WASTEWATER AND INDUSTRY
Water is an important requirement in many industrial processes, for example, heating, cooling, production, cleaning and rinsing. Overall, some 5–20 per cent of total water usage goes to industry (WWAP, 2009), and industry generates a substantial propor- tion of total wastewater. If unregulated, industrial wastewater has the potential to be a highly toxic source of pollution. The vast array of complex organic compounds and heavy metals used in modern industrial processes, if released into the environment can cause both human health and environmental disasters. Industry has a corporate responsibility to take action to ensure discharged water is of an acceptable standard, and accept costs of any required clean up. The most cost-effective solutions usually focus on preventing contaminants from ever entering the wastewater stream or developing a closed system of water use. Industry can also benefit from access to cleaner water resources with fewer impurities, as impurities can add costs to the production processes.
In many developing countries more than 70 per cent of in- dustrial wastes are dumped untreated into waters where they pollute the usable water supply (WWAP, 2009). Industrial dis- charge can contain a wide range of contaminants and originate from a myriad of sources. Some of the biggest generators of toxic industrial waste include mining, pulp mills, tanneries, sugar refineries, and pharmaceutical production.
In many instances wastewater from industry not only drains directly into rivers and lakes, it also seeps into the ground con- taminating aquifers and wells. This pollutes water supplies and in developing countries often goes undetected, as monitoring is expensive. Even if it is detected, remediation often does not occur as the source of the pollution must be addressed and decontamination carried out at the same time, which can be extremely difficult.
Mining has traditionally been a major source of unregulated wastewater discharge in developing countries. Tailings from mining operations can contain silt and rock particles and sur- factants. Depending on the type of ore deposit being mined, tailings can also contain heavy metals like copper, lead, zinc, mercury and arsenic. The contaminants in mine waste may be
carcinogenic or neurotoxic to people (e.g. lead and mercury) or extremely toxic to aquatic organisms (e.g. copper). There are many examples of persistent environmental damage caused by the discharge of toxic mine waste. In Papua New Guinea for ex- ample, companies discharge millions of tons of contaminated mine waste into rivers from the Ok Tedi, Porgera and Tolukuma mines (Christmann and Stolojan, 2001).
The food and agriculture processing industry can also be a major producer of wastewater particularly organic waste with high biochemical oxygen demand (BOD). BOD measures the amount of oxygen used by micro-organisms like bacteria in the oxidation of this material. Low oxygen levels or even an- oxic conditions may result if large amounts of organic waste are discharged into waterways. Slaughterhouses may produce water polluted with biological material such as blood contain- ing pathogens, hormones and antibiotics.
Cooling waters used in industrial processes like steel manufac- ture and coke production not only produce discharge with an elevated temperature which can have adverse effects on biota, but can also become contaminated with a wide range of toxic substances. This includes cyanide, ammonia, benzene, phe-
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