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If you own a restaurant, a cafeteria, a hotel or perhaps a hospital you would know about the challenges associated with the maintenance of a commercial kitchen. There are different impurities generated, excess of humidity, more of heat from the kitchen appliances/equipment and of course, the waste produced during the cooking process. And, you even need to stay by the laws that are quite stringent. All of these problems can be taken care of if you have a well-designed commercial kitchen. However, the main design challenge lies in tackling the grease problem. But you can certainly get out of this problem with the presence of Grease Trap or grease removal device in your plumbing system. It is one of the major solutions to the problems involved with the industrial grease management. So, before we move onto the solution, let us get to the core of grease problems.
Grease is a complex of chemical compounds found in an industrial kitchen. It is categorised into two different types: brown grease and yellow grease. The latter is regarded as Recycled Vegetable Oil (RVO) which is the resultant of the recycled cooking oil recovered from deep fryers and griddles. This yellow grease is actually as valuable as gold – due to its versatile nature it is used in manufacturing soap, rubber, detergents, fuel, animal feed and even clothes. So, it’s an incredible $2 billion industry On the contrary, the brown grease is the fats, oils, and fog generated as food waste during the cooking process. The brown grease is perceived to have of no use and so it is discarded down the kitchen sink which is typically connected to a sewer or a local wastewater disposal system. That is a different matter that new technology is showing a potential to recycle even the brown grease – though it is not happening currently at a substantial level. The amount of grease generated by commercial kitchen depends on the frequency and the type of cuisine prepared. Though it sounds good enough to get rid of this brown grease by discarding, it could create a havoc if not treated properly. When you dump the warm grease in the sink it appears in the liquid form. But as it moves through the plumbing ducts and the temperature falls, it turns into a thick sturdy mass which could cause a lot of serious consequences. (Think about the bad cholesterol that clogs your arteries when you don’t take proper care of your body. You know what happens right? The case is similar with the grease) Consequently, the hardened grease leads to blockages in sewer collection lines causing overflow of waste water from the sewers. It sticks to the inner walls of the drainage pipes and inhibits the smooth flow of water down the pipeline. Even use of detergents and bleach to clear the line cannot fix the issue. It may seem to solve it initially. But later the mixture turns back to thick solid mass. Have a look at the list of serious problems caused due to these blockages.
The overflow of wastewater can cause a severe damage to the property and environmental contamination in the locality.
The overflow can have a negative impact on the wastewater collection system where the wastewater is recycled. It may deteriorate a wastewater treatment facility’s ability to treat the wastewater appropriately.
Furthermore, the overflowing wastewater may enter rainwater pipes and gullies leading its way to streams and rivers. Ultimately, it pollutes our freshwater bodies and the natural ecosystem. This is a serious threat to the public health.
The clogged sewer lines outside your food establishment or the building can cause putrid grease backups into your kitchen, the parking lot or other possible areas. It can also invite a host of bacteria, viruses, parasites, fungi to cause serious diseases to your kitchen staff and other workers. Moreover, this may even put your customer’s health at risk. You may find it extremely difficult to find someone willing to dine at your restaurant while the entire place is filled with a foul odour.
The regurgitation of the grease can also lead to rat infestations.
All the points mentioned above will take a toll on your business and reputation. You will have to spend a hefty amount of money to treat the problem.
All in all, you will have to pay the fine to the local authorities for violating the grease management regulations. For example, one of the US cities has imposed a fine of $1000 per day for violating the grease rules.
Approximately, $2 million is spent annually on treating the aftermath effects of grease including the maintenance of infrastructure and management of overflow/spills
In the US, 50% of sewer overflows are due to grease blockages. About 10 billion gallons of raw sewage spills are encountered every year
The UK faces a total of 200,000 blockages in sewer lines every year. The most crucial point to be noted here is that 75% of these blockages are caused due to grease.
The clean-up costs due to blockages in the UK goes beyond millions of pounds which is reflected in the customer’s bills.
As per the EPA analysis, the leading cause of sewer overflows and blockages is grease.
According to EPA, 47% of blockages are reported due to grease discarded inappropriately from restaurants, commercial buildings and homes As you have already understood the negative impact of grease on your business, your neighbourhood and the city, we move onto prevent these problems in future with one simple but incredible solution – Grease Trap.
Grease trap or grease interceptor, its one and the same. You may also call it as a grease recovery device if it has grease removal capabilities or a grease converter. So, what exactly it does? A grease trap is a plumbing fixture (part of the plumbing system) that traps fats, oils and greases and lets the wastewater flow smoothly through the drainage system. In other words, it separates solid waste and grease from the liquid waste. A grease recovery device or grease removal unit is a grease trap with an inbuilt mechanism or process for removing the trapped grease and depositing it in a separate external container. These units usually come with solids filtration. The key benefits are that the unit does not need to be pumped anywhere near as often as a traditional grease trap. A grease interceptor is a box-like container made out of stainless steel, plastic, cast iron or concrete. It is installed in between the kitchen sink and the sewer system. It is placed in such a way that only kitchen wastewater can pass through it – meaning, it does not serve the entire drainage system which also includes waste from toilets. The size of the grease traps varies from having a capacity of 35 litres to 45,000 litres and greater. These can be found inside the industrial kitchen (under-the-counter), outside the building where it can be located above or below the ground. But how do these work? Let’s have look at the science behind its functionality.
