Stormwater Trash Separators

Practical Solution

The “How To”

Stormwater trash separators are filters which catch stormwater pollution before it is able to enter waterways. They catch most of the litter and silt but are not able to stop chemicals from escaping into the environment. The contents collected from the stormwater must be emptied on a regular basis and sent to a landfill. Additional information on trash separators can be found here. 

Items that are considered to be gross pollutants include:

• Domestic plastics, including plastic bags or clingwrap
• Industrial packaging
• Metals
• Plastic bottles
• Paper products, including cigarette butts
• Sediments
• Organic materials such as grass and garden clippings

Planning & Zoning

Municipal codes that consider the use of stormwater trash separators tend to be included in codes with other environmental best practices such as bioswales. In the St. Louis region, the Metropolitan Sewer District will not maintain the devices unless they are approved separators.

Dollars & Cents

The cost of a stormwater trash separator varies greatly depending upon the size of the unit and the model. Capital costs for the units range from approximately $4,000 to $300,000. Labor and installation costs can be 50-100% of capital costs.

The City of Los Angeles, California, in 2003 estimated that the cost of 40 units and maintenance for 10 years would total roughly $30,000,000. 

Measuring Success

The success of installing hydrodynamic separators can be easily noticed based on the condition of stormwater as it is being treated. With proper implementation, the stormwater should be free of large suspended solids and oils. The benefits of the use of these devices can also be seen in the treatment costs of the region utilizing them. If the devices are proving effective, then the treatment costs for the region should decrease.