No abstract

Halorespiring microorganisms have been detected in soils that were not polluted with chlorinated compounds. In this study, we describe alternative electron acceptor utilization by some halorespiring bacteria and phylogenetically related bacteria. It appears that oxidized metals like selenate, arsenate and manganese are rather common electron acceptors for halorespiring species of Desulfitobacterium and Sulfurospirillum and related bacteria. All tested microorganisms are able to reduce anthraquinone-2,6-disulfonate (AQDS) and four tested organisms (Desulfitobacterium hafniense DP7, Sulfurospirillum barnesii, Sulfurospirillum deleyianum and Sulfurospirillum arsenophilum) are able to oxidize reduced anthrahydroquinone-2,6,-disulfonate (AH 2 QDS) as well. The characteristic to reduce oxidized metals, and to reduce and oxidize quinone moieties coupled to energy conservation is a likely explanation for the presence of halorespiring microorganisms in unpolluted soils.

No abstract

A residential area that was formerly part of a silver factory site severely contaminated with chlorinated solvents was remediated using an in situ electro-bioreclamation technique. Electro-bioreclamation is a method for heating soil and groundwater combined with soil vapor and low-yield groundwater extraction and enhanced reductive dechlorination (ERD). During the first two years of remediation in the source area (the intensive phase), a total of 80 kg of volatile organic compounds (VOCs) was removed by heating combined with ERD. After another two years of ERD in the source and plume areas (the attenuation phase), the VOC concentrations were reduced to a level below 100 µg/L in groundwater. Given these satisfying results, electro-reclamation in combination with ERD turned out to be a successful in situ remediation technique for removing VOCs.

<p>As most of the industrial nations are located in the moderate climate zone with distinct summer and winter, global heating and cooling supply is less a matter of energy shortage than an issue of seasonal storage. Aquifer Thermal Energy Storage (ATES ) is capable of storing large energy volumes to bridge the seasonal mismatch between demand and supply of heating and cooling systems. However, there is a discrepancy in global ATES development, since more than 80 % of all ATES system are currently operating in the Netherlands and Scandinavia, which is mainly attributed to techno-economic barriers. Thus, this work analyses the technical performance of ATES based on monitoring data from 73 low temperature Dutch ATES systems. The analysis reveals total abstraction of 30 GWh of heat and 32 GWh of cold per year with average abstraction temperatures of 10 °C and 15 °C in summer and winter, respectively. However, while the temperature difference between abstraction and injection is 3-4 K smaller compared to the optimal design, the stored and abstracted amount of thermal energy is 50 % lower than the licensed capacities. This suggests inadequate interaction between the energy system and the aquifer as a result of the insufficient charging process of the subsurface. Nevertheless, the data showed only small thermal imbalances and small temperature losses during the storage period. Based on the comprehensive analysis, valuable conclusions can be drawn on the optimizations needs of current and future ATES projects.</p><p> </p>