William Schnabel

TREATMENT OF CYANIDE WASTE IN A SEQUENCING BATCH BIOFILM REACTOR

Abstract Biological treatment of a synthetic leachate containing cyanide was accomplished in a sequencing batch biofilm reactor (SBBR). A mixed culture of organisms growing on silicone tubing were provided with cyanide as a sole carbon and nitrogen source. Organisms consumed cyanide (20 mg/liter CN − WAD ) and produced ammonia in an approximate 1:1 molar yield. The SBBR was operated on a 24-h cycle. Over the course of each cycle, 20 mg/liter of cyanide was degraded to below 0.5 mg/liter. Results from four track studies are presented. It was demonstrated that, when supplied with glucose, the organisms would readily consume excess ammonia. For each mole of glucose added, 10 moles of NH 3 -N were removed from solution. The SBBR can be used as a mobile system for treatment of leachate from gold-mining operations. Large volumes of low concentration wastewater can be treated in the SBBR since it is not necessary to maintain a consortium of settling organisms.

The Effect of Mycorrhizal Fungi on the Fate of Aldrin: Phytoremediation Potential

ABSTRACT The objective of this study was to investigate the phytoremediation potential of mycorrhizal systems for the remediation of aldrin-contaminated soils. Feltleaf willow (Salix alaxensis) and balsam poplar (Populus balsamifera) were grown in soil spiked with 0.8 mg/kg aldrin- (1,2,3,4,10-14C). Daconil2787® was employed to suppress indigenous mycorrhizal infection. After 100 days of greenhouse incubation, mycorrhizal infection in the fungicide-amended willows was found to be 2.5 fold lower than in controls. Mycorrhizal infection in the poplar systems was unaffected by fungicide addition. Mycorrhizae were correlated with radiolabel uptake in the willow systems (r = 0.79), and not as strongly in the poplar systems (r = 0.58). Most of the radiolabel in the root material was bound product regardless of mycorrhizal infection, but 12 to 21% was found to be extractable dieldrin. Aldrin was not detected in any vegetative matrix. Dieldrin constituted less than 1% of the radiolabel in the willow leaf material, accumulating to approximately 5 μg/kg. Dieldrin was not detected in the poplar leaves (MDL ≈ 1 μg/kg), although the poplars took up approximately the same amount of radiolabel as the willows. Water-soluble transformation products were formed in the vegetated soils (6 to 12%) and nonvegetated controls (1 to 2%).

The Effect of Mycorrhizal Fungi on the Fate of PCBs in Two Vegetated Systems

ABSTRACT The objective of this study was to investigate the effects of mycorrhizal infection on vegetative uptake of polychlorinated biphenyls. Feltleaf willow (Salix alaxensis) and balsam poplar (Populus balsamifera) were grown in soil spiked with 6 mg/kg 3,3′,4,4′-tetrachlorobiphenyl-(UL-14C). The fungicide Daconil2787® was employed to suppress indigenous mycorrhizal infection. After 100 days of greenhouse incubation in semienclosed phytoreactors, mycorrhizal infection was found to be approximately threefold higher in the untreated willows vs. the fungicide-amended willows. Radio-label uptake was found to correlate most highly with mycorrhizal infection in the willow roots (R = 0.83). Over the same time period, mycorrhizal infection in the poplars was not significantly affected by fungicide addition. In the poplar phytoreactors, radiolabel uptake was most highly correlated with water use (R = 0.70). The overall vegetative radiolabel uptake was low (≈ 1%), but the limited uptake was attributed to soil sorption processes rather than vegetative limitations.

Assessing the Performance of a Cold Region Evapotranspiration Landfill Cover Using Lysimetry and Electrical Resistivity Tomography

In order to test the efficacy of a cold-region evapotranspiration (ET) landfill cover against a conventional compacted clay (CCL) landfill cover, two pilot scale covers were constructed in side-by-side basin lysimeters () at a site in Anchorage, Alaska. The primary basis of comparison between the two lysimeters was the percolation of moisture from the bottom of each lysimeter. Between 30 April 2005 and 16 May 2006, 51.5 mm of water percolated from the ET lysimeter, compared to 50.6 mm for the the CCL lysimeter. This difference was not found to be significant at the 95% confidence level. As part of the project, electrical resistivity tomography (ERT) was utilized to measure and map soil moisture in ET lysimeter cross sections. The ERT-generated cross sections were found to accurately predict the onset and duration of lysimeter percolation. Moreover, ERT-generated soil moisture values demonstrated a strong linear relationship to lysimeter percolation rates (R–Squared = 0.92). Consequently, ERT is proposed as a reliable tool for assessing the function of field scale ET covers in the absence of drainage measurement devices.

