Nature holds key to nurturing green water treatment facilities

A team of international scientists, led by water engineering experts from the University of Exeter, has pioneered an innovative new method to incorporate ecological processes to allow 'green' water treatment facilities.

The ground-breaking technique centres around creating a distinctive water system that uses both artificial and natural systems, incorporated within the treatment pipeline, to transform potentially harmful elements such as carbon, phosphorus and nitrogen from wastewater into renewable energy and materials.

The system, called REPURE, has the great potential to revolutionise wastewater systems used for agriculture and energy production worldwide in a sustainable manner, the researchers say.

The study is published in the journal Science Advances on 1st August 2018.

Professor Xu Wang, co-author of the paper and part of Exeter's Centre for Water Systems said: "Existing design schemes for wastewater systems focus merely on the technologies. If the system design could benefit from the abilities of nature, it could ensure infrastructure development within ecological constraints and could maximise other benefits.

"Therefore, our REPURE design includes the carbon capture and nutrient retention services provided by soils, as they were found to help reduce adverse environmental effects during the land use of the biosolids and reclaimed water. More importantly, this new design can be promoted in many places, as soil is a major component of the planet and exists in nearly every country."

With the pressure on wastewater facilities increasing due to the increase in populations in cities, more sustainable methods for water treatment are needed.

At present, removing pollutants from water requires a huge amount of energy. Recent figures showed that in the US alone, it accounted for around 3.4% of energy consumption -- making it the third largest energy consumer in the country. In addition, recent estimates point out that approximately 20% of the global demand for phosphate could be met by recovering phosphorus from waste.

The researchers believe that the new REPURE design would allow wastewater to be treated without the need for any energy at all, and also significantly reduce the carbon footprint of the systems, as well as provide attractive feedstocks for productions of renewable energy, fertilizers, biopolymers and other green chemicals.

Professor David Butler, a co-author said: "Restoring and improving harmony between human activities and nature is essential to human well-being and survival, and the role of wastewater infrastructure is evolving towards resource recovery to address this challenge.

"This integrative study advances our understanding and approaches of how to regain the balance between satisfying human demands and maintaining ecosystems."