The MV82 plant (STP) - The performances

The septage treatment plant MV82 exports sludges comparable to an agricultural enrichment compost and treated waters whose quality is comparable to those of Nègrepelisse’s WTP, corresponding to the same dumping norm.

The dumping norm

The plant’s efficiency regarding the dumping’s quality are imposed by a law on water (Dossier Loi sur l’Eau-DLE) with an official authorization. Expected contents:

1. During summer: no dumping
2. During winter: at the exit of the two ponds BOD5 filtered < 25 mg/l; COD filtered < 125 mg/l; SS < 150 mg/l.

Conclusion: the septage treatment plant MV82 rejects very little polluted water.
The MV82 project’s impact on the streams’ quality is marginal.
Indeed:

• The contributions to the environment are only in winter, when the natural flows are higher
• Regarding the daily volumes, the MV82 dumps represent 4.5% of the commumnal treatment plant’s dumpings for 4000PE, and 3% of the treatment plant’s dumpings for 6000 PE, for the same quality.

Filtrates quality

Expected filtrates quality at the constructed wetland outlet (in brackets: median value/ distance type measured on the Andancette STP’ pilot filtrates in 2007)

• COD : 1000 mg/l (1200/3558 mg/l)
• SS : 1000 mg/l (632/3202 mg/l)
• TKN : 100 mg/l (62/166 mg/l)
• NH4 : 30 mg/l (17 mg/l soit 27% de 62 mg/l)
• NO3 : 50 mg/l (29 mg/l soit 47% de 62 mg/l)
• Pt : 40 mg/l (36/41 mg/l)

High contents but these waters aren’t rejected in the receiving water.

Consult
all files's list