Biopolymeric Flocculants or Biosorbents (Bioadditive) forAdsorption of Contaminations Biosorbents (e.
g. commercial Bio-Ampetc., Mucor rouxii fungal biomass rich with chitosan) have been verified as anefficient way to remove grease trap, or emulsified oil (such as standardmineral oil, canola oil, Bright-Edge 80, etc.) in wastewater under differentoperational conditions. Some of influential parameters in adsorption processare contact time, pH, adsorbent dose, temperature, the rotational speed ofshaker or mixer, etc. (Srinivasan and Viraraghavan,2010; Ibrahim et al.
, 2012). 1.3.4 The Application of Chemical/Biological Adsorbents for OilyWastewater Adsorption Various forms of hydrogels, and bio-and chemical surfactants have been used for investing their impact on treatingoily wastewater.
A hydrogel is a network of polymer chains that arehydrophilic, sometimes found as a colloidal gel in which water is thedispersion medium. Hydrogels are highly absorbent natural or syntheticpolymeric networks. Beside, Surfactants are usually organic compounds that areamphiphilic, meaning they contain both hydrophobic groups and hydrophilicgroups. Therefore, a surfactant molecule contains both water insolublecomponent and water soluble component.Ø Hydrogel of chitosan-basedpolyacrylamide (Sokker et al., 2011)Ø Cotton-based hydrogel nanocomposite (Hosseinzadeh and Mohammadi, 2014)Ø Biosurfactant application (teasaponin) (Lie at al.
, 2013)Ø Natural materials used fordestabilization (Yuan et al., 2011) 1.3.5Treatment via Ultraviolet and Ultrasound ProcessesThrough a process designed by Kang et al. (2011), the efficiency of apretreatment system for oily wastewater treatment based on TiO2 andvacuum ultraviolet irradiation (185 nm) was testified. As a result, the best conditionsfor the system were found for the optimum time for irradiation, pH amount, flowrate of air, initial COD concentration, and the concentration of TiO2.
This process, i.e. TiO2/UV, significantly reduced COD and BOD2in high concentration of feed.
The influence of nanoscalezero-valent iron dosage and initial pH on COD removal percentage was studied byRasheed et al. (2011) to ascertain theirimpact on treating petroleum refinery wastewater by means of ultrasounddispersed nanoscale zero-valent iron. 1.3.6Co-digestion of Oily Wastewater in conjunction with Other Organic Wastewaterslike Landfill Leachate, Pig Manure etc.Co-digestion has formerly beenproved for treating vegetable oils or for other wastewater by which the role ofco-digestion of pig manure and vegetable oil has been shown and finally it wasverified that this policy could be a practical alternative of adding chemicaladdictive (Hidalgo et al., 2013).1.
1. Monitoring, Correlating, Modeling, Analyzing, and Optimizing theEffect of Operational ParametersFractionalfactorial design was used by Srinivasan andViraraghavan (2010) to monitor the factors affecting removal ofemulsified oil. Design Expert (RSM-CCD) has been applied to introduce theexperiments conditions, afterwards to correlate the interaction of operationalparameters, and finally determining optimum condition(Rastegar et al., 2011; Ishak and Malakahmad, 2013). Furthermore, Santo et al. (2013) applied the pseudo first-orderkinetic model to describe degradation rate with and without sludge recycling.Also, many literatures have used the artificial neural networks (ANN) as one ofthe most practical modeling methods for the modeling of membranes (Pendashteh et al.
, 2011). 2. Hybrid Systems for the Treatment of Oily Wastewaters It has been proved that a singletechnology cannot satisfy all of the reuse and disposal requirements fordifferent oily sludge wastes, therefore with the aim of achieving the overallimpact of the combined methods on the removal efficiencies of pollutants, theintegration 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: