The
elected officials had chosen not to rebuild their new station on the
same land as the old one, located on the edge of the Eure but enclosed in the
urban area. The new site, close to the incineration plant, was established
5 km away and 40 m above the discharge point. This situation
imposed a lifting of raw water that consumes a lot of energy.
The
group therefore imagined to partially compensate for this load by using
the energy produced by the treated wastewater. After a long administrative journey,
this proposal can finally be implemented by the operator Cm
Sanitation, a joint subsidiary of Aqualter and Chartres Métropole.
–
The
solution adopted consists of turbinating the water which descends to the
river by a pipe parallel to the discharge point. The turbine is one
200 kW power and a nominal flow rate of 800 l / s.
A
bypass and a safety valve were installed to allow the shutdown of the
turbine if necessary.
The
implementation of the solution requires a 5-year sales contract for
the energy produced, signed by the operator with the company ENERCOOP which
locally promotes renewable energy. This agreement will
produce 400,000 kWh / year and save 36 tonnes of CO2 by
year.
This
production of renewable energy is part of a more global desire
of circular economy: the wastewater treatment plant of Chartres Métropole produces
also heat from purified waste water, its sludge is dried
using solar energy, and a study is underway to reuse water
refined.
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