Wednesday, February 23, 2011

Environmental Site Assessments – Phase 3 – The Site Clean-Up

In the last blog we discovered that a Phase II Environmental Site Assessment (ESA) is used to test the soil and groundwater at a property to determine the “location and concentration” of suspected contamination.  If contamination is found and it is over the legal limit, a property owner may elect to clean-up or remediate the site. This clean-up process is call Phase III or Site Remediation.

Site remediation technologies can be divided into 2 categories:
  1. “In Situ” – Latin meaning ‘On Site’
  2. “Ex Situ” – Latin meaning ‘Off Site’
On site “In Situ” treatment methods involve treating the contamination right at the site. While “Ex Situ” methods involve physically moving the contaminated material to an “off site” location for treatment, then backfilling with a clean-fill material.

There are many factors to consider in choosing the best treatment method including: type of contamination and its concentration, soil conditions, time available, and budget. Depending on the situation, the best treatment method may not be the most effective or cost-efficient.

Consider the following example:  You own a commercial property and receive an offer to purchase for $2,000,000 but your site is contaminated.  Using "in situ" Bioremediation (using natural microbes which digest the contaminants) would cost approximately $20,000 but it will take 18-24 months to complete.  But if your sale closes in 90 days you will be forced to remove the contaminated soil using a more expensive “ex situ” method.  While you may remediate the site and complete your sale, the final clean-up cost could be closer to $250,000.

When it comes to dealing with environmental contamination it is better to be pro-active. Remember even if your site is found to be contaminated, you are the client, and the engineering firm is under no legal obligation to report their findings to any government body, unless it is believed that the contamination seriously endangers the safety or welfare of the public.

If you suspect contamination, have it tested.  Don’t ignore it. If it contamination does exists, it is often under the limits. If it happens to be over the limits then at least you have bought yourself time to explore cost-effective options.

No comments:

Post a Comment