The Remediation Technology Summit

February 26-28, 2019

Colorado Convention Center
Denver, CO

lubrechtMichael Lubrecht
Senior Geologist
Directed Technologies Drilling

Michael Lubrecht, LG, is the Senior Geologist at Directed Technologies Drilling, Inc. One of the company founders in 1995, Mr. Lubrecht has worked as an environmental and engineering geologist with consultants and state agencies for 27 years. He assisted in the development of many of the specialized techniques and tools that are used in environmental directional drilling, and is a co-developer of several patented technologies in the industry. Mr. Mr. Lubrecht has authored numerous technical articles on directional drilling technology, and is currently involved in research and development, marketing and intellectual property development for DTD. He holds a Bachelor of Science in Geology from Southern Oregon University.

PLATFORM PRESENTER - Getting Over It: Overcoming Site Challenges

Bioaugmentation Using Recirculating Systems in Horizontal Wells: Strategies and Successes

Background/Objectives. As bioremediation of soil and groundwater has gained popularity, novel approaches to the application of this technology have demonstrated significant benefits through more active treatment regimens, better distribution of substrates across contaminated zones, more reliable treatment, and reduced time to site closure.

Recirculating bioremediation systems establish a local groundwater circulation cell into which appropriate biological nutrients or other amendments are continuously injected at low application rates. By constructing these systems in combination with directionally drilled wells, circulation cells may extend across plumes or contaminated areas of substantial size, or may compartmentalize a large contaminated area into more manageable units. The simultaneous withdrawal of groundwater from one well or set of wells, combined with inoculation and reinjection of the water into corresponding injection wells provides control and management of the groundwater system, while avoiding the generation of treated or effluent water that must be disposed independently of the treatment program.

Recirculating systems also provide better control, in many cases, than single or multiple point injection programs, which rely on natural groundwater flow to mix and distribute the injected substrate through the contaminated zone. In many cases, multiple injections must be made to treat groundwater emanating from a source area, with corresponding “pulses” of more and less contaminated water moving downgradient. Recirculating systems maintain a continuous level of treatment, but one which may be adjusted to deal with seasonal variations in the water table, precipitation, or other factors.

Green and Sustainable Remediation practices strive to minimize the impact of treatment methods on the local environment. The use of recirculating systems conforms to these goals, by essentially eliminating excessive groundwater extraction for treatment, containing contaminant plumes, and utilizing low volume pumps with low energy consumption to effectively treat large volumes of groundwater. Compared with comparable single-injection treatment methods using direct push technologies at widespread points across a site, the recirculating approach using horizontal wells minimizes the impact of treatment on the site or adjoining properties. Once the system is installed there are no additional construction activities required, and directional drilling not only limits impacts on site activities, but increases the potential footprint of recirculating systems.

Approach/Activities. A typical approach to a recirculating system based on horizontal wells is discussed. In addition to the general model, several projects are described where the combination of horizontal wells and recirculating systems have accelerated site cleanup.

Results/Lessons Learned. Recirculating systems have been demonstrated to be effective at groundwater cleanup, often accelerating the time to site closure. The energy demands of these low-flow systems are considerably less than those of groundwater extraction and treatment systems, with less off-site impact and a smaller environmental footprint, since there is no ex situ treatment involved. Further, the ability to adjust the system while operating provides a more reliable and continuous treatment model than single or multiple injections done in a batch process. Treatment by recirculating systems has resulted in several site closures, completed within accelerated timelines.