WATER QUALITY TESTING WITH TDS METER
1. CHAPTER-1: INTRODUCTION
1.1 Introduction;
Water is a fundamental resource for life, and its quality has far-reaching implications for human
health, agriculture, and the environment. Water quality is commonly assessed by measuring
parameters such as Total Dissolved Solids (TDS), pH, and temperature. TDS indicates the
amount of dissolved solids in water, while pH measures its acidity or alkalinity, and
temperature affects the solubility and biological activity in water. Each of these parameters
plays a critical role in water chemistry, and their levels can indicate the potential presence of
pollutants.
The use of TDS meters, pH sensors, and temperature sensors allows for a quick and effective
assessment of water quality. However, while these sensors provide valuable data, they do not
offer a complete understanding of water safety. For example, high TDS levels may not
necessarily indicate harmful contamination, and pH and temperature fluctuations can result
from natural processes or human activities. This report investigates the application of these
sensors in monitoring water quality and the limitations of relying solely on these
measurements.
Total dissolved solids (TDS) is a measure of the dissolved combined content of
all inorganic and organic substances present in a liquid in molecular, ionized, or micro-
granular (colloidal sol) suspended form. TDS are often measured in parts per million (ppm). `
Generally, the operational definition is that the solids must be small enough to survive filtration
through a filter with 2-micrometer (nominal size, or smaller) pores. Total dissolved solids are
normally discussed only for freshwater systems, as salinity includes some of the ions
constituting the definition of TDS. The principal application of TDS is in the study of water
quality for streams, rivers, and lakes. Although TDS is not generally considered a
primary pollutant (e.g. it is not deemed to be associated with health effects), it is used as an
indication of aesthetic characteristics of drinking water and as an aggregate indicator of the
presence of a broad array of chemical contaminants.
Primary sources for TDS in receiving waters are agricultural runoff and residential (urban)
runoff, clay-rich mountain waters, leaching of soil contamination, and point source water
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pollution discharge from industrial or sewage treatment plants. The most common chemical
constituents are calcium, phosphates, nitrates, sodium, potassium, and chloride, which are
found in nutrient runoff, general stormwater runoff and runoff from snowy climates where
road de-icing salts are applied. The chemicals may be cations, anions, molecules or
agglomerations on the order of one thousand or fewer molecules, so long as a soluble micro-
granule is formed. More exotic and harmful elements of TDS are pesticides arising
from surface runoff. Certain naturally occurring total dissolved solids arise from the weathering
and dissolution of rocks and soils. The United States has established a secondary water quality
standard of 500 mg/L to provide for palatability of drinking water.
Total dissolved solids are differentiated from total suspended solids (TSS), in that the latter
cannot pass through a sieve of 2 micrometres and yet are indefinitely suspended in solution.
The term settleable solids refers to material of any size that will not remain suspended or
dissolved in a holding tank not subject to motion, and excludes both TDS and TSS.[2] Settleable
solids may include larger particulate matter or insoluble molecules.
Total dissolved solids include both volatile and non-volatile solids. Volatile solids are ones that
can easily go from a solid to a gaseous state. Non-volatile solids must be heated to a high
temperature, typically 550 °C, in order to achieve this state change. Examples of non-volatile
substances include salts and sugars.
1.2 Problem Statement
Water sources worldwide are increasingly subject to pollution, making regular water quality
monitoring essential. Traditional water testing methods can be expensive and time-consuming.
TDS, pH, and temperature sensors offer a more affordable and accessible alternative for initial
water quality assessment. However, these sensors have limitations, including their inability to
identify specific contaminants or microorganisms. This report explores these limitations and
the effectiveness of using multiple sensors together for comprehensive water quality testing.
Total Dissolved Solids (TDS) refer to the total concentration of dissolved substances in water,
including inorganic salts, organic matter, and minerals. TDS levels are a critical indicator of
water quality and can have significant environmental, health, and industrial implications.
