With a length of nearly 50 km, Annaba coast at the east of Algeria, offers an exceptional maritime front attracting 2 to 3 million tourists each year. It is also a major base of heavy industry in Algeria, including ArcelorMettal, ASMIDAL, Orelait, ENCG which use sea water in their manufacturing process as a direct or indirect receptacle of their discharges, causing its contamination. The wastewater treatment is intended to discharge into the natural environment water of acceptable quality affecting the environment the least possible. In order to further understand the implications, we proceed to a comparative study of the bacteriological quality of coastal waters around the city of Annaba, before and after the commissioning of the first sewage plant located at Lallelick, distant of approximately 10 kilometers to the southeast of Annaba, which has been operating since 2010 with a capacity of 683,000 population equivalent. The results show a decrease in bacterial contamination including that of Total Coliforms, Escherichia coli and Intestinal Enterococci in the summer of 2011, after the commissioning of the sewage plant with respective average rates of 87, 37 and 83 bact/100 ml, against rates up to 1100, 460 and 2400 bact/100 ml of seawater recorded in 2007, 2008, 2009 and 2010. The construction of the sewage plant in 2010 was part of the 2002 national action plan to reduce marine pollution from land-based activities with the enacting of a series of laws, including the coastal Law, the waste Act and the environment Act in the context of sustainable development.
