Combination of aquifer thermal energy storage and enhanced bioremediation: resilience of reductive dechlorination to redox changes

Abstract

To meet the demand for sustainable energy, aquifer thermal energy storage (ATES) is widely used in the subsurface in urban areas. However, contamination of groundwater, especially with chlorinated volatile organic compounds (CVOCs), is often being encountered. This is commonly seen as an impediment to ATES implementation, although more recently, combining ATES and enhanced bioremediation of CVOCs has been proposed. Issues to be addressed are the high water flow velocities and potential periodic redox fluctuation that accompany ATES. A column study was performed, at a high water flow velocity of 2 m/h, simulating possible changes in subsurface redox conditions due to ATES operation by serial additions of lactate and nitrate. The impacts of redox changes on reductive dechlorination as well as the microbial response of Dehalococcoides (DHC) were evaluated. The results showed that, upon lactate addition, reductive dechlorination proceeded well and complete dechlorination from cis-DCE to ethene was achieved. Upon subsequent nitrate addition, reductive dechlorination immediately ceased. Disruption of microorganisms’ retention was also immediate and possibly detached DHC which preferred attaching to the soil matrix under biostimulation conditions. Initially, recovery of dechlorination was possible but required bioaugmentation and nutrient amendment in addition to lactate dosing. Repeated interruption of dechlorination and DHC activity by nitrate dosing appeared to be less easily reversible requiring more efforts for regenerating dechlorination. Overall, our results indicate that the microbial resilience of DHC in biosimulated ATES conditions is sensitive to redox fluctuations. Hence, combining ATES with bioremediation requires dedicated operation and monitoring on the aquifer geochemical conditions.Electronic supplementary materialThe online version of this article (doi:10.1007/s00253-015-7241-6) contains supplementary material, which is available to authorized users.

The Innovative Concept of Cold District Heating Networks: A Literature Review

“…Finally, a combination of ATES and remediation is considered a promising new concept to achieve both energy savings and improvement of the groundwater quality [73]: however, the presence of soil and/or groundwater contaminants in many urban environments may limit applicability of ATES and hampers redevelopment of these sites.…”

Remediation Potential of Borehole Thermal Energy Storage for Chlorinated Hydrocarbon Plumes: Numerical Modeling in a Variably-Saturated Aquifer

“…Among the various combination concepts, in-situ treatment of the contaminated subsurface by thermally enhanced bioremediation has received the most attention. Several studies using experimental (Ni et al, 2015a;Ni et al, 2015b), field (Pellegrini et al, 2019) and modeling (Moradi et al, 2018;Roohidehkordi and Krol, 2021) approaches have demonstrated a good potential of combining UTES and biodegradation. Nevertheless, another potential remediation strategy, which is the enhanced volatilization of contaminants from groundwater and subsequent release to the atmosphere, has received relatively little attention in combination with UTES.…”

Comparative Life-Cycle Assessment of Aquifer Thermal Energy Storage Integrated with in Situ Bioremediation of Chlorinated Volatile Organic Compounds

“…Numerous investigations have also been performed, including field monitoring, − numerical modeling, − management and operating strategy, ,, and policy, , to analyze the efficiency of ATES and seek possible improvements and optimizations. Recently, the combination of ATES and in situ bioremediation (ATES–ISB) has gained attention due to its potential for simultaneously dealing with energy and environmental problems. ,,,− The ATES–ISB system is being investigated for the sustainable redevelopment of urban brownfields with energy demand and encountering groundwater contaminated by chlorinated volatile organic compounds (CVOCs). Previous laboratory studies have revealed that complete CVOC biodegradation not only proceeds under the high flow condition of ATES but also shows a 13-fold improvement with simulated ATES functioning .…”

“…Recently, the combination of ATES and in situ bioremediation (ATES–ISB) has gained attention due to its potential for simultaneously dealing with energy and environmental problems. ,,,− The ATES–ISB system is being investigated for the sustainable redevelopment of urban brownfields with energy demand and encountering groundwater contaminated by chlorinated volatile organic compounds (CVOCs). Previous laboratory studies have revealed that complete CVOC biodegradation not only proceeds under the high flow condition of ATES but also shows a 13-fold improvement with simulated ATES functioning . In addition, Ding et al considered ATES as a new source for thermally enhanced bioremediation, while two ongoing pilots also demonstrated a successful application of the ATES–ISB system under field conditions. ,, Although these findings put forward that ATES–ISB can serve as a new and sustainable approach for urban brownfield redevelopment, to what extent such a combined system is more sustainable than the conventional techniques or whether it is truly more environmentally friendly requires investigation.…”