The environmental study of the sewage plants in Madinah, Tabuk and Buraidah, where the study includes the work of collecting samples and preparing reports according to the requirements of the National Center for Environmental Compliance to issue environmental permits. This includes preparation of environmental studies for the emergency outfalls of each plant, as well as preparation of environmental study of the treated water transport system, tanks and pumping stations in order to benefit from the treated water from those plants.