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Bio-Friendly Stormwater Treatment

By Chris Workman, PE, Director of Environmental Services, Koontz-Bryant, P.C.

Many residential communities and commercial facilities have incorporated the use of bio-friendly stormwater treatment methods to address their stormwater runoff. Filterra© Bioretention Systems is one of these systems. Several surrounding counties require that the systems be consistently maintained and routinely inspected for proper operation. Chesterfield County in particular requires that these stormwater maintenance systems (SMSs) be inspected and certified by either a licensed Professional Engineer or a certified Filterra© Inspection Specialist every six months.

Our Professional Engineer Christopher A. Workman has attended Filterra© seminars on Stormwater Quality and Quantity Treatment Design and has received a Certificate of Achievement in methods relative to the design, implementation, and maintenance of stormwater management systems and the related stormwater regulations. These seminars specifically addressed proper maintenance and operation of the Filterra© SMSs.

Filterra© units are an effective method or BMP (Best Managed Practice) to remove or reduce pollutants specifically associated with stormwater-washed parking lots and residential community roadways. Each unit typically contains a bush or tree specifically selected for its ability to produce an effective bio-mass within the unit. Stormwater enters the unit through a curbside inlet and flows through a filtering system which is composed of mulch, the bio-mass, and a granular media, all contained within a concrete box. The stormwater is retained in the box long enough for the bio-mass to decompose the pollutants, and the remnants are subsequently dispersed within the granular media. Treated stormwater flows through the box to an underdrain located at the bottom of the box, where it exits the SMS and flows to the municipal stormwater system. During extremely heavy rains, excessive stormwater is routed around the Filterra© unit directly into the municipal stormwater system, capturing the “first flush”. These units have been shown to be effective in reducing TSS, Phosphorus, Nitrogen, Total and Dissolved Copper, Total Zinc, and Oil and Grease.

Mr. Workman has performed maintenance on many of the Filterra© units in the area, including the Midlothian McDonalds, Midlothian CarMax, West Broad Street CarMax, and the Ashland First Capital Bank. In addition to performing maintenance on the units, Mr. Workman has also “recharged” the mulch, inspected the units, and provided the required certifications. In the sparse cases where the associated bush or tree was excessively damaged (i.e., backed over by a car), Mr. Workman has provided replanting information and performed the necessary re-inspection and certification.

If your residential community or place of business has a Filterra© Bioretention System or Stormwater Management System (SMS), or if you have some other bio-friendly stormwater treatment system such as retaining ponds that require maintenance, inspection, and certification, contact Christopher A. Workman by email or at (804) 200-1920.