In ex situ biological treatment, wastewater, soil, and sediment are first moved to treatment stations and treated biologically. For soil, sediment, bedrock, and sludge, biopiles, composting, landfarming, slurry phase biological treatment can be used; natural subsurface and surface waters can be remediated by bioreactors and constructed wetlands. A series of bioreactors have been widely studied and applied . If based on oxygen environments, there are aerobic and anaerobic treatments; if based on reactor configuration, there are continuously stirred tank reactors (CSTR), plug-flow reactors (PFR), fixed-bed reactors (FBR), and fluidized-bed reactors.
Ex situ biological remediation generally requires shorter time periods than in situ remediation. There is more certainty about the uniformity of treatment because of the ability to monitor and manage the treatment. However, ex situ treatment requires transportation of contaminated water, soil, and sediment (e.g., pumping of groundwater), leading to increased costs and inconvenience in management. Other properties of ex situ biological remediation are similar to those of in situ treatment as discussed previously.
Was this article helpful?