PHA Production in Aerobic Mixed Microbial Cultures

Polyhydroxyalkanoate (PHA) is a common intracellular energy and carbon storage material in bacteria, which is considered as a bioplastic due to its plastic like properties. PHAs are versatile materials which are biodegradable and made from renewable resources. Commercial production of PHAs is currently based on pure culture processes employing...

Biofouling of spiral wound membrane systems

Biofouling of spiral wound membrane systems High quality drinking water can be produced with membrane filtration processes like reverse osmosis (RO) and nanofiltration (NF). Because the global demand for fresh clean water is increasing, these membrane technologies will increase in importance in the coming decades. One of the most serious...

Biogrout, ground improvement by microbial induced carbonate precipitation

Biogrout is a new ground improvement method based on microbially induced precipitation of calcium carbonate (MICP). When supplied with suitable substrates, micro-organisms can catalyze biochemical conversions in the subsurface resulting in precipitation of inorganic minerals, which change the mechanical soil properties. This study focuses on one...

The competition between polyphosphate-accumulating organisms and glycogen-accumulating organisms: Temperature effects and modelling

Due to relatively high phosphorus removal efficiency and economy, the enhanced biological phosphorus removal (EBPR) in activated sludge wastewater treatment systems is a widely applied process to control and prevent eutrophication in surface water bodies. However, the EBPR process can be prone to suffer of upsets and deterioration. Since...

Growth and metabolism of Anammox Bacteria

The anoxic ammonium oxidation (anammox) process is the conversion of nitrite and ammonium under anoxic conditions- to form dinitrogen gas. The process is performed by deep-branching Planctomycetes. The startup of the first full-scale anammox reactor in the world is described in Chapter 2. The described full scale reactor was a granular sludge...

Microbial ecology of phototrophic biofilms

Biofilms are layered structures of microbial cells and an extracellular matrix of polymeric substances, associated with surfaces and interfaces. Biofilms trap nutrients for growth of the enclosed microbial community and help prevent detachment of cells from surfaces in flowing systems. Phototrophic biofilms can best be defined as surface...

Aerobic granular sludge: Scaling up a new technology

Most conventional wastewater treatment plants need a large surface area for the treatment of their sewage. This is due to the open structure of the biomass used to convert the polluting components in wastewater. Because of the flocculated growth, sludge concentrations in reaction tanks are low and settling times need to be long in order to keep...

Treatment of source separated urine and its effects on wastewater systems

Abstract not available

Ecophysiological characterization of microbial communities in BioDeNOx

Nitric oxide (NO) and nitrogen dioxide (NO2) are both important Green house gases, which also cause air pollution. Industrial flue gas emissions are responsible for 17% of NOx/SOx released into the atmosphere. Treatment of flue gas to remove NO and NO2 had started a few decades ago and several chemical and biological processes have been...

Bioaugmentation of Nitrification in Activated Sludge Systems

Biotreatment of SO2 and H2S Contaminated Gas Streams

Theoretical and practical aspects of modelling activated sludge processes

This thesis describes the full-scale validation and calibration of a integrated metabolic activated sludge model for biological phosphorus removal. In chapters 1 and 2 the metabolic model is described, in chapters 3 to 6 the model is tested and in chapters 7 and 8 the model is put into practice. Chapter 1 is a general introduction to this...

Bulking sludge control. Kinetics, substrate storage, and process design aspects

The activated sludge process is the preferred technology for biological wastewater treatment. Despite decades of progress and operation serious operating problems still occur with this process. One major problem is the regular occurrence of excessive growth of filamentous bacteria, phenomena known as filamentous bulking sludge. Poor solid-liquid...

Model-based optimisation of sustainable biological nutrient removal processes

PHB metabolism and N-removal in sequencing batch granular sludge reactors

Multidimensional Modeling of Biofilm Structure