The urban wastewater treatment plant has a role to eliminate
the pollution contained in the domestic and industrials
effluents before their rejection in the natural environment. If
water, at the end of the treatment, was purified, initial
pollution was found stored and concentrated in sludge
resulting from the various water treatment stages. This sludge
can be considered like a recyclable waste and must be eliminated
in laws respect. Sludge management, valorization and
elimination, were problematic as well as the other waste
(OMS) [1]. Several paths exist for sludge treatment and valorization,
but the choice must be tributary of the installation
cost, sludge origin, the added value of the product which
results from it and of the environment impact that could have
the retained path.