Variability, Seasonality, and Persistence of Fecal Coliform Bacteria in a Cold-Region, Urban Stream

Fecal coliform FC analyses were conducted on weekly water samples collected from a single watershed over a 2-year period in Anchorage, Alaska. Although peak FC concentrations 100 FC/100 mL were observed primarily during the warmer months, lower FC levels 20 FC/100 mL could be observed throughout the year in the urbanized portion of the watershed. Me- dian annual FC counts ranged from 3 FC/100 mL at an undeveloped site to 49 FC/100 mL at one of the urbanized sites. Median FC concentrations were found to be significantly higher in the summer compared to the winter at two locations directly downstream from a lake p=0.011 and 0.029, but not at the sites up- stream or distant from the lake. FC-discharge relationships indicated a significant negative correlation between FC concentration and discharge at two sites p =0.030 and 0.035 and no significant correlation at the remaining three sites. In total, the results indicated that the water quality was impacted not only by peak

A Numerical Simulation of Evapotranspiration Landfill Cover Performance at Three Cold-Region Locations

The use of evapotranspiration (ET) covers for final closure of landfills has seen increased use over the last several years. This increase is in part due to economics and public acceptance. The ideal climatic regions for the use of ET covers are arid and semi-arid regions. To date the use of ET covers has not been thoroughly investigated in cold regions. The purpose of this paper is to investigate the use of ET covers in Alaska. Water and energy balances were calculated for hypothetical ET covers using daily weather data during the period 1986 to 1999 for the three population centers in Alaska Juneau, Anchorage, and Fairbanks. The SHAW (Simultaneous Heat and Water) model was used to make these calculations. Results from these simulations show that an ET cover would most likely be effective if used in regions with climatic conditions similar to Fairbanks and possibly Anchorage depending upon the type of soil selected. According to this analysis, these results are due to relatively cold and dry winters in these regions as well as the period of maximum evapotranspiration roughly corresponding with the period of maximum precipitation.

Surfactant addition enhances the hyphal uptake of PCBs and aldrin by mycorrhizal fungi in liquid culture.

Abstract Mixed liquid cultures of ectomycorrhizal fungi were incubated in the presence of common soil contaminants (aldrin and PCBs) and three commercial surfactants (Surfonic® L24–9, Surfonic® T‐20, and Rexophos JV‐05–015). Two surfactants (Surfonic® L24–9 and Surfonic® T‐20) significantly increased hyphal growth under carbon‐limiting conditions, thus implying surfactant biodegradability. All three surfactants increased the hyphal uptake of contaminant‐derived radiolabel during a 10‐day incubation. In addition, surfactants enhanced radiolabel uptake during an extended 30‐day incubation, while hyphal growth slowed considerably after ten days. Results of this experiment provided evidence that surfactant addition may be a useful augmentation to mycorrhizae‐mediated phytoremediation.

Evapotranspiration Cycles in a High Latitude Agroecosystem: Potential Warming Role.

As the acreages of agricultural lands increase, changes in surface energetics and evapotranspiration (ET) rates may arise consequently affecting regional climate regimes. The objective of this study was to evaluate summertime ET dynamics and surface energy processes in a subarctic agricultural farm in Interior Alaska. The study includes micrometeorological and hydrological data. Results covering the period from June to September 2012 and 2013 indicated consistent energy fractions: LE/R net (67%), G/R net (6%), H/R net (27%) where LE is latent heat flux, R net is the surface net radiation, G is ground heat flux and H is the sensible heat flux. Additionally actual surface evapotranspiration from potential evaporation was found to be in the range of 59 to 66%. After comparing these rates with those of most prominent high latitude ecosystems it is argued here that if agroecosystem in high latitudes become an emerging feature in the land-use, the regional surface energy balance will significantly shift in comparison to existing Arctic natural ecosystems.

Aerial Application of Herding Agents can Enhance In-Situ Burning in Partial Ice Cover

ABSTRACT In situ burning (ISB) aided by herding agents is a promising tool for oil spill response in Arctic waters. An advantageous aspect of the herder mediated ISB approach is that the applicatio...

Environmental Partitioning of Herding Agents Used During an In-Situ Burning Field Study in Alaska

ABSTRACT # 2017-148 2017 In-situ burning presents an attractive oil spill response option with high oil removal efficiency and low personnel requirements. In recent times, surfactant chemicals term...