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High TDS levels in water can result from natural processes like mineral dissolution and
anthropogenic activities such as agricultural runoff, industrial waste discharge, and urban
development. Elevated TDS levels can:
1. Affect Human Health: Consumption of water with high TDS levels may lead to adverse
health effects, such as gastrointestinal irritation, scaling, and potential exposure to
harmful substances like heavy metals.
2. Environmental Impact: High TDS concentrations can disrupt aquatic ecosystems,
altering the habitat and harming aquatic life due to changes in salinity and oxygen
levels.
3. Industrial Challenges: In industries, high TDS water can lead to scaling, corrosion of
equipment, and decreased efficiency in processes requiring pure water, such as
pharmaceuticals and electronics manufacturing.
4. Agricultural Concerns: Irrigation with high TDS water can affect soil quality, reduce
crop yields, and compromise long-term agricultural productivity.
1.3 Objectives
To evaluate TDS, pH, and temperature levels in different water sources:
• Drinking water
• Salt wate
• Dirty water.
1.4 Scope of the Study
This study involves collecting and analysing water samples from three different sources:
Drinking water, Salt water, Dirty water. The samples were tested using TDS meters, pH
sensors, and temperature sensors. The aim was to compare the readings from these sensors
against water quality standards and discuss their effectiveness in evaluating water quality.
The study of Total Dissolved Solids (TDS) encompasses a wide range of aspects related to
water quality, environmental sustainability, and public health. The scope of this study includes:
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1. Understanding TDS Composition and Sources
• Identifying and categorizing the components of TDS, including inorganic salts (e.g.,
calcium, magnesium, sodium, potassium), organic matter, and other dissolved
substances.
• Differentiating between natural sources (e.g., mineral dissolution, geological
formations) and anthropogenic sources (e.g., agricultural runoff, industrial effluents,
urban wastewater).
2. TDS Measurement and Monitoring
• Evaluating existing techniques for TDS measurement, such as conductivity meters,
gravimetric analysis, and spectrophotometry.
• Developing improved methodologies for accurate, real-time, and cost-effective TDS
monitoring in diverse water systems (rivers, lakes, groundwater, and treated water).
3. Assessing Environmental and Health Impacts
• Studying the effects of elevated TDS levels on aquatic ecosystems, including alterations
to salinity, biodiversity, and oxygen levels.
• Investigating potential health risks from consuming high-TDS water, including
gastrointestinal issues, exposure to heavy metals, and long-term chronic conditions.
4. Implications for Agriculture and Industry
• Analyzing the impact of TDS on agricultural productivity, soil quality, and irrigation
systems.
• Evaluating challenges faced by industries reliant on high-quality water, such as scaling,
corrosion, and reduced efficiency in industrial processes.
5. Development of Mitigation Strategies
• Exploring and testing various treatment methods for TDS reduction, including reverse
osmosis (RO), ion exchange, and electrodialysis.
• Promoting sustainable land-use practices and waste management to prevent excessive
TDS accumulation in water systems.
6. Policy Framework and Regulation
• Reviewing global and local standards for TDS levels in drinking water, industrial
discharge, and agricultural usage.
• Proposing regulatory frameworks and incentives for industries and municipalities to
adopt best practices in TDS management.
7. Socioeconomic and Technological Considerations
• Examining the economic feasibility and scalability of TDS treatment technologies,
especially in developing regions.
• Assessing the social impacts of TDS contamination on communities and advocating for
equitable access to safe water.
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8. Future Research and Innovations
• Identifying gaps in current knowledge and proposing areas for further research, such as
the long-term environmental effects of high TDS levels.
• Encouraging innovation in sustainable technologies for TDS reduction, monitoring, and
prevention.
This study aims to provide a comprehensive understanding of TDS and its implications,
facilitating the development of effective solutions to safeguard water resources for
environmental sustainability and human well-being.
