The volumes of all wastes generated depend on the geological-seismic operation,
chemicals dosage and time duration of oil and gas exploration. The earth water is
polluted by hazardous compounds like potassium formate, cementing waste (drilling
mud), lubricants, rubbing alcohol (cutting fluids) and bio-acids (well treatment
chemicals) to aid in the drilling of boreholes. The drilling fluids and cutting
chemicals have adverse influences on groundwater as well as surface water due to
their high pH as well as high salt content, during discharge and transportation.
8.2.2 Petroleum Refinery
After exploration and production, the crude is transported to the refinery. The
petroleum refineries convert crude oil into more than 2500 items including liquefied
petroleum gas, gasoline, kerosene, aviation fuel, diesel, lubricating oil and petrochemical feedstock to meet the market requirements. The petroleum refinery has
great influence on environment pollution (water, air and soil pollution) during
processing of crudes. During the various refinery operations and processes, the
water is contaminated with harmful hydrocarbons. These operations and processes
mainly include desalting, distillation, hydrotreating, cooling system, wash unit,
drainage of tank, flushing of equipment, surface water run-off. (Helmy and Kardena
2015; Damian 2013; Olajire 2014; Mareddy 2017; Central Pollution Control Board,
India 2018) According to the Environmental Protection Agency, a normal refinery
(production capacity; 150,000 barrel/day fuel oil) generates 357–476 barrel/day of
oily wastes (Environmental Protection Agency, Washington 1974).
Desalting Effluents
In the refinery, the first step for refining the crude oil is desalting for the removal of
different types of salts, drilling mud, cutting fluids, clay and other chemicals which
may cause corrosion of equipment or act as poisons to the catalysts. De-emulsifier is
usually added to break the oil-water emulsion during desalting. So, the desalter
effluents contain de-emulsifiers, organic-inorganic salts and oily water. The temperature of the wash water is also high (110–150
C) which reduces the dissolved
oxygen content of water (Central Pollution Control Board, India 2018).
Atmospheric Distillation
After desalting, the oil is subjected to atmospheric distillation unit for the production
of light fractions, naphtha, liquefied petroleum gas, gasoline, kerosene, diesel and
feedstock of lube oil. In this unit, the stripping stream comes in contact with different
hydrocarbon fractions, mercaptans, disulphide compounds, hydrogen sulphide and
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chemicals dosage and time duration of oil and gas exploration. The earth water is
polluted by hazardous compounds like potassium formate, cementing waste (drilling
mud), lubricants, rubbing alcohol (cutting fluids) and bio-acids (well treatment
chemicals) to aid in the drilling of boreholes. The drilling fluids and cutting
chemicals have adverse influences on groundwater as well as surface water due to
their high pH as well as high salt content, during discharge and transportation.
8.2.2 Petroleum Refinery
After exploration and production, the crude is transported to the refinery. The
petroleum refineries convert crude oil into more than 2500 items including liquefied
petroleum gas, gasoline, kerosene, aviation fuel, diesel, lubricating oil and petrochemical feedstock to meet the market requirements. The petroleum refinery has
great influence on environment pollution (water, air and soil pollution) during
processing of crudes. During the various refinery operations and processes, the
water is contaminated with harmful hydrocarbons. These operations and processes
mainly include desalting, distillation, hydrotreating, cooling system, wash unit,
drainage of tank, flushing of equipment, surface water run-off. (Helmy and Kardena
2015; Damian 2013; Olajire 2014; Mareddy 2017; Central Pollution Control Board,
India 2018) According to the Environmental Protection Agency, a normal refinery
(production capacity; 150,000 barrel/day fuel oil) generates 357–476 barrel/day of
oily wastes (Environmental Protection Agency, Washington 1974).
Desalting Effluents
In the refinery, the first step for refining the crude oil is desalting for the removal of
different types of salts, drilling mud, cutting fluids, clay and other chemicals which
may cause corrosion of equipment or act as poisons to the catalysts. De-emulsifier is
usually added to break the oil-water emulsion during desalting. So, the desalter
effluents contain de-emulsifiers, organic-inorganic salts and oily water. The temperature of the wash water is also high (110–150
C) which reduces the dissolved
oxygen content of water (Central Pollution Control Board, India 2018).
Atmospheric Distillation
After desalting, the oil is subjected to atmospheric distillation unit for the production
of light fractions, naphtha, liquefied petroleum gas, gasoline, kerosene, diesel and
feedstock of lube oil. In this unit, the stripping stream comes in contact with different
hydrocarbon fractions, mercaptans, disulphide compounds, hydrogen sulphide and
234
M. Samanta and D. Mitra