Nutrient Addition in Wastewater Treatment Plants

Nutrient TankNutrients are an important component in the operation of a wastewater treatment plant. Specifically, the two macronutrients nitrogen and phosphorus, otherwise known as N and P. They are critical building blocks for bacterial growth and reproduction, as well as energy transfer.

Just as people require a balanced diet including vitamins and minerals, bacteria require nitrogen and phosphorus at a certain ratio in order to reproduce quickly and degrade food to the best of their ability in the conditions they live within. The “food” is oftentimes referred to as BOD (biochemical oxygen demand) but BOD is really a laboratory test used to measure the quantity of biodegradable material left in a system after one or five days prior to discharge (BOD1 or BOD5). However, not every wastewater treatment plant requires the addition of nitrogen or phosphorus since some quantity of it may already exist in the water entering the WWTP. The key is having the correct ratio of nitrogen and phosphorus that a manufacturing plant’s microbiological system needs to run efficiently without overdosing or underdosing it on either N or P, thus compromising bacterial reproduction.

While the importance of nutrient availability for optimum wastewater system performance is generally well accepted, Environmental Business Specialists continues to develop techniques and strategies for optimizing nutrient application rates without compromising system performance. There are several approaches that EBS utilizes to assist our clients in optimizing performance while reducing nutrient cost.

In general, EBS takes a holistic approach that may include some or all of the following components:

  • Data evaluation, including BOD loading, nutrient balance, and nutrient application rates.
  • Development of a loading-based nutrient feed rate model.
  • Dosage and N:P ratio optimization using respirometry laboratory techniques.
  • Determining the best application point for nutrient addition to avoid loss from volatilization or precipitation.
  • Improve analytical approaches at the mill.
  • Installation of improved metering pumps.
  • Utilization of a continuous bioaugmentation approach utilizing the EBS Bacterial Acceleration Chamber or BAC Unit to reduce reliance on nutrients.
  • Routine analyses by EBS specialists on-site or in our laboratory to monitor system performance and proactive changes in nutrient ratio or addition rates.

Since 2002, EBS has worked with over thirty pulp and paper mills to optimize their nutrient programs. Mike Foster, CET (Certified Environmental Trainer) has given numerous presentations and participated in several panel discussions on the subject at both TAPPI and NCASI meetings. If you would like to like to know more about nutrient optimization and the EBS approach, contact us at at

Learn about the microorganisms in your wastewater treatment system.