Academy

A complex wastewater treatment system to avoid a prohibition of discharge by the local authorities.

Introduction In many industrial operations, the products produced in campaigns vary greatly in their composition. This is common in waste management companies, chemical and pharmaceutical production sites, as examples. These campaigns often change because of different input streams, smaller but different production lots, as well as frequent contract manufacturing. This may also lead to fluctuating…

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Pourbaix Diagram.

What is a Pourbaix diagram This section will explain the Pourbaix diagram and the parameters that influence the speciation of chemical elements in a solution such as pH Redox Ions in water can have different oxidation numbers depending on the potential of the water. Each different ion will dissociate into different species depending on pH.…

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Chromium removal from water

Where does chromium come from? Chromium, which is evenly distributed in the earth’s crust, is obtained from chromite ores, an iron chromium oxide mineral (FeCr₂O₄). The hexavalent chromium (Cr˅ˡ⁺) is very toxic and has both mutagenic and carcinogenic effects, in contrast to the trivalent elementary chromium (Crˡˡˡ⁺), which is an essential nutrient. Figure 1: Chromite ore.…

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Perchlorate (ClO₄¯) ion removal from water.

Perchlorate is poorly abundant on earth, except combined with sodium nitrate mineral in some specific arid areas. Natural perchlorate is extracted to produce fertilisers. Perchlorate is intensively used in the formulation of explosive propellant for various explosives and weapons. To cover this strategic need, perchlorate is produced industrially. Perchlorate Molecular structure of perchlorate. Perchlorate is…

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Nickel (Ni²⁺) removal from water using chelating resins.

Where does nickel come from? Pure nickel (Ni) is a silvery-white metal that is rarely found as a pure metal in the earth’s crust because it will oxidise when it comes into contact with oxygen. Pure nickel can be found in the interiors of larger nickel–iron meteorites that were not exposed to oxygen when outside the earth’s atmosphere or in ultramafic rocks. Nickel is…

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Mercury (Hg⁰ and Hg²⁺) removal from water.

Introduction Mercury species exists in various forms: elemental (or metallic); inorganic (e.g. mercuric chloride); and organic mercury (e.g., methyl- and ethylmercury), which all have different toxic effects. Mercury poisoning can result from exposure to water-soluble forms of mercury (such as mercuric chloride or methylmercury), inhalation of mercury vapour, or by ingesting any form of mercury.…

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Lead (Pb²⁺) removal from water using chelating resins.

Where does lead come from? Lead is most commonly found as lead (II) sulphide (PbS) in the mineral galenite. Cerussite (tin-lead ore), with the chemical composition lead (II) carbonate (PbCO₃), is a secondary mineral of lead formed by the chemical reaction of carbonated water with galena. A third important source of lead is anglesite (lead…

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Hydrogen sulphide (H₂S) removal from water.

The “rotten egg” odour in some water supplies is caused by sulphide in water. Sulphide can be treated using oxidation techniques, the goal being to convert the sulphide to high oxidation state species such as sulphate to eliminate the taste and odour concerns. Traditional oxidation techniques such as ozone and chlorine can be used but…

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Landfill Leachate – Jacobi Carbons Improves & COD Removal Process.

Introduction The properties of land fill leachate varies widely in composition depended on different factors such as the age of the landfill and the type of waste that is stored in the landfill. Water percolating through the waste will promote the micobiological decomposition of organics. This digestion process rapidily use up any available oxygen creating…

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Soil Remediation – New Building Mercury Removal.

The Problem During commissioning stages, mercury was detected in the air of a newly constructed building. Being set on a former light bulb production site, the link was quickly made between historical mercury contamination of the soil and the previous use of the site. Analyses of soil samples also showed contamination of other heavy metals,…

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