Industry cases - Commercial and civil sewage treatment and reuse

—— The invisible burden of urban development, the first line of defense of the ecosystem

Although domestic sewage is not highly toxic, it has become the most common, basic, and most easily overlooked key link in urban water pollution control due to its large total discharge volume, wide sources, and complex composition. Whether it is a residential community, a commercial complex, or an office building, a hospital, or a school, the efficient and standard-compliant treatment of domestic sewage has become an indispensable part of the construction of green cities and smart parks.
Sewage characteristics:
High concentration of organic pollutants: Domestic sewage contains a large amount of detergents, kitchen wastewater, human metabolites, paper towel residues, etc. The typical COD concentration is 300-600mg/L, and the BOD₅ is 150-300mg/L, which is a medium-to-high concentration of organic wastewater.
Significant nitrogen and phosphorus content: The ammonia nitrogen concentration is usually 30-60mg/L, and the total phosphorus is 2-8mg/L. If it is not treated, it is very easy to cause eutrophication and black and smelly phenomena in the water body.
Unstable suspended matter and grease content: Affected by the density of human traffic and seasons, the SS concentration is between 100–350mg/L. Grease, hair, and microplastics pose a challenge to system operation.
Pathogenic microorganisms are widely present: If not treated or treated incompletely, it may contain enterovirus, pathogenic bacteria, E. coli, parasite eggs, etc., which pose potential public health risks.
Wide range of discharge and strong intermittency: The drainage of commercial and residential areas has the characteristics of flow period fluctuation and high instantaneous impact load, which requires extremely high regulation capacity of the treatment system.