Complex organic chemicals industry

A range of industries manufacture or use complex organic chemicals. These include pesticides, Pharmaceuticals, paints and dyes, petro-chemicals, detergents, plastics etc. Waste waters can be contaminated by feed-stock materials, by-products, product material in soluble or particulate form , washing and cleaning agents, solvents and added value products such as plasticisers.

Nuclear industry

The waste production from the nuclear and radio-chemicals industry is dealt with at Radioactive waste treatment

Water treatment

Water treatment for the production of drinking water is dealt with elsewhere. Many industries have a need to treat water to obtain very high quality water for demanding purposes. Water treatment produces organic and mineral sludges from filtration and sedimentation. Ion exchange using natural or synthetic resins removes calcium, magnesium and carbonate ions from water, replacing them with hydrogen and hydroxyl ions. Regeneration of ion exchange columns with strong acids and alkalis produces a wastewater rich in hardness ions which are readily precipitated out, especially when in admixture with other wastewaters.

Treatment of industrial wastewater

The different types of contamination of wastewater require a variety of strategies to remove the contamination.

Solids removal

Most solids can be removed using simple sedimentation techniques with the solids recovered as slurry or sludge. Very fine solids and solids with densities close to one pose special problems. In such case filtration or ultra-filtration may be required. Alternatively, flocculation may be used using alum salts or the addition of poly-electrolytes

Oils and greases

Many oils can be recovered from open water surfaces by skimming devices. However, hydraulic oils and the majority of oils that have degraded to any extent will also have a soluble or emulsified component that will require further treatment to eliminate. Dissolving or emulsifying oil using surfactants or solvents usually exacerbates the problem rather than solving it, producing a very difficult to treat wastewater.

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