In the past five years, treatment systems in several major and smaller urban centres have undergone significant improvements ( Fig.
Au cours des cinq derniÃ¨res annÃ©es, des amÃ©liorations notables ont Ã©tÃ© apportÃ©es aux systÃ¨mes de traitement de plusieurs petits et grands centres urbains ( figure 4.5).