In this video, Dr. Barnard sets the stage for biological nutrient removal. Increased populations around the world have led to amplified nutrient levels in wastewater and agricultural runoff. This can lead to many problems, including but not limited to cyanobacteria, algal blooms, and fish kills. These drivers increase the challenge of keeping our receiving waters healthy.
This segment covers activated sludge and BNR basics, including hydraulic retention time, solids retention time, nitrification, and denitrification.
Biological Phosphorus Removal - Part 1
Dr. Barnard describes the drawbacks of chemical phosphorus removal and introduces the concept of biological phosphorus removal. The evolution of biological phosphorus removal strategies is explained.
Biological Phosphorus Removal - Part 2
Depending on climate, the extent of fermentation within collection systems varies. Many treatment plants have experimented with in-plant fermentation strategies. Dr. Barnard explains that phosphorus removal can be enhanced under deeper anaerobic conditions, with Tetrasphaera also taking up phosphorus.
Membrane Bioreactors (MBRs)
A recent innovation in the world of BNR is using membrane bioreactors. MBRs integrate membranes into the activated sludge process, which can produce a much higher effluent quality.
Phosphorus is a finite resource and recovering it is very important. Dr. Barnard explains complete phosphorus recovery through the WASSTRIP method as well as struvite precipitation technology alternatives.
Granular Activated Sludge
In normal activated sludge operations, “fluffy” flocs are formed. The granular activated sludge process, however, forms granulated flocs, which settle faster and can enhance phosphorus removal.
Anammox bacteria can take ammonia and nitrite and turn them into nitrogen gas. This process saves energy and has a smaller footprint.
Biological Treatment of Emerging Contaminants
Biological treatment takes up many of the carcinogens, personal care products, and pharmaceuticals commonly found in wastewater. Solids retention time is a key operating parameter for the degradation of these compounds.