Ans to Q4. Colloid is a particular state of matter. A colloidal system is a two-phase heterogeneous system consisting of two separate phases with distinct boundaries between them, viz., a continuous phase or dispersion medium made of one substance and a disperse phase of particles of another substance dispersed in the continuous phase. In contrast, a true solution is a single-phase homogeneous system without any physically demonstrable boundary between the solvent and the solute particles. In fact, dispersed particles of a colloidal system, though submicroscopic, are much larger than the solute particles of a true solution. So, they can be separated from true solutes and the dispersion medium by ultracentrifugation and dialysis. Dispersed colloidal particles are much smaller than the particles of a suspension; so, they do not sediment under gravity alone, and are not held back by ordinary filter papers. Ans to Q5. Natural Organic Matter (NOM) is the organic material present in surface or ground water. It includes both humic and non-humic fractions. The humic fraction includes high molecular weight organic molecules such as humic and fulvic acids. These substances with tanic acid are the major fraction of Dissolved Organic Matter (DOM) in water. These substances are oxidized very slowly and their solubility in water may vary with pH. The dissolved fraction of NOM may not be fully removed using conventional water treatment practices and have been shown to produce by-products such as trihalomethane during disinfection. On-line analysis of dissolved NOM is important for proper monitoring and control of enhanced or special treatment processes designed to remove prior to disinfection. An increase in the amount of NOM has been observed over the past 10-20 years in raw water supplies in several areas, which has a significant effect on drinking water treatment. The presence of NOM causes many problems in drinking water and drinking water treatment processes such as: i) negetive effect on water quality by causing colour, taste and odor problems, ii) increased coagulant and disinfectant doses which in turn results in increased sludge volumes and production of harmful disinfectant by-products, iii) promoted biological growth in distribution system and iv) increased levels of complexed heavy metals and absorbed organic pollutants. Solution Ans to Q4. Colloid is a particular state of matter. A colloidal system is a two-phase heterogeneous system consisting of two separate phases with distinct boundaries between them, viz., a continuous phase or dispersion medium made of one substance and a disperse phase of particles of another substance dispersed in the continuous phase. In contrast, a true solution is a single-phase homogeneous system without any physically demonstrable boundary between the solvent and the solute particles. In fact, dispersed particles of a colloidal system, though submicroscopic, are much larger than the solute particles of a true solut.

1. Ans to Q4.
Colloid is a particular state of matter.
A colloidal system is a two-phase heterogeneous system consisting of two separate phases with
distinct boundaries between them, viz., a continuous phase or dispersion medium made of one
substance and a disperse phase of particles of another substance dispersed in the continuous
phase. In contrast, a true solution is a single-phase homogeneous system without any physically
demonstrable boundary between the solvent and the solute particles. In fact, dispersed particles
of a colloidal system, though submicroscopic, are much larger than the solute particles of a true
solution. So, they can be separated from true solutes and the dispersion medium by
ultracentrifugation and dialysis.
Dispersed colloidal particles are much smaller than the particles of a suspension; so, they do not
sediment under gravity alone, and are not held back by ordinary filter papers.
Ans to Q5.
Natural Organic Matter (NOM) is the organic material present in surface or ground water. It
includes both humic and non-humic fractions. The humic fraction includes high molecular
weight organic molecules such as humic and fulvic acids. These substances with tanic acid are
the major fraction of Dissolved Organic Matter (DOM) in water. These substances are oxidized
very slowly and their solubility in water may vary with pH. The dissolved fraction of NOM may
not be fully removed using conventional water treatment practices and have been shown to
produce by-products such as trihalomethane during disinfection. On-line analysis of dissolved
NOM is important for proper monitoring and control of enhanced or special treatment processes
designed to remove prior to disinfection.
An increase in the amount of NOM has been observed over the past 10-20 years in raw water
supplies in several areas, which has a significant effect on drinking water treatment. The
presence of NOM causes many problems in drinking water and drinking water treatment
processes such as: i) negetive effect on water quality by causing colour, taste and odor problems,
ii) increased coagulant and disinfectant doses which in turn results in increased sludge volumes
and production of harmful disinfectant by-products, iii) promoted biological growth in
distribution system and iv) increased levels of complexed heavy metals and absorbed organic
pollutants.
Solution
Ans to Q4.
Colloid is a particular state of matter.

2. A colloidal system is a two-phase heterogeneous system consisting of two separate phases with
distinct boundaries between them, viz., a continuous phase or dispersion medium made of one
substance and a disperse phase of particles of another substance dispersed in the continuous
phase. In contrast, a true solution is a single-phase homogeneous system without any physically
demonstrable boundary between the solvent and the solute particles. In fact, dispersed particles
of a colloidal system, though submicroscopic, are much larger than the solute particles of a true
solution. So, they can be separated from true solutes and the dispersion medium by
ultracentrifugation and dialysis.
Dispersed colloidal particles are much smaller than the particles of a suspension; so, they do not
sediment under gravity alone, and are not held back by ordinary filter papers.
Ans to Q5.
Natural Organic Matter (NOM) is the organic material present in surface or ground water. It
includes both humic and non-humic fractions. The humic fraction includes high molecular
weight organic molecules such as humic and fulvic acids. These substances with tanic acid are
the major fraction of Dissolved Organic Matter (DOM) in water. These substances are oxidized
very slowly and their solubility in water may vary with pH. The dissolved fraction of NOM may
not be fully removed using conventional water treatment practices and have been shown to
produce by-products such as trihalomethane during disinfection. On-line analysis of dissolved
NOM is important for proper monitoring and control of enhanced or special treatment processes
designed to remove prior to disinfection.
An increase in the amount of NOM has been observed over the past 10-20 years in raw water
supplies in several areas, which has a significant effect on drinking water treatment. The
presence of NOM causes many problems in drinking water and drinking water treatment
processes such as: i) negetive effect on water quality by causing colour, taste and odor problems,
ii) increased coagulant and disinfectant doses which in turn results in increased sludge volumes
and production of harmful disinfectant by-products, iii) promoted biological growth in
distribution system and iv) increased levels of complexed heavy metals and absorbed organic
pollutants.