UNIDAD EDUCATIVA PARTICULAR JAVIER

BACCALAUREATE IN SCIENCE

MONOGRAFÍA

Water Purification Process

ESTUDIANTE:

Xavier Andrés Ibarra Iperty

ASESOR: LCDO. Ms. Laura Ortuño de Baquerizo

TERCERO BGU - PARALELO C

2017 – 2018

ACKNOWLEDGEMENTS

First of all, thanks to God for letting me do this investigation and finishing it without any

problems. Thanks to my tutor, Laura Ortuño Baquerizo, because she helped me a lot whenever I

asked for help, being patient with me and helping me realize how many mistakes did I had.

Thanks to Xavier Ibarra Larrea and Marcia Iperty Morante for putting me into pressure in order

to make this dissertation, helping me in all the things that I needed in order to do this

dissertation. And thanks to all the people involved in the elaboration of this dissertation, as little

the idea was, more progress did I had.

INDEX

INTRODUCTION ........................................................................................................................................... 5

CHAPTER I: Water purification .................................................................................................................... 6

History of water purification ................................................................................................................... 6

Concepts of water purification ............................................................................................................... 8

Terms used in water purification ............................................................................................................ 8

Purification process .............................................................................................................................. 10

Catchment ........................................................................................................................................ 10

Canalization ...................................................................................................................................... 10

Coagulation ....................................................................................................................................... 11

Flocculation ....................................................................................................................................... 11

Chemical Flocculation ....................................................................................................................... 11

Mechanical Flocculation ................................................................................................................... 11

Sedimentation................................................................................................................................... 11

Filtration ........................................................................................................................................... 12

Disinfection ....................................................................................................................................... 13

Alkalization........................................................................................................................................ 14

Distribution ....................................................................................................................................... 14

CHAPTER II: Water quality control ............................................................................................................ 15

Raw and potable water quality standards provided by the INEN ......................................................... 15

Basic concepts....................................................................................................................................... 15

Physic-chemical parameters ................................................................................................................. 16

PH ..................................................................................................................................................... 16

Turbidity ............................................................................................................................................ 17

Hardness of water ............................................................................................................................. 17

Alkalinity and acidity ......................................................................................................................... 17

Conductivity ...................................................................................................................................... 18

Concentration measures (PPM) ........................................................................................................ 18

Organic material ............................................................................................................................... 19

Total organic carbon (COT) ............................................................................................................... 19

Phenols ............................................................................................................................................. 19

Impurities in the water ..................................................................................................................... 19

Chlorides ........................................................................................................................................... 19

Sulfates ............................................................................................................................................. 20

Silica .................................................................................................................................................. 20

Total dissolved solids ........................................................................................................................ 20

Dissolved oxygen .............................................................................................................................. 21

Microbiological parameters .............................................................................................................. 21

Pathogens ......................................................................................................................................... 21

Aerobic mesophilic ............................................................................................................................ 21

Total coliforms .................................................................................................................................. 22

Fecal coliforms .................................................................................................................................. 22

Pseudomas ........................................................................................................................................ 22

Mushrooms and yeasts ..................................................................................................................... 22

CHAPTER III: Environmental impact of the collection of water for purification ........................................ 23

Environmental aspects affected by water purification processes ......................................................... 23

Sludge formation .............................................................................................................................. 23

Sludge management ......................................................................................................................... 23

Sludge drying .................................................................................................................................... 24

Final disposal of sludge ..................................................................................................................... 24

CONCLUSIONS ........................................................................................................................................... 26

RECOMENDATIONS ................................................................................................................................... 27

INTRODUCTION

Water is the most essential liquid for life to be possible, without it the human race could not

survive. Even though many water preservation campaigns exist, many people don’t look into the

process required for water to go from rivers, lakes and other water sources all the way to their

houses.

