In the Tier-1 cities like mumbai, delhi, kolkata the population is increasing on a higher rate which leads to many problems like scarcity of water, scarcity of land use, traffic problems, crowdy junctions etc. One of the major problem accounted is waste management. According to ministry reports, India generated nearly 1.45 lakh metric tons of waste per day till february this year out of which only 53% of waste was processed. Due to increasing population in urban areas there is a huge gap between the waste generated and waste processed. To overcome this problem government has come up with waste management policies and trying to adopt the part to whole form of policies to increase the percentage of waste processed. Bio-Methanation Plant is one of the best alternative to treat organic waste and to create wealth from waste. Therefore it is important to understand the working process of Bio-Methanation Plant.
Bio-Methanation Plant Process at PALAVA CITY
The process is divided in steps which are perform one after the another to treat the waste generated or collected.
Step 1: Waste Collection
In this step the waste was collected from the waste collection points inside the palava city. The waste is collected through waste collection trucks. The primary concept that is very important to be taken care of is 'segregation at source'. Adoption of this concept helps to save ample of time used to segregate of waste in Bio-Methanation plant.
Step 2: Weighing of Waste Trucks & Unloading of Waste
After the waste is collected from the township the waste trucks are weighted on the weighing pan, so as to calculate the amount of incoming waste to plant. The capacity of the Bio-Methanation Plant at Palava city is 15 tones per day (TPD). Once the weighing of waste trucks is completed the trucks are sent to unloading point to unload the waste.
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| Weighing Pan |
Step 3: Segregation of Waste
The Unloaded waste is then transferred on 'Feed Conveyor' to conduct the manual segregation of waste. The inorganic waste material is segregated by the local waste pickers but full segregation of waste is not possible manually therefore further the manually segregated waste is transferred to Trommel through the inclined conveyor. The trommel consists of two circular nets of 10mm and 50mm dia. The 10mm net is used to remove the dust particles situated in the waste and 50mm net is used to segregate the inorganic waste. The retained inorganic waste is collected and send to Nashik plant for using it as a raw material to generate fuel.
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| TROMMEL |
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| Manual Segregation |
Step 4: Shredder Table Process
In this process the segregated organic waste (approx 5TPD) is transferred to crusher with screw conveyor. With the help of crusher the the organic waste is transformed into smaller pieces and is transferred further to Shredder Table. On shredder table the crushed waste is been diluted with fresh water or recycled water (mainly used only at the initial working phase of plant and later on the recycle water from anaerobic digester is used). This process is carried out to make wet form of waste.
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| SHREDDER TABLE |
Step 5: Chambers Setup
Three chambers are setup of which 2 Inlet Chambers and 1 outlet i.e. recycle chamber is setup. The function of Primary Inlet chamber is to collect the wet form of waste and transferred it further to Anaerobic Digester, whereas the secondary chamber is used to store the wet form waste when primary chamber is full. The outlet chamber that is the recycled chamber collects the overflow wet form of waste through overflow line from anaerobic digester and transfer it to shredder table to reuse it to make wet form of waste.
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| CHAMBER PIT |
Step 6: Digester System
In this step the wet form of organic waste is transferred from inlet chamber to anaerobic digester through feed line. There are two digester primary and secondary digester each of capacity 2.5 TPD. Both digester have Scum Beaker arrangement, Sludge line arrangement at bottom, Overflow line at top and Biogas line. The wet waste is pressurised and transformed into gas which is sent to Raw Gas Balloon. The sludge collected is then sent to sludge tank.
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| Digester |
Step 7: Balloon Room
The Balloon Room is set up near the digester to store the gas generated from the anaerobic digester. There is a set up of primary and secondary balloon used to store the gas generated. Gas from these balloons to biogas genset where these gas is used to generate electricity. The excess gas is burned through the Bio-gas Flare setup.
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| Balloon Room |
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| Biogas Flare |
The important aspect that needs to be considered while construction of Bio-Methanation Plant is
- The amount of waste generated per day in the township
- location of Bio-Methanation Plant should be set up with consideration of wind direction to avoid odour problems.
- Feasibility study (If low amount of waste is generated the Organic waste Converter should be setup).
This Visit was conducted during my internship days in Research & Development Department in JP Infra Mumbai Private Limited. I would like to thank Mr. Vikas Sawant, Shristi Mam, Dhaneshree mam and Prasoon Sir for their through out guidance and support.
