I'll have some more pictures in a future update. The first one below shows the wick bed being leveled, with one of the infiltrators leaned out of the way to the right. The second shows the wick cinder fill nearing the top of the infiltrators, with the inspection pipes already in place.

This biofilter is somewhat more freeform. The first one here in east Hawai'i (see previous posts) was able to be excavated in broken (ripped) lava rock rubble, and used a shallow (partial depth) liner to prevent immediate movement of water and nutrients to sub-soil depths.

This second biofilter was built on top of what in this area we would call 'solid' rock (pahoehoe lava flow), though the rock is still relatively porous (does not hold standing water for any significant length of time). This was necessitated by site conditions and was not necessarily a 'problem' for this design. A suitable shallow depression in the forested area surrounding the dwelling, and close enough to the relevant part (bathroom with WC and lav) was located and cleared of ground cover foliage, small brush and saplings to provide adequate depth for the wick's cinder bed. Covering the infiltrators to final depth results in a mounded installation, however one which slopes easily into the surrounding lumpy lava flow terrain. Once planted out it will look something like a light-maintenance perennial raised bed installation (except for the visible inspections pipes and incoming nutrient drain from the house).

Bamboo will be the primary imported nutrient uptake and transpiration processor plant - small stature clumping bamboo (to be determined) will be planted along each side of the wick mound. Other perennials to be determined will provide groundcover and other lower layers of vegetation. It is expected that some surrounding plants may also quickly colonize the finished wick, as the 'jungle' grows fast and furious in this area.