(a) a first septic tank,

(b) at least one of a leach field or an infiltration pit,

(c) a second tank between the first septic tank and the leach field or between the first septic tank and the infiltration pit, the second tank divided into a plurality of adjacent chambers, at least one of the adjacent chambers being an aeration chamber configured to convert ammonia-nitrogen to nitrate-nitrogen and nitrite-nitrogen and configured to reduce biochemical oxygen demand, the aeration chamber containing one or more media fixed within the aeration chamber, the one or more media selected from the group consisting of limestone, a plastic bio-support media, a wood-based media and combinations thereof;

(d) a rigid tubular channel at or near a floor region of the aeration chamber, the floor region beneath the one or more media;

(e) a surface air pump and an air line hose, the air line hose: (i) being encased in the rigid tubular channel, and (ii) sized and positioned for performing air delivery to promote mixing and aeration within the aeration chamber, the air line hose being made of a flexible plastic material and having an impermeable section positioned and configured to transport air from the surface air pump to a permeable section of the air line hose that sits in the rigid tubular channel, at or near the floor region of the aeration chamber, and beneath the one or more media; and

(f) a second tank cover lid having two one or more substantially vertical access ports that extend from above the aeration chamber in the second tank, through the cover lid and to an above ground area, the one or more access ports configured and sized for inserting and removing, through said one or more access ports, the air line hose in the rigid tubular channel, from the above ground area without having to enter the second tank.