The City of Kinston had two existing WWTPs, Northside and Peachtree, and both consisted of an extended aeration activated sludge process in concrete lined basins. The City needed to upgrade the plants to meet an effluent TN limit of 3.5 mg/L, and due to flooding issues at the Peachtree site, ultimately decided to consolidate treatment at the Northside site. The plant was expanded, upgraded, and renamed the Kinston Regional Water Reclamation Facility.
The new plant consists of a Johannesburg activated sludge BNR process (Figure 1) followed by deep-bed denitrification filters. An online nutrient analyzer was installed at the denitrification filters facility to provide nitrate readings for use in the automatic methanol feed control scheme. To enable close tracking and optimization of the upstream activated sludge BNR system performance, an online analyzer capable of measuring ammonia, nitrate, nitrite and soluble phosphorus was installed to provide real-time nutrient data throughout the BNR process zones. Sampling locations include the BNR basin influent, the last anoxic zone (Zone E), Zone F and Zone G (corresponding to locations at one-third and two-thirds the length of the aerated zone), and at the secondary clarifier influent splitter box.