T2 Water Treatment
Certification Study Guide &
Practice Questions 2026/2027
,particulate very small solid suspended in water which can vary widely in size, shape, density,
and electrical charge. Colloidal and dispersed particulates are artificially gathered
together by the processes of coagulation and flocculation. Result from land erosion,
dissolved minerals, and the decay of plant material
color substances in water that impart a yellowish-brown color to the water. These
substances are the result of iron and manganese ions, humus and peat materials,
plankton, aquatic weeds, and industrial waste present in the water.
colloids very small, finely divided solids (particles that do not dissolve) that remain dispersed
in a liquid for a long time due to their small size and electrical charge. When most of
the particles in water have a negative electrical charge, they tend to repel each
other. This repulsion prevents the particles from clumping together, becoming
heavier, and settling out.
floc clumps pf bacteria and particles or coagulants and impurities that have come
together and formed a cluster. Found in flocculation tanks and settling or
sedimentation basins.
coagulation the clumping together of very fine particles into larger particles (floc) caused by the
use of chemicals (coagulants). The chemicals neutralize (destabilize) the electrical
charges of the fine particles, allowing them to come closer and form larger clumps.
This clumping together makes it easier to separate the solids from the water by
settling, draining, or filtering. Aluminum Sulfate (Alum) Cationic polymers (cat poly)
flocculation the gathering together of fine particles after coagulation to form larger particles by a
process of gentle mixing. Slow stirring causes small, coagulated particles to turn
into larger, settleable particles.
flash mixing. Mixes chemicals with raw water containing fine particles that will not readily settle or
filter out of the water. Process takes a few seconds because reaction time is short.
clearwell provides chlorine contact time for disinfection to occur and stores water for high
demand
polymer (cat poly)/polyelectrolyte a long chain molecule formed by the union of many monomers. Polymers are used
with other chemical coagulants to aid in binding small suspended particles to larger
chemical flocs for their removal from water
Alkalinity The capacity of water to neutralize acids. This capacity is caused by the water's
content of carbonate, bicarbonate, hydroxide, and occasionally borate, silicate, and
phosphate. Measure of how much acid must be added to a liquid to lower the pH to
4.5.
what is the ideal pH for coagulation? 5-7. Lower pH values tend to favor positvely charged species, which react with
negatively charged colloids and particulates, forming insoluble flocs.
what do coagulants react with? alkalinity in water. Residual alkalinity serves as a buffer (prevent pH from changing)
and aids precipitation of coagulant chemicals. Alkalinity can be increased by adding
lime or soda ash.
buffer solution or liquid whose chemical makeup neutralizes acids or bases, thereby
maintaining a relatively constant pH.
, detention time theoretical (calculated) time required for a small amount of water to pass through a
tank at a given rate of flow.
pi/4 .785
jar test lab procedure that simulates coagulation/flocculation with differing chemical doses.
The purpose of the procedure is to estimate the minimum coagulant dose required
to achieve certain water quality goals. Samples of water to be treated are placed in
6 jars. Various amounts of chemicals are added to each jar, stirred, and the settling
of solids is observed. The lowest dose of chemicals that provides satisfactory
settling is the dose used to treat the water.
head loss the head, pressure or energy, lost by water flowing in a pipe or channel as a result
of turbulence caused by the velocity of the flowing water & the roughness of the
pipe, channel walls, or restrictions caused by fittings. Water flowing in a pipe loses
head, pressure, or energy as a result of friction. The head loss through a filter is due
to friction losses caused by material building up on the surface or by the water
flowing through the filter media. Also called friction loss.
short-circuiting condition that occurs in tanks or basins when some of the flowing water entering a
tank or basin flows along a nearly direct pathway rom the inlet to the outlet. This is
usually undesirable since it may result in shorter contact, reaction, or settling times
in comparison with the theoretical (calculated) or presumed detention times.
sludge 1) settleable solids separated from liquids during processing 2) the deposits of
foreign materials on the bottoms of streams or other bodies of water or on the
bottoms and edges of wastewater collection lines, also considered biosolids.
specific gravity weight of a particle, substance, or chemical solution in relation to the weight of an
equal volume of water
laundering weir sedimentation basin overflow weir. a plate with V-notches along the top to ensure a
uniform flow rate and avoid short-circuiting.
Coagulation-flocculation process troubleshooting
Enhanced coagulation process designed to remove natural organic matter (NOM) from water by adjusting
both the coagulant dosage and pH to produce the greatest possible reduction of
dissolved or suspended organic carbon (color), total organic carbon (TOC),
trihalomethanes (THMs), and disinfection byproducts (DBPs).
TOC a measure of the amount of organic carbon in the water
THM Trihalomethane. Derivatives of methane, CH4, in which three halogen atoms
(chlorine or bromine) are substituted for three of the hydrogen atoms. Often formed
during chlorination by reactions with natural organic materials in the water. The
resulting compounds are suspected of causing cancer.