This investigation will look into the purification process required to “clean” water from many

impurities in order to become potable. The main objective is to give a simple, but complete

information about the purification of water, it´s history, the process, the factor taken into

consideration, and the impact that it leaves in the ecosystem.

This is important to know because water is a necessity for all living things. People use it for a lot

of things in their daily lives. As it is used daily it is very important to know how many risks the

water has in order to prevent or discover what is generating some diseases.

CHAPTER I: Water purification

History of water purification

Humans learned how to store and then distribute water centuries ago. In his

beginnings, when man was a hunter and gatherer, the water source from which he drank was

from the nearest river. As he began to establish himself in settlements. The first thing which was

located was a water source, either a lake or river. If there were none in the vicinity, man learned

to take advantage of the underground river sources, extracting water and digging wells.

Approximately 7000 years ago, in Jericho, wells were used as the main water source, in

addition to the development of water transportation and distribution systems. This transport was

carried out by means of simple channels, excavated in the sand or the rocks. Later hollow tubes

would be incorporated. In Egypt, for example, hollow palm trees were used while in China and

Japan they used bamboo logs. Ceramics, wood and metal were materials which were also put to

use in the process of distribution.

Around the year 3000 A.C. the city Mohenjo-Daro adapted some of the first facilities

which required a very large water supply. These are known to be some of the first public bathing

facilities, were hot water facilities and bathrooms were common in this city.

In ancient Greece run-off water, well water and rainwater were used in very early times.

Due to population growth they were forced to store and distribute water. The water used was

drawn through wastewater systems, as well as that of rainwater. The Greeks were the first to

have an interest in water quality. They used aeration reservoirs for water purification.

The Romans were the greatest architects especially when it came down to

constructing water distribution networks that have ever existed throughout history. They used

groundwater resources, rivers and runoff water for their provisioning. They also applied the

aeration treatment system was used as a purification method. The most popular and best quality

water descended from the mountains.

Aqueducts are the systems used to transport water. Through the aqueducts water flows for

thousands of miles. Pipeline systems in cities used cement, rock, and bronze, silver, wood and

lead. Water sources were protected from external contaminants.

After the fall of the Roman Empire, the aqueducts were no longer used. From the year

500 to 1500 D.C. there was little development in relation to water treatment systems. During the

middle ages hygiene became a major problem and the lead to the systems of water distribution

because the residues and excrement were poured directly into the waters The people who drank

these waters became sick and died. To avoid this, Water began to be brought into the city ,

carried in by water carriers, from areas not affected by the pollution.

The first drinking water supply system to provide for a complete city was built in Paisley,

Scotland, circa 1804 by John Gibb. In 3 years it began transporting filtered water to the entire

city of Glasgow.

In 1806 Paris begins to operate the largest water treatment plant. Water sediments for

12 hours prior to filtration Filters consist of sand, carbon and capacity is 6 hours.

Finally, in 1827, James Simplon constructed a sand filter for the purification of

drinking water. It is still considered the first effective system used for public health purposes.

Concepts of water purification

Purification is a process that is performed on any water to transform it into drinking water

making it absolutely suitable for human consumption. This is done mostly on waters originating

from natural springs and groundwater.

Terms used in water purification

Within the purification of water we find many terms which are frequented in the

different stages of this process.

Softening. - Elimination of calcium and magnesium to reduce the hardness of water.

Absolute.- The micron degree of a filter; indicates that any particle larger than a specific size will

be trapped within the filter.

Absorption.- When a solid takes molecules from its structure.

Acidity.- The quantitative capacity of water to neutralize a base, expressed in calcium carbonate

equivalent in PPM or mg / l.

Biodegradable pollutants.- Agents that are capable of being decomposed under natural

conditions.

Acid water.- Water containing a quantity of acidic substances that make the pH below 7.0.

Soft water.- Any water that does not contain large concentrations of dissolved minerals such as

calcium and magnesium.

Contaminated water.- The presence in the water of sufficient harmful or unpleasant material to

cause damage to the water quality.

