Nitrogen Reduction using a Small Budget and Big Ingenuity

This paper presents creative solutions at the Williamsburg Treatment Plant (WBTP), which reduced effluent total nitrogen (TN) from 7.4 mg/L to 2.5 mg/L on a monthly average basis. A calibrated Biowin process model was developed to assess various reactor configurations to determine the optimum process selection for the highest nutrient removal. Once the most advantageous configuration was selected, HRSD purchased, designed, and constructed all improvements required. HRSD staff utilized low cost materials to construct budget friendly baffle walls in-house, hand-built a large bubble mixing system, and modified existing equipment to implement the new configuration. Instrumentation and automation controls were integrated into the plant’s distributed control system (DCS) by staff instrumentation technicians. This case study showcases the ability to optimize and implement nutrient removal strategies at low cost when the utility supports creativity and ingenuity of plant staff.