What treatment solutions do you need for stormwater?

Cleanawater on 7 January 2020

Did you know that not every sewer is the same? Stormwater and wastewater are two completely different systems. Stormwater is clean water mostly generated by rain which falls on roofs and open surfaces. Wastewater is generated by commercial, manufacturing or industrial activity and has the potential to contain contaminants.

Reach out to Cleanawater for more information about oil water separators for stormwater.

Regulations for wastewater and stormwater

Wastewater is regulated by strict specifications and a permit system. The way it works is that businesses must enter into an agreement with their local water authority. Based on their permit, they may discharge wastewater into the wastewater network as long as it meets the agreed specifications.

Stormwater is covered by the Environmental Protection Act, which places the responsibility on all businesses to protect the environment. No business may operate in such a way that they allow contaminants to enter the stormwater system. This list includes hydrocarbon contaminants like oil, grease and lubricants.

Sources of oil in stormwater

oil water separator for stormwater

Unfortunately, not all surfaces where rain falls are completely free of oil. For example, you may observe a sheen of oil on rainwater runoff from a parking area. This is oil that accumulates from leaks and residue on the engines of the cars that park there.

Even though this oil is not generated from the activity of the business, it results in a threat to the environment. Any oil that enters the stormwater system will end up directly in Australia’s waterways and therefore poses a risk to plant and animal life.

Wash bays are another potential source of contamination for stormwater systems. An unroofed wash bay may have oil residue on the surface. When a rain event occurs, this oil must be diverted to an oil water separator before the clean rainwater is routed to stormwater. This is what a first flush system is designed for. After the area is flushed, clean rainwater can be routed to the stormwater sewer.

The importance of separation

The best method for keeping stormwater clean is the separation of areas. Any area that has the potential to generate contaminated water should be physically separated from stormwater sewers by bunding. Water from bunded areas should be routed to the wastewater sewer network because of the risk of contamination.

Separation of areas allow for containment of spills, ensuring they can be cleaned up before they enter the sewer system. As a last resort, if separation cannot completely resolve the problem, it may be necessary to treat stormwater before it leaves the premises.

Oil water separating options

Oil water separators are designed to remove traces of oil from water streams so that the water discharge meets the required standard. There are two main types:

stormwater oil water separator

Coalescing plate separators can remove oil down to 10 ppm while vertical gravity separators reduce oil content to about 50 ppm. It is important to discuss the options with the authorities and an experienced service provider to ensure you select the best unit for your needs.

Maintenance and servicing

Regulators require that treatment solutions have adequate maintenance strategies in place. Buying an oil water separator for stormwater from Cleanawater gives you access to maintenance and servicing by our trained technicians. This ensures your system keeps operating as per design and prevents unnecessary pollution events.

Cleanawater technicians have the knowledge and experience to provide this service and help you meet the regulators requirements.

Challenges of treating stormwater

Stormwater tends to have a highly variable flow rate. During a storm event, the flow rate will be high, but in dry conditions there may be no flow at all. The stormwater system and treatment solutions must be able to accommodate these variances without causing a pollution event.

One solution to the variable flow is to use stormwater pump stations. These act as buffer tanks and also enable stormwater to be routed to the correct sewer even if the gradient is not favourable. Pump stations have inbuilt pumps which pump the water out of the tank at a fixed rate.

Talk to Cleanawater for expert advice

Contact Cleanawater for all your oil water separator for stormwater needs. We have more than 20-years experience in the Australian market and can help you navigate the regulatory requirements.

Contact Cleanawater to find out more about oil water separators for stormwater.