Biopolymeric Flocculants or Biosorbents (Bioadditive) for
Adsorption of Contaminations
Biosorbents (e.g. commercial Bio-Amp
etc., Mucor rouxii fungal biomass rich with chitosan) have been verified as an
efficient way to remove grease trap, or emulsified oil (such as standard
mineral oil, canola oil, Bright-Edge 80, etc.) in wastewater under different
operational conditions. Some of influential parameters in adsorption process
are contact time, pH, adsorbent dose, temperature, the rotational speed of
shaker or mixer, etc. (Srinivasan and Viraraghavan,
2010; Ibrahim et al., 2012).
1.3.4 The Application of Chemical/Biological Adsorbents for Oily
Various forms of hydrogels, and bio-
and chemical surfactants have been used for investing their impact on treating
oily wastewater. A hydrogel is a network of polymer chains that are
hydrophilic, sometimes found as a colloidal gel in which water is the
dispersion medium. Hydrogels are highly absorbent natural or synthetic
polymeric networks. Beside, Surfactants are usually organic compounds that are
amphiphilic, meaning they contain both hydrophobic groups and hydrophilic
groups. Therefore, a surfactant molecule contains both water insoluble
component and water soluble component.
Ø Hydrogel of chitosan-based
polyacrylamide (Sokker et al., 2011)
Ø Cotton-based hydrogel nanocomposite (Hosseinzadeh and Mohammadi, 2014)
Ø Biosurfactant application (tea
saponin) (Lie at al., 2013)
Ø Natural materials used for
destabilization (Yuan et al., 2011)
Treatment via Ultraviolet and Ultrasound Processes
Through a process designed by Kang et al. (2011), the efficiency of a
pretreatment system for oily wastewater treatment based on TiO2 and
vacuum ultraviolet irradiation (185 nm) was testified. As a result, the best conditions
for the system were found for the optimum time for irradiation, pH amount, flow
rate of air, initial COD concentration, and the concentration of TiO2.
This process, i.e. TiO2/UV, significantly reduced COD and BOD2
in high concentration of feed.
The influence of nanoscale
zero-valent iron dosage and initial pH on COD removal percentage was studied by
Rasheed et al. (2011) to ascertain their
impact on treating petroleum refinery wastewater by means of ultrasound
dispersed nanoscale zero-valent iron.
Co-digestion of Oily Wastewater in conjunction with Other Organic Wastewaters
like Landfill Leachate, Pig Manure etc.
Co-digestion has formerly been
proved for treating vegetable oils or for other wastewater by which the role of
co-digestion of pig manure and vegetable oil has been shown and finally it was
verified that this policy could be a practical alternative of adding chemical
addictive (Hidalgo et al., 2013).
Monitoring, Correlating, Modeling, Analyzing, and Optimizing the
Effect of Operational Parameters
factorial design was used by Srinivasan and
Viraraghavan (2010) to monitor the factors affecting removal of
emulsified oil. Design Expert (RSM-CCD) has been applied to introduce the
experiments conditions, afterwards to correlate the interaction of operational
parameters, and finally determining optimum condition
(Rastegar et al., 2011; Ishak and Malakahmad, 2013). Furthermore, Santo et al. (2013) applied the pseudo first-order
kinetic model to describe degradation rate with and without sludge recycling.
Also, many literatures have used the artificial neural networks (ANN) as one of
the most practical modeling methods for the modeling of membranes (Pendashteh et al., 2011).
Hybrid Systems for the Treatment of Oily Wastewaters
It has been proved that a single
technology cannot satisfy all of the reuse and disposal requirements for
different oily sludge wastes, therefore with the aim of achieving the overall
impact of the combined methods on the removal efficiencies of pollutants, the
integration of various oily wastewater treatment technologies (i.e. physical,
physicochemical, chemical, and biological reactor) has also been investigated.
A list of some hybrid technologies has been categorized: