In the north-central area of Chile, initiatives are being developed to promote small-scale aquaculture and family-based smallholder agriculture farming. However, water scarcity forces us to develop efficient systems with water use. Pilot-scale prototypes were developed to evaluate agro-aquaculture biointegration.
The prototypes have 2 biofilters, one 1 m3 sump , 1 radial settler, one 0.5 HP hydraulic pump, one 1 HP blower, two 1 m3 cylindrical tanks for growing rainbow trout, and four 1 m 3 raceways for the co-culture of lettuce and river prawn.
The prototypes were deployed in four technical high schools, at the Instituto de Investigaciones Agropecuarias (INIA) and at the Universidad Católica del Norte (UCN). The systems operated for 10 months. TAN, nitrite, alkalinity, pH, temperature, and macronutrients were measured. The fish reached 500 g between 8 to 10 months. Lettuces were sensitive to the density of coculture with prawn . The geographical location of the prototypes affected the production of lettuce, with better growth in the coastal area than in the valley area. A differentiated lettuce growth was observed in the raceways associated with the hydraulics of the culture tank.
Suspended solids (SS) removed from the radial settlers were subjected to mineralization in bioreactors with a controlled aerobic and facultative environment. Tests were carried out at concentrations of 20 mL SS/L, 30 mL/L, 50 mL/L, 60 mL/L and 80 mL/L. The SS density and aerobic or facultative condition were determining factors in mineralization to produce micro and macronutrients.
It was concluded that technically and biologically it is feasible to develop biointegrated cultivation of rainbow trout, river prawn, and lettuce. Furthermore, the mineralization of SS allows the generation of nutrients for the development of vegetables.
ACKNOWLEDGEMENT : Research associated to Grant ANID IT20I0066 Director Dr. Germán E. Merino , Grant CYTED P422RT0090 Director Dra. Elisabeth von Brand, and Grant ANID GRC22003 Director Dr. Germán E. Merino