The increasingly growth of population led to an increase in the number of different industrial plants and to arise in their productive capacity which led to the formation of large quantities of waste products in their gas, liquid and solid forms. These waste products led , in turn , to pollute the air , water and soil. This pollution endangers the whole environment. In this paper we studied one of the aspects of waterpollution used in chemical fertilizers factories and the ways of treatment stations designing and the great role played by these stations in diminishing the great damage caused to rivers , lakes , seas and water –store. This has positively a good effect on environment and economy in general. It is necessary to operate the used-water treatment stations and recycling this water after purifying and refining it within the closed-circuit system effectively and by using modern computerized techniques concerning design , operation and investment. This study is of four chapters and a list of references. The first chapter includes a short glimpse about the treatment stations and their main lines concerning design and distribution. The second chapter is about the sections of the phosphate fertilizers factories and about the acidic water resulting from these sections. The third chapter gives a glimpse about the treatment of polluted water in the phosphate fertilizers factory. The fourth chapter includes the practical section with some designs and results. Finally , a list of the arabic and foreign references.