A Detailed Technical Overview with Components, Standards, Materials, and Safety
1. 🧪 Anaerobic Digester System
🔩 Main Components:
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Feedstock Storage and Preparation Tanks: Used for collecting and homogenizing organic waste.
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Primary Digester Tank (CSTR or UASB): Sealed reactor tank (typically cylindrical) where anaerobic fermentation occurs.
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Heating Coils & Insulation Jackets: Maintain thermophilic or mesophilic temperature range (35–55°C).
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Gas Dome or Membrane Cover: Captures produced biogas under pressure.
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Mixing Equipment (Agitators or Recirculation Pumps): Ensures even microbial activity and prevents sedimentation.
🧱 Material of Construction:
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Reactor Walls: Reinforced Concrete (ASTM C94 / BS EN 206), lined with Epoxy or HDPE.
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Gas Storage: Double-membrane biogas holders (PVC-coated polyester with UV resistance).
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Piping: Stainless Steel 316L or HDPE for corrosion resistance.
🏗️ Fabrication & Installation:
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Civil works include deep foundation and waterproofing.
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Precast or cast-in-situ digester tank construction.
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Membrane dome prefabricated offsite, installed with tensioned anchoring rings.
🔒 Safety Equipment:
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Pressure Relief Valves (PRV)
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Flame Arrestors
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Emergency Flaring Unit
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Continuous Gas Monitoring (CH₄, H₂S, CO₂)
📏 Design Standards:
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ASME BPVC (Boiler & Pressure Vessel Code)
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ISO 23553 (Biogas safety)
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DIN 51624 (Biomethane Quality for Vehicles)
2. 🧼 Biogas Purification System
🔩 Main Components:
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Scrubbers (Water or Amine): Remove H₂S and moisture.
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Activated Carbon Filters: Capture siloxanes and VOCs.
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Membrane Separation or PSA (Pressure Swing Adsorption): Removes CO₂ for upgrading biogas to biomethane.
🧱 Material of Construction:
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Columns: SS316L or FRP (Fiberglass Reinforced Plastic)
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Piping & valves: PTFE-lined or stainless steel
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Moisture traps and condensate drains are standard.
🏗️ Fabrication Process:
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Column vessels are fabricated per ASME standards.
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Skid-mounted PSA/membrane units are pre-assembled at factory.
🔒 Safety Features:
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H₂S detectors with alarm system
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Explosion-proof enclosures for electricals
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Anti-static grounding for gas flow systems
📏 Relevant Standards:
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ISO 15403-1 (Fuel quality for CNG)
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ATEX Directive for explosive environments
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NFPA 820 for combustible gas handling
3. 🛢️ Compressed Biogas (CBG) System
🔩 Main Components:
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Dryer & Cooling Unit: Removes final moisture traces.
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Compressors (Rotary or Screw type): Raises pressure up to 250 bar.
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Cascade Storage Cylinders: High-pressure gas storage for bottling or transport.
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Filling Station with Nozzle Interface: For cylinder or vehicle refueling.
🧱 Materials:
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Cylinder material: Carbon steel or composite (ISO 11439 compliant)
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Compressor housing: Cast iron with anti-explosion design
🏗️ Fabrication:
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High-pressure components certified to PED (Pressure Equipment Directive)
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Hydrostatic testing for cylinders and pipelines
🔒 Safety Systems:
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Pressure gauges, rupture discs, and back-pressure regulators
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Fire suppression and gas leak detection system
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Emergency shut-off valves (ESV)
📏 Standards:
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ISO 9809, ISO 11120 for gas cylinders
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OISD (Oil Industry Safety Directorate – India)
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ISO 16923: CNG refueling stations
4. 🔌 Energy Distribution System
🔩 Key Components:
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Pipeline Grid: For biogas delivery to nearby users.
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Cylinder Distribution System: For remote or rural areas.
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Smart Metering Units: Measures household or industrial consumption.
🧱 Material & Protection:
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Pipelines: MDPE (Medium-Density Polyethylene), ASTM D2513
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Joints: Electro-fusion type for leak-proof sealing
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UV-shielded external piping for above-ground exposure
🏗️ Fabrication:
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Trenching and directional boring for pipeline installation
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Prefabricated valve stations and flow control boxes
🔒 Safety:
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Odorant injection to detect leaks
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Over-pressure protection valves
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GIS-based leak monitoring (SCADA integration)
📏 Codes & Standards:
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IGEM/TD/3 for PE gas pipelines
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ASME B31.8 – Gas Transmission and Distribution
5. 🌊 Wastewater Treatment Plant (WWTP)
🔩 Key Components:
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Settling Tanks & Clarifiers: Separate solids from liquid digestate
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Aerobic Treatment Units (SBR/MBBR): Reduces COD/BOD
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Sludge Drying Beds or Centrifuge Units: Handles final sludge
🧱 Material & Equipment:
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Clarifiers: RCC with epoxy lining
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Aeration: Blowers (SS) with diffusers (EPDM or PTFE)
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Screens & filters in SS304
🏗️ Fabrication & Installation:
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Modular units pre-installed on skids
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PLC-based automation for dosing and aeration
🔒 Safety:
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PPE for operators (chemical resistant gloves, masks)
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Containment basins to avoid groundwater contamination
📏 Standards:
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ISO 10667: Treatment of Industrial Wastewater
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USEPA 503 for land application of biosolids
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SNI 6989 – Indonesian wastewater quality standard
6. ♻️ Byproduct Processing Unit
🔩 Key Functional Sections:
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Solid-Liquid Separator (Screw Press or Belt Filter): Separates digestate fractions
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Drying & Pelletizing Equipment: Converts solid digestate into fertilizer pellets
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Nutrient Recovery Systems: Extracts nitrogen, phosphorus for enriched fertilizers
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Formulation Station: Adds minerals to create soil conditioners or animal feed additives
🧱 Materials & Construction:
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Separator: SS304 housing, food-grade belts
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Pelletizer: Mild steel body with anti-rust coating
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Storage silos: Galvanized steel or HDPE-lined
🏗️ Fabrication:
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Assembled in modular units for transport
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Calibrated feeders and dosing pumps integrated
🔒 Safety Systems:
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Dust extraction units in pelletizing area
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Conveyor covers and automatic shut-off switches
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Fire extinguishers in drying zones
📏 Compliance:
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EU Fertilizing Products Regulation (FPR)
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ISO 22000 (for animal feed safety)
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FAO biofertilizer guideline
