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NOAA Technical Memorandum OAR ARL ; 278 (Series)

The Field Research Division of the Air Resources Laboratory (ARLFRD) of the National Oceanic Atmospheric Administration (NOAA), in collaboration with the University of Tennessee Space Institute (UTSI) and the Laboratory for Atmospheric Research at Washington State University (WSULAR), conducted a tracer field experiment at the Idaho National Laboratory (INL) during October 2013. It is the first of a series of new tracer experiments to study dispersion from continuous sources in flat terrain using technologies not available during earlier dispersion studies of the 1950s and 1960s. These releases are collectively being called Project Sagebrush. The October 2013 study is designated Project SageBrush phase 1 (PSB1). Five tests were conducted during PSB1, all during the daytime with conditions ranging from near neutral with higher wind speeds to unstable with low wind speeds. Each experimental period consisted of a continuous 2.5 hours SF₆ tracer release with consecutive 10-minute average bag sampling over the last two hours of the tracer release period. Bag sampling was done on four arcs of almost 90 degrees each ranging in distance from 200 to 3200 m from the source, depending on the stability conditions and aircraft availability. The bag sampling measurements were complemented by six fast response tracer analyzers, an airborne fast response analyzer, and an extensive suite of meteorological measurements. This included a 60 m tower arrayed with seven 3-d sonic anemometers and five sets of cup anemometers and wind vanes. Two additional towers at 10 and 30 m height had cup and vane anemometers mounted at 2 and 3 levels, respectively. Three additional sonic anemometers were arrayed on the 3200 m arc to examine the issue of horizontal homogeneity. Additional meteorological measurements were made by two sodars, a radar wind profiler, and radiosondes released just prior to and just after the two hour sampling period. Preliminary analyses have identified some key results. The PSB1 results for the horizontal plume spread parameter σy tended to be larger than the daytime σy found in Project Prairie Grass and those determined from stability class model dispersion schemes (e.g., Pasquill- Gifford curves). The discrepancies increased with increasing downwind distance. However, the σθ and turbulence intensities measured during PSB1 were similar to those measured during the daytime in Project Prairie Grass. The result is that the PSB1 ratios of σy/σθ tended to fall near the upper limit or somewhat above the historical range of values found in previous field studies. Another key point is that the evidence suggests that σy becomes independent of σθ for σθ greater than about 18 degrees. Finally, an investigation extending the comparison of σθ values into stable nighttime conditions found that the values of σθ reported during Project Prairie Grass and PSB1 differed significantly.

Like many mobile home parks, the Paradise Cove Trailer Park began as a getaway RV park located in a picturesque location by the sea. As it’s popularity grew, the park grew into a large mobile home park, outgrowing its wastewater infrastructure. With only septic tanks and seepage pits, the Owner resorted to frequent pumping, shifting sewage from one cluster of pits to another. Finally the Owner bought a pumper truck to handle the cost of transferring water out of failed seepage pits clusters on a daily basis. At that point, the Regional Water Quality Control Board stepped in with Waste Discharge Requirements and a schedule for repairs. The Owner agreed to upgrade collection, treatment, and disposal to substantially improve the system’s performance and reliability. The resulting system will collect wastewater from the 257 mobile homes using a cluster approach. The park flow of 40,000 gpd with peaks of 60,000 gpd will be collected by gravity sewers draining to septic tanks with effluent screens. Multiple tanks will drain to lift stations to pump the water in small-diameter pressure sewers to a centrally-located treatment facility site in a discrete area of the park. Wastewater treated in twenty AX100 textile filters will achieve an advanced secondary level. Disinfection using a redundant UV-ozonation system will match municipal requirements for disinfection. From a dosing tank, the disinfected effluent is redistributed throughout a 20-acre area and dispersed in subsurface drip fields and seepage pit clusters. Key issues associated with the project were the task of navigating through multiple agencies to obtain a permit; identifying a suitable and reliable disinfection system; specifying automatic controls for a system with a large number of distributed components. One of the Owner’s goals was to obtain incidental irrigation from the highly treated effluent, but regulations were seemingly conflicting or absent. This project is one case where a permit for a repair allowed multiple objectives to be met: (1) progress in onsite system technology, (2) incidental irrigation benefits in a water-poor state, and (3) preservation of public health. Incidental irrigation benefits were the vulnerable to prohibition, depending on interpretation where regulations are unclear. Standards for subsurface water recycling are needed to accommodate the agencies’ concerns while maintaining the affordability of the system.

Laboratory research has suggested that isotonic contrast media may be optimal for intravenous digital subtraction angiography (IV-DSA) by generating taller, narrower time-concentration curves. Clinical investigation of low osmolality contrast media has suggested that less patient discomfort is encountered with low-osmolality contrast media than with standard, high-osmolality agents. In order to directly compare isotonic contrast media with a standard hypertonic contrast media, isotonic ioxaglate (Hexabrix-20) was compared with Renografin-76 in a double-blind prospective clinical trial for IV-DSA examination of the carotid artery bifurcation. Isotonic ioxaglate produced superior contrast medium time-opacification curves and produced superior images across four scales of image quality: anatomic "openness" of the carotid bifurcation, contrast level within the carotid vessels, bone misregistration artifact over the bifurcation, and air (soft tissue) misregistration. The bilateral overall score for isotonic ioxaglate was 1.68 vs. 1.37 for Renografin-76, a 23% superiority. The bulk of the superiority occurred in the contralateral carotid artery. Over the four scales, isotonic ioxaglate was 37% better in image quality of the contralateral carotid artery bifurcation. Since the contralateral carotid artery is very often difficult to visualize during IV-DSA, isotonic ioxaglate represents a significant improvement for this imaging modality.