A compact, ground surface mounted wastewater treatment unit module. The module is surface mounted on a selected substrate such as a scarified native soil. A watertight receiving basin is located on the substrate. The basin is at least partially filled with a lower layer of packing media, suitable for support of biological growth, and then with at least a first and a final layer of a porous granular media. A standpipe introduces wastewater to be treated, and such wastewater is distributed to the packing at the lower reaches of the basin. The wastewater flows up through the packing, and into the first layer of a porous granular media, and thence upwardly and outwardly via capillary action and molecular attraction, and ultimately though the final porous granular media. Treated wastewater is either collected or absorbed in an absorption foot interface between the final medium and the native earth below.