The present invention provides a waste-liquid processing device, comprising: a first processing device and a mixing device, wherein the first processing device is provided with a first purifying unit for processing waste liquid from a waste liquid source to produce a purified liquid. The mixing device is used for mixing the purified liquid with a chlorine dioxide solution. The present invention also provides an air-pollution treatment device, comprising the waste-liquid processing device and a gas processing device. The gas processing device comprises an air extracting unit, a gas purifying unit, a gas-liquid separation unit, and an exhausting unit.
