Daniel Island WWTP | Charleston, South Carolina Wastewater Treatment Plant

Daniel Island WWTP is a municipal wastewater treatment facility located in Charleston, South Carolina, United States. It serves a population of approximately 3,333 residents, placing it in the small-to-medium agglomeration category. The plant is situated on Daniel Island within the Charleston metropolitan area. As a US facility, the plant operates under the Clean Water Act and is subject to National Pollutant Discharge Elimination System (NPDES) permitting, typically administered by the South Carolina Department of Health and Environmental Control. The designed capacity is 1.00 million gallons per day. The plant discharges treated wastewater into local waterways that ultimately drain into the Atlantic Ocean via Charleston Harbor and the Cooper River. The surrounding area includes tidal creeks and salt marshes that support diverse aquatic life, including fish, crabs, and migratory birds. The plant's proximity to the coast underscores the importance of nutrient removal to protect downstream estuarine ecosystems.

The plant's treated effluent flows into the Cooper River, which joins the Ashley River to form Charleston Harbor, an estuary that empties into the Atlantic Ocean. This watershed supports critical salt marsh habitats, oyster reefs, and nursery grounds for commercially important fish species. Nutrient loading from wastewater can contribute to algal blooms and hypoxia in the harbor, making effective treatment essential for maintaining water quality in this ecologically sensitive coastal zone.