a treater for electrostatically and / or mechanically separating emulsified brine from oil during longitudinal flow through a horizontally elongated metal tank , wherein adjustable distributor elements are provided for enhancement of the de - emulsification process . the adjustable distributor elements may be externally operated to more closely control the diffusion and distribution of the flowing emulsion across the transverse area of the treater . the emulsion may be first directed through electrical fields where the brine droplets take on an electrical charge , then move through the distributor elements to electrically grounded coalescing elements . de - emulsified oil is removed in a stream separate from the brine stream . the treater also operates mechanically , with reduced efficiency , when electrostatic operation is unavailable , and can also be operated if coalescing elements are not used . the externally - adjustable , louvered baffles may be accompanied by fixed , non - adjustable louvers at intermediate spacing between the externally - adjustable louvers to provide additional coalescing and flow direction that will enhance dehydration of the process stream , and become an integral extension component thereof .