**4.1 Activated sludge**

The Touggourt wastewater treatment plant (**Figure 14**) is located in Ben Yassoued (**Table 7**), in the municipality of Tebesbest. It covers an area of 5 hectares. It was commissioned on 20/11/1993 and rehabilitated in 2004 currently managed by the national sanitation office (ONA), planned for 62,500 population equivalents and a daily flow of 9360 m3 /d.

Among the ten stations treated in this document, we noted that the only station with an intensive process is that of Touggourt by activated sludge, its principle resides in an intensification of the self-purification processes that are encountered in natural environments [14]. The bacteria float in flakes in the wastewater and the purification process takes place under intense aeration (**Figure 15**). Aerobic and anaerobic (oxygen poor) conditions can be altered in space and time so that nutrients too (such as nitrogen and phosphorus) can be removed [15].

#### **Figure 14.**

*Touggourt wastewater treatment plant.*


#### **Table 7.**

*Coordinates of activated sludge station.*

*Reliability and Problems of Wastewater Treatment Processes in the Algerian Sahara DOI: http://dx.doi.org/10.5772/intechopen.96113*

**Figure 15.**

*Basic diagram of the activated sludge process [14].*

We have noted that this system offers good elimination of all the pollution parameters (COD, BOD5, MES, N) by nitrification and denitrification; plus an easier implementation of dephosphorization. It is a system suitable for the protection of sensitive receiving environments such as that of Oued Righ.

On the other hand, in addition to the investment cost and energy consumption of this type of stations are quite high, the station encountered several technical and managerial problems such as the need for qualified personnel and regular monitoring; sensitivity to hydraulic overload and difficulty in controlling sludge production.

As the situation of the station in the middle of an area of palm groves, among the most apparent problems in the region is the inflow of water from the water table and the surplus of parasitic irrigation in the sanitation network which can affect the performance of the two stations by the high salinity of the water that can be expected, and the rapid variation in the concentration of raw sewage.

#### **5. Conclusion**

Through this chapter, we tried to shed light on the wastewater treatment component in the Algerian Sahara through a description of the different systems used and to discuss their reliability and constraints.

The purification techniques adopted in the Algerian Sahara are limited to three processes: lagooning process, plant filter and activated sludge. Furthermore, the cost of installing and maintaining these sectors requires significant human and financial resources which are difficult to bear in our region.

We noted that the main objective of these stations in the Sahara is the protection of the environment and the almost non-existent tertiary treatment, for this the practice of reuse of purified wastewater remains very limited to the time that these regions have a subsoil. of the largest freshwater table in the world (Intercalary Continental).

The document clearly explained that 70% of stations in the Algerian Sahara using lagooning where 40% are stations by aerated lagooning, which remains a choice which has been subject to constraints such as high energy consumption, and the presence of electromechanical equipment. Requiring periodic maintenance by specialists. Only two pilot stations using plant purification; this system has not been developed in the region because of their strong footprint, the use of this system remains very delicate for issues of hydraulic control and cost compared to conventional channels.

Due to investment costs there are almost no active mud stations and the energy consumption of this type of station is quite high.

The improvement of these wastewater treatment techniques has resulted in an increase in by-products, these by-products, and particularly the sludge which represents the largest volumes, must be conditioned and disposed of in the most appropriate way, this which adds additional equipment to the wastewater treatment plants.

Therefore, it is necessary to explore new wastewater treatment technologies, reliable loads and adapted to the realities of our country Algeria.
