IMPACT REJECTIONS OF THE PURIFICATION STATION ON THE WATER QUALITY OF OUED MEDJERDA

Oued Medjerda is the principal river in Souk Ahras city, located at north east of ALGERIA. It received urban, industrial pollution and the purification station rejection of the waste water (STEP hnancha). The aim of this study was to investigate the Medjerda water quality before and after the rejection of STEP in order to estimate his impact and to predict the consequences of this source pollution. A monthly survey was conducted to follow the changes in the quality of water during five months from March to July 2009. Water experimental parameters (Temperature, pH, COD, BDO5 and SM) nutrients (NH4+, NO2-, NO3-) and metals (Pb, Cd) were determinated according to standard Algerian protocols. The physic-chemical parameters and nutrient concentrations varied temporally in OuedMedjerda. The quality of water is good before the rejection and it is polluated after. The highest concentrations of ammonium ion, organic matter and metals were observed during summer in revenge lowest concentrations were obtained accruing winter. All this anomalies affect the quality of Oued Medjerda water which can also be the origin of Dalia dam pollution.