When it rains, residues of fuels and other environmentally hazardous petroleum substances run off with rainwater into surface waters (streams, rivers, lakes) and can pollute them. Separators are used to prevent this from happening. By using separators, hydrocarbons are removed from water and stored, which helps to ensure that our activities are environmentally friendly.
Separator – a legal requirement?
Treatment rainwater from oil-based substances is a legal requirement, as stated in the Regulation of the Minister of Maritime Affairs and Inland Navigation of 12 July 2019. (Journal of Laws 2019, item 1311) on substances particularly harmful to the aquatic environment and conditions to be met when discharging wastewater into waters or into the ground, and when discharging rainwater or snowmelt into waters or into water facilities: § 17. 1. According to the regulations, rainwater must be treated to remove oil-based substances if the concentration of these substances is higher than 15 mg/l.
Such substances and harmful suspensions run off from large paved surfaces, on roads, motorways, car parks, petrol stations, car washes, bus depots, industrial plants, railway areas – wherever there are even small oil spills from internal combustion engines or diesel-powered machines.
Treating rainwater to remove oil-based substances is a legal requirement
Two technologies to choose from
Ecol-Unicon, and other companies in the market, offer two technologies that have found their application in oil separators. These are lamella technology, used in the ESL-Z separator and the coalescence technology, used in the ESK separator. Both solutions guarantee high efficiency and both can be installed in traffic zones as well as in green areas.
They are easy to install and operate. Separators can be hooked up to a sampling device. For full water protection separator should be complemented by a settling tank. We also offer devices combined in one chamber, i.e. a separator integrated with a settling tank.
When to choose a lamella separator?
Lamella separators enable rainwater treatment in larger catchment areas. They are recommended for use at the outlets of urban rainwater collectors, in large car parks, to protect surface waters at industrial plants, logistics centres, airports. They are also suitable for draining rainwater from motorways and roads with heavy traffic. They are designed in such a way as to be able to treat water with flows greater than nominal, and this is their greatest advantage.
The pretreatment efficiency is 5mg/m3 for the nominal flow rate, and it decreases as the flow rate increases, but water treatment still takes place. This is extremely important when dealing with large and very large surfaces from which rainwater flows. The use of lamella separators is then the only effective solution.
Lamella separators are suitable, among others, in the proximity of roads with heavy traffic
Their design allows separation and retention of both oil-derived substances and mineral suspended solids (sands, slurries) contained in rainwater and snowmelt runoff from any type of catchment area.
Lamella separators are recommended for large catchments where more or less rainwater may flow at different times, i.e. where there is a varied load of flow and different loads of oil and suspended solids.
When to choose a coalescence separator?
Coalescence separators provide rainwater treatment only for the nominal flow. The parameters of the device should be selected so that the nominal capacity of the separator is greater than the maximum flow of rainwater entering the device.
Coalescence separators are recommended for smaller catchments and catchments where pollutants are present in low concentrations, so they are suitable for garages and car washes, petrol stations, transport depots, smaller industrial plants, medium and small car parks, drainage of water from bridges and road overpasses.
Coalescence separators are a good solution for smaller catchment areas, such as garages and car washes
What to consider when choosing a separator?
In summary, when choosing the right type of separator, special consideration should be given to:
- the size of the area from which rainwater run-off occurs, which influences the volume of rainwater run-off,
- amount of suspended solids contained in rainwater,
- operation of the device during storm flow,
- the degree of protection of surface water into which rainwater flows – whether it is a protected zone, whether the body of water is enclosed, what the current velocity is and how long it takes for the river or stream to clean itself