Purpose:
Protecting sewer collectors from clogging with greasy wastewater. A grease trap (also known as a grease interceptor, grease separator, or grease catcher) is a container equipped with two chambers: primary settling and grease accumulation, secondary settling. The cleaning of greasy wastewater occurs in a gravity-driven mode. The principle of operation is gravitational. Greasy wastewater is directed to the first compartment for separating solid substances and sludge.
After separating the main mass of suspended solids, the water flows by overflow into the grease separation compartment. The separation of grease is based on the difference in the specific gravity of grease and water.
The separated fats float to the surface, while the purified water is discharged into the sewer system or further treatment through the outlet pipe. The degree of purification meets the discharge standards into the municipal sewer.
- Types of grease traps:
- Cylindrical vertical grease traps.
- Cylindrical horizontal grease traps.
- Rectangular grease traps.
Grease traps for sinks.
Components:
To control the processes occurring in the tank, it is proposed to use a level measurement system - a level indicator and level sensors. The level indicator is a device that determines the filling of the tank. It is available in several modifications:
- for oil (grease)
- for water
- for sand
The level indicator for grease (oil) is a device that determines the degree of filling of the sedimentation tank with a mixture of grease (oil). Grease (oil) accumulates in the tank on the surface of the water. The control device determines the amount of grease (oil) and emits light and sound signals if the volume of grease (oil) in the tank exceeds the norm. The volume of grease (oil) should not exceed certain limits. This is monitored by a tank sensor. Also, the device provides for the possibility of connecting a two-electrode overflow sensor, which monitors the degree of clogging of the drain pipe and, as a result, the overflow of the sedimentation tank. The sensor is connected to a measuring device, which is installed inside the building, in a convenient place for observation.
Operation Principle:
Fats and oils suspended in the effluents have lower density compared to water. The suspension settles, and fatty inclusions float to the surface. This is the basic principle of operation of the grease trap: to capture grease, collecting it on the water surface.
The collected grease and oil in the upper part must be periodically removed for subsequent disposal. The removal interval is selected to avoid the decomposition of rapidly decomposing organic matter and the occurrence of unpleasant odors.
Grease Trap Device: The grease trap is a cylindrical tank made of monolithic sheet polypropylene, the internal volume of which is divided by special-shaped partitions into four chambers. At the top of the housing is a manhole with an insulated cover.
The wastewater with oil and grease content flows through all chambers sequentially. Overflow in the partitions reduces the flow rate and temperature of the wastewater. Grease floats to the water surface, while solid substances settle at the bottom.
The purified wastewater is directed to the public sewage system. Grease, oils, and sediment gradually accumulate inside the tank, which is cleaned by specialized service companies as it fills up.
To prevent odors from escaping, the tank is hermetically sealed with a lid equipped with a seal.
Grease traps are designed to handle incoming wastewater in the temperature range from 0 to 60°C.
For accurate calculation, the following factors need to be considered:
Requirements for the degree of pollutant removal;
Number and type of connected water users;
Characteristics of incoming wastewater - both in terms of quality and quantity;
Configuration of the wastewater collection network;
Availability of space for installation;
Accessibility for maintenance;
Method and frequency of removing detained pollutants, etc