Measurements Of The Dispersion Of Liquid Industrial-Waste Discharged Into The Wake Of A Dumping Vessel

100,000 t yr −1 of acidic effluent with an organic content of 3–7% are dumped 15 km off the mouth of the River Tees in water 50 m deep. In order to achieve adequate dilution, the rate of discharge of this effluent has been restricted on the basis of calculations made using a formula adopted by the International Maritime Organisation (IMO, formerly IMCO). To ensure that these calculated minimum conditions were achieved in practice, field measurements of waste concentration in the wake of the dumping vessel were made on 3 days under different climatic conditions. The measurements were made by a number of methods, both in-situ and involving analysis in a laboratory onshore. The dilutions calculated from the “IMCO formula” were compared with those found in practice and the formula was found to underestimate dilution in this case. The results obtained are compared with other theoretical and practical studies.