Water Supply Midterm: Module 5

What is the presence of a substance where it should not be or at concentrations above background?

It is due to the influence or activities of people

It always creates harmful effects

It does not always create harmful effects.

“All pollutants are contaminants, but not all contaminants are pollutants.” T or F

6 Common Chemical Pollutants

3 Main Parameters of Water

contaminants that can cause sickness or illness at very low levels or low exposure

cause sickness or illness only after prolonged exposure to the contaminant in drinking water

6 common contaminants encountered in water treatment

11 Basic Water Quality Parameters

Measured hydrogen ion concentration. Negative log of hydrogen ion concentration. It reflects the acidity or alkalinity of solution

The measure of the ability of water to conduct an electric current and depends upon the number of ions or charged particles in the water, and is measured by passing a current between two electrodes that are placed into a sample water.

in measuring this, we consider the concentration of salt dissolved in the water.

Amount of gaseous oxygen (O2) dissolved in water.

The cloudy or muddy appearance of a naturally clear liquid caused by the suspension of particulate matter.

Is the amount of oxygen needed by aerobic biological organisms in a body of water to break down organic material present in a given water sample at certain temperature over a specific time period.

are caused by volatile substances associated with organic matter, living organisms, and gases

are caused by: Chlorides and sulfates of calcium, magnesium, and sodium; Organisms (algae); Industrial Waste

three categories of solids

are relatively larger and heavier particles that can settle under the influence of gravity within a specified time period

refer to solid particles that are small enough to remain suspended in wastewater without settling.

Particles that are dissolved in water and cannot be removed by physical separation methods.

Known as “Acid neutralizing capacity of water”. is a measure of the presence of bicarbonate, carbonate, or hydroxide constituents.

is the amount of dissolved calcium and magnesium in the water. Usually expressed as the number of parts per million (ppm).

they indicate the presence of fecal material and hence the presence of intestinal pathogens.

The maximum concentration of a chemical that is allowed in public drinking water systems.

what does NTU mean

MRDL

7 Water Treatment Processes

One of the problem comes from material that is less than one micrometer (0.001 mm) in size, which is called

The process of decreasing the stability of the colloids in water is called

Two opposing forces that impact the removal of colloidal material:

are those factors that help to keep colloids dispersed.

are those factors that contribute to the natural removal of colloids.

7 Most Common Coagulants

The amount of coagulant which should be added to the water will depend on the

It is a physical process of slowly mixing the coagulated water to increase the probability of particle collision.

It is an adhesion of atoms, ions or molecules from a gas, liquid or dissolved solid to a surface. involves its accumulation onto the surface of a solid called the adsorbent.

is a solid substance used to remove contaminants from liquid or gas that can harm the environment.

4 adsorbents

a process of settling that allows the flocculated or coagulated particles to settle by gravity in a sedimentation tank.

A physical process of separating suspended and colloidal particles from water by passing the water through a filter media.

can consist of silica sand, greensand, anthracite coal, activated carbon, and many other types of media.

offers high filtration efficiency due to the smaller pore sizes of the membranes.

Bag or cartridge filters capable off removing giardia and cryptosporidium

Membrane filters capable of removing pathogenic organisms larger than 0.1 micrometers in size.

Membrane filters capable of removing pathogenic organisms larger than 0.005 micrometers in size.

Membrane filters capable of removing pathogenic organisms and dissolved organic contaminants larger than 0.001 micrometers in size.

Membrane filters capable of removing pathogenic organisms, dissolved organic, and salts contaminants larger than 0.0001 micrometers in size. Water flows from side that has the highest concentration to the side with the lowest concentration by applied pressure.

Water flows from the side that has the lowest concentration to the side that has the highest concentration.

Water is clear after the filtration process but still contaminated by microorganisms which must be killed by using disinfectant.

boiling water and irradiation with ultraviolet light.

adding chlorine , bromine, iodine, and ozone to water.

2 Main Types of Disinfection

It kills vegetative bacterial cells, but spores, virus, and some protozoa may survive long periods

is an effective and relatively safe disinfection method, but is relatively expensive and not widely used.

is employed primarily for microbial disinfection.

kills microogranisms more effectively

formed when free chlorine reacts with other chemicals in water

the sum of free and combined chlorine

is the process of removing residual chlorine from disinfected wastewater prior to discharge into the environment.

is a strong oxidant, that produces hydroxyl free radicals that react with organic and inorganic molecules in water to kill microbes.

To remove hardness (Ca and Mg) in water.