Water footprint of whisky - Isabel at the LCA Food 2020 online conference

Isabel presented the results of the water footprint of single malt whisky at the LCA Food 2020 conference in mid of October. How much water is used for producing whisky in a craft distillery in Scotland? How can this water footprint be reduced? And what is the smartest way to use the valuable by-products, from a water perspective? These and other questions were answered in her poster presentation.

Held virtually from Berlin, this very well organised online event allowed for a lot of interactivity! Chat functions, breakout rooms with random researcher peers from around the world, a virtual photo booth, a pub quiz (you had to bring your own beer) and live forum discussions made it almost feel like a personal face-to-face meetup. No need to run after an author at the lunch buffet for asking a question – this could be done at any time by leaving a comment underneath the pre-recorded presentation. As registered participants can still watch all presentations for more than a month, no presentation has to be missed – as often in a normal conference where events are being held in parallel. You missed a detail on the slide? No problem, just pause and go back.

Researchers leaving comments for Isabel’s poster stated their surprise over cooling water being the main water use hotspot in the distillery. Indeed, this is common for many distilleries. But heat recovery and a (partially) closed cooling water loop offer interesting solutions, which is the topic of Isabel’s current research. In terms of by-product use, it seems to be most (water) efficient to use spent grain and pot ale for the replacement of imported protein feed such as soybean meal to be fed to livestock. Have a look at her poster below if you are interested in finding out more!

Many thanks go to Arbikie distillery for the fruitful collaboration and the funders of the Dwr Uisce project for supporting Isabel’s participation in the conference!

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Isabel’s poster, presented at LCA Food 2020: What are the water use hotspots in whisky distilling and how can we reduce the whisky’s water footprint?

Responding to the UN Sustainability Development Goals in Collaboration

By Katrin Dreyer-Gibney

Since my involvement with the European Dŵr Uisce research project I don’t think I have enjoyed a task more than coordinating the paper and presentation for the EURAM  2020 Conference, which will take place in the Trinity Business School, Trinity College Dublin from the 4th to 6th December 2020.

The overall Conference Theme is “The Business of Now: the future starts here”

Our paper deals with this theme as it addresses some of the biggest problems of “Now” and what businesses can do to address these problems for the future.

The paper is called “Responding to the UN Sustainability Goals through network action learning” - It explores how we – a cross-border, multidisciplinary team contribute to novel technology platforms, policy support and guidance and knowledge dissemination in collaboration with practitioners, government and community representatives.

Sustainability Development as a Wicked Problem

The UN Sustainability Goals challenge society to consider how it is behaving and to respond with new partnerships to sustain our communities, resources and planet. The scale and scope of this challenge is enormous and not amenable to single discipline actions, nor to actions which do not integrate research and practice. A challenge like this can be described as a “wicked problem”.

A wicked problem has countless causes, is hard to describe, and doesn’t have a right answer, climate change, war and poverty are classic examples of wicked problems. They are the opposite of hard but ordinary problems, which people can solve in a finite time period by applying standard techniques. Not only do conventional processes fail to tackle wicked problems, but they may exacerbate situations by generating undesirable consequences.

Wicked problems are amenable to action learning, where different people can advocate alternative courses of action in accordance with their own value systems, past experience and intended outcomes.

In our EURAM conference paper we present a particular response to the UN Sustainability Goals undertaken through network action learning. The problem setting is that of the creative application of novel technology with the potential to reduce the carbon footprint associated with water distribution and use. Increasingly, water, where available, is not in the right place at the right time. That is a well-recognised problem with implications for food production and human habitation. However, a less well recognised related problem is that the energy burden associated with water production and distribution is substantial. Treating raw water and wastewater to acceptable standards for consumption and disposal is energy intensive. Such activity accounts for 2–3% of the global energy use. Therefore, initiatives to reduce that energy burden have the potential to reduce the carbon footprint and sustain water as a resource.

