Industrial-waste-water TreatmentWhat is Industrial waste water?Industrial-waste-water covers the waters that have been contaminated in
Why Industrial-waste-water treatment is required?Treatment of Industrial waste water is essential to ensure that the effluent which ultimately discharged is not significantly polluted when reached the receiving end. Treatment processStep 1 - 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 the density of water pose special problems. In such case,
*Alternatively, flocculation may be used, using alum salts
Step 2 - Oils and grease removal 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. The Industrial-waste-water from large-scale industries such as
-oil refineries Commonly contain gross amounts of oil and suspended solids. Those industries use a device known as an API oil-water separator which is designed to separate the oil and suspended solids from their waste water effluents.
Step 3 - Removal of biodegradable organics Biodegradable organic material of plant or animal origin is usually possibleto treat using extended conventional wastewater treatment processes such as activated sludge or trickling filter 
a- Activated sludge process Activated sludge is a biochemical process for treating industrial wastewater that uses air (or oxygen) and microorganisms to biologically oxidize organic pollutants, producing a waste 
b-Trickling filter process A trickling filter consists of a bed of rocks, gravel, slag, peat moss, or plastic media over which wastewater flows downward and contacts a layer (or film) of microbial slime covering the bed media. Aerobic conditions are maintained by forced air flowing through the bed or by natural convection of air. The process involves adsorption of organic compounds in the wastewater by the microbial slime layer, diffusion of air into the slime layer to provide the oxygen required for the biochemical oxidation of the organic compounds. The end products include carbon dioxide gas, water and other products of the oxidation. 
Step 4 - Treatment of other organics Synthetic organic materials including -solvents -paints -pharmaceuticals -pesticides -coking products And so forth can be very difficult to treat Treatment methods are often specific to the material being treated. Methods include
-Advanced Oxidation Processing -distillation -adsorption -vitrification -incineration -Chemical immobilization or landfill disposal Some materials such as some detergents may be capable of biological degradation and in such cases; a modified form of wastewater treatment can be used. Step 5 - Treatment of acids and alkalis Acids and alkalis can usually be neutralized under controlled conditions. Neutralization frequently produces a precipitate that will require treatment as a solid residue that may also be toxic. In some cases, gasses may be evolved requiring treatment for the gas stream. Step 6 - Treatment of toxic materials Toxic materials including many organic materials, such as -Metals (such as zinc, silver, cadmium, thallium, etc.) -acids -alkalis -Non-metallic elements (such as arsenic or selenium) are generally resistant to biological processes unless very dilute. Metals can often be precipitated out by changing the pH or by treatment with other chemicals. Many, however, are resistant to treatment or mitigation and may require concentration followed by land filling or recycling. Dissolved organics can be incinerated within the wastewater by Advanced Oxidation Processes.
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