hollow chambers 54 formed by the tires 50 the tread walls 60 of the tires 50 are provided with apertures 62 for permitting effluent introduced by the delivery conduit 49 into the hollow chambers 54 of the tires 50 to seep into the adjoining earth 66 through the gravel bed 64 surrounding the tires the apertures 62 can be punched randomly in the tread walls 60 several different aperture patterns are shown in fig6 when steel belted tires are used it is preferable to punch the apertures 62 through the exposed portions of sidewalls 52 of the tires to prevent rust formation on the steel belts each end of the array of tires 50 is provided with a perforated end cover 67 which prevents the gravel 64 and adjoining earth 66 from flowing into the hollow chambers 54 of the tires 50 a connector 69 extends through the end cover 67 and interconnects the delivery conduit 49 to a second distribution conduit 71 which leads to additional leaching galleries not shown in constructing the leaching or drain field 18 a trench is dug by a backhoe and a small amount of gravel 64 is placed on the bottom of the trench the leaching galleries 48 which have been.