Municipal waste water, 1999

Waste water treatment plants (wwtp) are generally divided into three groups according to the type of treatment they provide: mechanical, biological or chemical. Some plants incorporate combinations of these basic types.

Mechanical waste water treatment plants include sludge separators, screens, strainers, sand traps and sedimentation plants. They remove only the largest particles from the waste water.

High-grade waste water treatment plants are those which provide a biological and/or chemical treatment phase. Biological treatment mainly removes readily degradable organic material using microorganisms. The chemical phase involves the addition of various chemicals to remove phosphorus. High-grade plants reduce the amounts of phosphorus and other pollutants in the effluent more effectively than mechanical plants.

The number of population equivalents (P.E) in an area is given by the sum of the number of permanent residents and the amount of waste water from industry, institutions, etc. reckoned as the number of people who would produce the same amount of waste water.

The hydraulic capacity of a treatment plant is the amount of waste water it is designed to receive.

The hydraulic load is the amount of waste water a treatment plant actually receives.

Separate waste water treatment plants are designed to treat amounts of waste water equivalent in amount or composition to that from up to seven permanent households or holiday homes (generally in scattered settlements).

The North Sea counties (or region) are the counties from Østfold to Vest-Agder, which drain almost entirely into the North Sea.

Not relevant