Abstract Oily wastewater is generally generated from the industries that are primarily engaged in the refining of crude oil, processing of food, transportation, and
extraction. The hazardous nature of the oily wastewater poses serious threats to the
environment and human health if it is disposed to the environment without proper
treatment. Most of the countries around the world have their distinguished wastewater discharge standards. Therefore, efficient oily wastewater treatment is utterly
important to improve the quality of the wastewater according to the wastewater
discharge standards before releasing it into the water streams.
In this chapter, we review the conventional and advanced technologies for the
treatment of oily wastewater. The major points are the following: (1) There are
several conventional oily wastewater treatments, such as flotation, coagulation, and
biological treatments. Among these three methods, biological treatment is the least
popular method for the oily wastewater treatment due to high difficulty in handling
the diverse microbe behaviors under different environmental conditions. (2) Membrane technologies, such as microfiltration, ultrafiltration, nanofiltration, and reverse
osmosis, are gaining significant attention due to high emulsion separation efficiency
with the minimum use of chemicals, as well as the easy and low-cost operation.
However, nanofiltration and reverse osmosis are not well received due to relatively
low flux and high energy consumption. (3) Electrochemical treatment is arguably the
most effective technique for oily wastewater treatment due to the energy saving
process, robust performance, versatility, and simple process control kinetics. This
treatment can achieve excellent removal of oil and grease, chemical oxygen demand,
and turbidity of more than 90%. (4) The integration of various technologies has
become an interest of studies for the improvement of oily wastewater treatment.
These hybrid technologies have shown enhanced treatment performances than the
treatment with a single technology.
Keywords Oily wastewater · Conventional wastewater treatment · Membrane
filtration · Electrochemical treatment · Hybrid technology
11.1 Introduction
Oil and grease have become an ever-growing environmental concern. It creates
significant coercions to the environment and human being due to the hazardous
nature of these contaminants (Karhu et al. 2013). Oil and grease are important in
most industries as they are made up of triglycerides with straight-chain fatty acids
attached to the main group (Wakelin and Forster 1997). The glycerides which exist
as a liquid at room temperature are known as oils, whereas those that exist as solids
are called fats (Sawyer et al. 2003). Generally, these common fatty acids are made up
of 12–22 carbon atoms. According to Sawyer et al. (2003), the principal acid
composing glycerides are listed in Table 11.1. They are nonpolar and hydrophobic
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M. H. D. Othman et al.
extraction. The hazardous nature of the oily wastewater poses serious threats to the
environment and human health if it is disposed to the environment without proper
treatment. Most of the countries around the world have their distinguished wastewater discharge standards. Therefore, efficient oily wastewater treatment is utterly
important to improve the quality of the wastewater according to the wastewater
discharge standards before releasing it into the water streams.
In this chapter, we review the conventional and advanced technologies for the
treatment of oily wastewater. The major points are the following: (1) There are
several conventional oily wastewater treatments, such as flotation, coagulation, and
biological treatments. Among these three methods, biological treatment is the least
popular method for the oily wastewater treatment due to high difficulty in handling
the diverse microbe behaviors under different environmental conditions. (2) Membrane technologies, such as microfiltration, ultrafiltration, nanofiltration, and reverse
osmosis, are gaining significant attention due to high emulsion separation efficiency
with the minimum use of chemicals, as well as the easy and low-cost operation.
However, nanofiltration and reverse osmosis are not well received due to relatively
low flux and high energy consumption. (3) Electrochemical treatment is arguably the
most effective technique for oily wastewater treatment due to the energy saving
process, robust performance, versatility, and simple process control kinetics. This
treatment can achieve excellent removal of oil and grease, chemical oxygen demand,
and turbidity of more than 90%. (4) The integration of various technologies has
become an interest of studies for the improvement of oily wastewater treatment.
These hybrid technologies have shown enhanced treatment performances than the
treatment with a single technology.
Keywords Oily wastewater · Conventional wastewater treatment · Membrane
filtration · Electrochemical treatment · Hybrid technology
11.1 Introduction
Oil and grease have become an ever-growing environmental concern. It creates
significant coercions to the environment and human being due to the hazardous
nature of these contaminants (Karhu et al. 2013). Oil and grease are important in
most industries as they are made up of triglycerides with straight-chain fatty acids
attached to the main group (Wakelin and Forster 1997). The glycerides which exist
as a liquid at room temperature are known as oils, whereas those that exist as solids
are called fats (Sawyer et al. 2003). Generally, these common fatty acids are made up
of 12–22 carbon atoms. According to Sawyer et al. (2003), the principal acid
composing glycerides are listed in Table 11.1. They are nonpolar and hydrophobic
354
M. H. D. Othman et al.