Quality of water :
It includes all the physical, chemical and biological parameters along with test to be used for defining water quality and water schemes for city
This presentation describes, how the water can be analyzed using the basic parameters like DO, COD, BOD, Alkalinity and so on. The physical, chemical, and biological parameters were discussed here.
Quality of water :
It includes all the physical, chemical and biological parameters along with test to be used for defining water quality and water schemes for city
This presentation describes, how the water can be analyzed using the basic parameters like DO, COD, BOD, Alkalinity and so on. The physical, chemical, and biological parameters were discussed here.
In this report we have analyzed different water samples of major areas of Dhaka city. Then we have analyzed the Mineral water Samples and some soft drinks of different brands. From the areas we have gone through almost 300 samples and tried to find out the best possible drinking water from a particular area. After analyzing the samples within area, we made a throughout analysis on the areas. Also we have found out that water qualities vary from area to area. For drinking water we found out that filtered water is the best option. Moreover, we analyzed the mineral water samples and found out some best possible options and analyzed the soft drinks too.
Water is one of the most important substances on earth. We already know another name of water is life. We human beings, all plants and animals must need water to survive. If there was no water there would be no life on earth. Apart from drinking it to survive, people have many other uses for water. It is used in both household and industrial purposes. Water is also essential for the healthy growth of farm crops and farm stock and is used in the manufacture of many products. But in our country Bangladesh, water pollution is one of the most significant dangers to general wellbeing. Especially water turns into curse for the city dwellers in Dhaka. Water pollution is common throughout our country but in Dhaka, it has presented itself as a very serious problem. A city which has nearly 20 million inhabitants, Dhaka faces challenges for inadequate sanitation, polluted rivers, and chemical outpouring from the surrounding industries, faulty sewage management etc. Most of these are resulting from the unplanned nature of urbanization. Also the people are not aware of that situation for that reason different health hazards like diarrhea, typhoid, dysentery, colon, kidney problems and many other health concerns are a direct result of city-wide water pollution. However, the quality of the mineral water samples of all brands is not standard and drinkable at all. The scenario for soft drinks is even worse.
To find out the current situation of water quality and to know more about water variation in different areas, we collected different samples of water from the different areas of Dhaka city under the ENV107 Lab. Here in this report we will present the water quality of Dhaka city.
This Presentation Clarifying about potable Water analysis and their methods which i gave training on operation and maintenance team for Oman Al Ghubrah Independence Water Project (SWRO Desalination 42 MIGD)
This presentation discusses the drinking water quality parameters, drinking water quality standards, water quality index and classification of water bodies and standards
Enhancing the adsorption of disinfection by products onto activated carbon us...Ahmed Hasham
The removal of contaminants from consumable waters by the traditional water treatment techniques is highly difficult. Disinfection of water alludes to the inactivation or pulverization of unsafe living pathogenic beings, which living in the water. Occurrence of disinfection by products (DBPs) during disinfection normally demonstrates lethal impacts on human health. Granular activated carbon (GAC) has the oldest history of decreasing of organic matters, but its role is reducing by time. TiO2 is used to accelerate the removal of the DBPs. TiO2 nanoparticles have good adsorption phenomena on the removal of those organic compounds at various pHs and temperatures and give good results. This study proved that TiO2 nanoparticles enhanced the efficiency of GAC to remove DBPs from water. While the elimination of trihalomethanes (THMs), dichloroacetic acid (DCAA) and trichloroacetic acid (TCAA) using 0.5 g of GAC was determined as 61.7, 69.8 and 83.2% respectively, the elimination of them by 0.1 g of TiO2 nanoparticles :GAC (1:1) was estimated as 100, 96 and 100%, respectively.
Lecture notes of Environmental Engineering-II as per Solapur university syllabus of TE CIVIL.
Prepared by
Prof S S Jahagirdar,
Associate Professor,
N K Orchid college of Engg and Technology,
Solapur
In this report we have analyzed different water samples of major areas of Dhaka city. Then we have analyzed the Mineral water Samples and some soft drinks of different brands. From the areas we have gone through almost 300 samples and tried to find out the best possible drinking water from a particular area. After analyzing the samples within area, we made a throughout analysis on the areas. Also we have found out that water qualities vary from area to area. For drinking water we found out that filtered water is the best option. Moreover, we analyzed the mineral water samples and found out some best possible options and analyzed the soft drinks too.
