Controlling and removing nutrients is one of the prime regulatory drivers for water resource recovery facilities. Achieving these increasingly stringent nutrient concentrations to protect local waterways requires a combination of tools, planning, and hands-on experience. 

In Pennsylvania, a facility created a mechanistic model to test several different biological nutrient removal scenarios using an intermittent aeration process. By breaking down how operational changes would affect the process, the facility developed a powerful tool to optimize treatment. 

New limits also often mean new process — in the case of nitrogen limits, this process often is denitrification, which requires readily available carbon for bacterial conversion of nitrate to nitrogen gas. Read about the pros, cons, and safety requirements of using methanol as this additional carbon source. 

On the other side of the nutrient equation, find out what every operator should know about biological phosphorus removal in Operator Essentials. 

Also in this issue:    

• A state of urgency. A New Mexico utility expanded a sewer pipe rating system to shift from simply repairing pipe segments to prioritizing and repairing the highest-risk segments before they failed.     
• Combining two pump stations into one. An Ontario pump station design overcomes several challenges, including two extreme hydraulic duty points.   
• “It’s like LEED for civil infrastructure.” The new ENVISION rating system provides users a way to measure the long-term benefits of up-front sustainability investments.