Enviro-Line Logo


Biological Nutrient Removal Overview

Biological Nutrient Removal System Treatment is the activity of removing Nitrogen and Phosphorus from the waste stream prior to discharge or reuse the water. N and P are contributors to the I "hypoxia" or lack of oxygen in the Mississippi River from point and non-point water sources. Since we only can control the point sources,WWTP discharges, our focus to provide high quality of discharge water below standards required by the Federal EPA and local regulatory authorities.

For example, water quality can discharge at the folowing levels for water quality:

  Level 1 Level 2 Level 3
BOD < 10 ppm < 5 ppm < 3 ppm
TSS < 10 ppm < 5 ppm < 3 ppm
Ammonia - N < 1.5 ppm < 1 ppm < 0.5 ppm
Nitrate - N < 6 ppm < 4 ppm < 2.5 ppm
Total Nitrogen < 8 ppm < 5 ppm < 3 ppm
Phosphorus < 1.5 ppm < 0.5 ppm < 0.3 ppm

The more stringent the water quality, the more controls and other influences to the tratment design are required. For example, influent organic strength and water temperature will provide the necessary outside influences to performance effectiveness. The cleaner the water the quicker the biological reactions. The more BOD organic strength, to a respectable level, the easier the dentrification and anaerobic requirements for BNR to occur.

BNR process requirements include aerobic, anoxic and anaerobic 'zones' which allow the bioogical 'bugs' to do their respective jobs.

Aerobic: Oxygen is provided the treatment system.

  Aerobic Oxic Anoxic Anaerobic
Oxygen Provided None Provided None Provided
Mixing Yes Yes Yes
BOD Reduces Reduces Reduces
Ammonia Reduces Increases Increases
Nitrate Increases Reduces Reduces
Phosphorus Adsorbed Adsorbed Released

label   label   label

Click images to view larger

Click here for video 1
Click here for video 2
Click here for video 3
Click here for video 4
Click here for video 5
Click here for video 6

  QuickTime is needed to view the videos,
To download, click here.