Characterization of Sludge Produced by Treatment of Water from the Ribaa and Bittit Karstic Springs (Meknes, Morocco)

Abstract

Problem Statement: Surface Water Treatment for potable supplies typically involves coagulation, flocculation, and processes. All water treatment plants produce sludge, during the purification of raw water, according to the level of the water turbidity. The aluminum sulfate is the most common coagulant used in water treatment plants of Morocco, as well as in many countries all over the world. It is difficult to manage sludge produced by the treatment plant. However, several studies, based on a set of jar test experiments, have demonstrated that it can be used in the process to improve the quality of the treated water and reduce the aluminum sulfate dose. Approach: In this study, the raw water treated and sludge produced in water treatment plant of Meknes, Morocco are investigated for chemical and bacteriological proprieties. The texture characterization of the dried sludge produced through the process of coagulation/flocculation and that of aluminum sulfate, used as coagulant aid, are obtained by nitrogen adsorption isotherms. Results: The physical properties of the raw water indicate its high turbidity during periods of heavy rainfall in the Bittit and Ribaa springs catchment area. However, these chemical properties indicate the quality of fresh water rich in magnesium, related to the dolomitic nature of the liastic aquifer. The bacteriological analysis of sludge produced in the treatment plant, confirms the elimination of pathogenic germs by the treatment process used. As regards the texture characterization the results demonstrated that the sludge presents some similarities with the sulfate. However, a clear difference is observed between the two solids, according to the pores distribution. Conclusions/Recommendations: Taking aluminum sulfate and sludge in comparison, it is possible to use the sludge for improving the coagulation process in water treatment.