tertiäärikäsittelyvaiheet

Tertäärikäsittelyvaiheet, or tertiary treatment, is an advanced stage in wastewater treatment designed to further purify water beyond the secondary treatment level. Its primary goal is to remove nutrients such as nitrogen and phosphorus, as well as any remaining suspended solids and pathogens. This stage is crucial for meeting stringent environmental discharge standards and for enabling water reuse.

One common method within tertiary treatment is nutrient removal. Nitrogen is typically removed through nitrification and denitrification processes, often requiring specific oxygen conditions and microbial communities. Phosphorus can be removed chemically through the addition of metal salts, which cause phosphorus to precipitate out, or biologically by encouraging microorganisms to absorb and store phosphorus.

Filtration is another key component of tertiary treatment. Various types of filters, including sand filters, membrane filters, or activated carbon filters, are used to remove fine suspended solids and other contaminants that may have passed through earlier treatment stages. Membrane filtration, such as microfiltration or ultrafiltration, can effectively remove even smaller particles and microorganisms.

Disinfection is often the final step in tertiary treatment to ensure the water is safe for discharge or reuse. This can be achieved through methods like chlorination, UV irradiation, or ozonation, all of which kill or inactivate remaining bacteria, viruses, and other pathogens. The specific combination of tertiary treatment processes employed depends on the influent wastewater characteristics and the desired effluent quality.