Precipitation, electrostatic electrical current through

Scrubbers. These are tanks where the waste gets sprayed by jets of water, before it reaches the chimneys. The water washes away smoke and dust, and dissolves some of the harmful gases. Electrostatic precipitators. In some factories, the waste is led into a chamber called an electrostatic predpitator, where an electric current is passed through it. The smoke and dust partides get charged, and cling to electrodes. In time, they fall to the bottom of the predpitator and are removed. 

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