Hard water.- Water containing a large number of positive ions. The hardness is determined by

the number of calcium and magnesium atoms present.

Receiving waters.- Where waste water is discharged. It may be a river, a lake, an ocean, a stream

or other watercourse.

Wastewater.- Residual fluids in a sewage system.

Aeration.- A technique used in water treatment that requires an oxygen source, commonly

known as biologically aerobic water purification.

Alkalinity.- It is a measure of the ability of water to neutralize acids.

Base.- An alkaline substance having a pH in excess of 7.5.

Activated carbon.- It is the most commonly used medium for absorption, produced by heating

carbonaceous substances or cellulose bases in the absence of air.

Clots.- Solid residue precipitated in the filter after filtration takes place.

Coagulants.- Liquid particles in higher suspension that are united to create particles with a

greater volume.

Flocculation.- Flocculated mass that is formed by the accumulation of suspended particles.

Neutralization.- The addition of substances to neutralize the water, such that it is neither acid nor

basic.

Parts per million.- Expressed as PPM; is a measure of concentration.

PH.- It is the value that determines if a substance is acidic, neutral or basic.

Turbidity.- Measurement of non-transparency of water due to the presence of suspended organic

matter.

Purification process

Catchment

The catchment is the place where the water that is going to be consumed is obtained,

these could come from groundwater and surface water. This here, which reaches the catchments,

is called raw water, to be distinguished from what we call drinking water; Here, water which

may contain chemical substances is regulated, kept in suspension awaiting water purification.

Canalization

The channeling, is what is called the process in which the water collected is conducted to

the water treatment plant, using two systems: the abduction and the driving.

If it is by adduction the water is transported by gravity since the supply source is higher than the

water treatment plant; If the water, on the other hand, is at a lower level than the water treatment

plant, the water is transported by means of pumps and is called impulsion.

Coagulation

It consists of destabilizing the colloidal particles that are in suspension, by the addition of

a coagulant, to favor their agglomeration; consequently, stable suspended matters are eliminated;

coagulation not only eliminates turbidity but also the concentration of organic matter and

microorganisms. This is done before flocculation.

Flocculation

Flocculation can be chemical and / or mechanical.

Chemical Flocculation

It is the process by which the particles in suspension are eliminated, increasing the size of

these, applying chemical substances called flocculants, the colloidal substances present in the

water are agglutinated, facilitating their decanting.

Mechanical Flocculation

Process of slow agitation that produces the compaction of the coagulated matter.

Sedimentation

Sedimentation refers to the separation of water, after the flocculating substances have

been applied, from physical bodies called sediments. In this process, the Stokes law

predominates, which indicates that the particles sediment more easily when their diameter is

larger, being that their specific weight is compared with that of the liquid, and the lower

the viscosity of the liquid.

Filtration

In this phase the water is separated from the suspended matter, passing it through a

porous element, the final result is a clearer water, in which 95% of microorganisms have been

eliminated. This one here is divided into several phases and several types. In this phase, water

goes through several stages:

Filtration through deep bed.- It is a filtering system that traps the larger particles suspended in

the water, remaining in different layers of sand.

Filtration through activated carbon.- It manages to eliminate any taste or smell that water has, as

is the case of chlorine or mercury. The passage of water has to be slow to allow you to remove

most of the impurities in the water.

Water softening.- It is done to remove water hardness. Resins are used that retain calcium,

sodium and magnesium, these can be natural or artificially created, the suspended suspended

solids of the resin are drained.

Reverse osmosis.- Known as ultra purification in which water is passed through at high pressures

through a semipermeable membrane that separates the highest salt water and low salt water. The

function of the semipermeable membrane is to remove most of the total dissolved solids from

95% to 99% of all bacteria. If necessary, the water is re-polished physically with a filter

containing a cartridge capable of retaining up to one micron or less.

