Legislation worldwide is aiming at a good balance between environmental protection and capital expenditure on water treatment systems. There is a clear trend to move from integral discharge parameters like BOD, COD and Dispersed Oil to more focused approaches aiming at Zero Harmful Discharge. The leading management tools are the Environmental Impact Factor from Norway and the Risk Based Approach being developed by OSPAR. Here the Toxic and Nontoxic contents are recognized. This has led to new water treatment technologies using other separation mechanisms than gravity/coalescence to achieve Zero Harmful Discharge. The Macro Porous Polymer Extraction (MPPE) technology uses liquid-liquid extraction to remove dispersed and dissolved toxic constituents. A real life experience on the disastrous effect of unknown toxic content on the bio treatment confirming the Environmental Impact Factor model will be presented. MPPE treats Offshore produced water since 1994 with a 99% removal performance of dissolved and dispersed Oil, BTEX, Poly Cyclic Hydrocarbons (PAHs) and other non-polar toxic constituents. Examples of applications in the North Sea, Europe (TOTAL, Statoil, Shell) and Australia (Woodside PLUTO, Shell FLNG PRELUDE, Inpex ICHTHYS) will be presented. The trend of aiming at Zero Harmful Discharge is supported by future projects in other Geo areas and other markets like shale oil. Finally benchmark studies on current MPPE units show a structural Mercury removal that is being further investigated.