We explore how network action learning impacts the application of novel technology to reduce the energy burden associated with water production and distribution and how, through learning in action, innovation capabilities are developed.  We combine research and project practices, to enable the timely production of valid, actionable knowledge and innovative solutions.

By doing so, we address the following UN sustainability goals:
Goal 6: Clean water and sanitation
Goal 7: Affordable and clean energy
Goal 9: Industry, innovation and infrastructure
Goal 11: Sustainable cities and communities
Goal 12: Responsible consumption and production
Goal 13: Climate action
Goal 17: Partnerships for the goals

Humanity is facing enormous challenges through climate change and water shortage.  These related problems cannot be solved in isolation. As shown in our research, a holistic approach can respond these problems and the associated UN Sustainability Goals. This study illustrates how a cross-border, multidisciplinary team of researchers working with practitioners from industry and governments addressed these challenges. The project continues for a further two years during which our further research will enquire into the diffusion of the innovations resulting from this study.

Reference:
Dreyer-Gibney, K., Coughlan, P., Coghlan, D., Wu, S.-H., Bello-Dambatta, A., Dallison, R., McNabola, A., Novara, D., Rafique, A., Schestak, I., Spriet, J., Walker, N., & Williams, P. 2020. Responding to the UN Sustainability Goals through network action learning. Paper to be presented at the EURAM 2020, Dublin.

Evaluating the potential for energy recovery in an industrial wastewater treatment plant

by Daniele Novara

Dairygold Co-Operative Society Ltd is an Irish dairy co-operative based in Mitchelstown, County Cork. A delegation from the Dŵr Uisce project visited the Dairygold Wastewater Treatment Works (WWTP) on 20/02/2020 to assess the potential for hydraulic energy recovery within the existing infrastructure.

In fact, Micro-hydropower schemes are an effective solution for energy recovery at the outfall of wastewater treatment plants and Pumps As Turbines (PATs) in particular are a hydropower technology particularly suitable on a small scale where a conventional turbine unit would not be economically viable.

The Dairygold WWTP is located at the foot of a hill just below the main industrial facilities, and next to the Mitchelstown municipal WWTP as shown in Figure 1. The main location investigated for energy recovery was the pipeline carrying pre-treated effluents from the industrial plant above head to the WWTP at the foot of the hill with a drop of around 12 m displayed in Figure 2. At the first step, flow and pressure data were gathered from the plant operators to provide a precise overview of the site conditions. Subsequently, the Pump As Turbine selection software developed at Trinity College Dublin as part of Dŵr Uisce research project has been applied to the selected site and helped to identify the ideal PAT and generator to be chosen.

Figure 1 the location of Dairygold Wastewater Treatment Works (WWTP)

Figure 2 the pipeline carrying pre-treated effluents

Eventually, the potential for energy recovery within the existing infrastructure of the Dairygold WWTP in Mitchelstown has been identified as 2 kW. The turbine may recover up to 7,400 kWh of electricity along a typical year, corresponding to a reduction of the electricity bill by nearly 1,200 €/year. However, given the low power output of the PAT the estimated payback time is between 11 and 14 years.

Recovering heat, saving space: Grease trap integrated heat recovery

By Jan Spriet

Wastewater from (commercial) kitchen drains can reach temperatures up to 55°C, consequently, they have a significant amount of embedded energy (that you paid for), that is currently being flushed down the drain. In commercial kitchens the installation of a pre-treatment system, to remove Fat, Oil & Grease (FOG) from the wastewater is mandatory, to avoid fatberg formation. In commercial kitchens, this pre-treatment is performed by a grease interceptor or grease trap. In the proposed prototype, this grease interceptor is used as a wastewater holding reservoir, avoiding temporal mismatches, and a heat exchanger is integrated into this grease interceptor. The heat recovered from the grease trap reduces the energy and fuel consumption of the kitchen’s traditional heating system. Integrating heat recovery in the grease trap would not only reduce the space requirements of heat recovery systems, and reduce their installation costs. It would also aid in the removal of FOG from the kitchen wastewater. In this article, we describe the operation of our prototype.

