Hydrocarbon-based solvent detergents used in car washing - their advantages and disadvantages.
Hydrocarbon-based solvent detergents are widely used in car washing because of their excellent dissolving properties. Detergents are typically composed of aliphatic, naphthenic and aromatic hydrocarbons. Aromatic hydrocarbons in particular are effective solvents, but they also pose the most significant health hazards.
Hydrocarbon-based solvent detergents are therefore classified as harmful and often chronic health hazards. As highly flammable and hazardous to the environment, they can also pose fire and explosion hazards, as well as risks of soil and groundwater contamination. Efforts are being made to replace hydrocarbons with renewable and safer solvents.
In northern climates, cars get dirty quickly and need effective washing processes and detergents to clean them. Hydrocarbon-based solvents are particularly suitable for removing greasy dirt from bitumen, fuel residues, oil and road salt that accumulates on car surfaces.
Washing processes and exposure patterns
Solvent detergent is typically applied to the surface of the car to be washed in a diluted micro-emulsion of about 5-30%. The detergent is applied as a thin mist and allowed to act for a few tens of seconds. The detergent is then brushed off and rinsed with water. The detergent and the dirt dissolved on the surface of the car run off with the water into the soil or the waste water collection system.
During detergent application, significant amounts of solvent mist and aerosols are present in the air of the washroom. For this reason, special attention must be paid to the ventilation of the washroom, but this alone is not enough. Personnel must wear personal protective equipment, as the solvent vapours and aerosols in the air can be absorbed into the worker's body through inhalation and can cause serious health problems.
Health and environmental hazards
Hydrocarbon-based solvent detergents cause various solvent-related diseases, the best known of which are various effects on the central nervous system. The most common symptoms include unusual fatigue, memory and concentration problems, headaches, mental changes, peripheral nervous system symptoms and dizziness. Some hydrocarbons, such as benzene, are also known to predispose to cancer. Therefore, when working with hydrocarbons, respiratory protection should always be worn and the vapours should be prevented from escaping to other work areas, for example through ventilation ducts.
- The amount of water used in a car wash is typically around 2 000-2 500 litres per hour. Washing is therefore the most significant part of the waste water from a car wash or fuel dispensing station.
- The chemicals used in washing are harmful to soil and groundwater if released into the environment. At high concentrations, they can also cause damage to the sewage system and the wastewater treatment process.
- A properly sized Class II oil separator will prevent oily water from entering the public sewage system. The operation of the separator must be monitored, the waste oil/solvent mixture accumulating in the separator must be removed frequently enough and disposed of properly as hazardous waste. In addition, the washing site must have a sampling and stop well before discharging the waste water into the public sewerage system. The discharge of industrial waste water into the sewerage system is always subject to a discharge agreement between the operator and the sewerage company.
Safety at work and storage and handling of dangerous chemicals
Hydrocarbon-based solvent detergents are classified as harmful and often chronic health hazards. For this reason, employers must provide workers with adequate training and instructions on the safe use of detergents, ensure that health checks are carried out, safety data sheets are displayed and workers are provided with the necessary personal protective equipment and their use is monitored.
Hydrocarbon-based solvent detergents are generally flammable liquids and can pose a fire and explosion hazard. For this reason, their storage and handling must take into account the requirements of chemical safety legislation and legislation relating to explosive atmospheres.
Entrepreneurs must assess the explosion risks associated with their activities, classify hazardous areas, such as solvent dosing and storage areas and the oil separator and its immediate surroundings.
He must also draw up an explosion protection document. When transporting hydrocarbon-based solvent detergents, the VAK regulations for the transport of dangerous goods must be taken into account.
1. The entrepreneur must take into account the safety of workers and customers when using hydrocarbon-based solvent detergents for washing.
2. Workers must wear personal protective equipment and there must be adequate ventilation in the washroom.
3. Vapours must be prevented from escaping to other work areas.
4. The use of solvents can pose a risk of fire and explosion and this should be taken into account in, for example, working methods and equipment selection.
5. The use of hydrocarbon-based solvent detergents requires appropriate technical solutions for the pre-treatment of the waste water from the washing process, as well as proper use and control.
6. Employers are always responsible for the safety of their employees.
Vehicle washing at petrol stations and similar establishments, Oil and biofuel industry association, 2015