Supplements to the oil separator – EnviroChemie application-specific solutions

Oil separators are used to protect sewage systems against blockages caused by mineral greases and oils. The operation of communal sewage plants can be considerably affected by these types of substances because they are hardly biodegradable. The installation of oil separators is therefore mandatory in accordance with DIN 1999 or DIN EN 858 in businesses such as petrol stations or for example, motor vehicle operators, in the transport sector and in the metal industry.

The operating principle of these plants for the treatment of wastewater is based on simple gravity: Due to the difference in density, mineral oils and fats rise to the surface of the water. Sediment, such as sand, settle on the bottom of the upstream or integrated sludge trap.


Oil separators must be assessed depending on the type and quantity of the wastewater collected. To ensure safe function, the content of the oil separator must be disposed of, cleaned and refilled with fresh water every six months.

Alternatively, the plant operator – in the event of less build-up of contamination – may check the sludge and oil layer thickness monthly and record it in an operating log. The intervals at which the content of the oil separators has to be disposed of, can then be extended by up to five years. In conjunction with this, a general inspection and leakage test are required. The following must not be discharged:

Wastewater containing faecal matter
Wastewater with animal or plant oils and fats.

With a properly dimensioned oil separator and regular content disposal, discharge values for hydrocarbons of < 20 mg/l can be achieved. However, in many cases, the effectiveness has been reduced by cleaning agents, pressure or temperature, so that continuous treatment (neutralisation, flocculation/precipitation, flotation, filtration) is required. In this case, the oil separator is used as a pre-treatment stage. With the variants for below-ground installation and building erection, there is a distinction between the two designs, which can also be combined.

In addition, EnviroChemie supplies different, application-specific solutions: If the fats and oils are also in an emulsified form and cannot be sufficiently removed by a separator, the wastewater pre-treated with the oil separator can be treated with the compact wastewater treatment plants from the product range Split-O-Mat® (physic-chemical wastewater treatment) and Lugan® (flotation plants) to the required discharge levels.