Production of Chlorella vulgaris Biomass on UV-treated Wastewater as an Alternative for Environmental Sustainability on High-Mountain Fisheries

Abstract

The sustained expansion of agricultural industry in Colombian high-mountain has led to an increased size of residues, especially untreated wastewater. This untreated water is an urgent matter for public and environmental health, not only by its nutrient concentration (composed especially of food residuals and feces) but also the presence of pathogens (virus, bacteria, etc.) which are discharged to the environment. The overall objective of this work is to evaluate the effect of UV-treated wastewater from a high-mountain fishery as culture media for the production of Chlorella vulgaris as a sustainable method for nutrient and water recirculation on the fishery production system. The UV-canal efficiency was evaluated by the implementation of an experimental factorial design (time, distance of the UV-lamps towards the canal, number of UV-lamps and the sample concentration) using STATISTICA 7.0 software. Results shown that time (3 to 5 minutes) and the number of lamps (3-4) of 15 Watts eliminate completely coliforms from the samples. After UV-treatment the resulting water was test as culture media for C. vulgaris production by the adjustment of C/N ratio (Sodium Carbonate/potassium nitrate) by the implementation of an experimental 23 factorial design. Results shown that higher nitrate concentrations (>0,22 g/L) and moderate carbonate concentrations(1 g/L) increase the final biomass concentration up to 4g/L in 20 days.