Page 34 of the COSCO sustainability report refers to liquid and water disposal as 'slop' and provides its measurement in tonnes.

Beyond the weight of discharge, no more information regarding the contents of this water is given. As such, density, temperature, and pollutants cannot be accounted for, thus assumptions must be made. i.e. the value above stands on the assumption that 1 tonne of 'slop' is equivalent to 1 cubic metre.

(density = 1000kg/m^3 )