Etude comparative du fonctionnement des stations d’épuration des eaux par lagunage d’Ouargla et Ghardaïa : rendement et fiabilité

Abstract

Treated wastewater from the wastewater treatment plant, Kaf Dokhan (Ghardaïa) and Saïd Otba (Ouargla), are discharged in the open area and they are constituated an important environmental pollution source and surface and groundwater in these areas. Is the treatment can protect that perimeter and those water sources?. For this, we have carried out this comparative study in order to highlight the arguments related to the failures of these stations and to have an idea about their performance and reliability. We undertook in the first place to theological description of functioning and highlight the technical aspect of the treatment processes. The physico-chemical analysis data for the inlet (raw water) and outlet (treated water) of each station: pH, electrical conductivity (EC), suspended matter (ESM), biological oxygen demand (BOD5), chemical oxygen demand (COD), temperature (T°), nitrates (N-NO3), nitrites (N-NO2), et dissolved oxygen (O2),...etc. The results of these analyses showed a neutral to basic pH, an average ESM content for Kaf Dokhan’s WTP and above the standard for Saïd Otba’s WTP, levels considered important for BOD5 and COD, an average T° and a low content of N-NO2 and NO3, average O2 content below. Purification and degradation are low to medium and require special attention at the pools level of organic matter degradation and the bacterial beds regeneration in order to regulate all the problems related to the oxygen supply and ensure both high reliability and high efficiency for each treatment plant.