The present work focuses on the characterization of the wastewater of the Cooperative Laitière du Maroc Oriental (COLAIMO) and to recommend an adequate treatment allowing its reuse, thus reducing the nuisance suffered by the receiving environment and also to remedy the loss of this water source in valorizable materials. The physico-chemical characterisation of the raw wastewater revealed that this liquid discharge is highly loaded with organic matter in terms of COD, which is 3900 mg O2/l, and 2300 mg O2/l of BOD5. Furthermore, the evaluation of the COD/BOD5 ratio = 1.69 underlines the biodegradable character of the COLAIMO wastewater, for which a biological treatment appears to be entirely suitable. Biological treatment processes are diverse, but after a comparative study of the different processes and a technical study evaluating the requirements of the cooperative, the "Sequential Biological Reactor (SBR)" process appears to be the most suitable for this type of industry and is the most efficient. For the implementation of a wastewater treatment plant, a study of the design of the plant before its realization is very interesting.