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Ⅰ. General Provisions of The Scheme
1. Core Objectives
Following the principles of compliant discharge, economic efficiency and controllable secondary pollution, this scheme adopts precise technical selection and systematic design for odor waste gas from different pollution sources. The concentration of odor-containing substances such as hydrogen sulfide, ammonia and VOCs is reduced below national and local emission standards (e.g., ultra-low emission requirements for the iron and steel industry: particulate matter ≤10mg/m³, SO₂ ≤35mg/m³). Meanwhile, optimized operating cost and long-term stable equipment operation can be realized.
2. Application Scope
This scheme covers major odor pollution sources including industrial production (chemical, pharmaceutical, rubber, etc.), garbage disposal, sewage treatment and livestock breeding. It is adaptable to various working conditions such as high/low concentration and large/small air volume waste gas.
Ⅱ. Waste Gas Characteristics and Pretreatment System Design
1. Analysis of Core Waste Gas Characteristics
Pollution Source | Main Odor Components | Typical Concentration Range | Air Volume Characteristics |
|---|---|---|---|
Chemical Enterprises | VOCs, Hydrogen Sulfide, Mercaptan | 100-1000mg/m³ | Medium and Low Air Volume |
Sewage Treatment Plant | Ammonia, Hydrogen Sulfide, Indole | 50-500mg/m³ | Large Air Volume |
Landfill Site | Methane, Ammonia, Volatile Organic Compounds | 200-800mg/m³ | Ultra-large Air Volume |
Livestock Farm | Ammonia, Hydrogen Sulfide, Skatole | 150-600mg/m³ | Medium and Large Air Volume |
2. Key Pretreatment Processes
(1) Dust Removal Process
Bag dust collector or cyclone dust collector is adopted to remove particulate matter with particle size ≥10μm, preventing subsequent equipment blockage such as packing hardening in biological filters and catalyst poisoning.
(2) Humidity and Temperature Regulation
A spray tower is applied to control the waste gas humidity at 40%-60% and reduce the temperature to 20-40℃, providing suitable conditions for biological treatment and catalytic oxidation. Weak alkaline solution can be used as spraying liquid to pre-absorb partial acidic odor substances such as hydrogen sulfide.
(3) Gas-Liquid Separation
A demister is installed to reduce the moisture content of waste gas to ≤80%, avoiding equipment corrosion and treatment efficiency decline.
Ⅲ. Core Treatment Technology Selection and Application Scheme
1. Mainstream Technology Comparison and Adaptation Scenarios
Treatment Technology | Core Principle | Treatment Efficiency | Investment Cost (10,000 Yuan / 10,000 Nm³) | Annual Operating Cost (10,000 Yuan / 10,000 Nm³) | Applicable Scenarios |
|---|---|---|---|---|---|
Activated Carbon Adsorption | Microporous physical adsorption + surface oxidation reaction | Medium-High (80%-90%) | 5-42 | 40-80 | Low-concentration VOCs, intermittent emission (e.g., printing industry) |
Chemical Absorption Method | Chemical reaction between acid-base solution and odor components | High (90%-95%) | 12-47 | 50-97 | High-concentration hydrogen sulfide and ammonia (e.g., chemical tail gas) |
Biological Treatment Method | Microbial metabolic decomposition into CO₂ and H₂O | Medium (75%-90%) | 10-40 | 6-12 | Medium-low concentration and biodegradable waste gas (e.g., sewage plant) |
Regenerative Catalytic Oxidation (RCO) | Catalyst-assisted combustion + heat energy recovery | High (95%-99%) | 40-100 | 4-8 | Medium-high concentration organic waste gas (e.g., coating drying line) |
Photocatalytic Oxidation Method | UV excites TiO₂ to generate hydroxyl radicals for oxidative decomposition | High (90%-98%) | 20-50 | 8-15 | Low-concentration and large-air-volume VOCs (e.g., plastic processing) |
2. Customized Schemes for Typical Industries
(1) Sewage Treatment Plant Scheme: Biological Trickling Filter + Chemical Scrubber Combined Process
Process Flow: Waste gas collection → Cyclone dust removal → Spray cooling → Chemical scrubbing (alkaline liquid for hydrogen sulfide removal) → Biological trickling filter (ammonia and indole degradation) → Online monitoring and discharge
Core Design: Porous ceramsite is selected as biological filter material, inoculated with nitrifying bacteria and denitrifying bacteria. The empty tower gas velocity is controlled at 0.5-1.0m/s with residence time ≥30s. The chemical scrubber adopts step-type spraying with liquid-gas ratio of 3-5L/m³.
