Chemical characterization of the ohmsett tank water: Filtration and potential impact on dispersion effectiveness

The dispersion effectiveness depends on a variety of factors, and in particular water chemistry. The current study had the goal of characterizing the chemical properties of the water in the Ohmsett wavetank in New Jersey, which is owned by the Department of Interior Bureau of Safety and Environmental Enforcement. In particular, the study aimed at evaluating the filtration efficiency of the cellulose/diatomaceous earth (CDiA) filter (operating continuously) and the powder activated carbon (PAC) chambers placed occasionally into the tank. It was found that the CDiE filter was effective in removing total organic carbon, benzene, and surfactants from water. The latter was deduced based on the increase in the water's surface tension following filtration. The results suggest that the PAC was not effective in removing TOC or surfactants from the water. The PAC actually leached ethylbenzene and xylene back into the water on the third and fourth day of sampling. This suggests that using the PAC is not needed in the Ohmsett tank for the purpose of conducting dispersion effectiveness testing. Measurement of the ions revealed that, occasionally, the hardness of the Ohmsett water, drops below the value observed in oceans, which is 6,500 mg/L as CaCO3, which could enhance oil dispersion in comparison to what occurs in oceans. Therefore, it is important not to only conserve the total ion concentration (i.e., salinity) but also hardness, and thus sodium or sulfate ions are good substitutes for calcium and magnesium ions.