Limnología de sistemas experimentales de lagunaje para el tratamiento de aguas residuales

Abstract

Biological and physico-chemical characteristics of water treated with two pilot-scale treatment systems based on the development of microalgae were studied. One was a natural pond, the other, a High Rate Algae Pond (HRAP). The natural pond mimics typical processes occurring in hypertrophic waterbodies, where vertical gradients in most limnological variables, organise the biological communities and the processes of interest for the treatment of the water: The High Rate Algae Pond, on the other hand, maintains biomass in constant turbulence. Thus, vertical gradients do not exist and, on the other hand, algal density can be much greater than in the first system, favouring a smaller demand for space by the algae and a higher capacity to process heavily loaded waters. Both systems were studied during two years, treating the same type of wastewater: Results show the HRAP eliminates organic matter more efficiently than the natural lagoon, and promotes greater algae production. The balance of nutrients also reflects the great capacity to eliminate nitrogen of the HRAP and the influence of retention time and pH of the system on depuration efficiency. The chlorophyte Monoraphidium sp. dominated the high-rate system, while in the natural pond both the chlorophyte Chlorella sp. and the cryptophyte Cryptomonas sp. were abundant. © Asociación Española de Limnoloyia.