Industrial outfall design, permitting, and construction oversight
- Client Name
- Chemtrade
- Location
- South Carolina, US
SLR conducted a comprehensive mixing zone study and designed a new multiport diffuser for Chemtrade’s chemical manufacturing facility in South Carolina. The project included permitting, construction oversight, and certification of the new diffuser.
Challenge
The facility’s existing diffuser, installed when discharge flows were higher, had accumulated silt due to low exit velocities, reducing its effectiveness in dispersing treated effluent. The client required design and evaluation of a new diffuser to meet water quality objectives, including compliance with Whole Effluent Toxicity (WET) limits in the draft NPDES permit. Additionally, the project required coordination with multiple regulatory agencies to secure construction permits and ensure proper installation.
Solution
SLR used the hydrodynamic model CORMIX to assess effluent dilutions and optimize a new multiport diffuser design suitable for current discharge conditions. Modeling results were applied to confirm that WET concentrations in the facility’s draft NPDES permit were met. Following the issuance of the final NPDES permit, SLR prepared and submitted a construction permit application to the South Carolina Department of Health and Environmental Control (DHEC) and assisted with a Joint Federal and State Application for Construction in Navigable Waterways with the U.S. Army Corps of Engineers. During construction, SLR performed oversight and certified the new diffuser’s installation through a formal letter to DHEC.
Impact
The new multiport diffuser restored effective effluent dispersion and minimized silt accumulation, ensuring the facility complies with state and federal water quality regulations, including WET limits. SLR’s work streamlined the permitting and construction process, reducing operational risk for the client and providing regulatory confidence in the facility’s discharge system. This project highlights SLR’s deep experience in industrial effluent management, mixing zone studies, and diffuser design for chemical and manufacturing facilities across the U.S.
