*3.3.2 Planted vertical flow filters*

The wastewater treatment plant by vegetation located in the commune of N'goussa (**Figure 13**). The station is located at the lowest point of the sewage network (**Table 6**). Installed in 2010 and has been in operation since 2011. Use of solar energy pilot project of the WWTP. The characteristics of the releases are typically those of a domestic release. The treatment plant with filters planted with vertical flow reeds is made up of four parallel basins planted with reeds, each basin is divided into three equal parts operating alternately. Each basin is made up

#### **Figure 13.**

*N'Goussa wastewater treatment plant.*


#### **Table 6.**

*Coordinates of vertical flow planted filters stations.*

of three main inlets evenly distributed along the basin (one entry to each part), where each inlet fork tubes intended for supply by tarpaulins. The treated water collects in front of the second basin for reuse in watering the trees of the station and the rest is thrown towards the Sebkha of N'Goussa. The station has a capacity of 11000 Eq/hab and a nominal flow of 1743 m3 /d for a residence time of 3 days for each basin.

This system offers ease and low operating cost with reduced management to a minimum of organic deposits retained on the filters of the 1st stage; and good adaptation to seasonal population variations [13].

Besides the risk of the presence of insects or rodents, managers talk about the constraints of regular exploitation, annual mowing of the aerial part of the reeds, manual weeding before the predominance of reeds.

Using this sector for capacities greater than 2000 pe remains very delicate for questions of control of hydraulics and cost compared to conventional sectors.