Disinfection

It is known as water disinfection to the extraction, deactivation or elimination of pathogenic

microorganisms existing in water. The destruction of these microorganisms supposes the end of

the reproduction and growth of these microorganisms. If these are not eliminated, the water is

not potable and is likely to cause diseases. Within the disinfection we find:

Chlorination.- It is the primary procedure of water disinfection in which chlorinated compounds

are used, it eliminates algae, molds and bacteria.

Ultraviolet light.- This is used here to kill bacteria, thanks to the spectrum it has, it becomes

possible to exterminate them, in this way the water becomes sterile.

Ozonification of the water.- It is used after the water has passed through the ultraviolet rays, it is

a gas that is injected into the water in the most direct possible way in combination with the air,

which when in contact with water, carries out the oxidation of the organic and inorganic

compounds of this, destroying them and avoiding the formation of algae. The effectiveness of

ozone disinfection has to do with the amount used and with the time it has contact with water.

Alkalization

Process in which lime is added to water to make it suitable for consumption. This must be done

here because the water becomes acidic thanks to the coagulant used, it is the final stage of the

process prior to the distribution of the water.

Distribution

As the name indicates, it is the distribution of the water once the purification process is finished,

this is carried from here to the pumping stations where it is distributed thanks to the existing pipe

network.

CHAPTER II: Water quality control

Raw and potable water quality standards provided by the INEN

Basic concepts

Potable Water.- Water whose physical, chemical and microbiological characteristics have been

treated in order to guarantee its suitability for human consumption.

Raw water.- It is the water that is found in nature and that has not received any treatment to

modify its characteristics: physical, chemical or microbiological.

CFU / ml.- Concentration of microorganisms per milliliter, expressed in colony forming units.

NMP.- Form of expression of biological parameters, most likely number, when the multiple tube

technique is applied.

Mg / l.- Units of concentration of physical-chemical parameters.

Pathogenic microorganism.- They are the potential cause of diseases for the human being.

Pesticides.- Chemical substance that is used alone, combined or mixed to prevent, combat or

destroy, repel or mitigate: insects, fungi, bacteria, nematodes, mites, mollusks, rodents, weeds or

any form of life that is harmful to agricultural crops, plant products and plants in general.

Disinfection.- Process of treatment that eliminates or reduces the risk of disease that can be

presented by pathogenic microbial agents, constitutes an essential preventive measure for public

health.

Disinfection byproducts.- Products that are generated when the disinfectant is applied to water,

especially in the presence of humid substances.

Nucleoid Radio.- Radioactive nuclei; nuclides: set of atoms that have nuclei with the same

atomic number Z and mass A.

MBAS, ABS.- Substances active to methylene blue; Alkyl Benzene Sulfate.

Residual chlorine.- Chlorine remaining in the water after at least 30 minutes of contact.

Total hardness.- Is the amount of calcium and magnesium present in water and expressed as

calcium carbonate.

Total dissolved solids.- Filterable fraction of solids that corresponds to colloidal and dissolved

solids.

Physic-chemical parameters

Are the parameters that must exist in drinking water for it is recognized as healthy,

among these we find:

PH

Measurement of the concentration of hydrogen. It measures the acidic or alkaline

nature of the aqueous solution. Most natural waters have a pH level between 6 and 8.

Turbidity

It is the difficulty of water to transmit light due to insoluble materials in suspension,

colloidal or very fine and that occur mainly in surface water, in general they are very difficult to

filter and can lead to deposits in the pipes, measurement is made by comparison with the

turbidity included by several substances, the measurement in PPM of SiO2 has been widely used

but variations according to the silica and the technique used are appreciated.

Hardness of water

It is due to the presence of calcium and magnesium salts, and it measures the capacity

of a water to produce scale. It affects both domestic and industrial waters and from the point of

view of reverse osmosis is one of the main parameters that must be controlled.

Waters with less than 50 PPM of CO3Ca are called soft.