Water is one of the most important substances on earth. We already know another name of water is life. We human beings, all plants and animals must need water to survive. If there was no water there would be no life on earth. Apart from drinking it to survive, people have many other uses for water. It is used in both household and industrial purposes. Water is also essential for the healthy growth of farm crops and farm stock and is used in the manufacture of many products. But in our country Bangladesh, water pollution is one of the most significant dangers to general wellbeing. Especially water turns into curse for the city dwellers in Dhaka. Water pollution is common throughout our country but in Dhaka, it has presented itself as a very serious problem. A city which has nearly 20 million inhabitants, Dhaka faces challenges for inadequate sanitation, polluted rivers, and chemical outpouring from the surrounding industries, faulty sewage management etc. Most of these are resulting from the unplanned nature of urbanization. Also the people are not aware of that situation for that reason different health hazards like diarrhea, typhoid, dysentery, colon, kidney problems and many other health concerns are a direct result of city-wide water pollution. However, the quality of the mineral water samples of all brands is not standard and drinkable at all. The scenario for soft drinks is even worse.
To find out the current situation of water quality and to know more about water variation in different areas, we collected different samples of water from the different areas of Dhaka city under the ENV107 Lab. Here in this report we will present the water quality of Dhaka city.
This Presentation Clarifying about potable Water analysis and their methods which i gave training on operation and maintenance team for Oman Al Ghubrah Independence Water Project (SWRO Desalination 42 MIGD)
This presentation discusses the drinking water quality parameters, drinking water quality standards, water quality index and classification of water bodies and standards
Enhancing the adsorption of disinfection by products onto activated carbon us...Ahmed Hasham
The removal of contaminants from consumable waters by the traditional water treatment techniques is highly difficult. Disinfection of water alludes to the inactivation or pulverization of unsafe living pathogenic beings, which living in the water. Occurrence of disinfection by products (DBPs) during disinfection normally demonstrates lethal impacts on human health. Granular activated carbon (GAC) has the oldest history of decreasing of organic matters, but its role is reducing by time. TiO2 is used to accelerate the removal of the DBPs. TiO2 nanoparticles have good adsorption phenomena on the removal of those organic compounds at various pHs and temperatures and give good results. This study proved that TiO2 nanoparticles enhanced the efficiency of GAC to remove DBPs from water. While the elimination of trihalomethanes (THMs), dichloroacetic acid (DCAA) and trichloroacetic acid (TCAA) using 0.5 g of GAC was determined as 61.7, 69.8 and 83.2% respectively, the elimination of them by 0.1 g of TiO2 nanoparticles :GAC (1:1) was estimated as 100, 96 and 100%, respectively.
Lecture notes of Environmental Engineering-II as per Solapur university syllabus of TE CIVIL.
Prepared by
Prof S S Jahagirdar,
Associate Professor,
N K Orchid college of Engg and Technology,
Solapur
Determination of the Ph &Turbidity Value in Betul Block Five YearIJERA Editor
Acidic and basic are two extremes that describe chemicals, just like hot and cold are two extremes that describe
temperature. Mixing acids and bases can cancel out their extreme effects; much like mixing hot and cold water
can even out the water temperature. A substance that is neither acidic nor basic is neutral. The ph of the water in
betul block is increasing year by year and day by day. It was observed that there are 0.5% increase in the ph of
water in betul block. The optimum pH will vary in different supplies according to the composition of the water
and the nature of the construction materials used in the distribution system, but is often in the range 6.5–9.5.
Extreme pH values can result from accidental spills, treatment breakdowns, and insufficiently cured cement
mortar pipe linings. No health-based guideline value is proposed for pH.
An explanation of water basics, designed to facilitate an understanding of typical water contaminants. This presentation will be very helpful for those interested in water filtration.
water pollution control and measurmentRekha Kumari
Today we all are facing the biggest problem that is scarcity of drinking water as the level of water is continually decreasing.
In many countries people die because of contaminated water as they do not have any water resources that contain pure water.
