Nordic Swan Ecolabelled Car Wash for Buses and Large Vehicles
Nordisk Vannteknikk har utviklet et renseanlegg for behandling av vann fra vaskehaller for buss og storbiler. Anlegget er svært effektivt og oppfyller kravene for svanemerket.
Recycling of wash water from bus washes
Vy buss is Norway's largest bus company and part of the Vygruppen, which is the largest land-based transport group in the Nordic region. As a major player in public transport in Norway, Vy buss takes its social responsibility seriously, and has expressed a desire to have its car washes certified by the Nordic Ecolabel. The Nordic Ecolabel sets strict requirements for, among other things, emissions and recycling, and Nordisk Vannteknikk was commissioned to develop a treatment plant that helps maintain these requirements.
The result was a compact plant built in a container solution consisting of an oil separator, chemical precipitation and a bio plant. In addition, the purified water is circulated through a sand filter, a carbon filter and a UV system.
This means that the plant removes the necessary pollution while also having the ability to recycle up to 95% of the wash water.
Since the first plant at Eidsvoll was opened, Nordisk Vannteknikk has delivered two other treatment plants to Hamar and Brummunddalen, respectively.
290 million liters of water per year
Washing a bus requires approx. 300 liters of water for a summer wash, and approx. 560 liters per wash in the winter months. A 90% reduction in water consumption means in practice that an average bus wash goes from using around 430 liters of water to using between 50 and 60 liters. An estimate from the Nordic Ecolabel shows that if all county bus washes had made similar savings, we would save 290 million liters of water annually. This is more than the annual drinking water needs of 300,000 Norwegians.
The facility
In order for the water to be reused as washing water for the buses, a high degree of purity is required, and in order to maintain the Nordic Ecolabel, the requirements are even stricter. In order to meet these requirements, several different purification steps are necessary.
Oil separator
The first cleaning step in the process is an oil separator. Oil residues often occur in connection with washing vehicles, and the oil separator ensures that these oil residues are separated before the water flows further.
The principle of the oil separator is quite simple. Since oil has a lower density than water, the oil will rise to the top of the tank and create a layer of oil film on top of the water. The oil separator is equipped with an oil separation filter that ensures that the oil particles are collected so that they rise to the top more quickly. Water free from oil therefore flows out through an outlet located in the middle of the tank. This is to avoid the oil film on the top at the same time as avoiding too much of the sludge that collects at the bottom.
Chemical precipitation
After the oil residues have been separated, the water goes to chemical precipitation. Chemical precipitation is a process where agents are added to increase the effect of sedimentation and remove larger amounts of particulate pollution in the water. This particulate pollution can be anything from asphalt residues to rocks and heavy metals, all of which vehicles can be exposed to on the roads.
The product added is the effective precipitant Polyclay. Polyclay is a powdered, semi-granular polymer that is added directly to the tanks without the need to mix with water first. Together with a coagulant and pH adjuster, Polyclay is added to a mixing tank where the additives are mixed well into the water before the water is passed on to larger tanks for sedimentation. Here, the particles collect at the bottom of the tank while the clean water flows on in the overflow.
Bio-plant
The bio-plant is an important step in the purification process for water from car washes. In addition to removing biological pollution that vehicles encounter on the road, the bio-plant also removes detergents used to wash the vehicles.
The bio-plant is two tanks filled with bio-filter balls. These balls are used to create a surface in the water on which bacteria can grow. When the water is passed through the bio-plant, these bacteria consume nutrients found in the water. When the bacteria die, they sink to the bottom of the tank and are collected together with the sludge from the chemical precipitation process.
Finishing
After both chemical precipitation and biological treatment processes, the water is led to a clean water collection tank. Before this water is reused for washing new buses, this water is run through a post-treatment cycle. Here, the water is pumped through a sand filter, a carbon filter and a UV system, before the water is returned to the tank.
This cycle runs continuously to maintain the highest possible water quality. When the need for water in the car wash arises, the car wash will automatically close the after-treatment cycle and send water to the car wash.
Sludge dewatering
During the cleaning process, a large amount of sludge will collect at the bottom of the tanks. This sludge must be removed and dewatered for the most efficient and economical handling.
Nordisk Vannteknikk supplies a number of different solutions for handling collected sludge. In this case, a simple and space-saving system has been used for handling the sludge from the plant, a simple dewatering container. A perforated container is placed on top of a collection basin for efficient drainage. A dewatering bag is placed in the container to collect the sludge that is pumped out from the bottom of the tanks. The water flows through the bag and the holes in the container and down into the collection basin below where it is pumped back to the tanks for cleaning. When the bag is full, it can be easily lifted out and a new bag placed in.
What do we offer?
Due to high demand for similar systems, Nordisk Vannteknikk has further developed and optimized the systems for even better performance. The systems can now be delivered with significantly higher capacity in a smaller footprint while still meeting the Nordic Ecolabel requirements at a lower price.
Nordisk Vannteknikk also supplies other solutions for washing vehicles and purifying wash water, including a mobile wheel washing system. You can read more about it here .
In addition, we offer consulting services and advice regarding Nordic Swan Ecolabelling of existing facilities.
Contact us
Would you like more information or a quote? Contact Hans-Kristian on tel. 916 59 500, or email hans-kristian@nordiskvannteknikk.no