Chapter 2: Literature Survey:
2.1 Water Quality and TDS:
TDS is a general indicator of water quality and reflects the concentration of dissolved salts,
minerals, and organic matter in water. Water with TDS levels between 300 and 500 ppm is
considered acceptable for drinking, while levels above 1000 ppm may indicate poor quality.
Elevated TDS can affect the taste of water and may be linked to higher concentrations of
harmful substances such as heavy metals.
Relationship Between Water Quality and TDS
1. Indicator of Water Purity:
o Low TDS values generally indicate purer water, which is suitable for drinking
and industrial applications. However, excessively low TDS can lead to water
that lacks essential minerals.
o High TDS values may indicate contamination from natural sources (e.g.,
mineral dissolution) or human activities (e.g., agricultural runoff, industrial
discharge).
2. Health Implications:
o Safe Range: The World Health Organization (WHO) suggests that TDS levels
below 300 ppm are excellent for drinking water, while levels above 1200 ppm
are unsuitable for human consumption.
o Potential Risks: High TDS may lead to health problems such as gastrointestinal
irritation and long-term exposure to harmful substances like heavy metals.
3. Impact on Ecosystems:
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o Elevated TDS levels can alter aquatic ecosystems by changing salinity and
reducing oxygen availability, impacting the health and biodiversity of aquatic
organisms.
4. Industrial and Agricultural Relevance:
o High TDS in industrial processes can lead to scaling, corrosion, and equipment
inefficiency.
o In agriculture, TDS-rich water can degrade soil quality and reduce crop yields
over time.
TDS Levels and Water Quality Classification
TDS Water Quality
Use Suitability
(mg/L) Classification
< 300 Excellent Ideal for drinking and domestic use.
300–600 Good Suitable for drinking and general use.
600–900 Fair Acceptable for domestic use but less desirable.
900–1200 Poor May not be suitable for drinking; treatment needed.
Unsafe for drinking and limited
> 1200 Unacceptable
industrial/agricultural use.
TDS Monitoring and Management
1. Measurement Methods:
o Gravimetric Analysis: Evaporation of water and weighing the residue.
o Conductivity Meters: Estimation based on electrical conductivity, which
correlates with TDS.
2. TDS Reduction Techniques:
o Reverse Osmosis (RO)
o Distillation
o Ion Exchange
o Electrodialysis
3. Prevention Strategies:
o Regulating industrial discharges and agricultural runoff.
o Promoting sustainable water management practices.
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o Protecting natural water bodies from overexploitation and pollution.
Sources of TDS
1. Natural Sources:
o Mineral dissolution from rocks and soil (e.g., calcium, magnesium, sodium, and
potassium).
o Organic decomposition in water bodies.
2. Anthropogenic Sources:
o Industrial effluents and waste discharge.
o Urban wastewater and sewage.
o Agricultural runoff containing fertilizers and pesticides.
2.2 pH and Its Impact on Water Quality:
pH measures the acidity or alkalinity of water. A neutral pH of 7 is ideal for most biological
processes. Water with a pH lower than 7 is acidic, while values higher than 7 indicate alkalinity.
Extreme pH values can harm aquatic life and reduce the effectiveness of water treatment
processes. The acceptable pH range for drinking water is between 6.5 and 8.5.
Understanding pH
• Acidic Water: pH < 7
o Indicates a higher concentration of hydrogen ions (H⁺).
o Can result from natural sources like acid rain or human activities such as mining
or industrial discharges.
• Alkaline Water: pH > 7
o Indicates a higher concentration of hydroxide ions (OH⁻).
o Can be caused by the dissolution of carbonate rocks or human activities like
wastewater discharge with high alkaline content.
• Neutral Water: pH = 7
o Ideal for most organisms and human consumption, though slightly acidic or
alkaline water may also be acceptable depending on the specific use.
