Journal of Environmental Science and Technology 3 (1): 35-46, 2010
(C) 2010 Asian Network for Scientific Information.
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Assessment of Using Chemical Coagulants and Effective Microorganisms In Sludge Dewaterability Process Improvement
M. S. Shihab
Department of Civil Engineering, University of Mosul,
College of Engineering, Mosul, Iraq
Abstract: The feasibility of using a combination of Effective Microorganisms™(EM) and conventional chemical conditioner was evaluated in this study to assess and discern the dewatering properties of the secondary sludge which was produced from wastewater treatment plant of the medical assebly in Mosul City. Conventional coagulants such as lime, alum and ferrous sulfate, or six doses for each coagulant type i.e., 5-30, 10-60 and 25-150 mg L -1, respectively, were used in the sludge conditioning processes for the enhancement of the sludge dewatering capacity. The characteristics of the conditioned sludge at each dose, such as Specific Resistance to Filtration (SRF), were determined. Experimental results indicated that EM seeds had a passive effect on SRF value which was about 71.4 and 75% in lime and ferrous sulfate respectively. While in the alum conditioning process, a significant effect on SRF reduction was accomplished which was about -47.9 and -32.8% for EM and alum dose increments, respectively. The optimum alum dosage, which gave minimum SRF 0.98348x1012 m kg-1, was 60 mg L -1 at 1% EM. However, a suitable linear relationship has been found to describe the variation of EM and coagulants dosage as a function of SRF.