Washington State Department of Ecology

Ecology home > Water Quality > Stormwater >Evaluation of Emerging Stormwater Treatment Technologies > Stormwater Treatment Technologies

Stormwater Treatment Technologies

The following list separates the types of treatment technologies, defines them and lists manufacturers who make them.

Ecology's use level designation is also listed as an acronym for each manufacturer:

GULD - General Use Level Designation
General Use Level Designation (GULD) technologies may be used Washington subject to use level designation conditions.

CUD - Conditional Use Level Designation
Conditional Use Level Designation (CUD) allows continued use of the technology for a specified time period during which field testing must be completed by the vendor and/or developer. Not all CUD technologies are required to conduct field testing. Units that are in place do not have to be removed after the specified time period. Use is subject to the use level designation conditions.

PLD - Pilot Level Designation
Pilot Use Level Designation (PLD) allows limited use of the technology to allow field testing to be conducted. PLD technologies may be installed provided that the vendor and/or developer agree to conduct field testing based on the TAPE at all installations.

Governments covered by a municipal stormwater NPDES permit must notify Ecology when a PLD technology is proposed (form is available in TAPE documentation). Use is subject to the use level designation conditions.

 

Pretreatment

Pretreatment is generally applied to:

Pretreatment is intended to achieve 50% removal of fine (50 micron-mean size) and 80% removal of coarse (125-micron-mean size) total suspended solids for influent concentrations greater than 100 mg/L, but less than 200 mg/L. For influent concentrations less than 100 mg/L, the facilities are intended to achieve effluent goals of 50 mg/L of fine and 20 mg/L of coarse total suspended solids.

Back to top

Oil Treatment

Oil treatment is intended to achieve the goals of no ongoing or recurring visible sheen and a daily average total petroleum hydrocarbon concentration no greater than 10 mg/L with a maximum of 15 mg/L for discrete (grab) samples.

**At each site where a pilot use level designation is proposed, a Quality Assurance Project Plan must be approved by Ecology before the device is employed.

Back to top

Basic Treatment

Basic treatment is intended to achieve a goal of 80% removal of total suspended solids for an influent concentration range of 100mg/L to 200 mg/L. For influent concentration less than 100mg/L the effluent goal is 20mg/L total suspended solids. For influent concentrations greater than 200mg/L a higher treatment goal is intended.

**At each site where a pilot use level designation is proposed, a Quality Assurance Project Plan must be approved by Ecology before the device is employed.

Back to top

Enhanced Treatment

Enhanced treatment is intended to achieve a higher level of treatment than basic treatment. Enhanced treatment is targeted at removing dissolved metals.

**At each site where a pilot use level designation is proposed, a Quality Assurance Project Plan must be approved by Ecology before the device is employed.

Back to top

Phosphorous Treatment

Phosphorus treatment is intended to achieve a goal of 50% total phosphorus removal for an influent concentration range of 0.1 to 0.5 mg/L as well as achieving basic treatment.

**At each site where a pilot use level designation is proposed, a Quality Assurance Project Plan must be approved by Ecology before the device is employed.

Back to top

Construction Site

Back to top

 

Copyright © Washington State Department of Ecology. See http://www.ecy.wa.gov/copyright.html.

Access Washington, Official State Government Web site Copyright © Washington State Department of Ecology
Contact Us | Privacy Notice | Site Info 		Information for Ecology staff