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Impact of pH on Water Quality
1. Effects on Aquatic Life:
o Most aquatic organisms thrive in a pH range of 6.5–8.5.
o Extreme pH levels can disrupt biological processes, reduce biodiversity, and
harm sensitive species like fish and amphibians.
2. Influence on Chemical Properties:
o pH affects the solubility and availability of nutrients and toxins in water.
o At low pH, metals like iron, copper, and lead become more soluble, increasing
toxicity.
o At high pH, essential nutrients like phosphorus may become less available for
aquatic plants.
3. Human Health Concerns:
o Low pH water: Corrosive, potentially leaching toxic metals from pipes, posing
health risks.
o High pH water: May cause an unpleasant taste and affect the skin and mucous
membranes.
4. Industrial and Agricultural Implications:
o In industrial processes, incorrect pH can cause scaling, corrosion, or
inefficiency.
o In agriculture, water with extreme pH levels can affect soil quality and plant
health.
Optimal pH Levels for Different Uses
Application Recommended pH Range Remarks
Drinking Water 6.5–8.5 WHO standards recommend this range for safety.
Aquatic Life 6.5–9.0 Optimal for most species, though it varies.
Irrigation 6.0–8.5 Extreme pH may harm soil and crops.
Depends on the industry and process
Industrial Use Specific to process
requirements.
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Factors Affecting pH in Water
1. Natural Factors:
o Geology: Interaction with carbonate or silicate minerals.
o Organic matter decomposition, releasing acids into water.
o Acid rain caused by atmospheric pollutants like sulfur dioxide (SO₂) and
nitrogen oxides (NOₓ).
2. Human Activities:
o Industrial effluents containing acidic or alkaline substances.
o Agricultural runoff with fertilizers and pesticides.
o Wastewater discharge from urban areas.
Monitoring and Managing pH
1. Measurement Techniques:
• pH Meters: Accurate electronic devices for measuring pH.
• pH Test Strips: Simple, color-changing strips for field testing.
2. Management Strategies:
• Neutralization: Adding acids or bases to adjust pH levels.
• Buffering: Using substances like lime or soda ash to stabilize pH.
• Pollution Control: Reducing emissions and discharges that alter pH.
• Treatment Systems: Implementing wastewater treatment plants with pH adjustment
capabilities.
2.3 Temperature and Its Role in Water Quality:
Temperature influences the solubility of gases, the rate of chemical reactions, and the activity
of microorganisms in water. Higher temperatures can reduce oxygen levels in water, leading
to fish kills and promoting the growth of harmful bacteria. Temperature is also an important
factor in determining the suitability of water for various industrial processes.
Water is an inorganic compound with the chemical formula H2O. It is a transparent, tasteless,
odorless, and nearly colorless chemical substance. It is the main constituent
of Earth's hydrosphere and the fluids of all known living organisms (in which it acts as
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a solvent). It is vital for all known forms of life, despite not providing food energy or
organic micronutrients. Its chemical formula, H2O, indicates that each of
its molecules contains one oxygen and two hydrogen atoms, connected by covalent bonds. The
hydrogen atoms are attached to the oxygen atom at an angle of 104.45°. In liquid form, H2O is
also called "water" at standard temperature and pressure.
Because Earth's environment is relatively close to water's triple point, water exists on Earth as
a solid, a liquid, and a gas. It forms precipitation in the form of rain and aerosols in the form
of fog. Clouds consist of suspended droplets of water and ice, its solid state. When finely
divided, crystalline ice may precipitate in the form of snow. The gaseous state of water
is steam or water vapor.
Water covers about 71% of the Earth's surface, with seas and oceans making up most of the
water volume (about 96.5%). Small portions of water occur as groundwater (1.7%), in
the glaciers and the ice caps of Antarctica and Greenland (1.7%), and in the air as vapor,
clouds (consisting of ice and liquid water suspended in air), and precipitation(0.001%), Water
moves continually through the water
cycle of evaporation, transpiration (evapotranspiration), condensation, precipitation,
and runoff, usually reaching the sea.