Figure 1. The working principle, in a nutshell.

Our previous research showed a technical heat recovery potential of 1.4 TWh (388 000 tons of carbon emissions) in the food and hospitality sector in the UK, each year, using currently available heat exchangers. However, it also showed that this potential was limited by temporal mismatches between supply and demand, a required vertical drop in the drain of 2m, and showed that these heat exchangers are not cost-effective for smaller kitchens. The idea of the developed prototype was to address these three bottlenecks. The solution was found by integrating heat recovery into grease interceptors. These grease interceptors are already a mandatory piece of equipment, this would thus not require additional space, and have a limited effect on costs.

Figure 2a. The grease trap with prototype DWHR device

Figure 2b. Picture of the prototype DWHR device

This prototype was tested in steady state conditions in the lab, using heated clean water to simulate the kitchen’s wastewater. This showed an effectiveness between 23% and 55%, and a recovered heat ranging between 600W and 1.8kW. It also reduced the temperature in the grease trap from around 41.5°C in normal conditions to 36.5°C at its lowest point

Figure 3. Heat recovery prototype in the lab set-up

The prototype is deemed profitable for kitchens with a consumption of more than 100 l/day, when complementing electric heating and 300-350 l/day when complementing traditional boilers (fuel oil, natural gas or bio-mass). Applying this prototype in the food and hospitality sectors results in over 150 000 food outlets, where installing the prototype is the most profitable solution. These outlets equate to 2348.52 GWH of heat recovery each year, the equivalent of 69 000 tons of greenhouse gas emissions.

The reduced temperature is expected to improve FOG removal efficiency, which in turn would increase the required emptying frequency of the grease interceptor, as more FOG would be collected. Collecting more FOG has the advantage that, when the removed FOG is treated in anaerobic digesters, additional bio-gas can be recovered.

Changing river water quality under a worst-case climate change scenario: Implications for drinking water supply

By Richard Dallison

Water service providers in the UK face a vast array of challenges when it comes to planning their future operations and services; the impact of climate change on the quality of water arriving at drinking water treatment plants (DWTPs) is just one of these. Changes in water quality are induced by a variety of factors, when considering non-point source inputs. Large or prolonged rainfall events, for example, can lead to greater washing of pollutants from the land in to rivers. Additionally, large streamflow events provide rivers with greater stream-power, enabling more erosion of river banks and the movement of larger particles. Very low streamflow events can also cause spikes in water quality issues, as there is less water available to dilute any pollutants. Therefore, any changes in future climate, and subsequent alterations in streamflow regime could have far reaching consequences in terms of water quality, this in turn could cause problems at DWTPs if they are unprepared for any such changes.

Using the Soil and Water Assessment Tool (SWAT) hydrological model, we have projected and analysed future (2021-2080) streamflows and water quality under a worst case scenario of future emissions, that being representative concentration pathway 8.5, as laid out by the Intergovernmental Panel on Climate Change. To account for uncertainty in future modelling, an ensemble of 12 regionally downscaled models derived from the Met Office Hadley Centre Global Environmental model (HadGEM3), and supplied by UK Climate Projections 2018, have been used as the future climate inputs to SWAT. Five catchments have been studied, the Clwyd and Conwy in north Wales; the Dyfi in mid Wales; and the Teifi and Tywi in south Wales; these systems represent a variety of catchment characteristics in terms of land use, soil types, underlying geology and topography. We have investigated annual and seasonal average changes for four water quality aspects, suspended sediment (SS); total phosphorous (TP); total nitrogen (TN); and dissolved oxygen (DO). Mann Kendall trend analysis was performed on the model outputs, in order to detect any statistically significant trends.

Figure 1. Study area and catchments showing streams larger than third order as defined by Strahler method.

