Innovating with the wet oxidation process run by the Veolia, its Epernay-Mardeuil wastewater treatment plant will be able to reuse this solid mineral waste. A first in France!
Using technosand for roads or in the ceramics industry is the technological feat successfully carried off by the OTV run Epernay-Mardeuil site.
On the banks of the river Marne, Epernay boasts an exceptional natural environment and the culture of the most famous French ambassador of all. Champagne. 4,200 hectares of vineyards that support the business of 1200 winegrowers and 1500 companies - the Epernay-Mardeuil wastewater treatment plant was designed and then opened in 2007 in the heart of this landscape.
The site had to meet the specific constraints of the wine business, which produces a large amount of effluent, especially during the grape harvest in September and during barrel washing in January and February. And in addition, spreading effluent is almost impossible in this highly protected area.
It was against this background that OTV, put in place a wet oxidation (WO) process. A first in Europe, it consists of reducing the sewage sludge to a mineral residue, and reintroducing it into the materials cycle. The treated water is discharged without any damage to the natural environment.
Champagne, sludge and ceramics
Upstream, the Athos technology, driven by OTV and Veolia, consists of a first "digestion" stage, which reduces the organic load in the sludge. It is then heated and injected with pure oxygen at high pressure, which destroys the organic substances and leaves just a very small amount of a mineral by-product behind.
The gas produced by the reaction is "clean", the organic liquid obtained is biodegradable and the limited amount of solid residues - composed of clays, limestone and phosphates and known as technosand – can be recycled.
The technosand can now be used in road works for backfilling trenches in the Epernay Pays de Champagne local authority area (7% technosand is added to the sand used in the bottom of trenches to support pipes). It will be possible to re-use 700 metric tonnes of technosand.
It took eight years of technical studies for this use of the residues to be validated. It is a major step forward for the exemplary Epernay-Mardeuil site. With a 77,000 to 150,000 population equivalent processing capacity and 30,000 metric tonnes / year of sludge digested, it was already one of the first sites to use wet oxidation in Europe. And now it’s the first one in France to receive authorization to reuse the technosand produced by this technology. Let’s break out the champagne!
Main picture: Phototheque VEOLIA - Salah Benacer