4. Conclusion
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The sludge lagoon studied in this work has proved effective for biogas production.
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The biogas production kinetic followed closely the anaerobic digestion phases:
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Hydrolysis-acidogenesis and acetogenesis which lasted 5 and 2 days respectively.
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Methanization in our conditions started from the 7th day. In this last phase we noted the gas flammability which gave a minimum rate of 45% methane.
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The digestion process has been boosted by the VFA and TA presence where the ratio did not exceed 0.5.
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The COD, BOD and TS reduction yields were 88, 90 and 81% respectively, followed by a total pathogenic flora destruction and particularly E. coli.
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Biogas efficiency during the anaerobic digestion was 30 Nml biogas/mg COD removed. This quantity corresponded to an energy production equivalent to 30.95 kWh per year.