Refinery

Desalter effluent (400-1000 mg L⁻¹ COD, up to 1000 mg L⁻¹ free hydrocarbons), sour water (300-12,000 ppm H₂S, 100-8,000 ppm NH₃), spent caustic, cooling tower blowdown, tank bottom draws requiring specialized treatment approaches.

Variation in feedstock characteristics and production schedules lead to sudden shifts in wastewater composition, requiring adaptive treatment systems to maintain consistent performance.

Stripped sour water targets H₂S < 10 ppm (often < 1 ppm), NH₃ < 100 ppm (often < 30 ppm), phenol up to 200 ppm with strict environmental compliance requirements.

Regulatory and operational priority requiring advanced systems to meet stringent quality standards for reuse in boiler feed, cooling, and process applications.

Desalter effluent up to 300°F, sour water stripper overhead > 80°C to avoid ammonium bisulfide salt formation, requiring specialized heat-resistant treatment systems.

Toxic H₂S evolution, handling of non-regenerable spent caustic, oil-water emulsion stability in desalters requiring intrinsically safe treatment approaches.