A cover member adapted to confine gaseous emissions from animal waste in a waste collection area having a base for contacting and floating on at least a portion of a surface of the animal waste and a cover with at least one surface extending from the base. The cover member can include a buoyant frame to define a generally pyramid shape. The cover includes a layer of geotextile material and can include organic filter material with the internal volume of the cover member. A plurality of cover members can be closely aligned to cover a substantial portion of the surface of the animal waste.