High phosphate concentrations due to VFA production from sieved activated sludge at WWTP Ommen: A source identification and resource recovery strategy

Environmental guidelines (EU WFD) impose a strict effluent phosphate target on wastewater treatment plants (WWTP). An abundance of phosphate (and other nutrients) in a water body is called eutrophication. Eutrophication can lead to algal blooms which result in very low oxygen concentrations in the water. Other species, like fish and aquatic...

Ionic strength of the liquid phase of different sludge streams in a wastewater treatment plant

In a wastewater treatment plant (WWTP), several sludge streams exist and the composition of their liquid phase varies with time and place. For evaluating the potential for formation of precipitates and equilibria for weak acids/bases, the ionic strength and chemical composition need to be known. This information is often not available in...

Anaerobic Conversion of Proteins in Aerobic Granular Sludge

In an aerobic granular sludge (AGS) reactor treating urban wastewater, nutrient removal depends on the availability of carbon source. Domestic wastewater consists of 40-60% of slowly biodegradable complex substrates, out of which proteins form a major fraction. Despite this, little is known about the mechanisms of protein degradation in AGS....

Aerobic Granular Sludge in Seawater

Increase in sea level will lead to an increase in salinity in domestic wastewater systems. In order to anticipate its effects on biological wastewater treatment, the impact has to be assessed with lab-scale experiments. Aerobic granular sludge (AGS) is a successful technology for simultaneous removal of organic carbon (COD), nitrogen, and...

Stress-induced assays for polyphosphate quantification by uncoupling acetic acid uptake and anaerobic phosphorus release

Phosphorus has been successfully eliminated from wastewater by biological techniques of enhanced biological phosphorus removal (EBPR) process, which relies on a specific microbiota of polyphosphate accumulating organisms (PAOs) that accumulate phosphate as polyphosphates (poly-P). Most methods for quantification of poly-P pools suffer from...

Impact of aerobic availability of readily biodegradable COD on morphological stability of aerobic granular sludge

Operational disturbances in aerobic granular sludge (AGS) systems can result in aerobic availability of readily biodegradable COD (rbCOD). Different from activated sludge, morphological consequences on the short and long term are not well described in literature. This study investigated the effect of incomplete anaerobic uptake of acetate on...

Trehalose as an osmolyte in Candidatus Accumulibacter phosphatis

Abstract: Candidatus Accumulibacter phosphatis is an important microorganism for enhanced biological phosphorus removal (EBPR). In a previous study, we found a remarkable flexibility regarding salinity, since this same microorganism could thrive in both freshwater- and seawater-based environments, but the mechanism for the tolerance to saline...

Characterization and modelling of full-scale aerobic granular sludge

Existing mathematical models for aerobic granular sludge have focused solely on lab-scale reactors. In this study, an effort was made to adapt these models to simulate the processes of full-scale installations. The model is the first aerobic granular sludge model to use transient radial diffusion and multiple granule fractions. Aerobic and...

Cooperation between Candidatus Competibacter and Candidatus Accumulibacter clade I, in denitrification and phosphate removal processes

Although simultaneous P-removal and nitrate reduction has been observed in laboratory studies as well as full-scale plants, there are contradictory reports on the ability of PAO I to efficiently use nitrate as electron acceptor. Such discrepancy could be due to other microbial groups performing partial denitrification from nitrate to nitrite....

Prevalence of ‘Candidatus Accumulibacter phosphatis’ type II under phosphate limiting conditions

P-limitation in enhanced biological phosphorus removal (EBPR) systems fed with acetate, has generally been considered as a condition leading to enrichment of organisms of the genotype’ Candidatus Competibacter phosphatis’ expressing the glycogen-accumulating organisms (GAO) phenotype. Recent studies have demonstrated in short-term experiments...