Water plays an important role in the world economy. Approximately 70% of the fresh
water used by humans goes to agriculture. Fishing in salt and fresh water bodies has been, and
continues to be, a major source of food for many parts of the world, providing 6.5% of global
protein. Much of the long-distance trade of commodities (such as oil, natural gas, and
manufactured products) is transported by boats through seas, rivers, lakes, and canals. Large
quantities of water, ice, and steam are used for cooling and heating in industry and homes.
Water is an excellent solvent for a wide variety of substances, both mineral and organic; as
such, it is widely used in industrial processes and in cooking and washing. Water, ice, and snow
are also central to many sports and other forms of entertainment, such as swimming, pleasure
boating, boat racing, surfing, sport fishing, diving, ice skating, snowboarding, and skiing.
2.4 Use of Sensors in Water Quality Testing:
TDS meters, pH sensors, and temperature sensors are widely used due to their affordability and
ease of use. These sensors provide real-time measurements, allowing for quick decision-
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making in water quality monitoring. However, they cannot detect specific pollutants or
microorganisms, which is why they should be used in conjunction with other water testing
methods for comprehensive analysis.
Sensors are used in water quality testing to measure the chemical composition and other
parameters of water:
• Turbidity: A key indicator of water quality, turbidity measures how much light is
scattered or absorbed by suspended particles in the water. High turbidity can indicate
the presence of harmful microorganisms and affect aquatic life.
• Residual chlorine: Measures the concentration of chlorine remaining in water after
disinfection. This helps ensure safe drinking water in swimming pools and distribution
systems.
• pH: A common sensor used to measure water quality.
• Oxidation-reduction potential (ORP): A common sensor used to measure water
quality.
• Total suspended solids (TSS): A common sensor used to measure water quality.
• Dissolved oxygen (DO): A common sensor used to measure water quality.
• Chemical oxygen demand (COD): A common sensor used to measure water quality.
• Biological oxygen demand (BOD): A common sensor used to measure water quality.
Sensors can also measure other parameters, such as salinity, pressure, and conductivity.
IoT sensors can be installed in water distribution networks, industrial sites, and water
production facilities to collect water quality data in real time
Chapter 3: Methodology:
3.1 Water Sampling Procedures:
Samples were taken from municipal water sources
Samples were collected in sterile bottles, and each sample was tested immediately after
collection to minimize the impact of storage on the readings.
3.2 Calibration of Sensors
Each sensor (TDS, pH, and temperature) was calibrated according to the manufacturer's
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instructions before use. For TDS, calibration solutions of known concentration were used. pH
sensors were calibrated using standard pH buffer solutions (pH 4.0, 7.0, and 10.0). Temperature
sensors were checked using a reference thermometer to ensure accurate readings.
3.3 TDS, pH, and Temperature Measurement Procedures
• TDS Measurement: The TDS meter was immersed in each water sample, and the
reading was recorded. The measurement was taken at room temperature (25°C) to
ensure consistency.
• pH Measurement: The pH sensor was placed in each water sample, and the pH reading
was recorded after the sensor stabilized.
• Temperature Measurement: The temperature sensor was immersed in the water, and
the temperature was recorded in degrees Celsius (°C).
Each water sample was tested in triplicate to ensure accuracy, and the average of the readings
was calculated for each parameter.
3.4 Data Recording and Analysis
Data was recorded in tables for each water sample, including TDS, pH, and temperature
measurements. The results were then analyzed to determine if the values fell within acceptable
limits as per the guidelines from the EPA and WHO. Data was also compared across different
water sources.
