Use of biosolids as a strategy for fertilization of water for aquaculture

Abstract

The use of biosolids (BS) was tested, comparatively to dicalcium phosphate (DP), and quail manure (QM), for water fertilization and the production of zooplankton and phytoplankton in experimental tanks. The experiments also included a control tank, without fertilization (WF). The control parameters were: Daphnia sp. biomass, chlorophyll a, water electrical conductivity (EC), pH, dissolved oxygen (DO), temperature, ammonia, organic nitrogen, total phosphorus, calcium and magnesium. The highest weight of Daphnia sp. biomass was found in the tanks fertilized with QM (35.98 g), followed by those with BS (16.80 g), WF (6.75 g) e DP (5.24 g). In general, the results consistently reflected the composition of the fertilizers used and the water quality dynamics in the respective tanks (regarding, mainly, the nutrients’ contents). Chlorophyll a concentrations and Daphnia sp. biomass were apparently correlated, probably reflecting the interactions between the phytoplankton and zooplankton communities. The results suggest that biosolids can be successfully used as water fertilizer for the production of phytoplankton and, consequently, zooplankton.