Glossary
A
Aerobic
"The presence of oxygen." In biological treatment, diffusers convey dissolved oxygen to remove organic pollutants.
Anaerobic
"The absence of oxygen" In biological treatment, the anaerobic stage further breaks down organic pollutants to denitrify the wastewater.
Anaerobic Digestion
The conversion of organic matter to methane through biological degradation.
B
Backwash
Water pushed through a membrane in the reverse direction to dislodge contaminants from a membrane's surface.
Biological Oxygen Demand (BOD)
The amount of dissolved oxygen demanded by bacteria and other microorganisms present in water and wastewater.
Biosolids
The solid byproduct of biological wastewater treatment.
Blowers
Large aeration devices that pump oxygen into the biological treatment process via diffusers.
C
Chemical Oxygen Demand (COD)
The amount of dissolved oxygen required to oxidise organic materials in water.
Clarification
The removal of suspended solids from raw water through flocculation and sedimentation.
Contaminants of Emerging Concern
Typically unregulated pollutants that show potential to harm human and ecological health.
D
Demineralisation
The removal of dissolved ionic impurities from water via ion exchange (IX).
Denitrification
The process of reducing nitrate (NO3) and Nitrite (NO2) to Nitrogen gas (N2).
Desalination
The removal of saline minerals from water. Often applied to convert sea and brackish water to potable water.
Diffuser
Typically made of membrane or ceramic material, a diffuser aerates wastewater to maintain the biomass needed in biological wastewater treatment.
E
Effluent
Treated wastewater that is discharged to the environment or reused.
F
Filtration
The separation of solid particles and water via a filter medium that allows water to pass while retaining the solid particles.
Flocculation
The process of solids forming larger clusters to hasten sedimentation.
I
Influent
The raw water or wastewater that enters a treatment plant.
M
Moving Bed Bioreactor (MBBR)
Biological wastewater treatment process that uses biofilm to cultivate a biomass that removes water pollutants.
N
Nitrification
The process of reducing ammonia (NH3) to nitrate (NO3) and nitrite (NO2).
P
PFAS
A group of synthetic chemicals that are difficult to remove and treat. Part of the Contaminants of Emerging Concern category.
Polymer
Coagulant is used to conglomerate suspended solids and catalyse settling, sedimentation, and dewatering.
Primary Treatment
The physical stage of biological wastewater treatment. Includes screening, grit removal, and sedimentation.
S
Secondary Treatment
The bacterial stage of biological wastewater treatment. Includes aerobic and anaerobic bacteria to remove organic compounds.
Sedimentation
A treatment process that uses gravity to remove suspended solids from water and wastewater.
T
Tertiary Treatment
Advanced treatment to polish effluent quality before discharge or reuse.
Total Suspended Solids (TSS)
The amount of undissolved solids in water or wastewater.
U
Ultrapure Water (UPW)
Ultrapure water is a high-purity standard for process water. UPW treatment removes organic and inorganic compounds, dissolved and particulate matter, volatile and non-volatile, reactive and inert contaminants.
V
Volatile Suspended Solids (VSS)
The amount of undissolved organic matter in a water sample that ignites at 600 Celsius.
W
Water Reuse, Recycling
The process of treating wastewater to make it suitable for use in residential and industrial applications.
Z
Zero Liquid Discharge (ZLD)
A water resource approach where all treated water is recovered for reuse and only solids are discharged.