The first question comes in mind when we talk about water management is how can we manage water. For this we need some well-planned strategies like if we know the places where heavy rainfall occur, then we can put extra efforts there in order to save water for future use.
wholesomeness, Requirements for Domestic Use. Impurities in Water. Objects & purpose of Water Analysis.Collection of Samples. Classification of Analysis of Water: Physical,
Chemical & Biological Examination of Water.
Saudi Arabia stands as a titan in the global energy landscape, renowned for its abundant oil and gas resources. It's the largest exporter of petroleum and holds some of the world's most significant reserves. Let's delve into the top 10 oil and gas projects shaping Saudi Arabia's energy future in 2024.
Sachpazis:Terzaghi Bearing Capacity Estimation in simple terms with Calculati...Dr.Costas Sachpazis
Terzaghi's soil bearing capacity theory, developed by Karl Terzaghi, is a fundamental principle in geotechnical engineering used to determine the bearing capacity of shallow foundations. This theory provides a method to calculate the ultimate bearing capacity of soil, which is the maximum load per unit area that the soil can support without undergoing shear failure. The Calculation HTML Code included.
NO1 Uk best vashikaran specialist in delhi vashikaran baba near me online vas...Amil Baba Dawood bangali
Contact with Dawood Bhai Just call on +92322-6382012 and we'll help you. We'll solve all your problems within 12 to 24 hours and with 101% guarantee and with astrology systematic. If you want to take any personal or professional advice then also you can call us on +92322-6382012 , ONLINE LOVE PROBLEM & Other all types of Daily Life Problem's.Then CALL or WHATSAPP us on +92322-6382012 and Get all these problems solutions here by Amil Baba DAWOOD BANGALI
#vashikaranspecialist #astrologer #palmistry #amliyaat #taweez #manpasandshadi #horoscope #spiritual #lovelife #lovespell #marriagespell#aamilbabainpakistan #amilbabainkarachi #powerfullblackmagicspell #kalajadumantarspecialist #realamilbaba #AmilbabainPakistan #astrologerincanada #astrologerindubai #lovespellsmaster #kalajaduspecialist #lovespellsthatwork #aamilbabainlahore#blackmagicformarriage #aamilbaba #kalajadu #kalailam #taweez #wazifaexpert #jadumantar #vashikaranspecialist #astrologer #palmistry #amliyaat #taweez #manpasandshadi #horoscope #spiritual #lovelife #lovespell #marriagespell#aamilbabainpakistan #amilbabainkarachi #powerfullblackmagicspell #kalajadumantarspecialist #realamilbaba #AmilbabainPakistan #astrologerincanada #astrologerindubai #lovespellsmaster #kalajaduspecialist #lovespellsthatwork #aamilbabainlahore #blackmagicforlove #blackmagicformarriage #aamilbaba #kalajadu #kalailam #taweez #wazifaexpert #jadumantar #vashikaranspecialist #astrologer #palmistry #amliyaat #taweez #manpasandshadi #horoscope #spiritual #lovelife #lovespell #marriagespell#aamilbabainpakistan #amilbabainkarachi #powerfullblackmagicspell #kalajadumantarspecialist #realamilbaba #AmilbabainPakistan #astrologerincanada #astrologerindubai #lovespellsmaster #kalajaduspecialist #lovespellsthatwork #aamilbabainlahore #Amilbabainuk #amilbabainspain #amilbabaindubai #Amilbabainnorway #amilbabainkrachi #amilbabainlahore #amilbabaingujranwalan #amilbabainislamabad
Water scarcity is the lack of fresh water resources to meet the standard water demand. There are two type of water scarcity. One is physical. The other is economic water scarcity.
Automobile Management System Project Report.pdfKamal Acharya
The proposed project is developed to manage the automobile in the automobile dealer company. The main module in this project is login, automobile management, customer management, sales, complaints and reports. The first module is the login. The automobile showroom owner should login to the project for usage. The username and password are verified and if it is correct, next form opens. If the username and password are not correct, it shows the error message.
When a customer search for a automobile, if the automobile is available, they will be taken to a page that shows the details of the automobile including automobile name, automobile ID, quantity, price etc. “Automobile Management System” is useful for maintaining automobiles, customers effectively and hence helps for establishing good relation between customer and automobile organization. It contains various customized modules for effectively maintaining automobiles and stock information accurately and safely.