Up to 100 PP; of CO3Ca, slightly hard.

Up to 200 PP; of CO3Ca, moderately hard.

And from 200 PPM of CO3Ca, very hard.

The frequent thing is to find waters with less than 200 PPM of calcium carbonate, but they can

reach up to 1000 PPM and even up to 2000 PPM. The elimination of the hardness is done by

decalcification or softening by ion exchange with resins.

Alkalinity and acidity

Alkalinity is a measure of neutralizing acids. They contribute, mainly to the alkalinity

of an aqueous solution the ions of bicarbonate, carbonate and oxidrile, but also the phosphates,

silicic acid or other weak acids. Its presence in the water can produce CO2 in boiler steam that is

very corrosive and can also produce foams and a drag of solids with boiler steam. It is measured

in the same units as hardness. It is corrected by descaling with lime, acid treatment or

demineralization by ion exchange.

Acidity is the ability to neutralize bases. It is quite rare that natural waters have acidity. It is

responsible for corrosion, is measured in the same units as alkalinity and is corrected by

neutralization with alkalis.

Conductivity

Electrical conductivity is the measure of the capacity of water to conduct electricity. It

is indicative of the ionizable matter present in water. Pure water does not conduct electricity

practically; therefore the conductivity that we can measure will be a consequence of the

impurities present in the water.

Concentration measures (PPM)

It is a unit of concentration measurement. It refers to the number of units of the

substance that there are per million units of the set.

Organic material

It presents the following divisions:

Total organic carbon (COT)

Indicates the total amount of carbon present in a sample, expressed in mg / l.

Phenols

They are hydroxiderivatives of benzene and polynuclear aromatic compounds. They

usually come from industrial activities, degradation of phytosanitary products and the

decomposition of vegetal matter.

Impurities in the water

Within these impurities we find:

Chlorides

The chloride ion forms very soluble salts, it is usually associated with the sodium ion,

this occurs logically in very saline waters. Fresh water contains between 10 and 250 PPM of

chlorides, but also much higher values are easily found. Brackish waters contain thousands of

PPM of chlorides, seawater is around 20,000 PPM of chlorides.

Sulfates

The sulfate ion corresponds to salts of moderately soluble to very soluble. Fresh waters

contain between 2 and 250 PPM, and seawater around 3000 PPM. Pure water is saturated with

SO4Ca at 1500 PPM, the presence of other calcium salts increases the solubility.

Silica

Silica, SiO2 is found in water dissolved as silicic acid SiO4H4 and as colloidal matter;

It helps to cause some alkalinity in the water. Natural waters contain between 1 and 40 PPM, and

can reach 100 PPM.

Total dissolved solids

Dissolved solids or total salinity, is a measure of the amount of dissolved matter in the

water. The origin can be multiple in both groundwater and surface water. For potable water a

maximum desirable value of 500 PPM is set; and the treatment process is that of reverse

osmosis.

The solids in suspension are usually separated by filtration and decantation. They are settleable

solids, not dissolved, that can be retained by filtration. The groundwater usually less than 1 PPM,

the superficial ones can have much more depending on the origin and form of catchment.

Total solids are the sum of dissolved solids and suspended solids.

Dissolved oxygen

Because of its oxidizing nature, O2 plays an important role in the solubilization or

precipitation of ions that has some insoluble form, its presence in water is vital for higher life and

for most microorganisms.

Microbiological parameters

Measurements and controls of the parameters, usual indicators and the main

microorganisms, these can be:

Pathogens

It is that element or means capable of producing some kind of disease or damage in the

body. The detection of these microorganisms is given as follows:

They are not always present in the source of contamination, but they can appear suddenly.

When diluted in water, they can remain in concentrations not detectable by laboratory methods.

They survive relatively little time in the water, so they can disappear before being detected.

The results of the bacteriological analysis of the water are obtained after it has been consumed,

so if there are pathogens, the population will have been exposed to the infection.

