Abstract: A wastewater collection system is provided with a gas withdrawal vent including a gas suction apparatus. The gas is preferably withdrawn at a rate in excess of the gas production by microbes in the wastewater collection system so that a slight negative pressure is created in the immediate vicinity of the gas withdrawal vent. A gas mixing chamber is coupled to the fan or blower to receive the gas withdrawn from the wastewater collection system. An ozone generation apparatus is also coupled to the gas mixing chamber that is adjusted to provide sufficient ozone to react with any noxious or malodorous components of the withdrawn gas. A reaction conduit is provided at an output of the gas mixing chamber to receive the withdrawn gas and ozone. The reaction conduit has surface features assuring turbulent flow of the gasses through the length of the conduit.