Innovative and scalable

Innovation

Septage treatment in an extensive on-site system is rarely practiced, with only two small-scale capacity applications in France and less than ten known uses abroad. However, returns from the French plant of Beaumont-la-Ronce in Indre-et-Loire and from pilot plant tests in Andancette in Drôme are encouraging.

Pioneer work of the MV82 project is complemented by structural innovations of the treatment process.

Decanting: adapting of existing equipment and practices to the particular context of Nègrepelisse (high number of watertight pits, seasonal character of septage collection etc.)

Pretreatment: adapting of existing systems to a new treatment process.

Constructed wetland: no septage treatment application at this scale, neither in France nor abroad

Treatment in existing ponds: no septage treatment application known at this scale
Spreading on a tree plantation: no application at this scale and no septage treatment worldwide.

Scalability

The plant is designed to treat 11 000 m ³/year. This capacity can be increased if necessary by construction of additional reed beds to the north of the initial plant. Stand-by sewers are foreseen to allow additional beds to be connected.

Download the diagram
of the septage treatment plant.

This extension will not be implemented for several years as the structures build in 2011 are sized with several security margins. For example:

• the total volume of the decanting pit is larger than the common truck volume (20 m ³>10 m ³)
• the storage tank is sized for a storage time of six days, larger than the minimum recommendation of 1 or 2 days
• the filters are sized for a rather low loading rate of 50 kgTS/m². year.