Power Plant Wastewater Treatment System

The power plant wastewater treatment system is a key link in ensuring ecological environment safety and achieving sustainable development.

The wastewater generated during coal and gas power generation processes contains heavy metals (such as mercury and arsenic), high salt content, suspended solids, and organic pollutants. If discharged directly without treatment, it will seriously pollute surface water, groundwater, and soil, damage aquatic ecosystems, and pose a threat to human health through the food chain.

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Types and characteristics of wastewater

Ash flushing wastewater

Source: Slag and dust collector flushing water, accounting for nearly 50% of the total wastewater in the power plant.
Characteristics: high suspended solids (SS), fluctuating salt content, heavy metals (such as arsenic) and fluorides, unstable pH value.

Desulfurization wastewater

Source: Discharge water from wet desulfurization (limestone/gypsum method) system.
Characteristics: high turbidity, high hardness, rich in heavy metals (mercury, cadmium, lead), high chloride ions (Cl ⁻>20g/L), and containing supersaturated sulfite.

Coal containing wastewater

Source: Coal transportation system flushing water and initial rainwater in the coal yard.
Characteristics: High suspended solids concentration (>5000mg/L), deep chromaticity (>400 times), fine coal powder particles that are difficult to precipitate.

Industrial wastewater

Source: Chemical water treatment waste liquid, cooling tower discharge, oily wastewater, etc.
Characteristics: Complex composition, containing acids, bases, oils, organic matter, and trace heavy metals, with large fluctuations in water quality and quantity.

Core processing technology

Preprocessing

Physical interception: Grille removes large particles of debris (such as coal slag and plastic fragments).
Adjust homogenization: Adjust the balance of water quality and quantity with pH 810 in the regulating tank.
Advanced oxidation (difficult to degrade organic compounds): Fenton method or ozone oxidation to decompose toxic substances.

Main processing technology

Wastewater type	Key technology	Effects
Ash flushing wastewater	Concentrated hydraulic ash removal (ash water ratio 1:5), closed-loop circulation of ash water, dry ash removal	Reduce water replenishment by more than 50% and recover coal slurry resources
Desulfurization wastewater	Triple box process (neutralization precipitation flocculation) or integrated treatment (electrochemical cyanide cracking+photocatalytic oxidation)	Heavy metal removal rate>95%, SS/COD stable compliance
Coal containing wastewater	Electrocoagulation technology (replacing traditional dosing), inclined plate precipitation+dissolved air flotation	Suspended solids removal rate>98%
Industrial waste water	Coagulation sedimentation (PAC/PAM)+air flotation oil removal+biofilter	Oil removal rate>90%, COD degradation rate>85%

Deep processing and reuse

Membrane technology: Reverse osmosis (RO) or nanofiltration (NF) deep desalination, with a water conductivity of ≤ 500 μ S/cm, used for cooling water supply.
Adsorption disinfection: Activated carbon adsorbs trace pollutants and UV inactivates pathogens.
Resource recycling: Coal slurry is reused in the coal yard, and desulfurization gypsum is recovered as a valuable byproduct. These recycling processes not only reduce waste but also enhance the sustainability of flue gas desulfurization wastewater treatment.