Wastewater Treatment

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twwtp sign 2016Durham County Triangle Wastewater Treatment Plant 2018-2019 Performance Annual Report

Sewer Use Ordinance - Amended March 11, 2013

The TWWTP is rated for an average daily flow of 12 million gallons per day and specifically designed to meet future nutrient load requirements for the Jordan Lake nutrient management strategy. The TWWTP serves the southeast portion of Durham County inside and outside the Durham City limits, and serves the Research Triangle Park areas within Durham County.

The TWWTP consists of the following treatment systems:

Influent Pump Station - sized for 12 MGD average flow, and located 2’ above the 100 year flood elevation to reduce flooding risk.

Fine Screens - removes insoluble materials larger than 1/4” prior to the beginning of the treatment process.

Grit Removal - removes small dense inorganic materials prior to the beginning of the treatment process.

Five Stage Biological Nutrient Removal System - provides the ability to biologically remove nitrogen and phosphorous during treatment with carbon source addition.

Chemical Polishing - sodium aluminate is used to remove additional phosphorus from water by chemical precipitation.

Clarifiers - quiescent zone where biomass is separated from treated water.

Tertiary Filters - filtering to remove additional biomass.

Ultraviolet Disinfection - disinfection process without harmful by-products.

Reaeration - supplemental dissolved oxygen provided prior to discharge to Northeast Creek.


Sludge Holding Facility

Sludge Handling Facility - Completed in February 2013