Staff should have a clear understanding of the characteristics of chemical wastewater prior to Wastewater Monitoring. This enables targeted treatment and ensures safe wastewater discharge. This article introduces seven key characteristics of chemical wastewater.
Presence of Irritant and Toxic Substances in Wastewater
- Toxic substances including arsenic, mercury, cadmium, cyanide, phenol’s, etc.;
- Refractory substances that accumulate in organisms over time and cause poisoning, such as organophosphate;
- Carcinogens such as poly-cyclicaromatic hydrocarbons;
- In addition, irritant and corrosive substances including alkali’sand inorganic acids.
The COD and BOD in Chemical Wastewater are Very High
This feature is prominent in petrochemical wastewater, which mainly contains alcohols, formaldehyde, acids, ketones, epoxy compounds and other substances. Direct discharge consumes large amounts of dissolved oxygen in water through oxidation and decomposition, posing risks to aquatic organisms.
Unstable pH Value
Wastewater from chemical processes may be strongly alkaline or strongly acidic with fluctuating pH values, which can cause harm to aquatic organisms and crops.
High Concentrations of Nutrient Compounds
Chemical wastewater generally contains high levels of nitrogen and phosphorus, which may trigger water eutrophication and massive reproduction of algae and microorganisms. Severe eutrophication may lead to red tides and mass mortality of fish.
High Wastewater Temperature
Most chemical reactions proceed under high-temperature conditions, resulting in high-temperature discharged wastewater. Direct discharge of hot wastewater causes thermal pollution, reduces dissolved oxygen in water and damages the living environment of aquatic organisms.
Common Oil Pollution
Petrochemical wastewater usually contains oil contaminants. Oil substances threaten the survival of aquatic organisms and increase the difficulty of wastewater treatment.
Difficult Restoration of Polluted Water Bodies
Once water bodies are contaminated by hazardous chemicals, it takes a long period to restore the original water quality even after pollutant discharge is reduced or halted. Heavy metal pollutants can be bio-accumulated, and pollution caused by such wastewater is difficult to eliminate.
