Applying circular economy solutions in industrial wastewater management: request of SME Associate to develop the necessary energy simulation tools for recovery of waste heat from industrial operations

Global competition for water is increasing and is expected to lead to social, economic, environmental and geo-political consequences. Desalination provides a promising solution for the water crisis but current technologies cause serious environmental impact, resulting in a wastewater effluent called ‘brine’.

According to the United Nations’ Coordinating Unit for the Mediterranean Action Plan, analysis shows that one of the two major emerging threats to the environment around the Mediterranean is the pollution caused by the increased number of desalination plants and the releases and the effects of brine into the Mediterranean Sea.

The managing director of SEALEAU, the company behind the EU-supported BRINE MINING project, is Dr Dimitris Xevgenos. He explains, “A pilot brine treatment system designed in line with the Zero Liquid Discharge principle, was developed by the SOL-BRINE project. The pilot system has a capacity to treat 2 m3 of seawater desalination brine per day and comprises three treatment steps: an evaporator, a crystalliser and a dryer. The energy requirements are supplied by solar energy.”

SOL-BRINE was recognised by the annual LIFE awards, Dr Xevgenos is proud that the project was selected as the best out of 4 306 LIFE projects implemented over the past 25 years, in the Environment category.

The BRINE-MINING project builds on SOL-BRINE’S findings and results and applies them to industrial wastewater. This is done through software modelling and stakeholder engagement, with the aim to promote circular economy solutions. “We want to apply eco-innovative technology developed in our previous EU projects to industrial environments, while exploiting available waste heat.” For industries this means that current limitations to increasing production capacity due to dumping wastewater regulations will be eliminated. This also provides an opportunity to increase production capacity.

SEALEAU identified opportunities to transfer the results into different industrial sectors, using the software tool that was developed within the project. This enables a sound calculation of techno-economic parameters for the industrial cases, as well as possibilities for integration with waste heat. The software tool is still being used to develop innovative projects. “Up until now we have examined 3 case studies: 2 process industries in the Netherlands and 1 coal mine case in Poland.”

Thinking of waste water as a resource, not a problem

It is estimated that 20-50 % of the energy used in industrial processes is lost in the form of hot exhaust gases, cooling water and heat losses from equipment and products. “We can integrate this form of energy into our process and provide a cost-effective way to produce water. At the same time, valuable minerals are recovered that can pro-vide another significant revenue,” explains Dr Xevgenos.

SEALEAU helps industries to provide process water by other sources than local water resources. This alleviates the local water stress and reduces water competition between the industry and other water users such as citizens and agriculture. “By using our technology, industries will increase their water efficiency and improve their Corporate Social Responsibility performance,” says Dr Xevgenos.

The waste water treatment developed by SEALEAU involves three phases involving an evaporator, a crystalliser and a dryer. The evaporator comprises two consecutive processes operated at decreasing levels of pressure, leading to the production of two streams, a water vapour which condenses and is recovered as fresh water and a concentration of particulates, such as brine, which is left behind. The concentrated stream passes to a crystallizer unit to produce slurry. The focus at this point is on energy efficiency through the combined use of vacuum technology and a heat pump. The slurry is then dried out, with solar power being the energy source at this point.

Reference source:request of SME Associate to develop the necessary energy simulation tools for recovery of waste heat from industrial operations