GLOSSARY

In wastewater terms, biological or sludge processing under oxygen-rich conditions

Plants that contain chlorophyll and require sunlight - they vary from microscopic forms to giant seaweed

In wastewater terms, biological or sludge processing under oxygen-deprived conditions

In wastewater terms, biological or sludge processing under oxygen-deprived conditions but with the presence of oxidized nitrogen

Actual Oxygen Demand of an aeration system for a specific site

When the filter media becomes dirty or clogged the flow of water is reversed in the filter and the media is cleaned.

Special electronic plug-in card mounted in racks inside the control cabinet for supply and control of lamp power

Best efficiency point of the pump

Mixing to blend two liquids

Biochemical Oxygen Demand is a measure of the quantity of oxygen used in the biochemical oxidation of organic matter in a specified time at a specific temperature.

Biochemical oxygen demand measured during five days

The process that reduces the amount of suspended matter in water

Chemicals added to water with suspended and colloidal solids to destabilize particles, allowing floc formation and removal by clarification, filtration, or both

Chemical Oxygen Demand which is the amount of oxygen required to oxidize carbonaceous material using a strong chemical oxidant, normally dichromate ion

A group of related bacteria comprised of the genera Escherichia, Enterobacter, and Klebsiella, commonly associated with the intestinal tracts of warm-blooded animals and shed in their fecal material

Pipe that is the width of a tank with orifices underneath that collects sludge to remove the solids from the bottom of a tank

A plastic or metal box that contains electronic devices that are used to manage a device such as a pump, filter, clarifier, etc.

Dissolved air flotation process that uses air dissolved in water under pressure that is released into the bottom of a treatment unit to attach to solids and float them to the surface where they are removed for subsequent processing

Biological reduction of nitrate with nitrogen gas as end product

Max. flow which has to be the basis for layout of the system

The process of stabilizing biological sludge for disposal and/or generate biogas

Dissolved Oxygen is the concentration of oxygen in aqueous solution

Dissolved solids of a sample. Often used with instead of TS with the meaning dry solids.

A type of underdrain that has two conduits alongside each other with a series of orifices between them that distributes air and/or water.

Flow of treated wastewater being discharged from the wastewater plant

Endocrine Disrupting Compounds (EDC’s, sometimes also referred to as hormonally active agents) are exogenous substances that act like hormones in the endocrine system and disrupt the physiologic function of endogenous hormones. Chemical (man made or natural) that mimics a hormone and disrupts growth, development and/or reproduction

The passage of water through a granular material for the removal of solids

High intensity mixing to effectively mix in i.e. chemicals

Usually a water soluble organic polymer that is used to agglomerate solids in the water to form large dense floc

The process of adding flocculants to create flocs for precipitation or sedimentation

Flocculation additive

The processes of separating water constituents and/or thickening sludge

The conduit or area in a filter where water is collected and backwash water distributed

Within 30 days the daily verified average value has to meet the required log reduction

Particles and heavy materials with high settling characteristics

A specific mixture of sand, cement and water

Pressure expressed as length of liquid column

The decrease of pressure or resistance to air and/or water flow

The flow which is transported into wastewater treatment steps

Mechanical type mixing used for blending, homogenization and water transport

State of a liquid in which it flows in a streamline

The flow rate per unit area, such as gallons per minute per square foot or meters per hour, etc.

Number of target microorganisms to be reduced in exponential figures (e.g. reduction of 10000 to 10 means a 4 log reduction)

Moving Bed Bioreactor is suspended biofilm technology for secondary treatment in wastewater treatment plants

Granular material such as anthracite (hard coal), silica sand, garnet, etc. used in a filter to collect dirt and/or grow biology

May consist of Endocrines, Pestizides, Hormones, Pharmazeutics, Dioxans

Mixed Liquour Recirculation in secondary biological treatment

Nitrogenous Biological Oxygen Demand

Fluid which has constant dynamic viscosity properties independent on the shear rate

Flow of a fluid having a viscosity that changes with increasing shear rate.

