turned to, to help address today’s global environmental and economic issues. One under-utilised biomass is Brewer’s Spent Grain (BSG), a waste biomass produced by beer breweries with a promising potential for the creation of renewable chemicals and materials, as well as protein as an additional value-added product.

More than a pint of beer

As Brits flock to beer gardens and their local pubs for their post lockdown pint, it’s no surprise that Brewer’s Spent Grain (BSG) is one of the major industrial biomass by-products in the UK. One unique feature of BSG is that it has a high protein content compared to other woody waste biomass that typically power biorefineries. However, the stubborn fibrous structure of spent grain limits its use as low-value animal feed for a few livestock species, where its nutritional value is solely in its protein. Here lies an opportunity to extract the protein in BSG to create higher-quality feed for a larger variety of animals – whilst producing bio-derived chemicals and materials from its non-protein portion. But the question is, how can such a biorefinery be developed?

The ionoSolv process

The answer (hopefully) lies in some of the work already done at Imperial. A process that has been developed in my research group, and is currently being commercialised by Imperial start-up Lixea, utilises low-cost ionic liquids for the pretreatment (i.e. fractionation) of biomass into its main components: cellulose, hemicellulose and lignin.

It is a one-size fits all process that has the ability to break down stubbornly structured plant matter, called lignocellulosic biomass. These include agricultural residues, commercial forest and wood waste. Thanks to Ionic liquids, a group of organic salts that are liquid at ambient temperatures, lignocellulosic biomass can be broken down safely with few steps and high solvent recovery, lowering the process and environmental costs typically associated with biomass pretreatment techniques. Once fractionated, the lignocellulosic biomass components can be used to make a plethora of biochemical based products: lignin-based carbon fibres, nanocellulose and other biobased composites to name a few. However, this technology is yet to be optimised for protein-rich biomass, such as BSG.

My project

Preliminary data shows that ionoSolv ionic liquids can successfully extract protein from BSG, leaving a cellulose rich fraction. The protein can be recovered in a separate fraction and has been shown to be pre-hydrolysed, making it easily digestible by the stomach. But there are steps that will need to be taken to optimise the extraction, recovery and purity of the proteins from BSG, while still maximising the quality of other components, if a successful biorefinery is to be built. My research aims to do this, with the ultimate goal of developing a biorefinery blueprint for all protein-rich biomass – not just spent grain.

Read PhD Insights: building a spent grain biorefinery using low-cost ionic liquids in full

By Sarah Kakadellis a LISS DTP PhD student and a member of  the second Transition to Zero Pollution PhD cohort and the SSCP DTP

Let’s face it: we live in a plastics world. Plastic pollution is doubtless a major societal challenge that raises serious questions about the sustainability of modern consumption patterns. The increasing amount of plastic waste generated each year, dominated by single-use plastics, has created an ecological and waste management crisis. Yet in difficulty often lies opportunity, and throughout history humankind has demonstrated its ability to overcome challenges with ingenuity. In the context of plastic pollution, recognising the ripple effects of a fossil-based economy – conventional plastics are traditionally made from crude oil – alternatives materials loosely referred to as bioplastics, have emerged on the market. But ‘bio’ doesn’t necessarily mean more sustainable and any material substitution must be carefully assessed. My PhD aims to assess the sustainability of these novel bioplastics to ensure they contribute towards tackling the plastics issue, rather than exacerbate it.

So far, my research has addressed the conflicts that emerge as we shift from conventional to bioplastics, while uncovering some of the opportunities too. Life-cycle thinking is at the core of my approach, which helps me look at the issue more holistically. For example, bioplastics are often biodegradable (not all of them are!), which makes them compatible with food waste recycling. However, this potential can only be fulfilled with an adequate and coordinated waste collection system. My latest findings highlighted the concerns over the suitability of biodegradable plastics in food waste treatment strategies, calling for increased collaboration between industry, academia and policy.

