Author/Authors :
Alipour، Vali نويسنده School of Public Health, Hormozgan University of Medical Sciences, Bandar Abbas, Iran Alipour, Vali , Moein، Faride نويسنده Islamic Azad University, Branch of Bandar Abbas, IR
Iran , , Rezaei، Leila نويسنده Hormozgan Environmental and Occupational Health Engineering Research Center Rezaei, Leila
Abstract :
Wastewaters with high salt content disturb the metabolic function
of microorganisms causing plasmolysis or activity loss in
microorganisms, so the efficiency of biological treatment of saline
wastewater by conventional microorganisms will decrease. This study
aimed to find the outbreak of disorder in the biological wastewater
treatment process and how much salt leads to low efficiency in the
wastewater treatment plant. A study unit consisting of two aeration and
sedimentation parts was used in this pilot research. Initially, 2 to 10
gr of NaCl was added to wastewater (WW) then aerated and settled for six
and two hours, respectively. During a 10-weeks period, 10 samples were
obtained and, the parameters of biological oxygen demand in 5 (BOD5),
chemical oxygen demand (COD), total suspended solids (TSS), pH,
turbidity, total dissolved solids (TDS) and mixed liquor suspended
solids (MLSS), were measured. All experiments were done according to
standard methods. Removal efficiency of qualitative parameter including
BOD, COD, TSS and turbidity showed a reduction of about 79.7, 73.9, 67.6
and 66%, respectively by addition of 8 gr/L of NaCl to wastewater. By
increasing TDS by more than 4000 mg/L, biological treatment was done at
a low efficiency and was disturbed with TDS of about 8000 mg/L, with
efficiency of the treatment system strongly decreasing. For wastewater
with high TDS content, modification such as dilution, collection system
sanitation, application of halophytic organisms, the use of
non-biological methods and so on is recommended.
