The global ornamental fish market was valued at $5.88 billion in 2022 and a compound annual growth rate of 8.5% (CAGR) has been projected from 2023 to 2030. Beyond aesthetics, aquariums offer psychological benefits (e.g., reduced anxiety, stress, and blood pressure), aids in calming hyperactive children and provides relief to Alzheimer’s patients. However, it is estimated that around 65% of users quit the hobby due to challenges in maintaining water quality. Aquariums are enclosed environments, requiring an efficient purification system. Fish excrete organic matter, nitrogen (ammonium (NH4+)), and phosphorus. Existing filters are able to oxidize ammonium into nitrate (NO3-), but this later is not removed, being accumulated over time. Nitrate poses a threat to fish health and behaviour, impacting growth, immunity, reproduction and causing mortality. It also fosters algae growth, further affecting fish health and creating a sense of dirtiness in the aquarium. Phosphate (PO43-) exacerbates algae proliferation and disrupts fish breeding and growth. In order to solve these issues, aquaria hobbyists conduct weekly maintenance routines (e.g. water replacement, algae cleaning) that sum up to 52-104 hours/year and a high water footprint (e.g., 520L/year for an aquarium of 100L).

The Aquaria4All project aims to create an electrified biofilter device (eFilter) designed to effectively eliminate nitrates and phosphates, thereby maintaining their levels within safe values (target < 50mgNO3-·L-1; < 1 mgPO43-·L-1). This innovation aims to significantly decrease the necessity for aquarium maintenance and water replacement (UN-SDG6). The eFilter uses minimal amount of electricity as the sole external input, thus suppressing the need of chemicals addition (UN-SDG12). Instead, it takes advantage of electroactive bacteria, which can remove pollutants by exchanging electrons with an electrode (Microbial Electrochemical Technologies, METs). The IP of the research team on nitrate electro-bioremediation (EP2925679B1) will be used as a basecamp for developing the device for both nitrates and phosphates removal, while keeping the other key parameters under control (e.g., target NH4+ undetected).

Aquaria4All innovation will guarantee fish health, thereby diminishing the demands of aquarium maintenance and the need for frequent water replacement (i.e., lower water footprint). Aquaria4All will democratize this hobby and the access to their psychological benefits (UN-SDG3, UN-SDG4).