The term “liquid waste” refers to any type of waste that exists in liquid form rather than as a gas or solid.
It is a broad term that encompasses even waste that was originally produced as a gas but was converted to liquid form for easier handling.
Human and animal excreta, household wastewater, cooking oil, fats, and grease are all examples of liquid waste.
What are the examples of liquid waste in kitchen?
Sewage and sullage are the most common types of liquid waste. Sewage is wastewater that contains human waste, whereas sullage is wastewater that generally results from everyday activities, such as washing and cooking residue, and does not contain human waste.
The final term, runoff, refers to water that naturally occurs as a result of natural activities such as rain and water from dams and ponds.
Runoff can carry a variety of waste, including human excrement, posing a significant health risk.
Read also: Types Of Food Waste In Restaurants
Commercial liquid wastes
The wastewaters from commercial areas, which include business establishments, shops, open market places, restaurants, and cafes, will be similar to those from households.
This is due to the fact that only human-related activities are carried out in these areas, as opposed to other activities such as industrial production.
Restaurant and cafe effluent may contain high levels of oil from cooking processes,
but this can be mitigated by installing a grease trap in their outlet pipes. A grease trap is a small tank or chamber that slows the flow of effluent.
Fats, oils, and grease float to the top of the wastewater in the grease trap and form a layer of scum that is contained within the tank.
Industrial liquid wastes
In industrial areas, liquid wastes are generated by processing or manufacturing industries’ kitchens, as well as service industries’ kitchens such as car repair shops. The composition of waste is determined by the type of industry.
Wastewater from food processing plants will not be harmful to humans, but wastewater from other industries may contain a variety of chemical compounds, some of which may be hazardous.
Industrial wastewaters containing hazardous substances must be treated and the hazardous substances removed before being discharged into the environment.
Although it is not a type of liquid waste in the same way that waste from residential kitchen, commercial kitchen, and industrial kitchen areas is, it is a type of wastewater.
Stormwater can be contaminated by a variety of pollutants, including faeces, soil, rubber from vehicle tyre wear, litter, and vehicle oil.
During the rainy season, many parts of Ethiopia are subjected to massive amounts of stormwater.
Stormwater may be channelled into sewers or flow into open ditches where there is a sewage network (a system of sewers).
Read also: Causes Of Food Waste In Restaurants
What are the characteristics of liquid wastes?
Solids: Wastewater may contain solid particles carried along in the flow. These could be settleable or suspended solids.
When the flow rate is reduced, such as when wastewater is stored in a tank, settleable solids sink to the bottom (settle out).
Suspended solids are small particles that remain suspended in water; they do not dissolve but are carried along in it.
By filtering and weighing the solids in a given volume of water, the solids content can be determined.
Temperature: Wastewaters are generally warmer than the surrounding air. This is because warm or hot water from domestic activities such as showering or industrial processing may be included in the waste stream.
Odour: Wastewaters can have an odour, which is usually caused by the release of gases as a result of biodegradation.
The breakdown (decomposition) of organic substances by bacteria and other microorganisms is known as biodegradation.
Organic matter is defined as any substance derived from living organisms, including human and animal waste, food waste, paper waste, and agricultural waste.
Odour detection is a subjective process, but it is possible to quantify it using odour units.
Proper waste disposal is required to keep your environment clean and healthy. Hotels ‘ owners must reduce food waste to avoid untidy environment and diseases.
The source determines the example and composition of liquid waste. Households, commercial establishments, and industries are the primary sources in urban areas.
To establish proper waste management processes for dealing with liquid wastes, we need accurate information on their characteristics.
This study session will teach you about the main sources of liquid waste and different ways to classify them.