Techno-economic performance assessment of malt-dust-derived biochar application for municipal wastewater treatment: A water reuse strategy

Waste reduction and recycling are two of the main strategies which have favorable effects in terms of a circular economy, and they are one of several environmental remedies included in the European Union's (EU) Green Deal. Also, the EU Blue Deal is aimed at the protection of vulnerable freshwater resources and includes recommended water reuse applications. Biochar is an innovative and effective technology for several environmental applications. From this point of view, malt dust, which is a by-product of the brewery industry, has been used as a biochar feedstock for the treatment of municipal wastewater in order to achieve a reclaimed water quality. A techno-economic performance assessment was carried out to reclaim water using this novel adsorbent. This paper mainly aimed to obtain reclaimed water using biochar application, with an aim of contributing to a circular economy. An average reduction of 41.4% in operational costs was reported compared to an activated sludge system. Turbidity, Biological Oxygen Demand (BOD₅), Total Suspended Solid (TSS), and E. coli analyses were performed to determine the effluent quality. In the end of the biochar adsorption process, a Class B reclaimed water quality according to EU legislation was obtained. This study validated that malt-dust-derived biochar is an efficient and low-cost adsorbent and can achieve a high quality of reclaimed water.