Previous work by the Dŵr Uisce project has shown that extreme streamflow events will become more frequent in the future, with winter and spring seeing more very large events, and summer and autumn seeing much lower streamflows. This is reflected in the water quality outputs, with increases in SS loads seen in winter and spring in four of the five catchments each. At annual average level, SS loads are increasing significantly (p <0.01) in all catchments except the Tywi, were a non-significant increase is seen. TP and TN display broadly similar trends, with concentrations increasing in all seasons, in all catchments except the Dyfi, where a decline is shown in winter, spring and annually on average. Summer concentrations of TP and TN in particular show a statistically significant increase in all catchments (except TP in the Tywi). DO levels show the most variation, although a decline is seen in all catchments in summer. The Teifi catchment is the most divergent, with a statistically significant increase in winter and spring DO levels, compared to declines seen in all other catchments for winter.

Figure 2. Overview of the direction and significance of annual and seasonal average trends in projected future (2021 – 2080) water quality concentrations, as detected by Mann Kendall trend analysis, based on the average of all 12 RCM model outputs.

Given the trends seen in river water quality, it is clear that for the vast majority of the time in the future, water quality will be worse than it is currently. This is an issue that needs to be managed at DWTPs in particular, to ensure that current operating systems, procedures, and technologies will be able to cope with more contaminated water in the future. This adaptation need comes hand-in-hand with the need to also ensure future water security, especially in summer and autumn, when lower precipitation and streamflows, as well as higher temperatures, are projected for Wales. It is clear that the projected changes in climate will have a large impact on catchments in Wales, this will have a significant knock-on impact on a variety of aspects of drinking water supply. Work is therefore needed now to plan and mitigate against these potential changes in order to maintain continued high-quality supplies in to the future.

Eco-code posters in English, Welsh and Gaelic languages

Szu-Hsin Wu

Previously, we have designed an English language version of eco-code poster which shares many water-saving tips. The poster was firstly published on our website and social media and posted across campus in both hard copies and digital format.

Due to the COVID19 pandemic, over the past months, we have all been adjusting our routines and behaviours to slow down the spread of the coronavirus. During the period, we also experienced water shortages in Ireland. We had only 25% of normal rainfall in April and decreased 5% of normal rainfall for May. We thought the sharing of these water-saving tips could also remind everyone making a small effort to collectively create a positive impact on our environment. To further promote these water-saving tips, we converted the poster into a Gaelic language version. These tips circulated to the mailing list of the Sustainability Network at Trinity College Dublin and were well received on many social media such as Twitter, Facebook and Instagram.

Following a positive response from social media, we also designed a Welsh language version of the eco-code poster. Now, these water-saving tips are communicated in three languages.

What’s the best way to use distillery by-products?

By Isabel Schestak

Cattles in Scotland, photographed by Isabel Schestak

By-product use from malt distilleries has a long tradition in Scotland, where it has probably been fed to cattle and sheep for more than 500 years (Crawshaw, 2001). Recently though, a shift from feed to bioenergy use has been observed, as incentives by the UK and Scottish government for renewable energy technologies have been taken up by the distillery sector (Bell et al., 2019). Though energetic use of by-products brings benefits for a distillery’s carbon footprint, from a water use perspective, also feed use might deserve recognition as environmentally favourable, when the protein rich by-products replace imported feed such as soybean meal. This has been shown already for greenhouse gas emissions, but not been looked at from a water perspective yet.

To find out which by-product use option performs best in terms of water use and to which extend it can improve the water footprint of spirits, we applied a recently developed methodology to the operations of a Scottish distillery. The method called AWARE (Available water remaining) does not only take into account the volume of water consumed for a process or product, but also the water availability or scarcity in the geographical area where the consumption takes place (Boulay et al., 2018). Water consumed in an arid region therefore is weighted stronger than that in a fairly water abundant area such as the UK. It is therefore not just a water, but a water scarcity footprint.

We looked at different scenarios for using spent grains and pot ale: 1) direct use as cattle feed in its fresh form and replacing a mix of imported soybean meal and domestic barley, 2) processing them first to dried distillers grains, thus producing a better conserving and more flexible to use feed before also replacing soy and barley, 3) processing to dried distillers grains but only replacing pure soy protein as feed and 4) anaerobic digestion to biogas, with subsequent combustion of the biogas to electricity and heat, and using the leftover digestate as fertiliser i.e. in total replacing grid electricity, heating fuel and fertilisers.

