How "green" can carwash be?

59 percent of all car owners wash their vehicle at least once a month - whether in the car wash or by self-care, e.g. in the wash box. This is the result of the DAT Report 2019. The DAT Report has been dealing with consumer behaviour in the automotive industry since 1974. It is considered the industry's standard work and provides neutral information on automotive attitudes in Germany. 

Car washing is an important topic for over half of vehicle owners. But what about the ecological side of car care? We provide answers to questions about this topic. 

In Germany, washing vehicles on one's own property or on public roads is only permitted under very specific conditions. The ban is not regulated nationwide, but by local ordinances. If at all, washing a vehicle at home is only permitted with fresh water. The use of cleaning agents is generally prohibited. In water protection areas there is a general ban on car washing. But why is that?

It is to prevent oil-containing dirt or fuel residues from being discharged into the public sewer system. In combination with the wrong cleaning agents, stable oil/water emulsions and environmentally hazardous substances can enter the sewage systems in an uncontrolled manner.

Demulsifying cleaners (e.g. ÖNORM tested) are used in professional washing facilities. The washing processes are designed in such a way that no stable emulsions are formed. Each washing plant has a multi-stage waste water treatment system with sludge trap and oil or coalescence separators. These systems prevent waste water containing oil from entering the sewage system. Furthermore, various water recovery systems are used to help reduce fresh water consumption.

Today, new car washes are only approved in conjunction with water recycling systems. Car wash operators are also required to retrofit such systems, which varies from region to region. 

From an ecological point of view, biological water treatment plants are particularly suitable. Here, oil and surfactant residues are broken down using various biological processes with the help of bacteria, and purified process water is fed back into the washing process. The recycling rates are 80-95%! These measures can save large quantities of fresh water, which also leads to cost savings for the operator. In gravel filter systems, too, the process water is treated for reuse. Here, small particles are bound with the help of a flocculant and then filtered out of the service water. The filtered water is then returned to the washing circuit. Both types of systems follow the approach of saving as much fresh water as possible through treatment.

The cleaning and preservation products used are biodegradable according to OECD standards. The operators of the car washes predominantly do without strongly acidic and strongly alkaline cleaners. There are also product lines made of plant-based surfactants (e.g. Green Line) that have special properties in this area.

One goal for the future should be to bring older car washes up to the state of the art and to make car washing greener through the use of renewable energy.

The use of well-biodegradable detergents can significantly increase the recycling rate of service water. This would mean that only drag-out water losses in car washes would have to be compensated with fresh water. The issue of fresh water consumption has come more and more into focus in recent years with the low rainfall. To avoid restrictions or bans on car washes in dry summers, the car wash industry and also the manufacturers of car washes and cleaning agents must address the issue. This is already taking place in many areas.

This includes intensive advice to car wash operators on ways to achieve good washing results with less aggressive and more degradable detergents. It is also important to involve the end customers, i.e. the vehicle owners, in this information process. Often, a lot of foam or strong fragrances are associated with better washing results, but this is usually not correct. Out of concern to annoy or lose customers, too much cleaner or water/energy is often used. Through training and broad information, we have to work towards a rethink.

With the GREEN LINE product line, we already have a comprehensive product series based on sustainable raw materials in our programme for our customers. The use of GREEN LINE products already leads to better service water qualities and saves large quantities of fresh water. We will now extend this approach to other product areas. 

Our field service also contributes to this by advising our customers. Our colleagues inform customers about correct application concentrations and consumption. This is not only better ecologically, but also economically. Through targeted advertising measures, we can inform and sensitise car wash operators and end customers alike.