Compact green dialysis: circular economy approach to advancing sustainability in resource-limited health-care settings.

BACKGROUND

Hemodialysis is highly water-intensive, with conventional reverse osmosis systems discarding approximately 40%-70% of treated water as reject waste. Although high-recovery reverse osmosis upgrades can mitigate these losses, they are often associated with substantial capital investment. Existing green dialysis models also require considerable physical space and, when combined with additional labor costs, are frequently unsustainable, thereby limiting their feasibility across many dialysis units.

OBJECTIVE

To evaluate the design and performance of a compact aquaponic reuse system using existing legacy dialysis reverse osmosis reject water, and to compare it with a previous larger-scale model.

METHODS

A reuse system was implemented within a 39.6 m² corridor adjacent to a dialysis unit. Reject water from a reverse osmosis system was channeled to aquaculture tanks and subsequently to hydroponic columns. Performance indicators included fish survival, vegetable yield, labor demand, water-reuse efficiency, economic outcomes, and comparison with an earlier 310 m² system.

RESULTS

Fish survival was 90% with 180 kg/year yield, while hydroponics produced 90 kg/year. Compared with the earlier model, the compact system used a 7.8-fold smaller footprint yet achieved 2.5-fold higher water-reuse efficiency, 2.3-4.7-fold higher fish biomass, and 7.3-14.7-fold higher crop yield per square meter. Labor requirements were approximately 3-fold lower and operating costs 2.5-fold lower, while net annual surplus was 8.2-fold higher with a 2-fold faster payback period.

CONCLUSIONS

This compact platform demonstrated that dialysis reverse osmosis reject water can be safely and productively reused within a confined footprint while delivering higher efficiency than a larger-scale model.