Many industrial sectors, such as agro-food, leather tanning or oil and gas use water for their operations and production processes. As a result of this, large quantities of wastewater that contains both, high amount of salt and organic pollutants are generated. In fact, approximately 5% of the globally produced wastewater is saline and this amount is expected to increase. For removal of organic pollutants from non-saline wastewater typically biological processes are used, in which microorganisms (bacteria) convert the organic pollutants, thereby preventing their flux into the environment. However, for removal of pollutants from saline wastewaters typically more expensive physical-chemical methods are used that require a large amount of chemicals, energy and produce hazardous sludge. The more expensive processes for saline wastewaters are typically chosen, because the cheaper – biological – process is hampered due to salt toxicity towards microorganisms. In this research we demonstrated the possibility of applying a biological process at high salinity during which organic pollutants of saline wastewaters are converted into biogas, that can be further used for energy generation. Both, insights into microbial adaptation to high salinity and the biological process performance under saline conditions were studied.