Effect of Temperature
According to Hailei et al. (2006) temperatures below 41
C and above 26
C are
favourable for granule formation. Zhiwei et al. (2009) optimized 30
C temperature
to be essential for matured granulation.
Dissolved Oxygen Concentration
Granules are observed to be formed across lower dissolved oxygen concentration
range of 0.7–1.0 mg/L (Dangcong et al. 1999) and at higher concentration of 2 mg/L
(Tay et al. 2002a) in sequencing batch reactors. It proves that dissolved oxygen is not
a significant parameter for aerobic granules. On other hand, Hailei et al. (2006)
found that below 2.5 mg/L dissolved oxygen concentrations resulted into unstable
and poor granulation. However, Sturm and Irvine (2008) demonstrated more importance of dissolved oxygen concentration and substrate removal kinetics than hydrodynamic shear force in aerobic granulation.
6.6 Applications in Hydrocarbon-Rich Wastewater
Treatment
Aerobic granulation technology is regarded as an emerging technology in oily
wastewater treatment. High chemical oxygen demand concentration and turbidity
of palm oil mill effluent is the major problem to find an efficient treatment process.
Abdullah et al. (2011) achieved stable granulation while treating palm oil mill
effluent in sequencing batch reactor. Matured compact granules dominated by
rods, cocci and spirilli organisms provided very good biomass accumulation and
settling characteristics in the reactor. An integrated biological and adsorption method
was also employed to treat palm oil mill effluent by Gobi et al. (2011). Aerobic
granules were biologically developed inside a sequencing batch reactor and the
waste aerobic granules were further utilized as an adsorbent to achieve significant
pollutant removal efficiency. In another study, Najib et al. (2017) cultivated microbial granules containing photosynthetic pigments by using palm oil mill effluent as a
nutrient source for granulation. Microbial identification revealed the presence of
three dominant bacteria Enterobacter cloacae, Bacillus cereus, Lysinibacillus sp.
and a fungi, Engyodontium album, with bacteriochlorophyll a and carotenoids as
photosynthetic pigments.
Zhang et al. (2011) cultivated aerobic granule in glucose-fed wastewater and
further treated real petrochemical wastewater in a sequencing batch airlift reactor. In
the presence of 100% of petrochemical wastewater, the mean granule size and
extracellular polymeric substances contents were abruptly reduced. Serious deterioration was also noticed in granule settleability and pollutant removal efficiencies.
6 Aerobic Granulation in Hydrocarbon-Rich Wastewater Treatment
185
According to Hailei et al. (2006) temperatures below 41
C and above 26
C are
favourable for granule formation. Zhiwei et al. (2009) optimized 30
C temperature
to be essential for matured granulation.
Dissolved Oxygen Concentration
Granules are observed to be formed across lower dissolved oxygen concentration
range of 0.7–1.0 mg/L (Dangcong et al. 1999) and at higher concentration of 2 mg/L
(Tay et al. 2002a) in sequencing batch reactors. It proves that dissolved oxygen is not
a significant parameter for aerobic granules. On other hand, Hailei et al. (2006)
found that below 2.5 mg/L dissolved oxygen concentrations resulted into unstable
and poor granulation. However, Sturm and Irvine (2008) demonstrated more importance of dissolved oxygen concentration and substrate removal kinetics than hydrodynamic shear force in aerobic granulation.
6.6 Applications in Hydrocarbon-Rich Wastewater
Treatment
Aerobic granulation technology is regarded as an emerging technology in oily
wastewater treatment. High chemical oxygen demand concentration and turbidity
of palm oil mill effluent is the major problem to find an efficient treatment process.
Abdullah et al. (2011) achieved stable granulation while treating palm oil mill
effluent in sequencing batch reactor. Matured compact granules dominated by
rods, cocci and spirilli organisms provided very good biomass accumulation and
settling characteristics in the reactor. An integrated biological and adsorption method
was also employed to treat palm oil mill effluent by Gobi et al. (2011). Aerobic
granules were biologically developed inside a sequencing batch reactor and the
waste aerobic granules were further utilized as an adsorbent to achieve significant
pollutant removal efficiency. In another study, Najib et al. (2017) cultivated microbial granules containing photosynthetic pigments by using palm oil mill effluent as a
nutrient source for granulation. Microbial identification revealed the presence of
three dominant bacteria Enterobacter cloacae, Bacillus cereus, Lysinibacillus sp.
and a fungi, Engyodontium album, with bacteriochlorophyll a and carotenoids as
photosynthetic pigments.
Zhang et al. (2011) cultivated aerobic granule in glucose-fed wastewater and
further treated real petrochemical wastewater in a sequencing batch airlift reactor. In
the presence of 100% of petrochemical wastewater, the mean granule size and
extracellular polymeric substances contents were abruptly reduced. Serious deterioration was also noticed in granule settleability and pollutant removal efficiencies.
6 Aerobic Granulation in Hydrocarbon-Rich Wastewater Treatment
185