In the feed scenarios, both soy and barley were replaced in order to substitute an equal amount of protein and metabolisable energy found in the by-products.

First results showed that the water scarcity footprint of whiskey can be reduced by about 20% by using the by-products as either direct cattle feed (scenario 1) or generating biogas (scenario 4). Thus, there is no clear benefit for the use of by-products for renewable energy purposes, in contrast to the suggested reduction of GHG emissions through the government incentivised bioenergy option. The water savings are partially “invisible”, indirect savings though, achieved outside the distillery or even abroad and therefore do not directly improve a distillery’s footprint.

Similar observations have been made by Leinonen et al. (2018), who conducted an assessment on greenhouse gas emissions from different by-product use scenarios from single malt whiskey: in terms of percentage reduction of burdens through by-product use, higher reductions were achieved when by-products were used as feed in form of dried distiller’s grains, replacing soybean and barley feed (40%) than through biogas production and digestate application (27%). Again, these were partially indirect savings connected to land use change for the cultivation of soy abroad.

The study will be expanded to include other water footprint methods and data from further distilleries to enhance the reliability of the results. But already now we may question the environmental benefit from incentivising biogas production from distillery by-products.

References:
Bell, J., Farquhar, J., Mcdowell, M., 2019. Distillery by-products , livestock feed and bio-energy use in Scotland, Sruc.
Boulay, A.M., Bare, J., Benini, L., Berger, M., Lathuillière, M.J., Manzardo, A., Margni, M., Motoshita, M., Núñez, M., Pastor, A.V., Ridoutt, B., Oki, T., Worbe, S., Pfister, S., 2018. The WULCA consensus characterization model for water scarcity footprints: assessing impacts of water consumption based on available water remaining (AWARE). Int. J. Life Cycle Assess. 23, 368–378. https://doi.org/10.1007/s11367-017-1333-8
Crawshaw, R., 2001. Co‐product feeds: animal feeds from the food and drinks industries, 1st ed. Nottingham University Press, Nottingham.
Leinonen, I., MacLeod, M., Bell, J., 2018. Effects of alternative uses of distillery by-products on the greenhouse gas emissions of Scottish malt whisky production: A system expansion approach. Sustain. 10. https://doi.org/10.3390/su10051473

Testing explanatory factors and proxy variables in economic and energy efficiency benchmarking

By Nathan Walker

Evaluating efficiency has many advantages to companies, such as enabling assessment of explanatory factors however, the process of doing so is not always easy. Sometimes missing data leads whoever is conducting the research to utilise proxy variables, which replace the ideal choices.

The explanatory factors* analysed in the study were: leakage, per capita consumption, number of sources, proportion of water through size 5-8 water treatment plants (the largest 50%) and average pumping head height. Leakage and number of abstraction sources were concurrent in their negative effect and significance across both the energy and economic assessments. These results were expected to an extent since for leakage the more water that is lost, the more water needs abstracting, treating and delivering, which all require energy and money. Although diversifying abstraction sources can be a positive attribute for companies to make their supply more resilient, it appears as though this is at the expense of a significantly increased energy consumption owing to more pumping being required through a larger network of piping. Average pumping head height displayed a significant negative effect for energy, whereas the variable proportion of water passing through the largest four treatment works was deemed to have a significant negative effect on economic efficiency. These exogenous factors, therefore, need to be corrected for in future benchmarking activities and have the potential to inform water companies about factors to prioritise in order to improve efficiency.