When the automobile is sold to the customer, stock will be reduced automatically. When a new purchase is made, stock will be increased automatically. While selecting automobiles for sale, the proposed software will automatically check for total number of available stock of that particular item, if the total stock of that particular item is less than 5, software will notify the user to purchase the particular item.
Also when the user tries to sale items which are not in stock, the system will prompt the user that the stock is not enough. Customers of this system can search for a automobile; can purchase a automobile easily by selecting fast. On the other hand the stock of automobiles can be maintained perfectly by the automobile shop manager overcoming the drawbacks of existing system.
CFD Simulation of By-pass Flow in a HRSG module by R&R Consult.pptxR&R Consult
CFD analysis is incredibly effective at solving mysteries and improving the performance of complex systems!
Here's a great example: At a large natural gas-fired power plant, where they use waste heat to generate steam and energy, they were puzzled that their boiler wasn't producing as much steam as expected.
R&R and Tetra Engineering Group Inc. were asked to solve the issue with reduced steam production.
An inspection had shown that a significant amount of hot flue gas was bypassing the boiler tubes, where the heat was supposed to be transferred.
R&R Consult conducted a CFD analysis, which revealed that 6.3% of the flue gas was bypassing the boiler tubes without transferring heat. The analysis also showed that the flue gas was instead being directed along the sides of the boiler and between the modules that were supposed to capture the heat. This was the cause of the reduced performance.
Based on our results, Tetra Engineering installed covering plates to reduce the bypass flow. This improved the boiler's performance and increased electricity production.
It is always satisfying when we can help solve complex challenges like this. Do your systems also need a check-up or optimization? Give us a call!
Work done in cooperation with James Malloy and David Moelling from Tetra Engineering.
More examples of our work https://www.r-r-consult.dk/en/cases-en/
Event Management System Vb Net Project Report.pdfKamal Acharya
In present era, the scopes of information technology growing with a very fast .We do not see any are untouched from this industry. The scope of information technology has become wider includes: Business and industry. Household Business, Communication, Education, Entertainment, Science, Medicine, Engineering, Distance Learning, Weather Forecasting. Carrier Searching and so on.
My project named “Event Management System” is software that store and maintained all events coordinated in college. It also helpful to print related reports. My project will help to record the events coordinated by faculties with their Name, Event subject, date & details in an efficient & effective ways.
In my system we have to make a system by which a user can record all events coordinated by a particular faculty. In our proposed system some more featured are added which differs it from the existing system such as security.
Hybrid optimization of pumped hydro system and solar- Engr. Abdul-Azeez.pdffxintegritypublishin
Advancements in technology unveil a myriad of electrical and electronic breakthroughs geared towards efficiently harnessing limited resources to meet human energy demands. The optimization of hybrid solar PV panels and pumped hydro energy supply systems plays a pivotal role in utilizing natural resources effectively. This initiative not only benefits humanity but also fosters environmental sustainability. The study investigated the design optimization of these hybrid systems, focusing on understanding solar radiation patterns, identifying geographical influences on solar radiation, formulating a mathematical model for system optimization, and determining the optimal configuration of PV panels and pumped hydro storage. Through a comparative analysis approach and eight weeks of data collection, the study addressed key research questions related to solar radiation patterns and optimal system design. The findings highlighted regions with heightened solar radiation levels, showcasing substantial potential for power generation and emphasizing the system's efficiency. Optimizing system design significantly boosted power generation, promoted renewable energy utilization, and enhanced energy storage capacity. The study underscored the benefits of optimizing hybrid solar PV panels and pumped hydro energy supply systems for sustainable energy usage. Optimizing the design of solar PV panels and pumped hydro energy supply systems as examined across diverse climatic conditions in a developing country, not only enhances power generation but also improves the integration of renewable energy sources and boosts energy storage capacities, particularly beneficial for less economically prosperous regions. Additionally, the study provides valuable insights for advancing energy research in economically viable areas. Recommendations included conducting site-specific assessments, utilizing advanced modeling tools, implementing regular maintenance protocols, and enhancing communication among system components.
Democratizing Fuzzing at Scale by Abhishek Aryaabh.arya
Presented at NUS: Fuzzing and Software Security Summer School 2024
This keynote talks about the democratization of fuzzing at scale, highlighting the collaboration between open source communities, academia, and industry to advance the field of fuzzing. It delves into the history of fuzzing, the development of scalable fuzzing platforms, and the empowerment of community-driven research. The talk will further discuss recent advancements leveraging AI/ML and offer insights into the future evolution of the fuzzing landscape.
