Oil-Water Seperation Flashcards
What is “oil and grease”?
Oil and grease is defined as any material soluble in n-Hexane solvent. This includes biological liquids (animal fat) and mineral hydrocarbons (gasoline, diesel oil and lubricants).
What types of industries produce wastewater containing “oil and grease”?
Petroleum (refining and storage), metal (grinding), food (animal processing) and textile (scouring natural fiber).
What is primary treatment of oily waste?
This is the process of gravity seperation of -FLOATABLE- oil and grease from water and emulsified oily material.
What is the secondary treatment of oily wastewater?
Treatment in which emulsified oil is treated and seperated from water.
What is the most common device for primary treatment of oily wastewater?
Gravity type seperators are the most common devices employed in oily waste treatment.
What is an oil-water emulsion?
A mixture of oil and water in which oil is held in suspension in water and does not easily float to the surface.
What affects the efficiency of a gravity oil seperator?
It depends on proper hydraulic design and the detention time of the liquid in the tank.
What is an “API” seperator?
API stands for American Petroleum Institute. The equipment is a common device used to seperate floatable oil from water, based on a design or standards set by the API.
What is the expected removal efficiency of floatable oil from a gravity (API) seperator?
For floatable oil, 60-99% removal can be expected.
What are considered grease and oils?
Hydrocarbons, fatty acids, soaps, fats, waxes, oils and any other materials extracted by n-Hexane from an acidified sample.
What kinds of problems can oil and grease cause for a biological wastewater treatment plant?
They are not easily decomposed by bacteria and tend to coat surfaces. The particles of oil and grease interfere with biological action and cause maintenance problems. In addition, oil and grease may increase the demand for oxygen.
What is the objection of allowing oil and grease to be discharged into streams?
They can interfere with natural re-aeration. They are toxic to certain species of fish and aquatic life. They can create a fire hazard, when present on the water surface in sufficient amounts. They can destroy vegetation along the shoreline. They can render boiler-feed and cooling water unusable. They can impact odor and taste of drinking water. They can create unsightly film on the surface of water.