The proxies that were tested were population served for drinking water and length of water mains, which replaced the output volume of drinking water produced and the input of CAPEX, respectively. These were chosen as they are frequently used as proxies in the academic literature. We found that the proxy population served for drinking water can adequately replace the volume of water produced as an input variable (Figure 1) in efficiency benchmarking when leakage and per capita consumption ranges are minimal since companies stayed at the same rank and explanatory factors displayed the same significance. Conversely, length of water mains performed poorly when replacing CAPEX as an economic input (Figure 2), implying companies were on average 12.6% more efficient, resulting in 10 companies changing their rank compared to the original variable and causing some explanatory variables to differ in direction of influence and significance. Further research is recommended on the energy and economic efficiency of WoCs and WaSCs, considering a wide range of exogenous variables and careful selection of (proxy) indicators.

Figure 1. The energy efficiency results with the primary set of variables, and a volume of water produced proxy (population served for drinking water). WoCs are featured as triangles and WaSCs are displayed as circles. 1 Is the optimum efficiency rank and everything above that is classed as the degree to which companies are inefficient.

Figure 2. The economic efficiency results with the primary set of economic variables, and a capital expenditure (CAPEX) proxy (kilometres of water mains network). WoCs are featured as triangles and WaSCs are displayed as circles. 1 Is the optimum efficiency rank and everything above that is classed as the degree to which companies are inefficient.

The full research with more details on the background, methodology and discussion is available here: https://doi.org/10.1016/j.jenvman.2020.110810

*Only explanatory factor results that showed significant results are discussed here.

Free Sustainability Webinars

What a strange time of the year? Usually, it is time our researchers travel to conferences and meetings to get inspiration and exchange ideas and knowledge. It is also the time we work closely with various stakeholders, including practitioners, academics and policymakers. We are used to face-to-face interaction, discuss emerging problems and come up with potential solutions. This year, we all are facing the challenges of Covid-19 pandemic and staying at home. We start to miss the inspiration, idea exchange and aha moment when we learn new things.

However, this is not a moment which stops us developing a more sustainable environment. Dŵr Uisce is planning to run a series of sustainability webinars. Visit our Twitter @Dwr_Uisce (https://twitter.com/Dwr_Uisce/status/1277517115143204864?s=20) and tell us which webinars you are interested in.

Learning in action: Generating actionable knowledge with stakeholders

Szu-Hsin Wu

In the Dŵr Uisce project, it is part of our innovative culture to working with stakeholders on co-designing, co-developing and co-implement green innovation which mitigate impacts on the environment.

In collaboration with National Trust (UK) and National Federation of Group Water Scheme, Dŵr Uisce researcher and stakeholders have installed micro-hydropower energy recovery system at two demonstration sites: Tŷ Mawr Wybrnant  and Blackstairs Group Water Scheme. The process of achieving green innovation has never been easy and straightforward. We encountered numbers of unknown problems and challenges. Without our valuable stakeholders being patience and continuously engaged in the collaboration process, we could not have achieved what we have today. Various forms of actionable knowledge were generated and accumulated from the process. For example, engineering researchers learned insights from realizing the system design in a controlled setting. Researchers from the management discipline also learned how to communicate innovation performance and commercialise the technology to stakeholders and a wider audience. All stakeholders obtained the codified processed experience from designing in the system, communicating with stakeholders and installing the system that can be used for the next cycle of green innovation.

Generating and accumulating new actionable knowledge was through intuiting, interpreting, integrating and institutionalizing. Through intuiting, engineers identified patterns, possibilities, similarities and differences between the two sites. Through interpreting the results of feasibility studies, we selected suitable energy recovery possibilities within specific domains or environments. Through integrating the knowledge, both the academic researchers and the practitioners developed a shared understanding of the objectives, engineering choices and criteria for evaluation and installed the system. This integration took place through direct interaction among group members in order to attain coherence. The Dŵr Uisce team then institutionalised the learning from Blackstairs Group Water Scheme demon site and leveraged it for Tŷ Mawr Wybrnant site and consolidating the learning for further application.

We know that innovation is rarely a linear process and rarely stop at a point of time. We work continuously and closely with stakeholders on innovation. And in the near future, we hope to share more insights from implementing our Wastewater Heat Recovery Systems at other demonstration sites.