In "the catcher in the water", we further discussed that the magnetic biochar can be obtained from the same raw materials used to have biochar. With the inclusion of iron or addition of magnetic precursors, biochar turns into a material which has magnetic separation capabilities. It is used for the treatment of wastewater pollution, such as removing heavy metals, nuclear and organic pollutants. After the treatment of water, the magnetic biochar which has collected the pollutants, can be easily removed from water by a magnetic field. (see please the Raman shift of the peaks given previously in the discussion about the laser power and the debris fingerprint).