Our society relies heavily on water to support human life and the earth’s ecosystems and climate, but it is also a ubiquitous resource which is embedded in all economic activities – particularly in agriculture, energy production, and in manufacturing.
We draw water from its natural cycle and use it to supply homes, industry, leisure activities, and to sustain our food production. Water is used both as a direct resource, but also as an indirect vector for transporting heat, minerals, nutrients and organic matter. Water therefore cascades through this artificial urban water cycle before being returned to its natural global environment.
Both water quantity and quality are threatened by increasing pollution, climate change, extreme weather events, and population growth – in particular urban population growth. In the EU an average of 40% of water consumption is used for food production, and another 40% is used for energy production and manufacturing. Hence, water scarcity and poor water quality could lead to potentially disastrous consequences for our society. The potential financial losses faced by industry and economic activity, and the potential threats to public health, sanitation, and to social and political stability are significant.
Water in the circular economy
These economic and environmental concerns have led to the emergence of alternative market models that promote a sustainable, low carbon, resource efficient and competitive economy. A key example of this is encompassed by the principle of a Circular Economy. This concept focuses on preserving the value of products, materials and resources, by actively maintaining them in economic cycles for as long as possible to minimise waste. This requires different sectors to work together with an integrated system approach, to find opportunities for alignment of interests, be it in collaboratively designing an optimised supply chain, in finding mutual interests for exchanging resources, or in creating innovative business models and engaging customers.
Whilst the concept may be extremely appealing, as it speaks to the growing values of sustainability and new opportunities for economic prosperity, there are a number of challenges to be overcome. Defining the appropriate regulatory framework that enables different sectors to collaborate and exchange value, defining appropriate quality parameters for recycled or recovered materials, and, most importantly, inspiring a common vision that can help overcome the initial activation energy for businesses and society to adopt a systemic change, are all essential to enabling a circular economy.
The European Commission (EC) has recently published an Action Plan for the Circular Economy. This is an initial platform with a number of proposed actions that should be embraced and amplified by national, regional and local initiatives, and also across different sectors. At the last meeting of the European Parliament’s Group on Water on 26 January 2016 in Brussels, Esther de Lange (MEP) stated that water would be the natural starting point for a circular economy when discussing this important new economic model.
In fact, with water being such a ubiquitous resource across social, industrial and economic activities, the preservation of water within a long lived urban water cycle is a perfect example of the concept of a circular economy. This stimulates the need to reduce both our dependency and impact on the natural water cycle, and yet at the same time to create the opportunity for water to be exchanged and recycled throughout different activities, with the increased added-value of resource recovery, and in particular energy production.
The European Commission recognises the crucial need for a shared and consensual regulatory framework and standards to facilitate the creation of value from waste products, and is currently focussing on revising and integrating the directives and national legislation to provide a common approach to fertiliser production from waste, and water reuse – in particular for artificial groundwater recharge and for irrigation.
This requires a commitment to produce or review standards and guidance documents on the minimum quality parameters acceptable for such products in order to manage risk – in particular with respect to the dispersion of emerging pollutants or pathogens. In parallel with this, the Commission is encouraging a systems-thinking approach, where it is incentivising water efficient technologies and practices, documented through the BREF documents for each industrial sector (BREF: Best Available Techniques (BAT) Reference documents). This reinforces the need for control of pollution at source by regulating and tracking chemical use in industry through programmes such as REACH.
To facilitate this the EC has allocated a number of funding tools to support research and demonstration projects through their LIFE programme, and more broadly their Horizon 2020 funding instrument. It has also provided funding to national and regional governments and businesses during this transition via instruments such as Industry 2020 in the Circular Economy, Structural and Investment Funds, and the European Fund for Strategic Investments.
Opportunities for water
Whilst both the European Commission and national and regional Governments are setting the scene with a much needed vision, financial incentives, and an appropriate regulatory framework, we are still at the beginning of this journey and there are a number of opportunities for water in the circular economy that are yet to be optimised, or even identified in the first place.
The key principles are to reduce water consumption through water efficiency measures, to reduce water pollution at point of source, to separate and treat contaminated waste streams rather than diluting them, and to promote water conservation through customer education and leakage reduction using smart metering and monitoring. In terms of water utilities, both drinking water production and waste water treatment produce different kinds of wastes or residues.
Examples are coagulation sludge (iron or aluminium oxides), softening sludge or pellets, waste activated sludge etc., not to mention other redundant or past end-of-life infrastructure such as old water distribution mains or sewer pipes. The circular economy principles also require the water sector to change the way of disposing of their residuals by considering new business opportunities for recovery of resources such as nutrients, mainly phosphorus but also nitrogen, critical materials and minerals, carbon, and energy.
