Wastewater Treatment Systems for Car Washing

Car Wash Wastewater Systems

Car washing may seem like an unburdensome activity when it comes to pollution and the environment. After all, high-pressure sprays are designed to be highly efficient and not waste much water, and the average car is usually not laden with dangerous chemicals.

But let’s think about it once more.

No matter where they have been driven, all cars will have some oil residue on their outer surfaces, and particle pollution from exhausts will inevitably accumulate. To wash everything off, disinfect properly and give the car the desired shine, various detergents are used – and a few (if any) of them are biodegradable or environmentally-friendly.

In fact, washing an average car will result in 750 milliliters of sludge contaminated with hydrocarbons, heavy metals, and surfactants.

Now multiply that with the number of cars that pass through a typical car wash per day, and it becomes easy to see that car wash runoff needs to be dealt with before it is released into the environment. The local environmental regulations are there to ensure proper carwash wastewater treatment.

However, here’s the good news.

The obligatory wastewater treatment and the water-saving methods (which can include even water recycling) make the professional car wash operations much less hazardous to the environment than home car washing, which discharges all runoff directly into the storm drain.

Besides complying with the regulations, another perk is that by installing the right equipment, you get to advertise your business as honestly environmentally-friendly.

How Is Car Wash Wastewater Dealt With?

The wastewater runoff from your car washing operation is dealt with through appropriate wastewater systems. The water is purified through the three primary phases:

  • The wastewater is prevented from escaping the site and is collected instead.
  • The polluting elements are extracted from the wastewater, which counts as treatment; the methods can vary.
  • The now-purified water is released into the storm drain system or recycled. Simultaneously, the collected pollutants are disposed of (to be stored, destroyed, or recycled) in a safe and regulation-approved manner.

Wastewater systems on today’s market are very diverse. Fox Environmental Wastewater Systems are renowned for their reliability, quality, and, last but not least, elegant engineering solutions.

What Types Of Wastwater Systems Are Used For Car Wash Operations?

First of all, car wash businesses are stationary, so the compatible wastewater systems that are likewise intended for stationary use. For non-stationary vehicle washdown operations, different systems within mobile wash stations are used.

Regarding the car wash wastewater systems, there are several options on the market.

Wash Down Diversion Systems

Fox Diversion Valve
Main Valve – DV150

Wash Down Diversion Systems do just what their name says – they divert, plus store the carwash runoff. After the water is collected and stored, it can be purified (treated) and ultimately end up either released or recycled within the car wash business – which would be the ultimate water-saving option.

As said previously, Wash Down Diversion Systems are intended for stationary car wash and other washdown operations only.

When the wash down starts, the valve of a wash down system like DD600 Automated Wash Down Diversion System is triggered to open automatically, which is why these types of systems carry a stamp that says “Automated.” This fact allows for easier operation without having to think if the valve is open or closed in the middle of a washing process.

The DD600 Automated Wash Down Diversion System requires no electricity to function.

Two valves are the main controllers of all operations within the DD600:

  • Fox Demand Valve
  • Main Valve – DV150

How it all works?

The demand valve sends the signal to the other valve to open the collection pit. That second, DV150 valve is like a gatekeeper, the way to the collection poly pit. It is housed in the pit itself and features a slit basket that prevents the gross pollutants from obstructing the valve.

The collection pit itself has a trade waste outlet and a stormwater outlet.

Besides car wash operations, the automated wash down diversion system can be used in all stationary wash down sites, where a significant number of vehicles get washed on a regular basis. These systems are built tough, making them suitable for more demanding roles, e.g., in truck washing or mining-related washdown operations. If that is the case, instead of the standard (Class B) Wash Down Diversion System, there is also a heavy-duty option.

First Flush Systems

First Flush System Model FF 600Somewhat different from the aforementioned diversion systems, the First Flush Systems are intended to divert and catch the first wave of stormwater runoff on sites that are too big for hose washing at the end of an activity, so it is the rain and other types of precipitation that ultimately away all the pollutants from the area.

With the First Flush System FF 600, its Programmable Logic Controller (PLC) enables you to program precisely the volume that needs to be collected, avoiding unnecessary collection – up to 2000L. The automatic (demand-driven) option is also present in First Flush systems.

While the pollutant-rich “first flush” remains captured for further treatment, clean stormwater is released through the first flush system.

Baffled Gross Pollutant Collection Trap


The Baffled Gross Pollutant Collection Trap is an advanced, customizable trap that is installed at the stormwater pipe’s ending. Once installed, it starts to restrain waste particles and pollutants immediately.

When runoff water enters the unit, solids of size up to 0.3 millimeters get trapped in a compartment called the sediment basket and drops to its bottom. From there, it can be manually collected and dealt with according to the local regulations.

However, the hydrocarbons remain floating in the water. That is why the remaining water is forwarded to the large chamber of the trap, which contains the baffle. As the baffle directs the flow of the water, the floating hydrocarbons are blocked by it. The now-cleaned water finds its way out beneath the baffle – through the exit system purposefully positioned below the baffle.

This type of Fox Gross Pollutant Collection Trap has no moving parts, making the operation hassle-free and its maintenance easy.

Final Thoughts

If untreated, car wash wastewater can carry an array of pollutants into our ecosystems and water supply. That is why car wash operations are required by law to install suitable wastewater collection equipment, making car-washing businesses genuinely environmentally-friendly.

Diversion systems and collection traps are commonly used for this purpose. Environmental Equipment Engineering offers robust Fox systems that are high-functioning, durable, and easy to operate and maintain.

Depending on various factors, different systems are suitable for different car wash operations. When deciding on the best system for your business, you will need expert advice. Luckily, Environmental Equipment Engineering can offer you free consultation and advice, based on more than 45 years in the business – to help you define and meet your requirements.