Treatment Effect: Hydrogen sulfide removal rate ≥95%, ammonia removal rate ≥90%. All emission concentrations comply with the Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant (GB 18918-2002).
(2) Chemical Enterprise Scheme: Adsorption Concentration + RCO Combined Process
Process Flow: Waste gas collection → Bag dust removal → Activated carbon adsorption and concentration → Hot air desorption → RCO catalytic combustion → Heat energy recovery
Core Design: Honeycomb activated carbon is adopted. After adsorption saturation, desorption is carried out with hot air at 120-150℃. The concentration of desorbed waste gas is increased by 10-20 times before entering RCO. Pt-Pd precious metal catalyst is selected with reaction temperature controlled at 300-400℃.
Treatment Effect: VOCs removal rate ≥98%, heat recovery efficiency ≥85%, meeting the Emission Standard of Pollutants for Petroleum Chemistry Industry (GB 31571-2015).
(3) Landfill Site Scheme: RTO + Hydroxyl Oxidation Advanced Treatment
Process Flow: Waste gas collection → Spray pretreatment → RTO incineration (800℃) → Hydroxyl oxidation tower → High-altitude discharge
Core Design: Three-chamber regenerator is equipped for RTO with thermal efficiency ≥95%. The hydroxyl oxidation tower generates ·OH radicals through micro-charge field to degrade residual VOCs and odor substances.
Treatment Effect: Total hydrocarbon removal rate ≥99%, odor intensity reduced below grade 1, complying with the Emission Standard for Odor Pollutants (GB 14554-93).
Ⅳ. System Supporting Facilities and Intelligent Control
1. Key Auxiliary Equipment
(1) Gas Collection System
Umbrella-shaped air suction hood (suction speed: 1-3m/s) or closed gas collection hood is arranged according to pollution source layout. The pipeline wind speed is controlled at 10-15m/s to reduce air leakage rate (≤5% in industrial scenarios).
(2) Fan Equipment
FRP anti-corrosion fan is selected. The wind pressure is matched with pipeline and equipment resistance with 10%-15% allowance.
(3) Exhaust System
The height of exhaust stack is ≥15m. Rainproof cap and online monitoring interface are reserved at the outlet. Monitoring parameters include particulate matter, SO₂, NOₓ, VOCs and other indicators.
2. Intelligent Control System
Adopt PLC main control unit + touch screen operation to realize one-click start-stop and variable-frequency air volume adjustment (automatically adjust fan speed according to waste gas concentration).
Sensors for temperature, concentration and pressure are installed. The system will automatically alarm and open the emergency discharge valve under abnormal conditions such as RTO temperature >450℃ or excessive waste gas concentration.
Connect to the environmental online monitoring platform to upload real-time emission data to the regulatory system of ecological environment department.
Ⅴ. Cost Analysis and Operation Maintenance Guarantee
1. Full Life Cycle Cost Composition
Cost Type | Proportion Range | Control Key Points |
|---|---|---|
Equipment Investment Cost | 40%-60% | Prioritize mature technology to avoid over-design |
Energy Consumption Cost | 20%-30% | Adopt frequency conversion fan and heat recovery system |
Consumable Replacement Cost | 10%-15% | Select long-life activated carbon and catalyst |
Labor Maintenance Cost | 5%-10% | Configure intelligent monitoring to reduce manual inspection frequency |
2. Operation and Maintenance Management Specifications
(1) Daily Maintenance
Check fan operating status and pH value of spraying liquid every day; clean dust hopper and inspect filter material integrity every week.
(2) Regular Replacement
Replace activated carbon every 6-12 months; regenerate or replace RCO catalyst every 2-3 years; update biological filter material every 3-5 years.
(3) Emergency Treatment
Formulate equipment failure emergency plan, equipped with standby fans and adsorption towers to ensure temporary compliant treatment of waste gas during shutdown.
Ⅵ. Environmental Compliance and Acceptance Standards
Emission Limit: Strictly comply with industry-specific standards (such as ultra-low emission requirements for iron and steel sintering waste gas) and regional environmental protection policies. If no industrial standard is available, implement the Emission Standard for Odor Pollutants (GB 14554-93).
Acceptance Requirements: Entrust a third-party testing institution to conduct 72-hour continuous monitoring after construction. All indicators such as emission concentration and equipment efficiency must meet the standards. Submit equipment account books and operation records to the ecological environment department for filing.