Quality defects in TMT Bars, Possible causes and Potential Solutions.PrashantGoswami42
Maintaining high-quality standards in the production of TMT bars is crucial for ensuring structural integrity in construction. Addressing common defects through careful monitoring, standardized processes, and advanced technology can significantly improve the quality of TMT bars. Continuous training and adherence to quality control measures will also play a pivotal role in minimizing these defects.
Cosmetic shop management system project report.pdfKamal Acharya
Buying new cosmetic products is difficult. It can even be scary for those who have sensitive skin and are prone to skin trouble. The information needed to alleviate this problem is on the back of each product, but it's thought to interpret those ingredient lists unless you have a background in chemistry.
Instead of buying and hoping for the best, we can use data science to help us predict which products may be good fits for us. It includes various function programs to do the above mentioned tasks.
Data file handling has been effectively used in the program.
The automated cosmetic shop management system should deal with the automation of general workflow and administration process of the shop. The main processes of the system focus on customer's request where the system is able to search the most appropriate products and deliver it to the customers. It should help the employees to quickly identify the list of cosmetic product that have reached the minimum quantity and also keep a track of expired date for each cosmetic product. It should help the employees to find the rack number in which the product is placed.It is also Faster and more efficient way.
TECHNICAL TRAINING MANUAL GENERAL FAMILIARIZATION COURSEDuvanRamosGarzon1
AIRCRAFT GENERAL
The Single Aisle is the most advanced family aircraft in service today, with fly-by-wire flight controls.
The A318, A319, A320 and A321 are twin-engine subsonic medium range aircraft.
The family offers a choice of engines
block diagram and signal flow graph representation
Water quality
1. Priodeep Chowdhury; Lecturer; Dept. of CEE; Uttara University.//Water Quality.
W A T E R Q U A L I T Y
Color
Pure water should not possess any color.
Most water available to us is colored to some extent due to the presence of various impurities (i.e.,
iron and manganese in association with organic matter from decaying vegetation).
Impurities may be in the colloidal form in water or it may be in suspended state.
Color caused by dissolved and colloidal form of impurities is called true color and that caused by
suspended matter, in addition to dissolved and colloidal matters, is called apparent color.
Ground water may show color due to the presence of iron compound.
Color intensity generally increases with an increase in pH. For this reason recording pH along with
color is advised.
Unit
Color is usually expressed in platinum-cobalt units (Pt-Co Units) which is based on the intensity of
color produced by a solution of Platinum and Cobalt salts that approximate the yellow-brown color of
natural waters.
For easier comparison color discs are prepared to represent various units of color. The sample is
compared with the color discs and the color is determined.
Limit
According to Bangladesh Environment Preservation Act (1997), drinking water standard for color is
15 units.
Environmental Significance
Colored water is not always harmful to man, but in most cases it is.
Even if the water is not harmful, it is not preferred by people for aesthetic reasons.
Also, disinfection by chlorination of waters containing natural organics (which produces color)
results in the formation of chloroform, other trihalomethanes, and a range of other chlorinated
organics, leading to problems which are a major concern in water treatment.
So it is important to limit the color of water for domestic supplies.
pH
pH is a measure of the acid or alkaline condition of water.
It is a way of expressing the hydrogen ion concentration, or more preciously, the hydrogen ion
activity.
pH is defined as follows:
pH = -log [H+
] (1)
Where, [H+
] is the concentration (or activity) of hydrogen ion (or proton) in moles per liter (M).
2. Priodeep Chowdhury; Lecturer; Dept. of CEE; Uttara University.//Water Quality.
Water dissociates to form hydrogen ion (H+
) and hydroxyl ion (OH-
) according to the following
equation:
H2O=H+
+ OH-
(2)
At equilibrium, we can write,
= [H+
][OH-
]/ [H20] (3)
But, since concentration of water is extremely large (approximately 55.5 mol/L) and is diminished very
little by the slight degree of ionization, it may be considered as a constant and its activity is taken as 1.0.