Working in a topical and highly mediatised research area is both a blessing and a curse. People immediately connect with the issue of plastic pollution, and tend to show genuine interest in the outputs of my work. However, it also means being acutely aware of all the false promises, misleading claims and unintentionally detrimental effects of public shunning of plastics. Ultimately, we need to recognise that achieving sustainability requires a systems-thinking approach. As Albert Einstein put it: “We cannot solve our problems with the same thinking we used to create them”. In practice, this will mean redesigning our linear consumption model, rather that retrofitting the system at the very end.

The infographic below covers some of the concepts explored here, in common parlance. Thinking about the big picture, my research aims to fulfill the ambitions of a circular economy, which is essentially about keeping materials and products inside the loop for a long as possible.

Read PhD Insights: Biodegradable plastics – a reality check in full

By Abigail Croker, a PhD student in the Science and Solutions for a Changing Planet DTP and the second Transition to Zero Pollution PhD cohort.

Around 86% of all global fire events occur in savannas. These fire events contribute to 10% of total annual carbon emissions. African savannas make up most (71%) of the total contribution of savannas to carbon emissions. Humans and savannas have co-existed, and co-evolved, for the last 400,000 years. However, long-term patterns in fire events – known as fire regimes – are changing due to human activity. Current fire regimes in East African savannas, and the new wildfire patterns that are emerging because of them, are complicated by four challenges: 1) the social construction of savanna ecosystems, 2) recent colonial history and persisting neocolonial influence, 3) population growth and urban expansion, and 4) the global environmental agenda.

In this blog I will outline these four challenges in the context of East African savannas and explain how my research contributes to the sustainable management of savanna fires.

A ‘Natural’ Narrative?

Evidence reveals the habitual use of fire by early humans across African savannas dating back to ~400,000 years ago (Bird and Cali, 1998). Fires have an ancient geological history on earth and have influenced global biogeochemical cycles and evolution independent of humans for millennia. However, elemental carbon studies have inferred that fire incidences in sub-Saharan Africa were low until this time, suggesting that humans have exercised significant control over savanna structure and fire regimes for centuries (Bird and Cali, 1998; Bowman et al. 2011). The co-evolution of humans and savannas makes it difficult, and perhaps impossible, to distinguish between natural and anthropogenic fire regimes (Reid, 2012; Laris and Jacobs, 2021).

Fire scientists have recognised a global shift in fire dynamics, a concept termed a ‘pyric transition’, whereby humans have fundamentally altered the two main conditions fires depend upon: geophysical dynamics, such as temperature and relative humidity, and vegetation (Bowman et al. 2013). Fires require living biomass to exist in the landscape (Sa et al. 2011) and human activity causes a departure from ‘natural’ background levels of fire activity by actively manipulating vegetation and soil, such as through agricultural practices, land use change (e.g., deforestation), ignition patterns (e.g., seasonality), and land management- and fire-related policies (e.g., active suppression).

In recent history, human-driven climate change and the transformation of ecosystems globally have resulted in a shift in human influence over the geophysical, as well as the vegetational conditions wildfires synthesise (Bowman et al. 2011), altering conditions above recorded natural variability levels (Jones et al. 2020). Jolly et al. (2015) show that fire seasons, defined by fire-prone weather conditions, lengthened across 25.3% of Earth’s vegetated surface between 1979 and 2013. This resulted in an 18.7% mean increase in the global fire season duration, with some regions, such as East Africa experiencing wildfire seasons more than a month longer than they were in the 1980s. This trend is predicted to accelerate due to this recorded extension having caused an 108.1% increase in burnable vegetated area. The interrelated environmental, social, economic, political, legal, and institutional systems that contextualise and precipitate current and future projected wildfires are, thus, inherently distinct from geologic past (Pyne, 2020).

Western-centric Fire Suppression Policy

Across Eastern Africa, this pyric transition, can be directly attributed to European colonization which led to adoption of a standardised suppression approach to eradicate fire from the landscape. In the late-nineteenth and early-twentieth century, western conservationists initiated a global movement towards the preservation of wilderness, resulting in the eviction of local and indigenous groups across vast areas of protected savanna ecosystems and a ban on their traditional fire practices. Globally, this has reinforced the wildfire paradox, whereby the exclusion of fire from the landscape has induced larger and more intense fires due to excess fuel accumulation and moisture availability. The intensification of fire conditions has not, however, increased the frequency and intensity of fires; many East African savannas that ecologically depend on fire now experience no fire at all.

