Phosphorus recovery as struvite from digested sludge - experience from the full scale.

There is an ongoing paradigm shift; wastewater is often not considered a waste any more, but a source of valuable resources: nutrients (N: nitrogen, P: phosphorus, and K: potassium), energy and water. The recovery of phosphorus from municipal wastewater has gained a lot of attention because of limited phosphate rock reserves and associated geopolitics, and pollution of phosphate rock. At the WWTP of Leuven, Aquafin operates a full scale installation to recover phosphorus as struvite from digested sludge.

Nitrous oxide gas emissions estimated by liquid-phase measurements: robustness and financial opportunity in single and multi-point monitoring campaigns.

A liquid-phase nitrous oxide sensor can be used as a proxy to estimate the gas emissions. Experiments conducted in a pilot-scale Anammox reactor, at different degrees of aeration intermittency, indicate a predictive error in the range of 13.4-19.

High-rate activated sludge systems combined with dissolved air flotation enable effective organics removal and recovery.

High-rate activated sludge (HRAS) systems typically generate diluted sludge which requires further thickening prior to anaerobic digestion (AD), besides the need to add considerable coagulant and flocculant for the solids separation. As an alternative to conventional gravitational settling, a dissolved air flotation (DAF) unit was coupled to a HRAS system or a high-rate contact stabilization (HiCS) system. The HRAS-DAF system allowed up to 78% removal of the influent solids, and the HiCS-DAF 67%.

Evaluation of the applicability of the aquatic ascomycete sp. UHH 5-1-03 for the removal of pharmaceutically active compounds from municipal wastewaters using membrane bioreactors.

Membrane bioreactors (MBRs) augmented with terrestrial white-rot basidiomycetes have already been tested for the removal of pharmaceutically active compounds (PhACs) from wastewaters. Within the present study, an aquatic ascomycete ( sp.) was initially demonstrated to efficiently remove several PhACs at their real environmental trace concentrations from nonsterile municipal wastewater on a laboratory scale.

Advanced biological activated carbon filter for removing pharmaceutically active compounds from treated wastewater.

Through their release of effluents, conventional wastewater treatment plants (WWTPs) represent a major pollution point sources for pharmaceutically active compounds (PhACs) in water bodies. The combination of a biological activated carbon (BAC) filter coupled with an ultrafiltration (UF) unit was evaluated as an advanced treatment for PhACs removal at pilot scale. The BAC-UF pilot plant was monitored for one year.

Modelling real-time control of WWTP influent flow under data scarcity.

In order to comply with effluent standards, wastewater operators need to avoid hydraulic overloading of the wastewater treatment plant (WWTP), as this can result in the washout of activated sludge from secondary settling tanks. Hydraulic overloading can occur in a systematic way, for instance when sewer network connections are extended without increasing the WWTP's capacity accordingly. This study demonstrates the use of rule-based real-time control (RTC) to reduce the load to the WWTP while restricting the overall overflow volume of the sewer system to a minimum.

Full-scale phosphorus recovery from digested wastewater sludge in Belgium - part II: economic opportunities and risks.

One of the options to recycle phosphorus (P) in the wastewater sector is to recover it as struvite crystals from digested sludge. Measurements on a full-scale demonstration plant in Leuven, Belgium, yielded a first indication of the profitability of struvite recovery, in function of different variables such as incoming PO(4)(3-) concentration, MgCl₂dosing, improved dewaterability, etc. An uncertainty and sensitivity analysis was carried out.

Energy saving on wastewater treatment plants through improved online control: case study wastewater treatment plant Antwerp-South.

This work provides a case study on how activated sludge modelling and computational fluid dynamics (CFD) can help to optimize the energy consumption of a treatment plant that is already equipped with an advanced control based on online nutrient measurements. Currently, aeration basins on wastewater treatment plant Antwerp-South are operated sequentially while flow direction and point of inflow and outflow vary as a function of time. Activated sludge modelling shows that switching from the existing alternating flow based control to a simultaneous parallel feeding of all aeration tanks saves 1.