Why is there a pile of dirty plates floating in the river in Bilbao?

• A sculpture representing a huge pile of dirty dishes as tall as a three-storey building is the core of a campaign by ACCIONA Agua to raise awareness about rational water consumption
• The 'Turn off the tap' campaign aims to raise awareness of the environmental and economic effects of the fact that each Spanish household generates an average of 1,000 litres of waste water every day

This morning, Bilbao woke to discover a giant pile of dirty dishes anchored in the river opposite the Euskalduna Conference Centre and Concert Hall; the sculpture, measuring 9 x 9 metres, is as tall as a three-storey building. It is part of ACCIONA Agua's 'Turn off the tap' campaign, which seeks to raise citizens' awareness of the need to consume water in a more rational way. The initiative is ACCIONA Agua's contribution to World Water Day, whose theme this year is waste water treatment, one of the major environmental challenges of our time.  

In Spain, each family generates a daily average of 1,000 litres of waste water, which have to be treated in sewage plants, with the resulting energy consumption and environmental impact. As a result, ACCIONA Agua, for which sustainability is a core value, wants to emphasise the importance of citizens being aware of their water consumption and the direct effect it has on the sustainability of the water cycle.  

This year, the main theme of World Water Day is Waste Water, as the United Nations' objective is to raise awareness of the urgent need for water to be treated and, as far as possible, reused. The goal is to motivate achievement of one of the Sustainable Development Goals: 'improve water quality by reducing pollution, eliminating dumping and minimizing release of hazardous chemicals and materials, halving the proportion of untreated waste water and substantially increasing recycling and safe reuse globally'.  

Only 20% of the waste water produced worldwide is treated properly, and there is a large gap between developed countries (which treat more than 70% of their waste water) and developing countries (which treat 8%). The consequences are not only environmental — failure to treat waste water affects public health and economic development. According to the UN, at least 1.8 billion people use a source of drinking water that is contaminated with faecal matter and close to 1,000 children die every day from preventable diarrhoeal diseases related to water and sanitation.  

To meet this challenge, it is necessary, on the one hand, to raise awareness about responsible water consumption so as to minimise the production of waste water, and, on the other, to develop water treatment technologies that are increasingly sustainable, in both economic and ecological terms.  

ACCIONA Agua has built more than 300 waste water plants, with a capacity of more than 13.5 million m3/day, serving more than 55 million people. Among its most famous waste water plants are Atotonilco (Mexico), the world's largest, and La Chira (Lima), which is helping to regenerate a stretch of coastline that was environmental impaired and socially impoverished.  

ACCIONA Agua is a leader in research to improve waste water plant efficiency by reducing energy consumption and improving the scope for reusing treated water. Its Barcelona R&D centre has participated in leading European research projects such as LIFE + RENEWAT, whose aim is to synchronise waste water treatment processes with built-in renewable energy systems to reduce plants' energy dependence by up to 30%;  the LIFE + Brainymem project, which, in addition to reducing energy consumption and greenhouse gas emissions, will reduce the concentration of recalcitrant pollutants (chemical residues) in waste water; LIFE + Celsius, which is developing a waste water treatment system for warm climates with an emphasis on low energy consumption; and LIFE+RAMSES, which intends to increase the quality of water for reuse at a lower cost using new approaches, the aim being to address Europe's water deficit.