Urban sewage pipeline harmful gas absorbing, storing and recycling system

The invention relates to an urban sewage pipeline harmful gas absorbing, storing and recycling system. The system comprises a collecting assembly, a suction assembly and a storage assembly with a storage cavity. The collecting assembly comprises a purifying box and a filter element, the purifying box is arranged in the pipeline, the purifying box is provided with a gas inlet and a gas outlet which are communicated with the position above the liquid level in the pipeline, the filter element is arranged in the purifying box so as to absorb harmful gas, the gas inlet is communicated with the gas outlet through the filter element, and the gas inlet is communicated with the gas outlet through the filter element. An electromagnetic valve is mounted at the air inlet and is used for controlling connection and disconnection between the purification box and the pipeline. The suction assembly comprises a gas source, the gas inlet end of the gas source is communicated with the gas outlet, and the gas outlet end of the ga