Why oil and grease determination in wastewater analysis is important?

Oil and grease includes fats, oils, waxes, and other related constituents found in water, generally wastewater. If these compounds are not removed before discharge of treated wastewater, oil and grease can interfere with biological life in surface waters and create unsightly films.

What are the sources of oil and grease in water?

Lakes, rivers, stormwater runoff, and wastewater are all monitored for oil and grease. Sources of oil and grease are mainly anthropogenic. Oil and grease typically needs to be contained and/or recycled to keep them from entering the environment.

How do you remove oil and grease from wastewater?

Removal requires chemical addition to lower the pH followed by addition of dissolved oxygen or nitrogen to remove the emulsified oils as they break free from the wastewater. Dissolved Oil is a true molecular solution within the water and can only be removed with biological treatment.

How does oil affect water?

Environmental impact of oil Just 1 litre of oil can contaminate 1 million litres of water. Oil pollution can have a devastating effect on the water environment, it spreads over the surface in a thin layer that stops oxygen getting to the plants and animals that live in the water.

Why oil and grease should be removed from waste water?

Removal of free oil and grease from a wastewater stream reduces the potential for equipment problems to occur further downstream. Removal requires chemical addition to lower the pH followed by addition of dissolved oxygen or nitrogen to remove the emulsified oils as they break free from the wastewater.

What is the need to determine the amount of oil and grease in a wastewater?

To determine the amount of oil and grease that present in the water sample we use the partition gravimetric method. This method involves the extraction of dissolved or emulsified oil and grease from water by using an extracting solvent.

How do you know if oil or grease is in water?

How is oil removed from wastewater?

Free Oil or floating oil is removed by either skimming the surface in the skim tank or by gravity separation in the API separator. Emulsified Oil is comprised of oil droplets in stable suspension within the wastewater.

How to test for oil and Grease in water?

Methods that employ CFC-113 as the extraction solvent and that were approved for testing of oil and grease in water at 40 CFR Part 136 are EPA Method 413.1 and Standard Methods No. 5520B. EPA withdrew these methods in the final rule published March 12, 2007. The only method approved for testing oil and grease in wastewater is EPA Method 1664A.

What happens to oil and Grease in wastewater?

Both natural oils and synthetic oils need to be addressed for wastewater treatment. Oils and grease within an industrial wastewater discharge can create problems for the following regulated parameters: heavy metals (like zinc and nickel) and organic loading (like BOD and COD) and turbidity (water is murky) and also TSS (total suspended solids).

How is the TPH of oil and grease determined?

N-Hexane was chosen as the alternate solvent because it most closely approximated the results of the Freon extractions. Total Petroleum Hydrocarbons (TPH, or the hydrocarbon portion of Oil and Grease) was determined using an Infrared Spectrophotometer, and with the updated method (EPA 1664) TPH can be determined gravimetrically.

How is hexane extracted from oil and grease?

Silica gel is added to the sample in the ratio of 3 grams for every 100 mg of hexane extractable material. Once mixed, the slurry is filtered, and the filtrate is heated to evaporate the hexane to leave behind the Hydrocarbon fraction in a pre-weighed vessel.