The guide to the SAS MIST - Step by Step
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SAS MIST Process
Today I am going to walk you through the SAS Environmental Services MIST process. This is a process for the treatment of liquid oil waste such as mud slops, oil sludge, and refinery waste. Normally, this waste will be stored in a tank, in a pit, in a lagoon, or in a mud skip.
Waste Preparation
The first thing we need to do is prepare this waste for effective and proper treatment and make sure we achieve the best results possible. We use a pump, because this is a liquid waste that we are dealing with to pump the waste from the storage. The slops or sludge is pumped into our Waste Preparation Module. This is a dual blend tank setup based within a 20-foot frame. What those to blend tanks allow us to do is ensure that the waste goes into the Separation Stage in the best possible condition for treatment.
The variability of oil waste is enormous and the more we can standardize what goes into the treatment phase, the more successful we will be in the outcomes. These dual blend tanks allow us to do a few things that are very beneficial in the treatment of oil waste.
First of all, if the waste is very high in solids, the blending tanks will allow us to reduce the solids content in the waste by adding some amount of water, oil or another solvent. This allows us to create waste with an overall lower solids content. This helps to improve the effectiveness of the decanter centrifuge at the separation stage. Also, there are times when we have very viscous waste, and adding a solvent can actually help reduce the viscosity. That in its own right can help at the separation stage when we want to remove the solids from the waste.
Innovative chemistry
The other thing we can do at the blending tanks stage is to add the SAS SludgeTreat products. This the chemistry that makes SAS-ES such a unique company. What the chemistry will do is start to work on the oil and the solids and begin to create that separation effect. We can do this inline right before the separation stage, but doing it at the waste preparation module stage gives us the opportunity to blend a little bit longer is needed. For example when the waste is particularly difficult, when there are as many different chemicals present in the waste, or when we have a higher solid loading.
The other benefit is that sometimes by blending chemistry and oil sludge for a longer period of time, it can actually reduce chemical dose rate a little bit. So, this is a very good capability to have in front of the separation stage. What it allows us to do by using those two blending tanks is that one blending tank is preparing the waste and mixing, the other blending tank is feeding the decanter. In effect, what we have enabled is a continuous batch process.
The SAS MIST Engineering
The MIST system itself, the separation stage, has a pump which will pump the waste from the relevant blending tank. This waste will then be processed through the decanter centrifuge which forms the core of our MIST treatment stage. This decanter is very robust. It has been proven in the field for decades. It does a fantastic job, and because our chemistry is now so thoroughly mixed into the waste, what you get is very dry solids recovered. These solids will come out the side of the MIST unit through a discharge port, and the solids are disposed off in a skip or in a pit that is located next to the treatment system.
The MIST process produces very dry solids, so we do not get a wet sludge coming out the side. And of course, dry solids minimizes the amount of waste for disposal because all the liquid that you would normally get into this “wet solids” discharge would have to be paid for at the disposal site. By producing a really dry, nice, powdery sludge, you get a fantastic result because of the SAS SludgeTreat chemistry.
The other discharge coming out of the decanter centrifuge is the liquid centrate. This is a mixture of the oil and the water. The centrate is pumped from the decanter out of the MIST system. The centrate is placed into a storage tank. In the storage tank, because the system has removed virtually all of the solids and because the SAS SludgeTreat chemistry is present, the oil and the water are simply going to separate under gravity.
The oil is going to float to the top. You can recover this oil. You can sell it. You can reuse it. You can run a generator of it. Sometimes, you might want to bring that oil back to the preparation stage and dilute heavy sludge if that is what you are treating, and on the other end, you will be recovering the water. The water can either be discharged to the surface, to a sewer, go to a wastewater treatment plant, undergo further cleaning or filtration, depending on where you are, what the regulations and your permits are.
That, in a nutshell, is the MIST process. It is very effective. It is very robust. It handles virtually any type of liquid oil waste. If you want to know anything more and you have any questions, then do not hesitate to email us or give us a ring and get in touch with us. We would love to hear from you. Thank you.