Sewage treatment protects the receiving water from organic matter, nutrients, bacteria and viruses. The removal efficiency can be explained in terms of primary and secondary oxygen consumption. In Egypt the biological treatment process didn't prevent eutrophication in the receiving water bodies. Phosphorus is often the limiting factor for the algal growth. Today chemical precipitation is more frequently discussed as an alternative or complement to biological treatment. In many closed governorates,(Dakahlia, Damietta, El- Gharbia, El-Monofia, El-Kaliobia,... etc. ), the most crucial factor in erecting biological sewage treatment plants is the availability of land. In this paper the emphasizes will be on the demonstration of the different aspects of chemical sewage treatment as an alternative or complementary for biological sewage treatment, in addition to an experimental investigation for the use of conventional coagulants in sewage treatment through direct precipitation.