How to keep your wash bay running smoothly

Cleanawater on 22 November 2021

Wash bays are designed to protect the environment by capturing used water for treatment or recycling before disposal. Careful consideration goes into each stage of design from the size of the wash bay, water capacity, and whether it is roofed or not. There are also the usual water processing sections like the silt trap and oil water separators.

Once a wash bay is designed and installed, it should still be serviced and maintained regularly to ensure it continues to protect the environment from polluted water.

Contact Cleanawater to find out about our servicing and maintenance options for wash bays.

Why servicing and maintenance are important

Car washes and other businesses that operate wash bays operate by permission of the local water authority. This permission takes the form of a trade waste permit, which governs how the business may discharge their trade waste to the wastewater network.

Trade waste permits set conditions for each business, for example:

  • Permits set limits on the max permissible level of various contaminants like oil content.
  • Permits set requirements for which trade waste pretreatment must be installed on-site. The conditions may also include a provision for servicing and maintenance of the equipment.

Failing to comply with trade waste permit conditions is a serious offence. It can result in severe fines or even site closure until the situation is rectified.

Of course, besides compliance, servicing and maintenance is important to keep a wash bay operating as per design. A wash bay should remove solids from the wastewater and capture all the wastewater for treatment. Servicing and maintaining a wash bay also means servicing and maintaining the wastewater treatment equipment like oil water separators.

Common servicing and maintenance tasks for wash bays

1. Cleaning the silt trap

All wash bays have a system for separating solid particles from the water and collecting it in a silt trap. Over time, this trap fills up and could overflow causing solids to carry over with the water.

Silt carryover is very harmful to downstream processing equipment like oil water separators. The tiny solid particles can get trapped in the internal structure of the separator. This reduces its capacity and its efficiency. Unfortunately, the drop off in oil water separator performance may not be noticed until there is an oil carryover into the wastewater system resulting in an environmental incident and the possibility of a fine.

2. Disposing of oil from the oil water separator

Oil water separators have an oil compartment where the oil and sludge collects. This compartment has limited space and has a similar risk to the silt trap should it overflow. Sludge and oil will flow back into the oil water separator and disturb the operation of the system. Oil will be carried over into the wastewater stream resulting in an incident and a possible fine.

The oil compartment of an oil water separator should be regularly inspected and cleaned. The oil should be disposed of in a safe and environmentally friendly manner. While the compartment is empty, it should be function checked to ensure the level float is working properly.

3. Inspecting the wash bay floor

Wash bays are designed to collect water from washing activities for processing and disposal. Any leak in the wash bay will allow contaminated water to enter the ground water system directly or flow into a stormwater drain. For this reason, the floor and perimeter bund walls of a wash bay should be regularly inspected to check their integrity. Leak tests can be performed by flooding the bay with water and looking for signs of a flow of water escaping.

4. Check the operation of the first flush diversion system

When heavy rainfall falls onto an open wash bay, there is no need to process this water through the wastewater treatment equipment because it is clean water. It has not been used for washing vehicles or equipment. However, the first deluge of water may pick up contaminants that are deposited on the wash bay floor.

This first flush of water should pass through the wastewater treatment and after that, all the rainwater should be diverted to stormwater. A first flush is typically defined as the first 10 mm of rainfall. First flush diversion systems protect the wastewater treatment network from being overloaded with clean water.

First flush systems use a rain gauge to measure the rainfall which then activates the diverter system via a controller. To check the operation of the system, both the rain gauge and the diverter valve should be function checked:

  • Fill the rain gauge manually and test that the controller receives a signal to divert the water.
  • Check the valve to ensure there is no debris interfering with its movement. Check that the controller signal opens and closes the valve as per design.

Talk to Cleanawater for expert wash bay advice

Contact Cleanawater for expert advice about your wash bay application. We offer service and maintenance contracts to give you peace of mind that your system is compliant and operating effectively.

Contact Cleanawater to find out more about our servicing and maintenance contracts.