 Greetings students, my name is Mahirubhale, I am assistant professor in civil department double ed to Solapur. Today we are going to discuss the topic that is root zone technology. So what are the learning outcomes? At the end of this session students will be able to understand the concept of root zone technology. So approximately 70% of the domestic water is released as a west water. Most of which can be recovered if we are going to treat it very properly. So what we have to do is to change our mentality and to think that domestic water as a resource but not as a best. So domestic west water is mainly classified into two categories. One is grey water. The water which is generated from kitchens, laundry, bathrooms etc. And another one is black water. The west water which is coming out from toilets which is containing a large amount of vehicle matter and urine which is also called as sewage. So now to treat this kind of a domestic west water the new technology has come up that is the root zone technology. First of all we will understand what is meant by root zone. Root zone is a scientific term used to cover all the biological activity among different types of microbes, the root of plants, water, soil and the sun. It consists of planted filtered beds containing gravel, sand and soil. The root zone west water treatment in short RZWT system utilizes nature's way of biologically processing domestic and industrial effluents. The root zone west water treatment the system makes use of biological and physical treatment processes to remove pollutants from west water. Now in the picture you can see the west water which is being collected in the settling chamber is now preferred as an inlet into the root zone technology system. In which the red part that is having a lot of gravel on which the reed bed plants have been implanted. They have been grown on this gravel. So their roots will automatically going to be percolated inside the gravel and they will be providing a lot of resource sphere area so that whatever the microorganisms which are near the roots and which are added to the gravels will automatically going to take out whatever the organic matter which is flowing through this water. So automatically the organic matter which has been captured by microorganisms will going to be treated aerobically. Why? Because whatever the carbon dioxide which is present in the atmosphere will easily taken up by the plants and they will convert it and they will throw out lot of oxygen through the roots. And in the roots that is near by the resource sphere automatically oxygen will be allowed to be taken to the microorganisms. So microorganisms will get lot of sufficient of oxygen and also they will be getting lot of organic matter from the west water. So automatically they will be treated and with the help of gravity the treated water or the effluent will be collected in the next chamber. So in this fashion the root zone technology works. Now in the more complicated way you can see the diagram where the inlet has been shown on the left part and through the gravels the west water is coming inside the root zone. Where the roots is giving out lot of oxygen from the atmosphere and the near by the root lot of resource sphere is being created where the microorganisms which are residing on the gravel is taking lot of oxygen and taking lot of organic matter through the flow of west water. The gravel should be in between 8 to 16 mm and the slope for which the west water should flow is given around 1%. As the west water flows slowly slowly it is being treated by the microorganisms they will be taken out from the outlet. These reed plants or we can use different plants which should be capable to grow themselves on the gravel. We have to use that plants and we have to ensure that large amount of oxygen should be taken from the atmosphere and they should be given out in the gravel area. New technologies have come up and they have been commercialized. So let us see what is the new technology which has been enveloped and which is being used very much at a higher rate. So if you see there are four compartment methods which have been used. First one is Settler in which the influence is coming inside the biodigester where the no oxygen is present inside the biodigester. So automatically it is using the anaerobic method for the treatment. In which you can see whatever the scum which is present above is being taken out and the west water which is having large amount of organic matter is being treated anaerobically and the sludge is being produced in that tank. It is acting as a septic tank. The effluent is taken out and whatever the supernatant which is present is again taken out and it is shifted to the second chamber or the second compartment and whatever the sludge which is being resided at the bottom is taken out and is being disposed of. In the second compartment that is anaerobic baffled reactor the same process is going on that is anaerobic digestion process is going on. So in one compartment various digesters are being put up. Now at the last digester the effluent flow that is the supernatant is taken out again it is given to the anaerobic filter. Here also the same thing is happening but there is one change is suppose in that supernatant some suspended particles are still there that is taken out by filtration system. So at the first part we are providing the anaerobic digester which have been provided in the settler also and in the anaerobic baffled reactor also. So in the anaerobic filter first we are providing the anaerobic digester and the effluent is taken and again we are providing a large amount of filter media and water is made to push from the bottom to upper part where whatever the suspended particles which are still present in the water is being here choked up and automatically they have been removed off. Now the clearer water is again made to pass through the next filter media and similarly to the next filter media. So here serially three filter media is being provided. Now the effluent from the anaerobic filter that is our here outflow is taken to the planted gravel filter that is our root zone technology main technology where the inlet is been made to pass through the gravel where the reed plants have been implanted and automatically the clearer water will be taken out as a clear water and it is been reused for the gardening or for the bathrooms or for the toilets. So reuse of waste water can be easily happen. Now talking about the efficiency of root zone technology you can get to know the effluent water is having the turbidity removal efficiency around 75 percent. The TSS removal is around 70 to 80 percent. The coliform bacteria removal efficiency is around 85 to 90 percent. BOD removal efficiency is relatively lower but if we are going for multi digester systems it can increase but for pure root zone technology it is around 60 to 70 percent. Talking about COD it is having 75 to 85 percent. Ammonium nitrogen is having the removal efficiency of 50 to 58 percent and organic nitrogen is having the highest removal efficiency that is 95 to 99 percent. Talking about its advantages it is the most innovative and eco-friendly system both grey water and black water can be suitably treated and again reused. It is having a low cost it is virtually zero energy and maintenance free system. No need to add any input such as chemical or mechanical pumps or external energy it reduces the maintenance and green energy cost. The water flow from one device to another using natural slope that is one percent bottom slope and without any external energy input such as motor pump. Once the reed plants create an established stand the reed bed requires very little or no maintenance. So let us have few review questions. Root zone is specific term used to cover all the biological activity among different types of microbes, roots of plants, water soil and sun or all of the above. The waste water flow through the root zone in horizontal or vertical way where organic pollutants are decomposed biomechanically by the bacteria. It is due to the presence of resource sphere in the plant roots whether this statement is true or false. The filter media in RZWT is selected carefully to provide favorable conditions to reed plants, bacteria, avoid clogging or all of the above. So let us see their answers. Root zone is specific term used to cover all the biological activity among the different types of microbes also, roots of plants, water, soil and sun also. The statement that is the waste water flow through the root zone in horizontal or vertical way where organic pollutants are decomposed biomechanically that is using microorganisms due to the presence of resource sphere. The sphere which is nearly the roots of plant where the oxygen provision is given to microorganisms. So this statement is very much right. The filter media in RZWT is selected carefully to provide favorable conditions to whom to reed plants also, bacteria also and also to avoid clogging. So all of the above is the right answer. These are the references I have used to make this video. Thank you.