Certification Study Guide &
Practice Questions 2026/2027
,particulate very small solid suspended in water which can vary widely in size, shape, density,
and electrical charge. Colloidal and dispersed particulates are artificially gathered
together by the processes of coagulation and flocculation. Result from land erosion,
dissolved minerals, and the decay of plant material
color substances in water that impart a yellowish-brown color to the water. These
substances are the result of iron and manganese ions, humus and peat materials,
plankton, aquatic weeds, and industrial waste present in the water.
colloids very small, finely divided solids (particles that do not dissolve) that remain dispersed
in a liquid for a long time due to their small size and electrical charge. When most of
the particles in water have a negative electrical charge, they tend to repel each
other. This repulsion prevents the particles from clumping together, becoming
heavier, and settling out.
floc clumps pf bacteria and particles or coagulants and impurities that have come
together and formed a cluster. Found in flocculation tanks and settling or
sedimentation basins.
coagulation the clumping together of very fine particles into larger particles (floc) caused by the
use of chemicals (coagulants). The chemicals neutralize (destabilize) the electrical
charges of the fine particles, allowing them to come closer and form larger clumps.
This clumping together makes it easier to separate the solids from the water by
settling, draining, or filtering. Aluminum Sulfate (Alum) Cationic polymers (cat poly)
flocculation the gathering together of fine particles after coagulation to form larger particles by a
process of gentle mixing. Slow stirring causes small, coagulated particles to turn
into larger, settleable particles.
flash mixing. Mixes chemicals with raw water containing fine particles that will not readily settle or
filter out of the water. Process takes a few seconds because reaction time is short.
clearwell provides chlorine contact time for disinfection to occur and stores water for high
demand
polymer (cat poly)/polyelectrolyte a long chain molecule formed by the union of many monomers. Polymers are used
with other chemical coagulants to aid in binding small suspended particles to larger
chemical flocs for their removal from water
Alkalinity The capacity of water to neutralize acids. This capacity is caused by the water's
content of carbonate, bicarbonate, hydroxide, and occasionally borate, silicate, and
phosphate. Measure of how much acid must be added to a liquid to lower the pH to
4.5.
what is the ideal pH for coagulation? 5-7. Lower pH values tend to favor positvely charged species, which react with
negatively charged colloids and particulates, forming insoluble flocs.
what do coagulants react with? alkalinity in water. Residual alkalinity serves as a buffer (prevent pH from changing)
and aids precipitation of coagulant chemicals. Alkalinity can be increased by adding
lime or soda ash.
buffer solution or liquid whose chemical makeup neutralizes acids or bases, thereby
maintaining a relatively constant pH.
, detention time theoretical (calculated) time required for a small amount of water to pass through a
tank at a given rate of flow.
pi/4 .785
jar test lab procedure that simulates coagulation/flocculation with differing chemical doses.
The purpose of the procedure is to estimate the minimum coagulant dose required
to achieve certain water quality goals. Samples of water to be treated are placed in
6 jars. Various amounts of chemicals are added to each jar, stirred, and the settling
of solids is observed. The lowest dose of chemicals that provides satisfactory
settling is the dose used to treat the water.
head loss the head, pressure or energy, lost by water flowing in a pipe or channel as a result
of turbulence caused by the velocity of the flowing water & the roughness of the
pipe, channel walls, or restrictions caused by fittings. Water flowing in a pipe loses
head, pressure, or energy as a result of friction. The head loss through a filter is due
to friction losses caused by material building up on the surface or by the water
flowing through the filter media. Also called friction loss.
short-circuiting condition that occurs in tanks or basins when some of the flowing water entering a
tank or basin flows along a nearly direct pathway rom the inlet to the outlet. This is
usually undesirable since it may result in shorter contact, reaction, or settling times
in comparison with the theoretical (calculated) or presumed detention times.
sludge 1) settleable solids separated from liquids during processing 2) the deposits of
foreign materials on the bottoms of streams or other bodies of water or on the
bottoms and edges of wastewater collection lines, also considered biosolids.
specific gravity weight of a particle, substance, or chemical solution in relation to the weight of an
equal volume of water
laundering weir sedimentation basin overflow weir. a plate with V-notches along the top to ensure a
uniform flow rate and avoid short-circuiting.
Coagulation-flocculation process troubleshooting
Enhanced coagulation process designed to remove natural organic matter (NOM) from water by adjusting
both the coagulant dosage and pH to produce the greatest possible reduction of
dissolved or suspended organic carbon (color), total organic carbon (TOC),
trihalomethanes (THMs), and disinfection byproducts (DBPs).
TOC a measure of the amount of organic carbon in the water
THM Trihalomethane. Derivatives of methane, CH4, in which three halogen atoms
(chlorine or bromine) are substituted for three of the hydrogen atoms. Often formed
during chlorination by reactions with natural organic materials in the water. The
resulting compounds are suspected of causing cancer.
