Environmental Engineering Reference
In-Depth Information
hydrogen chloride and fluorine compounds. The removal of magnesium from aluminum
alloys, demagging, has the potential for emission of chlorine, hexachloroethane, chlorin-
ated benzenes, dioxins, and furans (World Bank, 1999).
During mining of iron ores, dust—produced during extraction, crushing, beneficiation,
transportation, and traffic—is the main contributor to air pollution with levels that range
from 0.003 to 27 kg/tonne of ore extracted. Coke manufacturing, which is an ingredient for
pig iron production from ore, produces “particulate matter (PM), volatile organic com-
pounds (VOCs), polynuclear aromatic hydrocarbons (PAHs), methane (approximately
100 grams per metric ton (g/t) of coke), ammonia, carbon monoxide, hydrogen sulfide
(from 50 to 80 g/t of coke from pushing operations), hydrogen cyanide, and sulfur oxides
(SOx) (30% of sulfur in the feed)” (World Bank, 1999). During the transformation of pig
iron into steel by the basic oxygen furnace process, main air pollutants are particle matter
(15-30 kg/tonne), sulfur dioxide, and nitrogen oxides. In electric arch furnaces, the main
sources of air pollution are particles, nitrogen oxides, acid and fumes (World Bank, 1999).
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Liquid
The oil and gas industries produce several liquid waste streams including produced water,
hydrocarbon wastes, polyols, and glycols. Produced water is the largest waste stream in oil
fields. It is underground saline water mixed with water injected from the surface to enhance
oil and gas extraction. Hydrocarbon waste is constituted of dirty diesel fuel that is contami-
nated during the pressure testing of pipelines. Polyols and glycols are additives used as anti-
freeze in the production of natural gas (“Pollution prevention opportunities in oil and gas
production, drilling, and exploration,” 1993).
Production of cellulose pulp and paper manufacturing use massive amounts of process
water that is then discharged into bodies of surface water. These days, many paper mills reuse
water, so the final discharge is consequently reduced. The main pollutants in wastewater
streams are mainly dissolved inorganic and organic compounds and small amounts of chlorine
chemically bound to organic matter (Blanco et al., 2004). The rate of wastewater discharge
ranges between 20 and 250 m
3
/tonne, with a biological oxygen demand of 10-40 kg/tonne,
10-50 kg/tonne of total suspended solids, and 4 kg/tonne of organic halides (all expressed per
tonne of air dried pulp) (World Bank, 1999).
During the production of minerals from ores, acid mine drainage is the typical effluent. It
happens as a consequence of ground disturbance, which allows the access of water and oxy-
gen to sulfide deposits that are deep inside mountains. Water and oxygen react with sulfide
compounds to produce sulfuric acid. Typically, acid mine drainage has a pH below 3.0 and
concentration of sulfate between 800 and 1800 mg/L, which dissolves other metals such as
copper, iron, zinc, and cadmium (World Bank, 1999). The drainage often reaches bodies of
surface water (i.e., spring, creeks, rivers, and lakes), which alters aquatic life and the surround-
ing ecosystems.
During the production of steel, process water is utilized for rinsing and cooling. Rinse
water may contain suspended solids, lubricant oils, and other contaminants depending on the
process. In aluminum production from ore, beneficiation plants generate water effluents with
high content of solids (World Bank, 1999).
Solid
The oil and gas industry, which produces the feedstocks for most plastics, generates a diverse
assortment of solid waste, most of them hazardous in nature. Elshorbagy and Alkamali (2005)
estimate that the amount of solid waste is 0.37 kg per barrel of crude oil and 1.6 kg per cubic
meter of gas. Solid waste comes from nonhazardous activities associated with facility