Aerobic mesophilic

Determine the effectiveness of water treatment.

Total coliforms

They indicate the contamination coming from the soil and the water itself.

Fecal coliforms

They indicate the fecal contamination existing in the water.

Pseudomas

They indicate deterioration in water quality or show a re-contamination.

Mushrooms and yeasts

If there is water, it would mean the existence of a low pH level, indicating that the water

is not suitable for consumption.

CHAPTER III: Environmental impact of the collection of water for purification

Environmental aspects affected by water purification processes

When talking about the environmental impacts caused by the purification of water,

there is one which can be noticed as time goes by, as is the formation of sludge after the water

has gone through the process of water purification catchment served.

Sludge formation

Semi-solid waste generated in the process of a sewage treatment plant is called sludge

or sludge. These sludges are generated by the sedimentation or precipitation of organic and

inorganic matter contained in the water.

Sludge management

These sludges have a significant importance for public health because:

They may contain pathogenic microorganisms, such as bacteria, viruses and parasite eggs.

They can contain heavy metals such as lead, cadmium, copper, mercury, nickel, selenium, zinc,

arsenic.

According to their degree of maturation we can classify them in:

Crude .- Are those from the primary decanting stage.

Stabilized.- Those with a significant reduction in the attraction potential of vectors, which

normally occurs at the end of the treatment.

Sludge drying

At the time of drying the sludge we can obtain:

Sludge Class A. - Are those which can be applied to soils without inconvenience, because there

is no risk to human, animal or plant health. To be considered a stabilized sludge of class A it

must have a maximum of 1000 fecal coliforms per gram of solid, and lacking viable helminth

eggs in 4 grams.

Sludge Class B. - Is one whose application will depend on the location and type of soil and

crops. To be considered a stabilized sludge of class B it must have a maximum of 2x106 fecal

coliforms per gram of solid.

Hazardous Sludge.- These are high risk to health and should be handled as hazardous waste. It is

one that contains more than 2x106 fecal coliforms per gram of solid.

Final disposal of sludge

The stabilized sludge can be arranged in:

Sanitary landfills.- In a volume not exceeding 8%, of the total domestic waste. In this case the

humidity of the mud will be 70% or less. Only allows muds A and B.

Wastewater treatment plants.- Where a mono-fill can be enabled as an annexed facility, also with

daily coating.

Independent mono-fillings.- With waterproofing system, odor control and daily coating. The

coating frequency can be increased if necessary.

Soils.- Those that must comply with certain requirements of security, location, humidity, rainfall,

composition, acidity and slope.

The sludge application area should be more than 300 meters from towns, hospitals,

schools, food stores and sources of groundwater collection for human use, more than 100 meters

of isolated houses, and the area of application is fenced and signaled.

CONCLUSIONS

To conclude with this investigation it is possible to extract that the knowledge gathered and

presented throughout this paper is of great importance, especially because most people ignore the

process necessary for water to become available for human consumption as well as the risks and

environmental impact this process involves. With the information provided it is possible to

inform and raise awareness about the risks involved in water purification as well as the

environmental impact involved in the disposal of sludge and other impurities that remain after

being separated from water. It is very important to know all the parameters that the water has in

order to become consumable for humans, not only drinking it, but also using it for domestic uses.

Water is not to be threaten as little as it is threated by people, it requires a lot of knowledge to

process this liquid in order to use it; if it is processed incorrectly it can become in a danger for

us. And lastly, it is important how to deal with the sludge that water leaves in the process, not

only for being toxic, but also for the big impact that it can generate in the ecosystem.

RECOMENDATIONS

Finishing this work, it is recommended to not rely completely in my investigation, as I put the

results that I obtained, there were some things that I didn’t take into consideration. I recommend

that if you, the person that need results in order to do an investigation, want to take on my data,

then prove it yourself. Not that I am not sure about my information, but it is always better to do

something yourself when you are conducting an investigation.