COMPONENTS:
1. TDS Sensor
2. pH Sensor
3. Temperature Sensor (LM35)
4. Arduino uno 3
5. 16x2 LCD Display
6. Power Supply ( 9V Battery or USB for Arduino)
7. Buzzer
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1.TDS Sensor:
Figure 1
• Function: The TDS sensor measures the Total Dissolved Solids (TDS) in water. TDS
refers to the total concentration of dissolved substances, such as salts, minerals, and
metals, in the water. High TDS values can indicate contamination, while low TDS
levels suggest that the water is either very pure or lacks essential minerals.
• Working Principle: The TDS sensor works by measuring the conductivity of the water.
More dissolved solids increase the water’s ability to conduct electricity, which is what
the sensor detects.
A TDS (total dissolved solids) sensor measures the concentration of dissolved solids in a liquid,
like water, by measuring the electrical conductivity of the liquid:
1. Electrodes: Two electrodes are placed in the liquid.
2. Electrical current: An electrical current is passed between the electrodes.
3. Resistance: The meter measures the resistance to the current.
4. TDS value: The greater the resistance, the higher the concentration of dissolved solids
in the liquid.
The TDS value is usually measured in parts per million (ppm) or milligrams per liter
(mg/L). For example, a TDS value of 40 ppm means that there are 40 dissolved ions from a
million particles in the water.
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TDS sensors are used in many applications, including water treatment, aquaculture,
hydroponics, and monitoring water quality in pools and aquariums. However, TDS sensors do
not measure contaminants in water, so they can't be used alone to determine if water is safe to
drink.
Factors that can affect the accuracy of a TDS measurement include water temperature and flow
rate. The standard measurement temperature is 25°C, and the TDS value increases by about
2% for each 1°C increase in temperature.
2. pH Sensor:
• Typical Model: pH Sensor
Figure 2
• Function: The pH sensor measures the acidity or alkalinity of water. pH is a scale
used to specify the acidity or alkalinity of a solution, ranging from 0 (very acidic) to 14
(very alkaline), with 7 being neutral.
• Working: A pH sensor works by measuring the hydrogen ion concentration (H⁺) in a
water sample, which determines its acidity or alkalinity. The sensor typically consists
of a glass electrode, which is sensitive to H⁺ ions, and a reference electrode, which
provides a stable voltage. When the sensor is immersed in water, the glass electrode
interacts with the hydrogen ions, generating a small electrical potential. This potential
is proportional to the pH of the solution and is measured by the sensor’s electronics.
The reference electrode ensures that the measurement is stable and unaffected by
external factors.
• The sensor's electrical signal is then processed and converted into a pH value using a
calibration curve. The pH scale typically ranges from 0 to 14, with values below 7
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indicating acidity, values above 7 indicating alkalinity, and a value of 7 representing
neutral water. To ensure accurate readings, pH sensors must be regularly calibrated with
standard buffer solutions that have known pH values. Additionally, temperature
compensation is often integrated into the sensor, as pH readings can be affected by
temperature changes.
• Output: The pH sensor provides an digital output, which is converted to a pH value
by the Arduino using calibration.
2. Temperature Sensor (e.g., LM35):
Figure 3
Temperature influences the solubility of gases, the rate of chemical reactions, and the activity
of microorganisms in water.
• Function: The LM35 is a temperature sensor that measures the temperature of the
water in degrees Celsius (°C). Temperature affects various water quality parameters
like solubility of gases (oxygen) and biological activity.
• Working: The LM35 temperature sensor is a semiconductor-based device that
measures temperature in Celsius (°C). It works by generating a voltage that is linearly
proportional to the temperature, with a typical sensitivity of 10 millivolts per degree
Celsius (10 mV/°C). The sensor consists of a temperature-sensitive diode, which
produces a small voltage output that increases as the temperature rises. This output
voltage is then read by a microcontroller or other analog-to-digital converter (ADC),
which processes it to determine the current temperature.