Thus, Eq. 3 may be written as:
Kw = [H+
][OH-
] (4)
Where Kw = Equilibrium Constant
For pure water at 25 C, 1Kw = 1477
101010
. This is known as the ion product of water or
ionization constant for water. In other words, water (dc-ionized or distilled water) at 25 0C
dissociates to yield 10-7
mol/L of hydrogen ion (H+
) and 10-7
mol/L of hydroxyl ion (OH-
). Hence,
according to Eq. 1, pH of deionized water is equal to 7.0.
The pH is usually represented by a scale ranging from zero to 14 with 7 being neutral.
Most natural waters are slightly alkaline due to the presence of bicarbonate and less often carbonate.
Water with pH outside the desirable neutral range may exhibit sour tastes and accelerate the corrosion
of metallic plumbing fittings and hot water services.
Aeration removes carbon dioxide and hence causes a rise in pH value.
Limit
According to WHO & Bangladesh Environment Preservation Act (1997), drinking water standard for
pH is 6.5 - 8.5.
Environmental Significance
A controlled value of pH is desired in water supplies, sewage treatment and chemical process plants.
In water supply pH is important for coagulation, disinfection, water softening and corrosion control.
In biological treatment of waste pH is the most significant. Organisms involved in treatment plants
are operative within certain pH range.
Turbidity
Turbidity is defined by the International Standards Organization (ISO) as the reduction of
transparency of a liquid caused by the presence of undissolved matter.
Turbidity can be interpreted as a measure of the relative clarity of water and often indicates the
presence of dispersed, suspended solids; particles not in true solution such as silt, clay, algae and
other microorganisms; organic matter and other minute particles.
Turbidity is the phenomena where by a specific portion of a light beam passing through a liquid
medium is deflected from undissolved particles.
3. Priodeep Chowdhury; Lecturer; Dept. of CEE; Uttara University.//Water Quality.
The diffusion of light caused by undissolved particles in the medium to a lesser or greater degree of
the deflection depends on:
the type of the particles (absorbance)
the size of particles
the concentration (the number of particles)
the type and shape of particles
the wavelength of the light
the angle of measurement
Unit
Nephelometric Turbidity Unit
The propensity of particles to scatter a light beam focused on them is now considered a more
meaningful measure of turbidity in water. Turbidity measured this way uses an instrument called
a nephelometer with the detector set up to the side of the light beam. More light reaches the detector if
there are lots of small particles scattering the source beam than if there are few. The units of turbidity
from a calibrated nephelometer are called Nephelometric Turbidity Units (NTU). To some extent, how
much light reflects for a given amount of particulates is dependent upon properties of the particles like
their shape, color, and reflectivity. For this reason (and the reason that heavier particles settle quickly
and do not contribute to a turbidity reading), a correlation between turbidity and total suspended
solids (TSS) is somewhat unique for each location or situation.
Jackson Turbidity Unit:
There are several practical ways of checking water quality, the most direct being some measure
of attenuation (that is, reduction in strength) of light as it passes through a sample column of water. The
alternatively used Jackson Candle method (units: Jackson Turbidity Unit or JTU) is essentially the
inverse measure of the length of a column of water needed to completely obscure a candle flame viewed
through it. The more water needed (the longer the water column), the clearer the water. Of course water
alone produces some attenuation, and any substances dissolved in the water that produce color can
attenuate some wavelengths. Modern instruments do not use candles, but this approach of attenuation of
a light beam through a column of water should be calibrated and reported in JTUs.
Environmental Significance
Excessive turbidity, or cloudiness, in potable water is aesthetically unappealing, and may also
represent a health concern.
Turbidity can provide food and shelter for pathogens. If not removed, turbidity can promote re
growth of pathogens in water distribution systems, leading to waterborne disease out-breaks, which
have caused significant cases of gastroenteritis throughout the world.
Suspended solids (the particles of turbidity) provide shelter" for microbes by reducing their exposure
to disinfectants.
Further, waters with high turbidity from organic sources may give rise to a substantial chlorine
demand.
This could result in reductions in the free chlorine residual in distribution systems as protection
against possible recontamination.
4. Priodeep Chowdhury; Lecturer; Dept. of CEE; Uttara University.//Water Quality.
Alkalinity
Alkalinity is a measure of the acid-neutralizing capacity of water.
It is an aggregate measure of the sum of all titratable bases in the sample.
