Oil Spill Dispersants
Response to an oil spill at any stage has one important primary goal - to minimize the impact of the spill on the environment. Complete recovery of oil is rarely possible due to weather conditions or the size of the spill.
The challenge then becomes one of preventing oil from reaching the shoreline where damage to natural and commercial resources can be considerable.
All of Nalco’s oil spill dispersants have to pass stringent third part performance evaluations before being accepted for use by the Environmental Protection Agency (EPA). Furthermore, extensive environmental testing has to be performed on all oil spill dispersants to ensure that their impact on the aquatic environmental is minimal. For this reason, only those components that are known to have favorable environmental properties are used in oil spill dispersant products. Many of these components are readily used to stabilize food products, cosmetics or in pharmaceuticals.
How Dispersants Work
Dispersants contain both surface-active agents (surfactants) and solvent systems. Each surfactant molecule has both a water-soluble ‘head’ group and an oil-soluble ‘tail’. After contacting an oil slick on water, these molecules diffuse through the oil to the oil/water interface under the slick.
The surfactant acts to lower the oil/water interfacial tension, which means it lowers the energy needed to mix the oil into the water. This makes it easy for the oil to disperse into the water phase as discrete droplets. Each droplet has a molecular layer of surfactant molecules around it which helps to prevent the droplets from recombining and keeps them dispersed in the water phase. Through wind and wave action, the droplets are formed, dispersed throughout the water column and removed from the surface spill location. The droplets remain in suspension in the upper water column, stabilized by the surfactant molecules, thereby minimizing the adherence to fish, birds, boats and the shoreline. The tiny oil droplets are then consumed by natural bacteria in the water column removing the oil from the ecosystem.