A dirty job: dishwasher wastewater reuse and upcycle through an ad hoc engineered microbial consortium

In the framework of regenerative circular economy and Sustainable Development Goals #6, this study addresses water demand and wastewater production by conceiving the Zero Mile system to reuse and upcycle dishwasher wastewater (DWW) for fertilizing a vertical garden and for the subsequent dishwasher rinsing cycle. The core is a biofilter based on an ad hoc engineered microbial consortium exploiting autotrophic–heterotrophic mutualism to sustain biodegradation over time. Two semi-batch tests evaluated consortium capability and efficiency under Zero Mile–like conditions: volumes of 50 and 500 mL with replenishment every 4 days of one-quarter of the DWW. The consortium thrived in DWW, tolerated volume and replenishment rates, and maintained stable taxonomic composition (NGS). Chemical analyses demonstrated very high bioremediation efficiency (total nitrogen and phosphorus removal). Consortium-treated DWW improved plant fertilization, as shown by pigment contents and quality indices (total phenols, flavonoids, soluble solids) in lettuce grown in the Zero Mile demonstrator and irrigated with reclaimed DWW.

Annamaria Alabiso, Sara Frasca, Valerio Cantelmo, Marco Maria D'Andrea, Roberto Braglia, Francesco Scuderi, Fiammetta Costa, Saverio Savio, Roberta Congestri, Luciana Migliore