Exact Stormwater Management

A stormwater quality separator is a type of infrastructure used in stormwater management systems to remove pollutants from stormwater runoff before they are discharged into natural water bodies or groundwater. These pollutants can include sediment, debris, oil, grease, heavy metals, and other contaminants picked up from surfaces like roads, parking lots, and roofs during rainfall events.

Water quality separators typically consists of several components including an inlet, treatment mechanisms, a sediment chamber, and an outlet structure. The inlet structure is where stormwater enters the separator. Some inlets include areas where floatable materials like oil and grease get trapped. Inlets often include a mechanism to alter the direction of speed of the flow of runoff. The treatment mechanisms work by modifying the flow of water. Some separators work by slowing the flow of water through the system, allowing gravity to pull particles out of the water. Other units create a vortex inside the unit, causing the water to swirl around inside the structure, which also causes sediments to drop out.

If you're wondering where sediments drop, that's where the sediment chamber comes in. This is the area that provides storage for collected sediment, and that will need to be cleaned out periodically. The Outlet is where cleaned stormwater exits the separator which may include additional features to control flow rates and prevent re-suspension of settled pollutants.

The operation of a stormwater quality separator relies on physical processes such as sedimentation, filtration, and gravitational settling to remove pollutants from stormwater runoff. Proper maintenance, including regular inspection and cleaning of the separator components, is essential to ensure its continued effectiveness.

Water quality separators are an important tool in urban stormwater management, as their small footprints help to protect water quality in far less space than most land-based systems like bioretention or dry ponds. There are many different types of water quality separators, and they each function a little differently. If you need help understanding your separator and the regular maintenance it needs to continue protecting downstream waters, Exact can help identify what system you have and how it works, along with what type of inspection and maintenance schedule is necessary to ensure your system continues to protect receiving water bodies to mitigate the impacts of urbanization on aquatic ecosystems.

Inspecting a stormwater quality separator is crucial to ensure it functions effectively in removing pollutants from stormwater runoff. Inspections of newer systems should be done quarterly through systems first year of use, and then at least annually thereafter. It's also a good idea to check on your separator after any major storm events to ensure its working properly and no large objects are jamming up water flow through the unit.

The first step of any inspection is to check for any signs of damage or deterioration to the separator structure itself, including cracks, corrosion, or leaks. Ensure that all lids, access ladders, and other components can be safely utilized.

Next, inspect the inlet and outlet structures for blockages, debris buildup, or erosion around the edges. Check al screens or flow control devices to make sure they are clear, with no obstructions. Look for signs of sediment accumulation in the sedimentation chamber or treatment units. If your separator is functioning properly, it's likely you'll see sediment in the sediment chamber. That doesn't necessarily mean it's time for maintenance, though. Use a long pole (we call them stadia rods) to push through the top of the sediment to get an idea of sediment depth, and follow the manufacturer guidelines to determine when it's time to perform maintenance.

Be sure to keep good records of your inspection findings, including any observations, maintenance needs, or corrective actions taken. Keep that in a log that includes inspection dates, findings, and maintenance activities for regulatory compliance and future reference.

If all of this sounds entirely too messy, or if you have concerns about your separator, consider hiring qualified professionals like Exact for a more comprehensive inspection.

Regular inspections are an essential first step to ensure that stormwater quality separator continues to operate effectively and comply with regulatory requirements.

Maintaining a stormwater quality separator is essential to ensure its continued effectiveness in removing pollutants from stormwater runoff. Separators can trap (literally) tons of sediment and debris, and removing and disposing of that material not only keeps the system working properly, but also prevents the removed material from becoming resuspended and exiting the device during a larger storm. Proper maintenance also helps prevent clogging and upstream flooding, as well as prevents discharging polluted water to your downstream neighbors.

Different types of separators require different processes to perform maintenance, and some even require confined space entry which can be pretty hazardous. You will almost always need professional help to maintain your separator, and here's what you should expect from them:

Maintenance should always be triggered by an inspection that documents what needs to be done. While any structural deficiencies noted in the inspection should always be handled first to ensure the rest of the process is completed safely, typical maintenance for water quality separators involves removing the collected sediment and debris from the sediment chamber and all the operational components. Some of that may be done by hand, but most systems are designed to be cleaned out with standard jet-vac equipment to avoid the hazards (and cost) of confined space entry.

Maintenance activities should also include the outlet structures. Clear any obstructions and ensure proper flow out of the separator. Remove debris, vegetation, and any other materials that may impede flow, and, if the treated water outlets to a drainage swale or natural waterway, check the outfall to ensure there's no erosion or blockages which could create problems.

If your separator has been neglected for some time, there may be accumulation of sediments upstream of your system, so it can be useful to check the upstream drainage network and jet that out, if necessary.

Keep detailed records of all maintenance activities, including pictures and descriptions of what was done. If you're using professional help, they should provide a full photo-documented report for your records. Keep the report in your inspection/maintenance log.

By performing regular maintenance you can ensure that your stormwater quality separator remains effective in protecting water quality, meet your regulatory requirements obligations for stormwater quality, and avoid dumping polluted water on your downstream neighbors.

Installation of a stormwater quality separator can be a pretty big task and is usually handled by a professional contractor. The process involves excavating the area and installing the (typically) very large, concrete structure using cranes or large equipment to move the components. Setting the structure at precisely the correct elevation is critically important to ensure water flows through the system properly. All water quality separators work on gravity, so being off - even by a few inches - can have drastic impacts on performance.

Once the system is installed, the inlet and outlet connections are made, and the system can be backfilled. Pavements or various surface treatments can be used above the separator, and the access hatches can be installed, which allow the system to be inspected and maintained later on. Getting all of this work done properly is no small task, so be sure to get a professional stormwater contractor like Exact on your team to work through the details of a successful installation.