Mixing of brine waste in Puck Bay (the south Baltic Sea) in the light of in-situ measurements

In the north-eastern part of Poland, the underground gas stores are being constructed by diluting salt deposits. Brine, a by-product of the technology applied, is discharged into the coastal waters of the south Baltic Sea by a system of diffusers. To assess the intensity of brine mixing in the near-field of the discharge installation, a monitoring program was carried out. The results demonstrated that under the mildly dynamic conditions of Puck Bay, the discharge of brine (saturation 250 kg m^-3, discharge 300 m³ h^-1) leads to salinity excess below 0.5 PSU. For parameters of a real brine discharge, the dilution coefficient estimated by formulas derived from analytical solutions, predictive models and laboratory experiments for stagnant water conditions, varied in the range of 123÷360. The dilution coefficient value estimated on the basis of measurements was 1.27÷3.72 times higher than its value obtained by the use of predictive models, while estimated by formulas obtained from laboratory experiments was in the range of 1.41÷2.26 of the dilution coefficient based on measurements.