ABSTRACT

Eco-engineered bioreactors (EEBs) are kinds of attached growth, in-ground, natural wastewater treatment methods that evolved from sub-surface flow (SSF) Constructed Treatment Wetlands (CWs), but differ greatly from them. Despite EEBs being identified with one or other kinds of anoxic conditions, there will always be microenvironments in their biofilms where the opposite conditions are found. Microorganisms are largely present in EEBs in bacteria-generated biofilms attached to substrates and other surfaces under the water level, and the bacterial metabolic functions in them dominate contaminants-of-concern (CoC) transformations. The CoCs that it is desired to transform in EEBs can be present in soluble, colloidal and suspended solids forms, as well as part of entrained solids. In general, despite having much smaller surface areas than CWs, EEBs are much more efficient at removing CoCs from WWs passing through them. SSF EEB cells retain heat much better than do other kinds, and their sides and surfaces can be insulated to even further retain heat.