Dual-purpose biological filter device

The utility model discloses a dual-purpose biofilter device which comprises a water inlet system, a dual-purpose biofilter body, a backwashing system, an aeration system and a carbon source adding system, the water inlet system comprises a water inlet well, one side of the water inlet well is provided with a water inlet pipe, one side of the water inlet well is provided with an upper-layer water inlet main channel, and the other side of the water inlet well is provided with a lower-layer water inlet main channel. Two symmetrical single-cell water inlet channels are arranged on one side of the upper-layer water inlet main channel, single-cell water inlet pipes are arranged below the single-cell water inlet channels, a lower-layer water outlet main channel is arranged below the upper-layer water inlet main channel, and the two biological filter tank bodies are located on the side, away from the single-cell water inlet channels, of the upper-layer water inlet main channel. The device is relatively simple in stru