Waste Water Treatment

The sewage treatment plant in the chemical industrial park receives wastewater from various upstream chemical enterprises. The wastewater has a complex composition and high color levels, with poor biodegradability, making biological treatment difficult. Additionally, the wastewater has already undergone primary pretreatment and secondary biological treatment at the upstream chemical enterprises, leaving behind mostly stubborn pollutants that are difficult to biodegrade, further complicating the biological degradation process.

High-salinity wastewater refers to wastewater with a total salt concentration of at least 3.5%. This type of wastewater primarily originates from industries such as chemical manufacturing and the extraction and processing of oil and natural gas. It contains soluble inorganic salt ions like Cl⁻, SO₄²⁻, Na⁺, and Ca²⁺. The generation of high-salinity wastewater is widespread, with a complex and diverse composition. The high salt content significantly inhibits microbial growth, making the treatment of high-salinity wastewater particularly challenging. As a result, it is a major focus and difficult area in wastewater treatment research.

Hard-to-degrade wastewater often contains a variety of complex organic and inorganic compounds, such as aromatic compounds, heterocyclic compounds, and heavy metal ions. Some organic compounds, like phenols and anilines, are highly toxic. These characteristics result in poor biodegradability, meaning that traditional biological treatment methods struggle to effectively degrade the contaminants.

Deep Treatment of Wastewater refers to the advanced processes applied to municipal or industrial wastewater after primary and secondary treatments. This further treatment aims to meet specific reuse standards, allowing the treated water to be recycled for production or domestic use. The processes are designed to remove trace amounts of organic pollutants (COD and BOD), suspended solids (SS), high concentrations of ammonia and phosphorus, and salts.

With the rapid urbanization and industrial development in China, environmental protection issues, especially urban wastewater treatment, have become a research focus worldwide. However, the influx of large volumes of domestic and industrial wastewater into rivers, lakes, or groundwater has led to severe water pollution, affecting water used for fisheries and daily life. Urban wastewater pollution has become a critical factor limiting national development, prompting the government to impose increasingly stringent discharge standards on wastewater treatment plants.