Dephosphatation biologique et denitrification d'effluents piscicoles marin et dulcicole par reacteur sequentiel a lit mobile avec bac de concentrat.

摘要

The partially closed circuit (PCC) is a means of reducing water consumption by fish farms. However, the accumulation of dissolved pollutants leads to sanitary and environmental problems. To reduce the concentrations of nitrate and phosphate in such systems, an original biofilm process operated as a sequencing moving bed reactor coupled to a concentrate stock tank has been developed. This process aims to use a phosphorus-removing and denitrifying biomass to transfer phosphates from the water to be treated to water external to the CPF. This external water is maintained under anaerobic conditions and is stocked in a tank adjacent to the biological reactor. After modeling the process using ASM3 and the EAWAG BioP module to validate the implementation of the system, a first experiment was conducted to treat water from the St. Lawrence Mesocosm (SLM). This salt water ecosystem reproduces the estuary and golf of the St. Lawrence River at the Montreal Biodome. This experiment did not allow the growth of a phosphorus-removing biomass as had been predicted by modeling, possibly because of the high calcium concentration in the water. To confirm that the process itself was not at issue, a second experiment using a synthetic fresh water effluent yielded a 20% phosphorus removal, lowering the concentration from 14.2 mg P/L to 4.7 mg P/L. These performances remain inferior to those mentioned in the literature for similar systems but several parameters seem to be improved to enable better performance of this process.