Moura et al. (2019) identified three main legacies of colonial fire management on East African savannas. Firstly, widespread tensions and conflicts between governments, authorities, and local and indigenous communities, often resulting in the extradition of the latter and repudiation of their rights. This has been widely recognised as a leading factor in unsustainable and exploitative natural resource management. Secondly, the accumulation of ground fuels and an increase in late dry season (LDS) fires that burn extensively and intensively. LDS fires are often associated with extreme wildfire events (EWEs) that adversely impact both human and natural biotic and abiotic systems, including short- and long-term increases in GHG emissions. And thirdly, accelerating ecosystem degradation due to woody and unpalatable shrub encroachment, causing a decline in vegetation and soil health, widespread biodiversity loss (e.g., affecting the life history traits of species that inhabit East African savannas, such as migratory herds that follow distinct rainfall and nutritional gradients), and therefore, increased inter- and intra-species competition for resources (Archibald, 2016).

My research

My research explores the opportunities for equitable institutions, governance, and policy for addressing wildfire challenges across post-colonial East African savanna ecosystems – where all stakeholders and rights holders are recognised, equably represented, included in the decision-making process, and have access to the opportunities and benefits of implemented measures. Fires have a complex socio-ecological history in East African savannas, where wildfire challenges witnessed today reveal underlying environmental, social, economic, and political conflicts and struggles. To understand how different fire management practices and policies affect the delivery of ecosystem (dis)services across the Greater Serengeti-Mara Ecosystem (Kenya and Tanzania), I am going to create a socio-ecological systems model where each practice and/or policy is modelled under projected future climate-socioeconomic scenarios. Due to the diversity of voices and vested interests existing across this landscape, this model will allow us to explore how current and proposed fire management practices affect socio-ecological systems at multiple stakeholder and spatio-temporal scales. In addition to this, a series of workshops will be carried out with local stakeholders and rights holders to investigate local attitudes, empirical realities, and constructions of fire, and scope of future policy and management.

Read PhD Insights: The role of savannas in the transition to zero pollution in full

By Daniel Greenblatt, a member of the Transition to Zero Pollution cohort 1.

A cornerstone of the modern society is the freedom and ease of movement. In the UK, transportation accounted for a third of carbon dioxide emissions in 2018, of which over half came from cars and taxis. In order to transition to a zero-pollution society, vehicles must be further optimised to increase fuel economy while simultaneously reducing pollutant emissions, including but not limited to carbon dioxide. Other vehicle emissions, such as nitrogen oxides, play a major role in the air quality within our urban areas and must also be tackled. The solution is multi-faceted and will require continued development of the combustion devices within current and new vehicles to meet both our expectations and the standards set by governments.

My research is part-funded by Toyota, a leading manufacturer of hybrid vehicles, and aims to further optimise the hybrid powertrains in their vehicles. With cutting-edge experimental methods, we can probe the fundamental nature of the combustion of bio-derived fuels and fuel components under extreme conditions. This greater understanding of these novel combustion modes directly translates, through the use of computational models, to more efficient and cleaner vehicle technologies within relatively short time frames.

While extracting reliable and valuable data in order to ensure that the computational models used are accurate may often seem tedious, the direct applicability to current technology is a reminder of the instant impact that my research can have. Toyota produces close to ten million vehicles a year and in 2017 on average they emitted 101.2 grams of carbon dioxide per kilometre driven. Improving these vehicles by as little as 1% would result in over 10 tonnes per kilometre less carbon dioxide emitted. This is the equivalent emission from the average electricity usage of 17.7 households in the UK for a calendar year. The average car in the UK travels about 16,000 km a year. That means this saving is the equivalent of 283,000 houses!

Due to the nature of global economies of scale, the small improvements researchers can make could have a profound impact.

Read PhD Insights: Optimising hybrid vehicles as part of a transition to zero pollution in full