The problems of wastewater treatment from animals’ farms are presents in agrarian countries, including Moldova. The physical and chemical methods of wastewater treatment are expensive and don’t have expected results. For this reason the base and most reliable wastewater treatment method remains biological. In the results of biological treatment many from waste compounds are transforming in neutral products and biomass. The biological process of wastewater treatment represents the passing of organic and other substances from water to cells and vice versa. The advantage of biological method consists in its simple application and in its cheapness as compared with chemical method. Most of this, in the result of biological method is obtaining biomass, which can be used as feed supplement for the same beards and animals. In the quality of biological agents for the wastewater treatment from animals’ farms we have used selected strains of micro– and macroalgae from phylum Cyanophyta and Chlorophyta: Synechocystis salina, Spirulina platensis, Nostoc linckia, Chlorella vulgaris, Dunaliella salina, Chlamydomonas reinhardii, Scenedesmus acutus, Chaetomorpha linum, Hydrodictyon reticulatum, Cladophora fracta, Dictyosphaerium pulchellum, etc. The selection of this strains have been done in such way that algae to be tolerant at cultivation conditions and in the same time the obtaining biomass to can use in the quality of feed supplement for beards and animals. It have been elaborated the cultivation technology for each strain in the scope of inoculums using for intensification of biological wastewater process. All using us algae species are active assimilating organic compounds and also many toxic substances, eliminating oxygen which is necessary for bacterial oxidation of organic compounds. In such way algal photosynthesis and bacterial biosynthesis make up the bases of biological treatment of natural waters and wastewater with divers origin. The obtaining experimental results are shown that the process of wastewater treatment using algae can be dividing in three steps. In the thirst step in which in water is highest concentration of nitrogen, phosphorus and other nutrients the algalization are done with cultures of Synechocystis salina and Chlorella vulgaris. In this case are disappearing disagreeable smells of these waters. On the second step the algalization are done with species of Chlamydomonas reinhardii, Scenedesmus acutus, S. quadricauda and in the last step in the water are introducing the species of genus: Cladophora, Chaetomorpha, Hydrodictyon. In the results of the using the steps of different species of algae the content of total nitrogen and phosphorus from wastewaters decreasing till 94–99% and obtaining biomass can be used in the quality of feed supplement for beards and animals.