Study of Physicochemical and Bacteriological Properties of Wastewaters Released Directly into The Natural Environment of Annaba City (North-East Algeria)

摘要

The present study was aimed to assess the quality of wastewaters released in different regions of Annaba city (northeast Algeria). The physicochemical and bacteriological parameters (pH, temperature, conductivity, 5-Day biochemical oxygen demand (BOD5), chemical oxygen demand (COD), coliform and faecal loads, faecal streptococci and sulfur-reducing bacteria of wastewaters) released into the natural environment of this city, and their comparison with those applicable in the national legislation have been determined using standard methods. The results showed marked variations in the studied parameters of Annaba wastewaters during the four seasons. The pH, water conductivity, temperature, and COD were increased in seasons, but in winter the conductivity was decreased. Further, the maximum level of total dissolved oxygen (10 mg/l) and suspended matters of wastewaters (1700 mg/l) were observed during winter, since the maximum level of BOD was 515 mg/l, and a lower value (300 mg/l) during winter. The level of minerals (nitrates, nitrites, and phosphorous) was increased in seasons for both waste sites. In addition, the bacterial loads in wastewaters were higher during autumn, spring, and summer than those seen during winter for both waste sites. Consequently, wastewaters released into Annaba natural environment are responsible for serious effects on the health of citizens.