Evolution Of Physico-Chemical Parameters And Pathogenic Microorganisms Of Sludge Of Dar El Gueddari Wastewater Treatment Stations (Morocco)

IJEP 41(7): 785-789 : Vol. 41 Issue. 7 (July 2021)

H. Griou*, S. Njimat, M. Aboulouafa and S. Ibn Ahmed

University Ibn Tofail, Laboratory of Materials, Electrochemistry and Environment, Faculty of Sciences, Department of Chemistry, Kenitra, Morocco


The purpose of this study is to evaluate the effect of the storage of sewage sludge in Geotube® on the physico-chemical and microbiological parameters of the sludge resulting from the cleaning of the anaerobic basins of the Dar El Gueddari treatment plant between October 2013 and May 2017. The results obtained during this study revealed an increase in the pH of sludge from 6.5-7.2 and a gradual reduction in odour according to the drying time. The dryness reaches an optimal value of 76%, the variation of the C/N ratio goes from 9.62-11.80 (lower than 15), which indicates that these sludges have fast mineralization of organic matter. For nutrients, there was a slight decrease except for total nitrogen, which dropped from 1.3 to 0.8 ppm. The contents of metallic trace elements (Cd, Cr, Cu, Hg, Pd and Zn) and the organic trace components [7 PCBs (28, 52, 101, 118, 138, 153, 180)], fluoranthene, benzo(a)fluoranthene, benzo(b)fluoranthene are in small quantities and well below the French regulatory standards. For the microbiological component, the obtained results showed a decrease in the bacterial load over time and it is eliminated completely from the second year. The so-called dewatering treatments applied to sludge play a major role in the elimination of most or all pathogenic micro-organisms.


Sewage sludge, Physico-chemical, Microbiological parameters, Wastewater


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