Alkalinity in most natural waters is due to the presence of carbonate (CO3
2-
), bicarbonate (HCO3),
and hydroxyl (OH-
) anions.
However, borates, phosphates, silicates, and other bases also contribute to alkalinity if present.
This property is important when determining the suitability of water for irrigation and/or mixing
some pesticides and when interpreting and controlling wastewater treatment processes.
Alkalinity is usually reported as equivalents of calcium carbonate (CaCO3).
Hardness
Hardness is most commonly associated with the ability of water to precipitate soap.
As hardness increases, more soap is needed to achieve the same level of cleaning due to the
interactions of the hardness ions with the soap.
Chemically, hardness is often defined as the sum of polyvalent cation concentrations dissolved in the
water. The most common polyvalent cations in fresh water are calcium (Ca++
) and magnesium
(Mg++
).
Hardness is usually divided into two categories: carbonate hardness and noncarbonate hardness.
Carbonate hardness is usually due to the presence of bicarbonate [Ca(HCO3)2 and Mg(HCO3)2]
and carbonate (CaCO3 and MgCO3) salts.
Non-carbonate hardness is contributed by salts such as calcium chloride (CaCl2), magnesium
sulfate (MgSO4), and magnesium chloride (MgCl2).
Total hardness equals the sum of carbonate and non-carbonate hardness. In addition to Ca++
and
Mg++
, iron (Fe++
), strontium (Sr++
), and manganese (Mn++
) may also contribute to hardness (APHA
et al. 1998).
Table. Principal cations causing hardness and the major anions associated with them
Cations causing
Hardness
Anion
Ca2+
HCO3
-
Mg2+
SO4
2-
Sr2+
Cl-
Fe2+
NO3
-
Mn2+
SiO3
2-
However, the contribution of these ions is usually negligible.
Hardness is usually reported as equivalents of calcium carbonate (CaCO3) and is generally classified
as soft, moderately hard, hard, and very hard.
5. Priodeep Chowdhury; Lecturer; Dept. of CEE; Uttara University.//Water Quality.
Table: Water hardness classifications (reported as CaCO3 equivalents) used by the U.S. EPA
(EPA 1986).
It is best to report results as the actual equivalents of CaCO3 since the inclusive limits for each
category may differ between users of the information.
Pseudo-Hardness
Sea, brackish, and other waters that contain appreciable amounts of Na+
interfere with the normal
behavior of soap because of the common ion effect. Sodium is not a hardness-causing cation, and so
this action which it exhibits when present in water in high concentration is termed pseudo-hardness.
Significance of Hardness
Hardness can also affect the utility of water for industrial purposes. Hard water is often the source of
scale formed in hot water heaters and industrial systems where water is heated. This scale results from
the precipitation of calcium carbonate, which becomes less water soluble as the temperature increases
(Snoeyink and Jenkins 1980). In these situations, water is usually softened by precipitating the CaCO3 or
by using ion exchange softening methods.
Sources of Alkalinity and Hardness
Water alkalinity and hardness are primarily a function of
1) The geology of the area where the surface water is located; and
2) The dissolution of carbon dioxide (CO2) from the atmosphere.
The ions responsible for alkalinity and hardness originate from the dissolution of geological minerals
into rain and ground water.
Rainwater is naturally acidic, which tends to solubilize some minerals more easily.
Surface and ground water sources in areas with limestone formations are especially likely to have
high hardness and alkalinity due to the dissolution of bicarbonates and carbonates.
Chemical Action:
The interaction of CO2 with the dissolved minerals is described by the carbonate system.
The carbonate system describes a series of chemical equilibrium with CO2(g) in the atmosphere and
various bicarbonates and carbonates dissolved from surrounding mineral deposits. CO2(g) readily
dissolves in water (Eq. 1).
The dissolved CO2(aq)reacts with water molecules to form carbonic acid (H2CO3*), which is very
unstable and quickly dissociates, yielding H+
and a bicarbonate ion (HCO3
-
) (Eq. 2 and 3).
Soft <75
Moderately hard 75–150
Hard 150–300
Very hard >300
6. Priodeep Chowdhury; Lecturer; Dept. of CEE; Uttara University.//Water Quality.
At pH = 6.3, the amount of CO2 dissolved in water equals the amount of bicarbonate ion (HCO3
-
).
