Ensieh Taheri, Mahdi Hajian Nejad, Mohammad Mahdi Amin, Hossein Farrokhzadeh, Maryam Hatamzadeh, Marzieh Vahid Dastjerdi,
Volume 5, Issue 1 (4-2012)
AR-SA
MicrosoftInternetExplorer4
Background and Objectives: Aerobic sludge granulation is an
advanced phenomenonin which its mechanisms have not been understood.
Granulation can be a promising and novel biological wastewater treatment
technology to eliminate organic and inorganic materials in future. High
salinity is a parameter which leads to plasmolisatian and reduction of the cell
activity. This could be a problem for biological treatment of the saline
wastewater. Aerobic granule was formed and investigated during this study.
Materials and Methods:
This study is an intervention study on the treatment of wastewater with
500-10000 mg/L concentration of NaCl by sequencing batch reactor. Asynthesized
wastewater including nutrient required for microorganism's growth was prepared.
Input and output pH and EC were measured. Range of pH and DO varied between
7-8, and 2-5 mg/L, respectively. SEM technology was used to identify graduals
properties.
Results: In terms of color, granules divided
into two groups of light brown and black. Granule ranged in 3-7mm with the
sediment velocity of 0.9-1.35 m/s and density of 32-60 g/L.Properties of
granules were varied. Filamentous bacteria and fungi were dominant in some
granules. However non filamentous bacteria were dominant in others. EDX
analysis indicated the presence of Ca and PO
4.
Conclusion: Granules
with non filamentous bacterial were compact and settled faster. Presence of
different concentrations of salinity leaded to plasmolysis of the bacterial
cells and increased concentrations of EPS
in the system as a result of
which granulation accelerated
.
