The other biological process is the anaerobic method where the sewage generated
by the industrial taskforce is treated in a septic tank in presence of bacteria to reduce
biochemical oxygen demand by about 35%–40% in 1–2 days (Alireza 2014;
Shahryar 2017).
Anaerobic Digestion
In this wastewater treatment, microorganisms digest the organic matter of sewage in
absence of oxygen in a digester chamber. The organic pollutants are consumed by
hydrolysis of bacteria and converted into ammonia, hydrogen, organic acid, hydrogen sulphide, bio-methane, etc. (Mareddy 2017; International Petroleum Industry
Environmental Conservation Association 2010).
Anaerobic Lagoon
Anaerobic lagoons are mainly used for treatment of organic pollutants devoid of
oxygen like a septic tank but not underground. Lagoons should be lined with
reinforced material to avoid seepage. The anaerobic bacteria, protozoa digest the
organic matter and evolve methane, nitrogen, hydrogen sulphide, carbon dioxide and
ammonia gas. This gas may be utilized as biogas (Alireza 2014; Environmental
Protection Agency, Washington 2011; Walczyk and Gorny 2018).
After treatment, the purified water (parameters meeting specifications) is
recycled, reused and few times, it is discharged to a nearby aquatic body. However,
treated water must be analysed before being discharged to ensure that the parameters
meet the required specifications (Shahryar 2017; Alireza 2014).
8.4.4 Refinery Wastewater Treatment
A typical petroleum refinery has different wastewater treatment facilities based on
effluent quantity and quality. The refinery wastewater treatment consists of preliminary treatment, primary treatment, secondary treatment, tertiary treatment and
advanced treatment if required (Mareddy 2017; International Petroleum Industry
Environmental Conservation Association 2010; Patwardhan 2008).
Preliminary Treatment
The preliminary treatment is essential for smooth performance of subsequent treatment processes as well as for the protection and maintenance of equipment of the
facility. Mainly this process protects the pumps and heat exchangers from getting
clogged by eliminating the large suspended solids, heavy hydrocarbons, floating
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M. Samanta and D. Mitra
by the industrial taskforce is treated in a septic tank in presence of bacteria to reduce
biochemical oxygen demand by about 35%–40% in 1–2 days (Alireza 2014;
Shahryar 2017).
Anaerobic Digestion
In this wastewater treatment, microorganisms digest the organic matter of sewage in
absence of oxygen in a digester chamber. The organic pollutants are consumed by
hydrolysis of bacteria and converted into ammonia, hydrogen, organic acid, hydrogen sulphide, bio-methane, etc. (Mareddy 2017; International Petroleum Industry
Environmental Conservation Association 2010).
Anaerobic Lagoon
Anaerobic lagoons are mainly used for treatment of organic pollutants devoid of
oxygen like a septic tank but not underground. Lagoons should be lined with
reinforced material to avoid seepage. The anaerobic bacteria, protozoa digest the
organic matter and evolve methane, nitrogen, hydrogen sulphide, carbon dioxide and
ammonia gas. This gas may be utilized as biogas (Alireza 2014; Environmental
Protection Agency, Washington 2011; Walczyk and Gorny 2018).
After treatment, the purified water (parameters meeting specifications) is
recycled, reused and few times, it is discharged to a nearby aquatic body. However,
treated water must be analysed before being discharged to ensure that the parameters
meet the required specifications (Shahryar 2017; Alireza 2014).
8.4.4 Refinery Wastewater Treatment
A typical petroleum refinery has different wastewater treatment facilities based on
effluent quantity and quality. The refinery wastewater treatment consists of preliminary treatment, primary treatment, secondary treatment, tertiary treatment and
advanced treatment if required (Mareddy 2017; International Petroleum Industry
Environmental Conservation Association 2010; Patwardhan 2008).
Preliminary Treatment
The preliminary treatment is essential for smooth performance of subsequent treatment processes as well as for the protection and maintenance of equipment of the
facility. Mainly this process protects the pumps and heat exchangers from getting
clogged by eliminating the large suspended solids, heavy hydrocarbons, floating
250
M. Samanta and D. Mitra