Dissolved CO2 is dominant when pH < 6.3.
At higher pH, the HCO3
-
dissociates to yield H+
and a carbonate ion (CO3
2-
) (Eq. 4).
CO2(g)↔CO2(aq) Eq. 1
CO2(aq) + H2O↔H2CO3* Eq. 2
H2CO3*↔H+
+ HCO3
-
pKa= 6.3 Eq. 3
HCO3
-
↔H+
+ CO3
=
pKa= 10.3 Eq. 4
At pH 10.3, the bicarbonate ion concentration equals the carbonate ion concentration.
CO3
2-
is dominant at pH > 10.3, and HCO3
-
dominates between pH 6.3 and 10.3.
The pH of most natural waters falls in the 6 to 9 range because of the bicarbonate buffering.
Alkalinity and Hardness Relationship
Alkalinity and hardness are related through common ions formed in aquatic systems.
Specifically, the counter-ions associated with the bicarbonate and carbonate fraction of alkalinity are
the principal ions responsible for hardness (usually Ca++
and Mg++
) (Eq. 3 and 4).
As a result, the carbonate fraction of hardness (expressed as CaCO3 equivalents) is chemically
equivalent to the bicarbonates of alkalinity present in water (Burton Jr. and Pitt 2002) in areas where
the water interacts with limestone (Timmons et al. 2002).
Any hardness greater than the alkalinity represents non-carbonate hardness.
7. Priodeep Chowdhury; Lecturer; Dept. of CEE; Uttara University.//Water Quality.
Calculating Calcium Hardness as CaCO3
The hardness (in mg/L as CaCO3) for any given metallic ion is calculated using following Equation:
Problem1.
A water sample has calcium content of 51 mg/L. What is this calcium hardness expressed as CaCO3?
Solution
Problem 2.
The calcium content of a water sample is 26 mg/L. What is this calcium hardness expressed as CaCO3?
Solution
CALCULATING MAGNESIUM HARDNESS AS CaCO3
Problem 3.
A sample of water contains 24 mg/L magnesium. Express this magnesium hardness as CaCO3.
Solution
8. Priodeep Chowdhury; Lecturer; Dept. of CEE; Uttara University.//Water Quality.
CALCULATING TOTAL HARDNESS
Calcium and magnesium ions are the primary cause of hardness in water. To find total hardness, we
simply add the concentrations of calcium and magnesium ions, expressed in terms of calcium carbonate
(CaCO3)
Problem 4.
A sample of water has calcium content of 70 mg/L as CaCO3 and magnesium content of 90 mg/L as
CaCO3.
Solution
Total hardness (mg/L) = 70 mg/L + 90 mg/L
= 160 mg/L as CaCO3
Problem 5.
Determine the total hardness as CaCO3 of a sample of water that has calcium content of 28 mg/L and
magnesium content of 9 mg/L.
Solution
Express calcium and magnesium in terms of CaCO3:
9. Priodeep Chowdhury; Lecturer; Dept. of CEE; Uttara University.//Water Quality.
CALCULATING CARBONATE AND NONCARBONATE HARDNESS
As mentioned, total hardness is comprised of calcium and magnesium hardness.
Once total hardness has been calculated, it is sometimes used to determine another expression
hardness — carbonate and non-carbonate.
When hardness is numerically greater than the sum of bicarbonate and carbonate alkalinity, that
amount of hardness equivalent to the total alkalinity (both in units of mg CaCO3/L) is referred to as
the carbonate hardness; the amount of hardness in excess of this is the noncarbonated hardness.
When the hardness is numerically equal to or less than the sum of carbonate and non-carbonate
alkalinity, all hardness is carbonate hardness, and non-carbonate hardness is absent.
Again, the total hardness is comprised of carbonate hardness and non-carbonate hardness:
Total hardness = carbonate hardness + non-carbonate hardness
When the alkalinity (as CaCO3) is greater than the total hardness, all the hardness is carbonate
hardness:
Total hardness (mg/L) as CaCO3 = carbonate hardness (mg/L) as CaCO3
When the alkalinity (as CaCO3) is less than the total hardness, then the alkalinity represents
carbonate hardness and the balance of the hardness is non-carbonate hardness:
When carbonate hardness is represented by the alkalinity: