 Greetings students, my name is Mahirupalai, I am assistant professor in civil department WIT, Sallapur. Today we are going to discuss the topic that is up flow anaerobic sludge blanket reactor that is UASB. What are the learning outcomes? At the end of this session students will be able to understand the concept of up flow anaerobic sludge blanket reactor that is UASB. So let us understand that what is been by UASB and why we need to go for UASB. First of all this technique is been developed in 1970 by Gaj Latinga in the netherlands. It is very much suitable for high strength wastewater where BOD or COD is very much higher than normal BOD or COD but it is very much still useful for domestic sewage in warm conditions also. So it can be used for both for the normal strength and for the high strength sewage. It also differs from anaerobic reactors. How? First of all the existence of granular sludge that is resistance to toxic shocks which is having very much high methanogenic activity that is 0.5 to 2 COD per VSS per day or high mechanical strength or good settling properties that is 30 meters to 80 meters per hour. So such type of a system will always provide you to have the highest amount of anaerobic digestion relative to normal anaerobic digestion. It also has the internal three phase GSL separator system that is gas, solids and liquid separator system. By addition of these two systems we can say that USB is normally very much higher to take up and it is having very much higher proximity to consideration for anaerobic treatment. So let us study how the USB mechanism works. So you can see the diagram where the influent is having a lot of pores to come into this treatment facility. It is fully packed as it is anaerobic in nature no oxygen is allowed to pass inside the reactor. Here you can see with the help of distributors the waste water which is coming inside this USB reactor is being separated out throughout the surface area. As the water passes inside this area is known as inlet zone. So this is the first zone. As the water passes above the up flow means above the waste water is flowing above. So as the waste water flows above there is one area in which the waste water is being linked to the microorganisms which are present in this middle part of the tank. Whatever the microorganisms or anaerobic microorganisms which are present in this tank will attack on the organic matter which is present in the waste water and automatically they are going to be digested. And they are going to be digested to form two things. One is biogas and another one is biomass or the sludge. Normally biomass is around 5% of the total organic matter. So it means 95% efficiency of USB can be there. So this area where the digestion of organic matter is takes place. This middle area is known as sludge blanket zone. This middle area is known as sludge blanket zone. As the treated water is continuously passing above the sludge blanket now as it is up flow so the treated water along with some solids and along with the gas that is biogas is continuously moving up. So there is one facility which is given that is gas liquid solid separator that is GLS separator. In which you can see this is the filtration system or the baffles is being provided where the solids have been removed off. If it is taking up the gas which is collected in the middle part easily the gas is separated. Two things are remaining. One is solid and another one is liquid. The water is made to pass through this filtration system and whatever the solids which is having the higher density will be collected on these baffles and easily it is taken on this wear and easily it is made to settle down. So automatically biogas is going to be settled down in this bottom part and whatever the remaining liquid which is still coming out from these baffles that is this upper part is collected as an effluent. So in this way the gas liquid and solid separator is being used to separate this biogas and treated effluent. So such type of a system we will call it as gas liquid and solid separator. This is the third phase. Whatever the sludge which is being settled down is known as settling zone or settled zone. Now let us see its process. First waste water enter the reactor from bottom and it will flow upward. Then the waste water passes through the anaerobic sludge blanket. Then the microbes in the sludge will get contact with the organic matter or the waste water substrates. The organic matter is broken down by anaerobic digestion. Then large amount of biogas such as methane is collected and removed from the top which is the result from breakdown process. Then the treated effluent is also being removed from the top. So these are the notes which I have discussed earlier. So those who want to take the notes please pause this video, take a screenshot of this slide or note it down and we will resume it again. So again this slide is also having the same thing which I have explained earlier. So please pause this video again, take a screenshot of it and again resume it. After talking about its parameters normally the depth of usb is given around 4.5 to 5 meter for the sewage. The sludge blanket zone depth is around 2 to 2.5 meter for sewage and if the strong water is coming we can increase it. Upflow velocity is normally kept about 0.5 meter per hour that is for average flow we can increase up to 1.2 meter per hour. The volumetric organic loading is typically given around 1 to 3 kg COD per meter cube per day it is for domestic sewage and 10 to 15 kg COD per meter cube per day for agro industrial sewage. The sludge production is generally around 0.15 to 0.25 kg TSS per meter cube sewage treated. The HRT is typically kept around 8 to 10 hours for average flow and minimum 4 hours should be given for peak flow. HRT is typically kept around 30 to 50 days or more. BOD and COD removal efficiency is around 75 to 80% and 74 to 78% respectively. Nitrogen and phosphorus removal efficiency very much low that is 5 to 10% only. TSS production is typically around 0.38 meter cube per COD removed. Let us see its advantages it is having a very much high reduction of BOD it can also withstand high organic and hydraulic loading rates. Low sludge production is there that is only 5% and thus infrequent desludging is required that is removal of sludge is required very much lesser. The biogas can also be used for energy no aeration system is required so automatically less energy consumption is there for running this USB. Affluent is rich in nutrients and can be used for agricultural irrigation. The low land demand is there to be construct and it is typically underground therefore the surface area required is very much lesser. So it requires the locally available material to construct so automatically no need to put lot of cost for the construction. The reduction of CO4 and CO2 emissions are there in USB. Let us see its disadvantages it may be unstable with variable hydraulic and organic loads. It requires operation and maintenance only by the skilled labour. The long start-up time is to be required at work to run at full capacity a constant source of electricity is continuously required. Not all parts and materials may be available locally it requires expert design and construction. Affluent and sludge requirement for further treatment and or appropriate discharge is required here. Not adopted for cold climates. So let us have few review questions in which USB is which type of a process anaerobic aerobic facultative or none of the above. USB have internal 3GSL separator system true or false. In USB organic decomposition takes place in inlet zone, settling zone, sludge blanket zone or all of the above. So let us have their answers first USB is anaerobic process USB have internal 3GSL separator system this statement is true in USB organic decomposition takes place in sludge blanket zone the middle zone of the USB these are the references I have used to make the video thank you.