Remediation Technologies Flashcards

Thermal conductive heating (TCH) treats contaminated soil by:

Answer: Using electrical resistance heating elements to conduct heat uniformly through soil

TCH uses steel heating elements inserted into the subsurface that conduct heat directly through soil, raising temperatures sufficiently to volatilize and destroy contaminants including DNAPLs.

The primary goal of a soil vapor extraction (SVE) system is to:

Answer: Extract volatile and semi-volatile organic contaminants from the vadose zone

SVE applies a vacuum to extraction wells in the vadose zone, inducing airflow that volatilizes and removes VOCs from soil pores for above-ground treatment.

Ex situ bioremediation using a slurry-phase bioreactor offers which advantage over land farming?

Answer: Enhanced contact between microorganisms, nutrients, and contaminants due to mixing

Slurry-phase bioreactors mix contaminated soil with water and nutrients in a tank, maximizing contact and mass transfer, which accelerates biodegradation compared to static land farming.

In phytoremediation, rhizofiltration specifically refers to:

Answer: The use of plant roots to absorb, concentrate, and precipitate contaminants from water

Rhizofiltration uses plant roots grown in contaminated water to adsorb and concentrate heavy metals or radionuclides, then harvested plant material is disposed of as hazardous waste.

A remedial action objective (RAO) for a RCRA corrective action site must be based on:

Answer: Cleanup levels protective of human health and the environment, considering exposure pathways

RAOs define the cleanup goals needed to be protective of human health and the environment for current and reasonably anticipated future land and groundwater uses, considering all relevant exposure pathways.

Pneumatic fracturing is used in remediation primarily to:

Answer: Increase permeability of low-conductivity formations to improve contaminant extraction

Pneumatic fracturing injects high-pressure air into tight, low-permeability formations (silts, clays) to create fractures that improve fluid flow and enhance SVE or other remediation technologies.

Which document formally concludes a CERCLA remedial action and confirms cleanup goals have been achieved?

Answer: Closeout Report or Completion Report

A CERCLA Closeout Report (or Completion Report) documents that all remedial action objectives have been met, triggering the formal closeout of remedial activities and transitioning to long-term monitoring or deletion from the NPL.