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Virus removal during rapid transport in an unconfined, low-temperature (68C) sand and gravel aquifer was investigated at a riverbank field site, 25 km south of Trondheim in central Norway. The data from bacteriophage MS2 inactivation and transport experiments were applied in a two-site kinetic transport model using HYDRUS-1D, to evaluate the mechanisms of virus removal and whether these mechanisms were sufficient to protect the groundwater supplies. The results demonstrated that inactivation was negligible to the overall removal and that irreversible MS2 attachment to aquifer grains, coated with iron precipitates, played a dominant role in the removal of MS2; 4.1 log units of MS2 were removed by attachment during 38 m travel distance and less than 2 days residence time. Although the total removal was high, pathways capable of allowing virus migration at rapid velocities were present in the aquifer. The risk of rapid transport of viable viruses should be recognized, particularly for water supplies without permanent disinfection.

This paper presents an estimation of the service life of three filters composed of sand and three alternative adsorbents for stormwater treatment according to Norwegian water quality standards for receiving surface waters. The study conducted pilot scale column tests on three adsorbent amended filters for treatment of highway runoff in cold climates under high hydraulic loads. The objectives were to evaluate the effect of high hydraulic loads and the application of deicing salts on the performance of these filters. From previous theoretical and laboratory analysis granulated activated charcoal, pine bark, and granulated olivine were chosen as alternative adsorbent materials for the present test. Adsorption performance of the filters was evaluated vis-à-vis four commonly found hazardous metals (Cu, Pb, Ni and Zn) in stormwater. The results showed that the filters were able to pass water at high inflow rates while achieving high removal. Among the filters, the filters amended with olivine or pine bark provided the best performance both in short and long-term tests. The addition of NaCl (1 g/L) did not show any adverse impact on the desorption of already adsorbed metals, except for Ni removal by the charcoal amended filter, which was negatively impacted by the salt addition. The service life of the filters was found to be limited by zinc and copper, due to high concentrations observed in local urban runoff, combined with moderate affinity with the adsorbents. It was concluded that both the olivine and the pine bark amended filter should be tested in full-scale conditions.

Generally, studies on alternative adsorbents focus on adsorbent removal capacity, as a function of pollutant concentration, and other practical aspects, such as costs, environmental impact and end of life costs, that can affect the upscaling of adsorbents for real-life applications, are not explicitly considered. Therefore, this study combines multi-criteria modeling with experimental evaluation to integrate both technical and non-technical factors in assessing the upscaling potential of alternative adsorbents. The experimental step was used to verify the reported pollutant removal as well as testing environmental stability, of the alternative adsorbents, in cold climates. Important factors/criteria for the upscaling process were identified with the help of principal component analysis. The results indicated that adsorbents such as pine bark, olivine and charcoal were the best available options for upscaling. The statistical analysis revealed that factors such as initial costs, hydraulic loads and end-of-life costs were important for the upscaling process and, therefore, should be explicitly included in any future evaluation of the alternative adsorbents.

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