Estimating diluted bitumen entrained by suspended sediments in river rapids using O2 absorption rate

Abstract

Suspended sediments and river rapids can cause oil slicks to fragment and sink, greatly complicating the cleanup process of a spill. Responders need methods for estimating the severity of spilled oil entrainment in rivers in order to properly plan resource allocation. This work presents a novel technique for predicting the amount of oil entrained by suspended sediments in rivers, using the atmospheric oxygen absorption rate of rivers as a way to estimate the surface turbulence. The technique may be used by measuring the gas transfer velocity or by using parametric equations for gas transfer velocity based on river parameters such as slope, depth, and discharge rate. In very turbulent rapids, 13 % of a diluted bitumen slick could be brought down by clay-sized sediments in about 10 min if the sediment concentration is high enough, and 80 % would be brought down in 2 h.

A Review of River Oil Spill Modeling

“…On the one hand, these studies have provided valuable information and guidelines for future research and development, as well as techniques and tools for practical use. For example, the study by Danchuk and Willson [47] has highlighted the need for implementation of detailed shoreline mapping in order to provide more realistic model results for contingency planning, Perez et al [49] has provided the oil spill responders with a tool for estimating the amount of oil entrained by suspended sediments in the river, and Zhu et al [50] have developed a management tool for potential clean-up activities.…”

“…Based on the obtained results, Perez et al [49] have reported that in very turbulent rapids, approximately 13% of a diluted bitumen slick can be entrained by clay-sized sediments in a period of roughly 10 min, while 80% of a diluted bitumen slick would be entrained in approximately 2 h. The authors have also noted that sediments attached to oil probably remain in suspension until turbulence level drops, with oil-sediment combination later sinking to the bottom of the river. The authors conclude that by using readily available GTV data, the developed technique can be used by oil spill responders to make rapid predictions of quantities of oil entrainment by sediments.…”

“…Perez et al [49] have developed a novel technique for predicting the amount of oil entrained by suspended sediments in rivers, with the techniques being based on the use of the river's atmospheric oxygen absorption rates to estimate the surface turbulence. Namely, the authors have hypothesized that the gas transfer velocity (GTV) of atmospheric oxygen into water can be used as a substitute for turbulence in order to extrapolate the laboratory results to real-life river environment.…”

Methylated cycloalkanes fuel a novel genus in the Porticoccaceae family (Ca. Reddybacter gen. nov)

“…MCH was the most abundant cycloalkane in Macondo oil and it was the most abundant compound released aside from natural gases (Reddy et al, 2012). MCP and MCH are additionally frequent components of natural gas condensate or natural gas liquids which enable pipeline transport of heavy oils and bitumen, with multiple high‐profile pipeline ruptures in the recent past (Supplementary Table 1; Agrawal et al, 2011; Perez et al, 2016; Walker et al, 2016). MCH and MCP are additionally of interest because their carboxylic acid counterparts (cyclohexane carboxylic acid and cyclopentane carboxylic acid) are often intermediate compounds in beta‐oxidized alkylated cycloalkane and alkylated cyclo‐carboxylic acid (also called naphthenic acid) degradation (Herman et al, 1993; Perry & Gibson, 1977).…”