Environmental Risk Analysis as an Approach to Achieve the Sustainability for Lake Mariut, Alexandria, Egypt

Until the eighties, most of Alexandria’s domestic sewage and much of the industrial wastewater were discharged directly into the Mediterranean Sea through a number of outfalls along the coast of Alexandria. Pollution of beaches and the inshore waters caused severe impact on Alexandria as a summer resort which forced the local authorities to divert these discharges into Lake Mariut‘s Main Basin. At that time, the discharge consisted of raw sewage without any treatment what so ever mixed with industrial effluents. The lake’s main basin became highly eutrophic and polluted with various chemicals. In addition to the problem of organic inputs, there were many hazardous discharges. Latter, two primary treatment plants were built and started operation in the nineties. The sewage water passes through screens and then sedimentation tanks and a dewatering facility to remove the sludge. Furthermore, some untreated wastewater is discharged directly into the Lake. Excessive eutrophication of lakes is a serious international problem. There has been a great need for a comprehensive information source usable in developing future rehabilitation/protection program.