Grease Trap is a plumbing fixture where all the solid fats, grease and fog accumulate. It is a tank-like structure that allows the hot wastewater from the kitchen sinks to enter. The conventional Grease Traps also known as passive Grease Interceptors work on the principles of gravity. As the hot wastewater enters the Grease Trap, it acts as a reservoir and controls the flow of water until the grease separates from the wastewater. However, the flow of water is not controlled by the trap but an internal baffling or a control unit that slows down the flow of wastewater. In the meantime, hydrolysis takes place inside the Grease Interceptor. A process where complex solid particles breakdown due to reaction with water. In simple words, when the temperature of wastewater decreases, the fog starts separating. The fog disintegrates into glycerols and fatty acids. Because glycerols have a higher density than water, they settle down as solid fats at the bottom. The fatty acids are lighter than water and float on the top. In between is the wastewater. As soon as the glycerol and fatty acids are separated by the impact of gravity, the Grease Trap lets the rest of the wastewater flow out of the tank smoothly down the ducts. The rate at which the grease (fatty acids and glycerols) separates highly depends on factors like temperature, viscosity, grease particle size and the retention time. For the optimum functioning of the Grease Interceptors, it is crucial to use standpipes, internal baffles and flow control devices. These additional units maximise the retention time and provide more space by lengthening the flow path. At a later stage, the flow control device also allows mixing of air for effective separation of grease from effluents. These additional units are installed at the inlet side of the Grease Traps. The larger traps are the passive traps that entirely depend on gravity mechanism. The smaller traps used indoors are known as the hydro-mechanical Grease Interceptors. In a grease removal device the trapped grease is usually skimmed into an external container.
Size of an industrial Grease Interceptor is very important to consider. It should perfectly align with the size of the plumbing fixtures. A trap that is larger in size may damage things down the pipeline due to the production of sulphuric acid within the tank. If it is smaller than the size required, it may not effectively trap the grease and demand for a frequent clean-up. The size of the Grease Trap is measured taking the rate of the incoming flow into account. This rate is measured in gallons per minute (GPM). Three most significant factors that influence the size of Grease Interceptor are:
Values of Drain Fixture Unit (DFU)
Volume of total number of fixtures in the flow path
Wastewater pipe’s diameter
To find out which size suits best, it is crucial to have a professional or manufacturer that can provide the necessary charts and calculations along with the info on GPM and the diameter of the pipe. Based on the local laws you may also have to consult the local health and hygiene department to ensure that the Grease Trap you are installing fits your requirements.
It goes without saying that if you don’t maintain the Grease Trap as per the guidelines, it is equal to not having the trap installed at all. So, have a look at the necessary guidelines for optimum maintenance.
The Grease Interceptor should be cleared as soon as the amount of grease, fog and oils reach 25% of the total depth of the trap (the tank)
Or clear the tank every 90 days (depends which one occurs first)
Have a thorough check of all components that may affect the proper functioning of Grease Trap
Avoid use of enzymes and other agents that may cause the grease to leave the trap along with the wastewater.
The Code of Uniform Plumbing recommends not to attach dishwashers to the trap. As detergents and other chemicals can emulsify the fog, making the trap unusable Try keeping a record of the maintenance activities and necessary guidelines Empty any solids filter baskets or grease collection containers when full The guidelines mentioned above require an inspection by the waste management team. They can also help you to open the Grease Interceptor for the periodic check. Besides maintaining the trap, it is important to clean your drainage lines regularly. How often you need to clean the drainage lines depends on the fall in the lines, the usage and other factors. Well, if you want your drainage line to work at its best, have it cleaned at least once in a year – or perhaps at a higher frequency if the need arises.
Following certain green practices inside the industrial kitchen can enable your Grease Trap to serve you for years together. There are few very simple guidelines that can reduce the amount of grease, oils and solid fats entering the Grease Interceptors. Avoid disposing of used cooking oils in the sink. Instead, keep it aside for recycling. Scrap the food from serving plates and dishes before washing it. Avoid disposing of hot wastewater into the sink. It is best to reduce its temperature and then dispose of. This will enhance the functionality of the Grease Trap. Have the details about the wastewater volumes generated in your commercial kitchen along with the flow rate. Both the factors should correspond to the trap’s design capacity. Try installing pre-treatment devices that minimise the contaminant levels in wastewater from sculleries or kitchens Avoid using running water for thawing frozen food. Train your kitchen staff to follow the green guidelines. This will help you stay away from the grease problems discussed above. More importantly, it will help you to keep your property premises and the neighbourhood clean and green. So, when the food and health inspectors come for the regular rounds, you need not worry at all. Thus it is crucial to install grease trap into your plumbing unit. Now that you have mastered the significance of using Grease Interceptors, we are sure you will have them installed and maintained diligently.