The growing interest in compact neighborhoods, walkability and all things connected to sustainable living has brought a new vision of urbanity. From a personal standpoint I am no longer looked at wide-eyed and with pity when I say I grew up in a city without a car, but with something closer to admiration. For example here in the Puget Sound Region, while many argue over exact numbers, the population of our urban areas is projected to grow drastically over the next three decades. This sustainable movement has also led to a surge in the land values of our urban cores, focusing attention on how to get the most out of our city's square footage. The need for more affordable urban land has left cities, which are already in dire financial situations to seek new and creative solutions for affordable housing options. Herein lies a component of the spurred new interest in under-utilized contaminated land known as brownfields.

Brownfield redevelopment seems logical enough – take land that is no longer needed for its industrial or forgotten commercial use and bring it back to life to suit the needs of current residents. According to the Washington Department of Ecology there are over 2,000 such properties that have been reported and for every 150 completed sites 300 new sites are identified. Unfortunately due to the complex nature of contamination from what we see as harmless activities, restaurants, dry cleaners (some of the most hazardous sites), carwashes, nurseries etc., almost always the redevelopment of these sites are extremely costly, and extremely bureaucratic. In an effort to alleviate some of the challenges of this conundrum. The Washington Department of Ecology published the Washington State Brownfield Policy Recommendations, found at the above hyperlink, which discuss the challenges and opportunities of brownfields as well as policy changes that would assist in making their redevelopment more possible. The cost factor, given the current economic climate, is what stands in the way of many projects moving forward unless the finished product can sell or lease above market value, which doesn't assist in creating more affordable units. There may be in some very specific cases two options for addressing this issue that the Department of Ecology does not mention in this publication known as bioremediation and phytoremediation. Bioremediation isthe treatment of pollutants or waste (as in an oil spill, contaminated groundwater, or an industrial process) by the use of microorganisms (as bacteria) that break down the undesirable substances, phytoremediation is a similar process but which uses plants to break down these substances.

Using bioremediation or phytoremediation are both non-invasive procedures, unlike capping or dredging. They also cost up to 1000 times less than more invasive processes. Unfortunately, placing microorganisms or plants in contaminated soil isn't always a possible. Oftentimes, contaminants have seeped deep down into the soil on a site below the reach of plants root systems or microorganism's ability. There are particular contaminants that remain on the soil surface including lead, arsenic, and other heavy metals that are some of the most costly contaminants to remove. On average, removing arsenic and lead costs over $650.00 a ton versus around $20.00 a ton for clean soil. Think about that across a 2 to 3 acre site and it adds up quickly. Often we think of these contaminated sites as lots in industrial yards that no one would want to live in anyway, but that's not quite the case. Any site with a home on it built prior to 1970 is close to guaranteed to have lead contaminated soil surrounding the building or where the building once stood due to the use of lead paint.

Phyto and bioremediation also have the challenge of taking a much longer period of time to remove contaminants. Developers may not wish to wait the months or even years it takes for the natural processes of remediation to occur. This is why it's my opinion that right now in the down economy bio and phytoremediation may be great option for managing some of the thousands of brownfields awaiting remediation.  In discussions with environmental lawyers, they've noted that over the last several years during the recession some of their work has been positioning development for when the market improves such as getting permits approved from the department of ecology so that things are ready to go when the market improves. Using the new green technologies of phyto or bioremediation would be a similar positioning move. This would be a way to repare contaminated sites in a low cost manner so that a few years down the road when the market has stabilized development can move ahead without requiring millions of dollars in remediating costs to the developer. As an additional benefit this savings might possibly even enable the units to be kept at affordable rates for the projected growth of our urban centers.  

More information about bioremediation was posted on this site in December of 2010  which looked more at the ecological benefits of phytoremediation instead of the economic benefits. Worth checking out!