Water treatment device and method

The invention relates to the field of water treatment, in particular to a water treatment device and method. The water treatment device comprises a first barrel, wherein a first reaction part is arranged in the first barrel, and a water inlet is formed in the first barrel; a second barrel which is arranged in the first barrel, wherein a second reaction part is arranged in the second barrel, and a water outlet and a dripping hole communicated with the first barrel are further formed in the second barrel; a circulating assembly which is arranged in the first barrel and is used for introducing the sewage in the first barrel into the second barrel. When the water treatment device is actually used, sewage is guided into the first barrel and then reacts with the first reaction part to primarily purify the sewage; through circulation of the circulating assembly, sewage subjected to primary reaction in the first barrel is guided into the second barrel for secondary reaction; and then the sewage permeates into the fir