In this instance, chemical treatment is used to flocculate the oil droplets and solid particles. The larger the floc, the more gas bubbles are trapped underneath the floc structure. The flotation process is significantly more quiescent than the induced processes, hence does not tend to break up flocs. Separation is therefore based on the amount of bubbles that are trapped underneath the floc, and the maintenance of uniform flow distribution to avoid floc shearing. The influent/gas bubble carrier flow distributor and mixing chamber design determines the efficiency of a DAF unit.

Ferric compounds work in a similar way to cationic polymers except where polymers are specific to the charge on the oil droplet; metal salts swamp the bulk solution leading to charge destabilization by disassociating on addition to water. As a result, the dose rate is typically higher than for a solution polymer. The solubility of metal ions is limited and hence they tend to generate weak flocs, which means that they are better used as part of a two-stage treatment, usually in conjunction with an anionic polymer. As an example, one facility described by Berne and Cordonnier uses 10mgL~1 aluminium sulfate with 1mgL~1 anionic polyelectrolyte. However, this does result in a large volume of sludge, 10-30 m3 day-1 in this case. Use of organic coagulants alone can significantly reduce sludge volumes (3-5 m3 day-1 in this example).

Solar Panel Basics

Solar Panel Basics

Global warming is a huge problem which will significantly affect every country in the world. Many people all over the world are trying to do whatever they can to help combat the effects of global warming. One of the ways that people can fight global warming is to reduce their dependence on non-renewable energy sources like oil and petroleum based products.

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