In many countries activated sludge resulting from waste water treatment is spread on agricultural land. At one level this gives a benefit by providing a renewable source of fertiliser, but there are also disadvantages. In the first place the sludge has to be stored until farmers come to collect it for spreading onto their land. Furthermore, collecting and transporting it to the land is relatively expensive and has a high carbon footprint, due to the large volumes that need to be moved.
Secondly, activated sludge is actually not a high quality fertiliser as the nutritional potential is often unknown due to variable quantities of nitrogen and phosphorous, which are often not in an optimal ratio. Modern agriculture has very precise requirements for optimisation of crop production, and these are very difficult to meet when using activated sludge as a resource. Finally the sludge has additional constituents that can pose environmental or health risks. Land application can lead to run-off of nutrients and pathogens to surface water, and residual pharmaceuticals can end up in the food chain.
An alternative to land application of sludge is to adapt the waste water treatment process so that nutrients are recovered during treatment. In this way a much higher quality fertiliser can be produced, and the disadvantages mentioned earlier can be reduced or eliminated. The enhanced revenues from this new fertiliser product can be used to offset the investment for additional treatment steps. The newly proposed measures on a circular economy model from the EC allow some of the barriers to implementation of such a process to be reduced.
Amongst other projects, the Water Innovation and Research Centre at Bath is collaborating with Wessex Water and GENeco at Bristol Waste Water Treatment Plant (WWTP) in the UK in order to enhance the renewable energy and low emissions benefits from the generation of biogas during waste water treatment. The opportunity is to turn the ‘waste’ concept on its head, and view waste water, sewage biosolids, and food processing waste streams as a source of water, energy and nutrients that can be recovered for reuse in higher value or sustainable opportunities.
A second example of value recovery is production of iron rich sludge during groundwater treatment. This material often contains large amounts of water, requiring large storage volumes and long durations for dewatering prior to disposal. In many cases the material is processed into construction materials, for instance for road foundations, but this route to disposal is expensive. Recent research has indicated that the sludge can be processed into a granular filter material that can be used for phosphate removal from surface waters to prevent eutrophication, and thus added value is generated.
A third example comes from the Netherlands, where water utilities apply centralised softening using fluidised bed reactors. These reactors produce small spherical calcium carbonate beads, known as softening pellets. Centralised softening has been in the Netherlands for more than 25 years, and many benefits for water quality and the environment and a reduction of societal costs are apparent.
This is only the starting point on a long journey, as businesses need to recognise this opportunity as a viable option for the near future. This means a dramatic change from ‘business as usual’. There are a number of examples that can serve to inspire, in particular the Kalundborg site illustrates a successful industrial ecology project, or as they call it – Industrial Symbiosis. Since 1995 different industries and businesses in the small industrial city of Kalundborg, Denmark, have recognised the enormous value that lies in effective communication and collaboration. They have found economically viable solutions that provide mutual benefit via both economic growth and environmental protection.
The project leaders emphasise that the key ingredient is people and healthy and open communication. So how can we promote this approach across all different sectors and communities?
One possibility is to encourage the use of accelerators and incubators that link different people, businesses, authorities and academia, as is the in case with the Milwaukee Water Council. This would be a viable way to rethink the shifting paradigm from ‘water utilities’ to ‘resource recovery facilities’ to ‘resource production hubs’. This would enable the utilities to collaborate through public-private partnerships and with specialised SMEs to create different opportunities for sharing resources from nutrients, energy, oils, minerals and rare-earth metals, and even water itself. This would address the difficulty in setting up the supply chain at an appropriate scale, since often the volume of residuals from individual water utilities is too small to create a viable supply chain.
Also the investment costs for a residuals processing facility are too high and the lone water utility may lack the expertise to operate in the new market. This approach would also allow better regional or national management of resources to secure a constant production stream.
The above examples show that water utilities can adapt to a circular economy, where waste and residuals can be seen as resources for new added value products. In some cases this requires adaptation of water or waste water treatment processes, and corresponding economic models, but there are no significant technical barriers. Of course investments in additional technology are needed, but in many cases proof exists that a positive business case can be achieved.
It is clear that these new European policies require the water sector to be proactive and respond to the targets set by the Commission. Innovation will not happen in one day and a multi-disciplinary approach is needed, involving technical, environmental, managerial, policy and economic research.
Published: 16th Feb 2016 in AWE International