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

Abstract

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.

Keywords

Sewage sludge, Physico-chemical, Microbiological parameters, Wastewater

References

  1. Hiroux, G., G. Lefevre and M.A. Gaffet. 1983. Organic composition and decomposition in the soil of mixed sludge from an urban wastewater treatment plant. Soil Sci., 1:17-26.
  2. Krogmann, U. 2001. Composting : Sludge into biosolid : Processing, disposal and utilization. In Sous la direction. Ed L. Spinosa and P.A. Vesilind. Iwa Publishing, Londres, R.U.
  3. Jebari, H. 2014. Sludge management from the Grand Nador wastewater treatment plant. Workshop on the management and recovery of sludge from ONEE-Water branch, Rabat, Morocco. Proceedings, pp 15.
  4. Boudreault, P. and J.F. Blais. 2002. Optimization of STABIOX technology for the stabilization, deodorization and improvement of the dewatering of paper mill sludge. Workshop on R and D in waste recovery, Sainte-Foy Quebec. Proceedings, pp 122.
  5. Haut-commissariat plan. 2014. General population census : City of Dar El Gueddari.
  6. BRL. 2015. Update study of the master plan for integrated water resources development in Gharb plan. BRL ingeniere.
  7. ISO 10390. 2005. Soil quality determination of pH.
  8. AFNOR, NF ISO 11265, X 31-113. 1995. Normadoc.
  9. BS EN 13342. 2000. Characterization of sludges. Determination of Kjeldahal nitrogen.
  10. ISO 16649-2. 2000. Microbiology of food and animal feeding stuffs-Horizontal method for the enumeration of beta-glucuronidase-positive Escherichia coli–Part 2:Colony count technique at 440C using 5-bromo-4-chloro-3-indolyl beta-D-glueuromide.
  11. IMANOR NM ISO 6888-2. 2016. Food microbiology : Horizontal method for the enumeration of coagulase positive staphylococci Staphylococcus aureus and other species. Part 2 : Technique using gelose medium with rabbit plasma and fibrinogen.
  12. ISO 11290-1. 2017. Microbiology of the food chain-Horizontal method for the detection and enumeration of Listeria monocytogenes and of Listeria spp. Part I : Detection method.
  13. ISO/TS6579-2. 2012. Microbiology of food and animal feed–Horizontal method for the detection, enumeration and serotyping of Salmonella. Part 2: Emumeration by a miniaturized most probable number technique.
  14. ONEE, 2013. Sludge spreading plan from the Dar El GueddariWWTP.
  15. Noble, C. 1997. Treat and recover sludge. OTV.
  16. Rigby, H., et al. 2016. A critical review of nitrogen mineralization in biosolids-amended soil, the associated fertilizer value for crop production and potential for emissions to the environment. Sci. Total Env., 541:1310-1338.
  17. Tremblay, J., et al. 2008. Storage and long-term stability of municipal sewage sludge decontaminated and stabilized by chemical or biological means. J. Env. Eng. Sci., 7(4):357-368.
  18. Tu, J., et al. 2012. Heavy metal concentration and speciation of seven representative municipal sludges from wastewater treatment plants in northeast China. Env. Monit. Assess., 184(3):1645-1655.
  19. ONEE. 2004. Characterization study of wastewater in the city of Dar El Gueddari.
  20. Berthou, M. 2010. Evaluation of the efficiency of filter gardens® for the treatment of urban and industrial sludge. Ph.D. Thesis. Universite ‘Henri Poincare’; INPL-Institute National Polytechnique de Lorraine.