• The LM35 operates with a wide voltage range (usually between 4V and 30V) and offers
good accuracy, with a typical tolerance of ±0.5°C. The temperature output is relatively
easy to interface with other systems, as it provides an analog voltage directly
corresponding to the temperature. Since the LM35 does not require calibration and can
be used in a variety of applications, including weather monitoring, industrial
equipment, and home automation, it is a popular and cost-effective temperature sensor.
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3. Arduino (Microcontroller):
• Typical Model: Arduino Uno
Figure 4
• Function: The Arduino is the brain of the water quality testing system. It reads the
data from the sensors, processes the information, and either displays it on an LCD or
sends it to a computer.
• Working Principle: The Arduino uses analog-to-digital conversion (ADC) to convert
the analog signals from the sensors into digital values. These values are then processed
to get meaningful readings (TDS, pH, and temperature).
• Output: The processed data can be displayed on an LCD or sent to a computer via
serial communication.
4. LCD Display (16x2)
• Function: The LCD is used to display the output from the sensors (TDS, pH, and
temperature) on a screen for easy monitoring and analysis.
• Working Principle: The Arduino sends the sensor data to the LCD, which converts the
digital data into a readable format (numeric values). The 16x2 LCD can display up to
16 characters in 2 lines.
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• Output: Shows real-time data of TDS, pH, and temperature for the user.
• Typical Model: 16x2 LCD Display.
Figure 5
6. Power Supply
• Function: Powers the Arduino and connected sensors.
• Working Principle: A power supply (like a 9V battery USB connection) provides the
necessary voltage and current to run the entire system.
• Output: Supplies stable power to the Arduino and sensors.
• Typical Model: 9V Battery, 5V USB, DC Adapter.
Figure 6
8. Jumper Wires and Breadboard.
• Function: Jumper wires are used for connecting components, and the breadboard is
used to arrange the components without soldering.
• Working Principle: Jumper wires are plugged into the breadboard or directly into the
Arduino to make the necessary connections for the sensors.
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• Output: They allow easy assembly of the circuit and facilitate prototyping.
• Typical Model: Female-to-Male Jumper Wires, Breadboard (400
points).
Figure 7
How the Circuit Works:
1. TDS Sensor detects the concentration of dissolved solids in water and sends an analog
signal to the Arduino.
2. pH Sensor measures the acidity or alkalinity of the water and sends its data as an analog
voltage to the Arduino.
3. Temperature Sensor (LM35) measures the temperature of the water and outputs an
analog signal proportional to the temperature.
4. Arduino reads the analog signals from each sensor using its Analog Input Pins. It then
converts the readings into meaningful values (TDS in ppm, pH level, and temperature
in °C).
5. The data is either displayed on the LCD in real-time or sent to a serial monitor on a
computer for further analysis.
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Basic Circuit Diagram for Water Quality Testing:
1. TDS Sensor - Measures Total Dissolved Solids (TDS) in water.
2. pH Sensor - Measures the pH (acidity/alkalinity) of the water.
3. Temperature Sensor - Measures the temperature of the water.
Each sensor will be connected to a microcontroller (Arduino) to read and process the sensor
data. The outputs can then be displayed on a screen or sent to a computer.
Circuit Diagram:
Explanation:
• TDS Sensor: This sensor will have an analog output pin connected to one
of the Analog Input Pins on the Arduino. It measures the conductivity of
water, which correlates with the amount of dissolved solids (TDS).
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• pH Sensor: Similarly, the pH sensor has an analog output connected to an
Analog Input Pin on the Arduino. The sensor provides a voltage output
corresponding to the pH level of the water.
• Temperature Sensor (e.g., LM35): The LM35 temperature sensor will
have an analog output connected to another Analog Input Pin on the
Arduino. The LM35 provides a voltage that can be easily converted to
temperature (in Celsius).
• Arduino: The microcontroller is used to read the values from each sensor,
process the data, and display it on a screen. It will also calculate any
required conversions (like temperature in Celsius) and send the results to
an LCD or serial monitor.
