What is FOG?
FOG stands for “Fats, Oils and Grease” found in kitchens and food service establishments (FSEs). The main contribution of FOG is from discharge of used grease from cooking processes. Also, many of the foods we eat contain FOG; these include meats, sauces, salad dressings, deep-fried dishes, cookies, pastries, butter and many others. Generally, food scraps washed down the drain contribute to FOG in the sewers. Grease accumulation in the sewer system causes obstruction by constricting flow of the sewer pipes, and interfering with the normal operation of the wastewater treatment system.
FOG stands for “Fats, Oils and Grease” and is found in your kitchen or garage. The main contribution of FOG is from discharge of used grease from cooking processes, but can also be caused by machinery lubricants discharged into floor drains. Many of the foods we eat contain FOG; these include meats, sauces, salad dressings, deep-fried dishes, cookies, pastries, butter and many others. Generally, food scraps washed down the drain also contribute to FOG in the sewers. Grease accumulation in the sewer system causes obstruction by constricting flow of the sewer pipes, and interfering with the normal operation of your community wastewater treatment system.
Fog is a cloud which is in contact with the ground. Much like clouds in the sky, fog forms when the air becomes supersaturated, meaning that it can no longer hold moisture in the form of vapor. As a result, water precipitates out of the air, forming a fine mist of water droplets. If the air becomes saturated enough, the droplets will turn into drizzle or rain. If you’re curious, the foggiest place on Earth appears to be the Grand Banks, an area off the coast of Newfoundland. The warmer air is, the more moisture it can hold in the form of vapor. Fog and clouds, therefore, form when air is rapidly cooled, and the moisture in the air adheres to particles such as dust or sea salt. Clouds form because humid air cools as it rises into the Earth’s atmosphere. Fog can form in a number of ways, although most fog breaks down into either advection or radiation fog. In both instances, the cloudy air is often markedly cooler than neighboring clear air, and it can feel clammy because of all the drop
There are several different types of fog. In the valley, we often see radiation fog which forms when there is light wind, clear skies overnight and moisture near the ground. Moisture within cooling air condenses into water droplets thus forming fog. This is an especially common type of fog in the fall and winter, with the longer cooler nights. Another type is upslope fog which is common in the foothills or the Sierra. This occurs when wind forces moist air up the side of a hill or mountain. As the moist air rises, it condenses and forms little water droplets and then clouds. If the temperature drops below freezing, these water droplets may freeze to surfaces forming rime ice and is called freezing fog. Along the coast we have coastal or advection fog. As warm air passes over the cool Pacific water through advection (wind) it is cooled forming a marine layer. This air is then carried inland by a front or wind created by pressure differences. The fog can be quite thick and will cool temp
A fog is a suspension of liquid droplets captured in a gas – generally air. Both water-based and oil-based liquids can be made into a fog. Because the size of individual droplets in a fog varies greatly, many people describe a fog by its VMD (volumetric mean diameter, or the size of an “average” droplet). You can also describe a fog qualitatively: dry for (under 15 micron VMD), wet fog (20-40 microns), mist (40-100 microns), and fine spray (above 100 microns).
