The interaction between a bubble plume and the near-field in a stratified medium: Implications for water quality amelioration

FERNANDEZ, ROCIO; BONANSEA, MATIAS; TESTA, A.; SUBSECRETARÍA DE RECURSOS HÍDRICOS (PROV. DE CÓRDOBA)

Mar del Plata

Simposio; International Symposium on Outfall Systems; 2011

Artificial destratification of the water column is a common means of addressing water quality problems with the most popular method of destratification being the bubble-plume diffuser. The air or oxygen distribution along submerged multiport diffusers is based on similar basic principles as those of outfall disposal systems. Moreover, the disposal of sequestered greenhouse gases into the ocean, as recently proposed by several researchers to mitigate the global warming problem, it requires an analogous design criteria. In this paper, the influence of a bubble-plume is evaluated using full-scale temperature and water quality data collected in the San Roque Reservoir, Argentina. A composite system consisting of seven separated diffusers connected to four 500 kPa compressors was installed at this reservoir at the end of 2008. The original purpose of the air bubble system was to reduce the stratification so that the water body may completely mix under natural phenomena and remain well oxygenated throughout the year. By using a combination of the field measurements and modeling, this work demonstrates that artificial mixing may improbé water quality; if improperly sized or operated, however, such mixing can also cause deterioration. Any disruption in aeration during the destratification process, for example, may result in an accelerate decrease of oxygen levels due to the higher hypolimnetic temperatures.