• LCD Display: The LCD is connected to the Arduino to display the values
of TDS, pH, and temperature. This part is optional, as data can also be sent
to a computer for further processing.
Working Principle:
• The sensors (TDS, pH, temperature) continuously send analog signals to
the Arduino.
• The Arduino reads these analog signals and converts them into meaningful
data using appropriate formulas or look-up tables.
• The data is displayed on the LCD, or sent to a computer for further analysis.
Code for Arduino uno:
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Coast of the component:
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CHAPTER 4 :RESULTS AND DISCUSSION:
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CONCLUSION AND FUTURE SCOPE:
In conclusion, Total Dissolved Solids (TDS) serve as a critical indicator of water quality,
directly influencing its suitability for consumption, agricultural use, and industrial processes.
Monitoring and managing TDS levels are essential to ensure water safety and prevent adverse
health and environmental impacts. With the increasing global focus on water sustainability,
understanding and controlling TDS concentrations can help mitigate water-related challenges,
such as pollution and resource scarcity, thereby promoting long-term ecological balance and
public health.
Advancements in technology, such as IoT-enabled monitoring systems and innovative water
treatment solutions, offer promising avenues for efficiently managing TDS levels in diverse
applications. By integrating scientific research, technological innovations, and policy
interventions, the challenges associated with TDS can be effectively addressed. This holistic
approach will not only secure access to quality water resources but also contribute to achieving
broader environmental and sustainability goals in the future.
The future scope of Total Dissolved Solids (TDS) research and management is significant,
particularly in the context of water quality and sustainability. As water scarcity and pollution
intensify globally, monitoring and controlling TDS levels will play a crucial role in ensuring
access to safe and clean water for human consumption, agriculture, and industrial applications.
Advanced water treatment technologies, such as reverse osmosis, nanofiltration, and
electrochemical methods, are expected to evolve further, offering more efficient and cost-
effective solutions for TDS reduction.
In addition, the integration of real-time TDS monitoring systems using IoT-enabled sensors
and data analytics will allow for proactive management of water resources. This can help
industries comply with environmental regulations, optimize water usage, and reduce waste.
Research into the ecological impacts of TDS on aquatic ecosystems will also inform better
conservation strategies. Furthermore, the development of sustainable desalination and brine
management techniques will contribute to addressing challenges related to high TDS levels in
water from various sources, ensuring long-term water security and environmental balance.
Department of mechanical engineering Page | 23
WATER QUALITY TESTING WITH TDS METER
REFERENCES:
• Kumar, P., & Gupta, N. (2021). "Water Quality Testing with TDS, pH, and
Temperature Sensors in Rural India." Journal of Environmental Science and
Technology, 13(4), 200-214.
• Ministry of Jal Shakti, Government of India. (2020). National Water Quality
Monitoring Guidelines.
• World Health Organization (WHO). (2020). Guidelines for Drinking Water Quality
(South-East Asia Region).
• "What Is The Acceptable Total Dissolved Solids (TDS) Level In Drinking
Water?". The Berkey. Archived from the original on 2020-02-22. Retrieved 2020-02-
22.
• DeZuane, John (1997). Handbook of Drinking Water Quality (2nd ed.). John Wiley
and Sons. ISBN 0-471-28789-X.
• ^ Wetzel, R. G. (2001). Limnology: Lake and river ecosystems. San Diego: Academic
Press.
• "Total Dissolved Solids (TDS): EPA Method 160.1 (Gravimetric, Dried at 180 deg.
C)". Washington, D.C.: U.S. Environmental Protection Agency (EPA). 1999-11-16.
Archived from the original on 2016-02-23
• C.M. Hogan, Marc Papineau et al. Development of a dynamic water quality simulation
model for the Truckee River, Earth Metrics Inc., Environmental Protection Agency
Technology Series, Washington D.C. (1987)
Department of mechanical engineering Page | 24
