Odor Problem

Wastewater treatment generates malodorous gases primarily H₂S with ammonia, mercaptans, and VOCs. Odors affect nearby communities causing complaints and regulatory violations. Scrubbing removes odorous compounds before atmospheric release.

Scrubber Design

Vertical tower with foul gas inlet at bottom, packing media providing gas-liquid contact area, scrubbing solution sprayed at top flowing downward, clean gas outlet overhead, recirculation sump and pump, chemical dosing system.

Packing Media

Random packing like Pall rings or structured packing providing high surface area. Packing depth 8-20 feet depending on gas loading and removal efficiency. Media resists fouling and provides low pressure drop.

Chemical Systems

Sodium hydroxide solution for H₂S removal forming sodium sulfide. Sodium hypochlorite oxidizes sulfides to sulfate regenerating capacity. Alternative systems use permanganate or hydrogen peroxide. Chemistry selection depends on contaminants.

Operating Principle

Foul gas flows upward through packing contacting descending caustic solution. H₂S absorbs into liquid reacting with caustic. VOCs scrub into solution. Clean gas exits meeting odor thresholds typically under 5 ppm H₂S.

Material Construction

FRP construction resists caustic solution and corrosive gases. Polypropylene or PVC packing. Stainless steel or plastic recirculation pump. Materials prevent degradation from chemical environment.

Performance Specifications

Removes 95-99% H₂S achieving outlet concentrations under 1 ppm. VOC removal 70-90% depending on compound volatility and solubility. Pressure drop 2-6 inches water column through packing.

Gas Flow Rates

Typical 1000-50,000 CFM handling ventilation from multiple treatment processes. Scrubber sizing based on maximum design flow with velocity preventing flooding or entrainment.

Applications

Wastewater treatment plant headworks, primary clarifiers, sludge processing areas, wet wells, and any wastewater facility generating odorous emissions requiring control before atmospheric release.

Chemical Control

pH monitoring maintains caustic solution strength typically 10-12 pH. ORP measurement indicates oxidizer concentration. Automated dosing adjusts chemicals maintaining scrubbing efficiency. Blowdown prevents salt accumulation.

Liquid Management

Recirculation rate 2-5x minimum wetting providing adequate liquid distribution. Makeup water replaces evaporation. Blowdown controls dissolved solids. Proper liquid management maintains performance.

Monitoring Systems

H₂S analyzers on inlet and outlet verify removal efficiency. Pressure drop measurement indicates packing condition. Flow measurement ensures proper gas velocity. Data logging documents compliance.

Performance Benefits

Eliminates odor complaints from wastewater facilities. Ensures regulatory compliance for emissions. Protects community relations. Proven chemical scrubbing technology with reliable performance.

Construction Standards

FRP vessels per manufacturer standards. Chemical systems per applicable codes. Electrical systems for hazardous classification if required. Complete documentation with removal efficiency specifications.

ERGIL odor control scrubbers provide effective H₂S and VOC removal eliminating odors from wastewater treatment plant off-gases.