Glossary

AGS

Aerobic granular sludge: Aggregates of activated sludge, larger than 200 µm of microbial origin, that do not aggregate and settle significantly faster than activated sludge flocs.

SBR

Sequencing Batch Reactor: a type of wastewater treatment system, in which all processes happen sequentially in the same reactor.

UASB

Upflow Anaerobic Sludge Blanket reactor: wastewater treatment process based on anaerobic granular sludge.

PAO

Phosphorus Accumulating Organisms: a group of bacteria that can remove large amounts of phosphorus from wastewater, in AGS often Ca Accumulibacter phosphatis, by sequestering VFA’s from wastewater anaerobically.

GAO

Glycogen Accumulating Organisms: a group of bacteria than compete with PAO for VFA in wastewater, without the benefit of removing large amounts of phosphorus from the wastewater.

RHDHV

Royal HaskoningDHV: an international engineering consultancy firm with headquarters in Amersfoort and the company I am working for.

PNU

Prototype Nereda Utrecht: a 1000 m³ full-scale Nereda^® pilot, located in Utrecht.

mUCT

modified University of Capetown process: wastewater treatment process consisting from anaerobic, anoxic and aerobic reactors, accommodating biological nitrogen and phosphorus removal.

SND

Simultaneous Nitrification and Denitrification: a process where under aerobic condition in a biofilm nitrification and denitrification happen simultaneously.

VFA

Volatile Fatty Acids: fatty acids with less than six carbon atoms. Especially acetate and propionate can be sequestered by PAO and GAO.

EBPR

Enhanced Biological Phosphorus Removal: a wastewater treatment configuration stimulating growth of phosphorus accumulating organisms.

DWF

Dry Weather Flow: flow from a sewer network during dry weather conditions.

RWF

Rainy Weather Flow: flow from a sewer network during rainy weather conditions. Typically 5 - 10 x larger than the DWF

GRTD

Granule Residence Time Distribution: a aerobic granular sludge reactor has granules of different age, up to 150 d. This distribution is an important parameter for the reactor performance.

ASM

Activated Sludge Model: mathematical framework for simulating wastewater treatment processes.

CAS

Conventional Activated Sludge: wastewater treatment system based on activated sludge flocs in a continuous flow-through application.

VER

Volumetric Exchange Ratio: the relative reactor volume that is replaces during influent during the feeding phase of an SBR reactor.

HDSR

Hoogheemraadschap de Stichtse Rijnlanden: Dutch water authority in the Utrecht region.

GFS

Granule Forming Substrate: substrates that can lead to formation of aerobic granules, such as VFA’s or other readily biodegradable substrates.

NGFS

non-Granule Forming Substrate: substrates that will not directly lead to formation of aerobic granules.

PBM

Population Balance Model: mathematical modelling technique, in which growth of individuals in a population is simulated.

MLSS

Mixed Liquor Suspended Solids: concentration of suspended solids in a wastewater treatement process.

EF

Emission Factor: relative emission of N₂O, related to the total nitrogen load in the influent of a wastewater treatment plant.