Net Positive Suction Head Available in the pumping system

Net Positive Suction Head Required which is a pump-specific value required to avoid cavitation. NPSHR < NPSHA is required.

Nitrogen and phosphorus removal

test report of a small scale field approval for a UV system (carried out by National Water Research Institute)

An opening of specific size used to control or restrict the flow of air and/or water

Oxygen Transfer Efficiency

Ditch (with aerobic conditions at some point) where wastewater is biologically treated by circulating the liquid in lanes

Ozone or trioxygen (O3) is a triatomic molecule, consisting of three oxygen atoms. It is an allotrope of oxygen that is much less stable than diatomic O2.

Phosphorous Accumulating Organisms

The percentage with which the required log reduction has to be achieved (e.g. 98 percentile, means that in 100 analysed samples 98 have to fulfil the disinfection target).

Empirical approach for calculation of the actual UV dose applied to the wastewater

A flat panel that allows air and water to pass but does not allow media to pass through. The porous plate takes the place of graded gravel

Ditch (with or without oxidation) where wastewater is biologically treated by circulating the liquid in lanes

Box inside the control panel where the ballasts are plugged in (6 cards per rack)

Return Activated Sludge which is a fraction of the sediment settled sludge that is returned to the secondary treatment biological processing to maintain sufficient concentration of activated sludge in the aeration tank.

Percentage of effluent water that is reused in the process

the ratio between pipe surface roughness and pipe diameter which is used for friction loss calculations in pump systems

Waste water is reused for irrigation purposes instead of discharged into a river (see regional reuse directives for your area).

Dimensionless number used to evaluate head losses of a system

In wastewater terms, the properties of the sludge

Tank where water and air is mixed and a reservoir of saturated water is available for use in the process

Sequential Batch Reactor

Pressure term which is parallel to the face of the flowing liquid

Hydraulic process in which a low enough pressure created at the discharge allows a fluid to flow upward and be transferred as long as the discharge point is at a lower elevation than the siphon starting point

A term that is being replaced by residuals. The accumulated solids separated from liquid in the wastewater treatment process.

Collection device that removes solids from the tanks in the separation process of the treatment plant

Standard Oxygen Requirement

Standard Oxygen Transfer Rate

Suspended Solids

In wastewater terms, the processes of reducing biological activity of sludge and reduce putrefaction potential

Graded silica stone of a specific size used to prevent the passage of media through the orifices of an underdrain but allows the passage of air and water.

Microorganism (viruses, bacteria, spores, protozoa) which has to be deactivated (dose definiton by a basic-factor referred to a reference organism)

The weight per unit volume of solids remaining after the sample has been filtered to remove suspended and colloidal solids. The solids passing the filter are evaporated to dryness.

Total solid is the total amount of dry solid in a sample.

Total Suspended Solids is the measure of all suspended solids in a liquid

Measurement of light scatter and absorption in a sample of liquid

Flow characterized by chaotic behaviour and variations in the velocity profile

Ultimate Biochemical Oxygen Demand which is a maximum BOD value calculated from BOD5

A device that supports the gravel and media during filtration and collects the filtered water while in backwash distributes the backwash water to clean the media

The product of lamp-intensity and retention time (reduced by turbity, lamp aging, fouling, scaling and other intensity reducing factors)

Deactivation of microorganisms (viruses, bacteria, spores, protozoa) DNA by UV-C light at a wave length of 254 nm.

Volatile Fatty Acids

The measure of the mixing intensity in the water process. It is dependent on the power input, the liquid viscosity, and the tank volume

A fluid's resistance to stress

Waste Activated Sludge which is a removed fraction of the sludge that is generated from secondary treatment sedimentation

A plastic, fiberglass or metal half-pipe that distributes water during filtration and collects the backwash water during backwash.

The aeration lagoon is a basin in which wastewater is treated and oxygen is supplied usually by means of surface or diffused aeration units. The action of the aerators and that of the rising air bubbles from the diffuser is used to keep the contents of the basin in suspension. Depending on the amount of mixing, the lagoons are anaerobic or aerobic-anaerobic.

The stress at which a liquid starts to deform