Towards a zero-waste aquaponics-centered eco-industrial food park

Abstract

The scarcity of natural resources, rising energy prices and strict environmental policies are incentives for the food industry to reform current production strategies. As part of this shift, the eco-industrial park concept is gaining momentum. Industrial aquaponics, integrating aquaculture and hydroponics, emerges as a pioneering food production system. Its focus on reusing and conserving resources aligns with eco-industrial parks. The novel concept of an aquaponics-centered eco-industrial food park fits into a biobased circular economy and supports large-scale exploitation to overcome current economic constraints that prevent commercial adoption. However, balancing aquaponics-centered eco-industrial food parks to minimize external inputs as well as waste is challenging. The present study aims to investigate how a quasi-dynamic optimization method can be used in the design of aquaponics-centered eco-industrial food parks under different seasonal weather conditions. The food park encompasses an aquaculture-hydroponic and anaerobic digestion system that mineralizes internal waste streams. The study prioritizes enhancing nitrogen and phosphorus use-efficiency and self-sufficiency. The results unveil specific optimal hydroponic system sizes for a standardized 100 m3 aquaculture volume. Cooler regions thrive around 0.6–1.0 ha hydroponic system, while warmer areas excel at 0.2–0.3 ha with corresponding nitrogen and phosphorus use-efficiencies of 90% and 67% and self-sufficiencies of 88% and 95%, respectively. A supernatant nitrification step with light supplementation improved the design with maximum self-sufficiency and high water use-efficiency of 88% for a hydroponic-aquaculture area-volume ratio of 0.22:100. Complete nitrogen and phosphorus self-sufficient, near zero-waste, food park was achieved by introducing mineralization of chicken manure for a hydroponic-aquaculture ratio of 1.1:100. Moreover, the food park yielded a 6.7-fold lower carbon footprint compared to an optimized traditional on-demand coupled aquaponics system with a hydroponic-aquaculture ratio of 0.15:100.