cultivated sludge process
treatment process in oxidation ponds in which microorganisms
are maintained in suspension within the liquid; the activated sludge process was
developed around 1914 for the removal of oxygen-consuming substances
aerobic treatment
a biological treatment processes in the presence of oxygen,
such as the activated sludge process
anaerobic treatment
a biological treatment processes in the absence of oxygen; anaerobic treatment of organic wastes may be used to obtain methane gas
for energy production
artificial infiltration
surface water treated through passage through the ground,
e.g. in an esker, by pumping it into the ground at one place and extracting it
several kilometres away
biological treatment
the step in wastewater treatment to remove organic substances
by the activity of micro-organisms; by modification of the biological treatment
processes it is possible to obtain removal of nitrogen and/or phosphorus;
biological treatment is often called secondary treatment
black water
wastewater arising from toilet water; it is more polluted and
of a comparatively smaller volume than grey water
boiler water
water used in the production of steam and electricity;
chemicals added to the boilers, as well as constituents removed from the raw
water, add to this wastewater flow
chemical treatment
a treatment process with oxidation of pollutants or in which
chemical precipitation is used for the removal of for instance phosphates by the
addition of iron salts and aluminium salts or lime, and metals by the addition
of hydroxide or carbonate of sulphide
clean technology, cleaner production, CP
changes in use of chemicals, production technology,
re-circulation schemes, etc., that reduces the volume of wastewater from an industry as well as its degree of pollution
cloacae
sewers in old Rome to carry off the sewage and rainwater
together and emptied directly into the river, Tiber, thus polluting its waters,
which were used not only for bathing but also for drinking purposes
complementary treatment
a step in wastewater treatment using a chemical precipitation
step or a filtration step; other complementary treatment methods could for
instance be activated carbon, ion exchange, reverse osmosis and the use of
wetland or land treatment; complementary treatment is often called polishing or tertiary treatment
cooling water
the largest volume of wastewater from industries, often not
at all polluted except for thermal pollution; it does not pose a serious environmental problem
dilution method
transport of untreated or only partially treated wastewater
to a large recipient where, it is assumed, it would be made safe through the
self-purification and the assimilatory capacity of the recipient
ecological method
a treatment process using oxidation ponds, wetlands, and land
treatment; ecological methods imitate natural self-purification reactions in
land and water and require large areas
evapotranspiration
loss of water through evaporation from plants
grey water
wastewater arising from laundry, kitchen, personal hygiene, etc.
ground water
water in the ground; it constitutes about 99% of fresh water on Earth
industrial wastewater
wastewater arising from industries, which may be toxic or may
accumulate in the sludge at the treatment plant; pre-treatment of the industrial
wastewater is therefore often necessary
irrigation
to add water to growing crops; the largest use of water
world-wide, accounting for about 70% of the total volume
natural water cycle
the cycle where water evaporates from the surface of the
Earth to the atmosphere where it forms clouds and returns to the land surface as
precipitation; on land the water passes through ground water, smaller streams,
larger rivers to lakes, and finally to the sea
nutrient removal
advanced wastewater treatment methods to remove nutrients, nitrogen and phosphorus
physical treatment
the step in wastewater treatment using sedimentation for the
removal of suspended solids; the treatment efficiency may be improved by the
addition of precipitation chemicals; physical treatment is often called mechanical or primary treatment
potable water
water used for drinking
pre-treatment
the step in wastewater treatment in order to remove coarse particles and sand
process water
water used in the industrial process itself; in some
processes, such as traditional pulp and paper production, the amounts of water
used are often very large and the water becomes heavily polluted; today in many
plants process water is re-circulated, saving both pollution of the environment
and costs in the industrial process
raw water
water that enters a water works
recipient
water body in which the wastewater, treated or not treated, is emptied
runoff
the difference between precipitation and loss of water
through evaporation from plants and from ground; runoff is the fresh water available for consumption
safe water
water without bacteria and toxic substances and other
pollutants; lack of safe drinking water is a major cause of health problems in
the developing world, causing about 30% child mortality
sanitary wastewater
water from toilets, kitchens, etc.
self-purification
the capacity of a recipient for assimilating wastewater
sewage (also sewerage)
wastewater, especially toilet wastewater
sewers
originally a system of pipes or channels with the purpose of
removing rainfall without causing inconvenience or flooding, later to remove
wastewater; today pipes to remove wastewater
sludge
the thick residue from primary, secondary and tertiary
processes consisting of particles suspended in the water
sludge handling
a treatment process to reduce the sludge volume by thickening
and dewatering and in some cases by drying or incineration and to stabilise to
sludge to avoid odor problems and for hygienisation
storm runoff water, or storm water
water collected from an industrial or urban area after rainfall; this water may be contaminated by all kinds of spills in the
industrial process, such as oil products
storm water
surface water collected in an area after rain or snow,
discharged to one system of sewers which lead to the wastewater treatment plant or point of outfall
submarine outfalls
transporting of untreated or only partially treated
wastewater into a marine area, such as the Baltic Sea, often one or a few kilometres outside the coast
surface water
water in lakes, rivers and streams
water consumption cycle
the cycle in which people retract water from groundwater
(wells and springs) and surface water (rivers and lakes), treat it in water
works, transport it to consumers (population, industries, general purposes,
etc.), collect it as wastewater, sometimes pass it through a wastewater
treatment plant, and discharge it to the recipient, i.e. a river or a lake
water works
an installation where raw water is collected and often
treated, e.g. by chlorination or ozonation, before it is sent to the consumer
wastewater
water after usage, that is usually more or less polluted, from an urban area, industry, etc.
wastewater treatment plants
sewage purification plants