Glossary

Acidity:

The capacity of wastewater or water to neutralize bases.

Activated sludge:

Sludge generated in wastewater by the growth of microbes in aeration tanks. In other words it is flocculated sludge of micro-organisms.

Advanced primary treatment:

Primary treatment using additives before treatment to augment settling.

Aeration:

The process of adding air to water.

Aerobic processes:

Biological treatment processes in the presence of oxygen.

Aqua-privy:

Watertight tank placed immediately below the latrine floor where excreta drop directly into the water tank through a pipe.

Algae:

Variety of plant without distinct functional plant tissue.

Algal bloom:

Increase in algae population in water.

Alkalinity:

A measure of a substance's ability to neutralize acid.

Alumina:

Synthetically produced aluminium oxide that is used as a starting material for the production of aluminium metal.

Anaerobic processes:

Biological treatment processes that occur in the absence of oxygen.

Anoxic denitrification:

This process is also known as anaerobic denitrification. In this process nitrate nitrogen is converted to nitrogen gas biologically in the absence of oxygen.

Aquifer:

Water stored in the saturated zone below the water table.

Attached-growth processes:

The biological treatment processes in which the microbes are attached to media.

Autotroph:

Organism that uses carbon dioxide as the only carbon source.

Backflow prevention:

Preventing the reverse flow of water in water supply system.

Backflush valve:

three-way diaphragm valves used in filtration applications.

Backpressure:

Pressure opposing the free flow of liquid/gas; it can suck foreign substances into the water-supply system.

Backsiphonage:

Backflow due to a differential pressure that sucks foreign substances into the water-supply system.

Batch reactor:

Reactors that are operated in batches.

Biochemical oxygen demand (BOD):

Measure of the quantity of oxygen used by microbes to degrade organic matter.

Biodegradability:

Capable of being decomposed by living things, especially micro-organisms.

Biodiversity:

Overall diversity of organisms in the world.

Biogas:

Mixture of gases released from anaerobic digestion.

Biological wastewater treatment:

wastewater treatment using living organisms.

Biological nutrient removal:

The term applied to the removal of nitrogen and phosphorus in biological treatment processes.

Biosolids:

The nutrient-rich organic materials from the treatment of sludge.

Or

Organic, rich material left over from aerobic wastewater treatment.

Or

Treated sludge from wastewater treatment.

Blackwater:

Wastewater with high organic and pathogen content, consisting of urine, faeces, flushing water, anal cleansing water and greywater.

Boiler feed water:

Water fed to a boiler for the generation of steam.

Borehole latrine:

The borehole latrine is an excreta disposal system where a borehole is combined with a slab as well as a superstructure.

Borewell:

Wells made by drilling boreholes in the earth.

Bottle irrigation:

The bottle is first filled with water and then placed in the ground next to the plant and water is made to trickle through it.

Brackish water:

Water containing less salt than salt water and more salt than fresh water.

Brownwater:

Water consists of faeces and flushwater.

Bund:

Embankment constructed from soil.

Capnophilic:

Organisms that require increased carbon dioxide.

Carbonaceous BOD:

BOD exerted by carbon fraction of organic matter.

Carbon sequestration:

The elimination of atmospheric carbon dioxide by biological or geological processes.

Chemical oxygen demand (COD):

Standard technique to measure the amount of organic compounds that cannot be oxidized biologically in water.

Chlorination:

A process in a water-treatment system where chlorine or a chlorine compound is added to kill harmful micro-organisms such as bacteria.

Clarifier:

A tank used for reducing the concentration of suspended solids present in a liquid.

Cluster wastewater system:

Wastewater collection and treatment system, which serves some of the dwellings in the community but less than the entire community.

Coagulation:

A process of aggregation of colloidal suspended solids by floc-forming chemicals.

Combined sewer:

Combining the storm drainage with municipal sewer systems.

Constructed wetlands:

Wetlands designed and constructed to treat wastewater.

Cross-connection:

The result of a connection between contaminated and noncontaminated water in a water network.

Dead zone:

Low-oxygen (hypoxic) areas in the oceans.

Decentralized wastewater treatment:

A system divided into groups or clusters where wastewater is treated independently instead of a centralized system.

Denitrification:

Microbiological process where nitrities/nitrates are reduced to nitrogen gas, or, removing nitrate biologically and converting it to nitrogen gas.

Desalination:

Process of removing salt from water.

Detention time:

The time required for a liquid to pass through a tank at a given rate of flow.

Dewatering:

Removing water from sludge for further handling and disposal.

Direct surface groundwater recharge:

Groundwater recharge to the aquifer via soil percolation.

Disinfection byproduct:

Chemical byproducts, formed after disinfection.

Downstream ecosystem:

Ecosystem of a lower watercourse.

Drip irrigation:

Irrigation in which plants are irrigated through special drip pipes.

Drying bed:

Shallow ponds with drainage layers used for the separation of the liquid and solid fraction of sludge.

Dual flush toilet:

Flush toilet designed with two handles/buttons to flush different levels of water to save water.

Economic instruments:

Fiscal and other economic incentives along with disincentives to include environmental costs as well as benefits.

Ecosystem services:

The services provided by ecosystem like habitat for flora and fauna, biological diversity, oxygen production, biogeochemical cycles and so forth.

End-of-pipe approach:

Waste-treatment methods conducted at the end of the process stream.

Enteropathogenic serotypes:

E. coli strains that can cause harmful effects to human beings when consumed in contaminated drinking water.

Eukaryotes:

Organisms whose cells contain a nucleus as well as other organelles enclosed within membranes.

Eutrophication:

A process of transformation from nutrient-deficit conditions to nutrient-rich conditions, leading to algal blooms in water bodies.

Factor of safety (safety factor):

Capacity of a system beyond the expected loads.

Facultative processes:

Biological treatment process in which the microbes can function in the absence or presence of oxygen.

Filamentous organism:

Threadlike bacteria serving as the backbone of floc formation.

Floc:

Particulate or bacterial clumps formed during wastewater treatment.

Flocculation:

The process of forming flocs.

Fog harvesting:

Collecting fog for anthropogenic activities.

Food to micro-organism ratio (F/M):

Amount of food (BOD) available to micro-organisms per unit weight microbes (usually analysed for mixed liquor volatile suspended solids).

Free water surface wetland:

A constructed wetland exposed directly to the air.

Green infrastructure:

Also known as blue-green infrastructure which highlights the importance of natural environment when making decisions about planning the use of land.

Grey water:

Wastewater from baths, sink and wash that can be recycled for in situ consumption.

Grit chamber:

A chamber or tank in which primary influent is slowed down to remove inorganic solids.

Groundwater:

Available natural water found underground in the soil or in between rocks.

Headworks:

Structure at the head of a waterway. In the context of water/wastewater treatment, the commencement of the treatment.

Heavy metal:

Heavy metals...