“Water recycling installation” at
De Polder – Antwerp Belgium
During 2004 at the premises of De Polder, a Veolia Transport Belgium company, a biological “Water recycling installation” for the treatment of waste water containing mineral oil, has being put into service.
The water coming from the vehicle wash installation, further named “Car- wash”, is treated and is used again for washing the buses.
The water delivered, after treatment, has a high quality as it is requested for the use at a “Car wash”. Through the biological water recycling installation and with the use of cleaning products which are biological degradable, the legal standards concerning draining water quality are reached.
De Polder has currently, at the end of 2004, 192 buses in service; the amount of water used at the Car wash installation has been estimated at 3.275.000 liters for 2004.
The waste water from the Carwash is send to “Separator filters” for the use of separating the sludge and hydrocarbons. There are two filters installed, in series with each other, to be able to separate the dirt in two steps.
The precleaned water is then being sent to buffer reservoir, here-in further sedimentation of components is done. In a fourth reservoir a stainless steel basket is installed, it is mounted in an airflow supplied by an air pump. The oxygen brought into the water is improving the deterioration of the organic substances in the waste water and is preventing bad smell caused by rotting death bacteria.
The water is then pumped to the cleaning installation.
This installation has the following components:
Pre filter (1), buffer reservoir (2), self cleaning hydro cyclone unit (3), supply tank (4) and an installation for increasing the water pressure (5).
The pre-filter (1) is used to filter the bigger parts out of the water. The removable filter has a filtering width of 800 to 200 µm. The filter has been put in a basket which is fixed inside the housing; it has to be cleaned on a regular basis.
The installation for pressure increasing (5) is pumping the water out of the buffer reservoir (2) and into the hydro cyclone unit (3), the self cleaning hydro cyclone unit guarantees a save washing of the buses and is preventing early wear of the pumps and nozzles by draining dirty water.
The cleaned recycled water is running from the cyclone to the supply tank (4) and is now available for being used at the Car wash installation.
The system is controlled by an ECU, and is responding to the different demands of water (day, night, week and weekend).
After washing with soap the rinsing of the vehicles is still done with tap water, because of this a lot more water is being drained back into the system, therefore the buffer reservoirs have an overflow system to be able to drain some of the water to the sewerage.
In case of a shortage of cleaned water in the system, the level will be adjusted with tap water.
With the implementation of this system, savings are made on the water bill but also on the amount of soap to be used.
The system also allows us to decrease the amount of water that is being drained into the sewerage after washing the buses, the water given back is clean.
The capacity of the system is about 10.000 L/hour.