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The main drive for establishing a CE is the present environmentally unsustainable ‘take-make-consume waste’ economic system
The circular economy (CE) concept has gained considerable global attention during the past decade among private and public sectors.
However, despite their vital role in practically all human activities, water and water-related ecosystems have been largely missing from conceptualisations and scientific definitions of the CE.
A water-smart CE would serve multiple purposes, including:
reduce losses of water, energy and valuable substances,
improve water efficiency and productivity,
reuse treated wastewater, and
better protect and lessen pressure upon water-related aquatic and groundwater ecosystems.The main drive for establishing a CE is the present environmentally unsustainable ‘take-make-consume waste’ economic system.
Climate change, environmental degradation, biodiversity loss and freshwater scarcity are increasingly challenging problems. The CE is, therefore, generally regarded as a system-level proposition to correct problems arising from present consumption and production patterns.
Resources are maintained for as long as possible and used for different purposes, opposing the current linear pattern of production and consumption in the circular system. A circular economy offers an alternative economic model, whereby natural resources, including water sources, are kept at their highest value for as long as possible.
A smart water circular economy considers water abstracted from the environment for various economic purposes as well as water-related ecosystems. The concept will also identify circular solutions directly connected to water and water-related ecosystems and the risks posed by the CE to these ecosystems.
Illustrating a water circular economy
A general framework, proposed by Salminen et al, (2022), is based on several principles and stats regarding sustainable water resource use. This includes water abstraction from surface and groundwater sources that must occur within the limits of the renewal rate of the water resource.
For instance, at the level of an individual aquifer, abstraction must not result in a continuous decrease in the groundwater level. Another example is the abstraction of surface water, which must not threaten the sufficiency of environmental flows and water abstraction for other human activities.
Losses, including abstracted water leakages and nutrient losses due to transport by runoff waters from agriculture, must be avoided.
Water abstracted to the technosphere must be used efficiently. To achieve this, closed circulation and reuse within production sites can be applied.
Substances dissolved in process waters are utilised at production facilities. Substances harmful to the environment, such as pharmaceuticals or toxic chemicals, are removed from wastewater at an appropriate stage to minimise their environmental impact.
Towards this end, local, facility-specific treatment technologies are applied to decrease the load of harmful substances in sewerage and centralised wastewater treatment plants (WWTPs), which are generally not optimised to remove such substances. Accordingly, WWTP operations and the quality of recovered substances are improved.
Energy absorbed and substances dissolved in wastewater are recovered at WWTPs. Appropriately treated wastewater can be reused in, for instance, manufacturing industries and aquaculture, for sanitation, for the irrigation of crops or green areas, like golf courses, or for the generation of artificial recharge.
In all cases, however, risk identification high standards must be maintained, and assessment and management must monitor the microbiological and chemical quality of the reused water, thereby ensuring the environment and human health are protected and that – at a minimum – legislative requirements are upheld. ESI |
