PhD Defence Mauricio Barreto Carvajal

The title of his thesis is: Sidestream Superoxygenation and Activated Sludge Pre-Conditioning in a High-Solids Membrane Bioreactor (MBR) for Wastewater Treatment

Research summary: 

This research work tackles the operational limitations that arise when an aerobic membrane bioreactor (MBR) operates at higher than conventional mixed liquor suspended solids concentrations (MLSS). Under high MLSS conditions, the oxygen transfer capabilities of conventional fine bubble diffusion methods are reduced so drastically that it creates a process barrier, preventing the application of more capable wastewater treatment systems that are smaller and more portable, particularly in the emergency sanitation context where these characteristic are of great value. By implementing an alternative sidestream superoxygenation method known as the Speece cone, it is possible to push such process limitations and increase the MLSS concentration in the bioreactor up to ten times as compared to conventional aeration methods and still have oxygen transfer efficiency (OTE) rates higher than 80%. In addition to improved aeration performance, an alternative MBR process configuration is proposed to include not only the Speece cone but also a hydrocyclone that can reduce the fouling potential of high solids activated sludge and minimize its negative impact on membrane fouling via sludge pre-conditioning using the solid-liquid separation capabilities of hydrocyclones to create a low-solids stage in between the aerobic bioreactor and the membrane tank.

You can watch the defence live through this link.