Natural Resources
Water Resources – Availability & Quality Aspects
Water is the most essential natural resource for all forms of life on Earth. Understanding its availability and quality is crucial for sustainable development.
Water Availability
- Global Water Distribution: 97.5% saltwater, 2.5% freshwater
- Freshwater Breakdown: 68.7% glaciers, 30.1% groundwater, 0.3% surface water, 0.9% other
- Renewable Water Resources: Precipitation, river flow, groundwater recharge
- Water Stress: Situation where demand exceeds available amount during a certain period
- Water Scarcity: Physical shortage of water or economic water shortage
Water Quality Aspects
| Parameter | Description | Acceptable Limits |
|---|---|---|
| pH Level | Measure of acidity/alkalinity | 6.5-8.5 |
| Turbidity | Clarity of water | Less than 5 NTU |
| Dissolved Oxygen | Oxygen available for aquatic life | 4-8 mg/L |
| BOD | Biochemical Oxygen Demand | Less than 3 mg/L |
| Total Dissolved Solids (TDS) | Total dissolved minerals | Less than 500 mg/L |
Water Quality Parameters
- Physical: Temperature, color, odor, taste, turbidity, suspended solids
- Chemical: pH, dissolved oxygen, BOD, COD, nitrogen compounds, phosphorus, heavy metals
- Biological: Bacteria, viruses, algae, parasites, coliform count
Water Borne Diseases & Water Induced Diseases
Water Borne Diseases
Diseases transmitted through contaminated water by ingestion of water containing pathogens.
Causative Agent: Vibrio cholerae bacteria
Symptoms: Severe diarrhea, dehydration, vomiting
Prevention: Safe drinking water, sanitation, hygiene
Causative Agent: Salmonella typhi bacteria
Symptoms: High fever, weakness, stomach pain, headache
Prevention: Safe water, proper sanitation, vaccination
Causative Agent: Shigella bacteria or Entamoeba histolytica
Symptoms: Severe diarrhea with blood and mucus
Prevention: Clean water, handwashing, proper waste disposal
Causative Agent: Hepatitis A virus
Symptoms: Jaundice, fatigue, abdominal pain, nausea
Prevention: Safe water, vaccination, proper hygiene
Causative Agent: Giardia lamblia parasite
Symptoms: Diarrhea, gas, stomach cramps, nausea
Prevention: Treated water, proper sanitation
Causative Agent: Poliovirus
Symptoms: Paralysis, muscle weakness, fever
Prevention: Vaccination, safe water, sanitation
Water Induced Diseases
Diseases transmitted through water contact, vector breeding, or water-related environmental conditions.
Transmission: Mosquito bite (Anopheles mosquito breeds in water)
Symptoms: Fever, chills, flu-like illness
Prevention: Eliminate breeding sites, use bed nets, insecticides
Transmission: Aedes mosquito breeding in water containers
Symptoms: High fever, severe headache, joint pain
Prevention: Eliminate standing water, use repellents
Transmission: Contact with freshwater containing parasites
Symptoms: Abdominal pain, diarrhea, blood in stool/urine
Prevention: Avoid contact with contaminated water
Transmission: Mosquito bite (breeds in water)
Symptoms: Swelling of limbs, lymphatic system damage
Prevention: Vector control, eliminate breeding sites
Fluoride Problem in Drinking Water
Fluoride in Water: Benefits and Risks
Fluoride is naturally present in water but can cause health problems when concentrations exceed safe limits.
Safe Limits and Standards
- WHO Guideline: 1.5 mg/L (maximum acceptable concentration)
- ISI Standard: 1.0 mg/L (desirable limit), 1.5 mg/L (permissible limit)
- Natural Occurrence: Found in rocks, soil, and water sources
Fluorosis: Health Effects
- Dental Fluorosis: Discoloration and pitting of teeth
- Skeletal Fluorosis: Joint pain, stiffness, bone damage
- Non-skeletal Effects: Neurological problems, kidney damage, thyroid issues
Geographic Distribution
- High Fluoride Areas: Rajasthan, Gujarat, Andhra Pradesh, Telangana, Tamil Nadu
- Causes: Geological factors, deep bore wells, arid conditions
Removal Methods
- Precipitation Method: Using lime, aluminum sulfate, or calcium chloride
- Adsorption Method: Using activated alumina, bone char, or activated carbon
- Membrane Method: Reverse osmosis, electrodialysis
- Alternative Sources: Rainwater harvesting, surface water
Energy
Different Types of Energy
Energy of motion; depends on mass and velocity of an object
Stored energy due to position or configuration
Energy associated with heat and temperature
Energy stored in chemical bonds of substances
Energy from flow of electric charge
Energy released from nuclear reactions (fission/fusion)
Energy carried by electromagnetic waves
Sum of kinetic and potential energy in a mechanical system
Conventional Sources of Energy
- Fossil Fuels: Coal, petroleum, natural gas
- Nuclear Energy: Uranium-based fission reactions
- Characteristics: Finite resources, environmental concerns, reliable supply
- Advantages: Established infrastructure, high energy density, consistent supply
- Disadvantages: Depletion, pollution, greenhouse gas emissions
Non-Conventional Sources of Energy
- Renewable Sources: Solar, wind, hydro, biomass, geothermal
- Characteristics: Inexhaustible, environmentally friendly, sustainable
- Advantages: Clean energy, sustainable, reduces carbon footprint
- Disadvantages: Intermittent supply, high initial costs, location dependent
Solar Energy
- Technology Types: Photovoltaic (PV) panels, solar thermal systems
- Applications: Electricity generation, water heating, space heating/cooling
- Advantages: Abundant resource, zero emissions, low maintenance
- Disadvantages: Intermittent, high initial cost, weather dependent
- Efficiency: Commercial PV panels: 15-22%, Concentrated solar: up to 40%
Wind Energy
- Technology: Horizontal and vertical axis wind turbines
- Applications: Electricity generation, water pumping, mechanical power
- Advantages: Clean, renewable, cost-effective, scalable
- Disadvantages: Intermittent, noise, visual impact, wildlife concerns
- Capacity Factor: 25-35% for onshore, 35-50% for offshore
Hydrogen as Alternative Energy
- Production Methods: Electrolysis, steam methane reforming, biomass gasification
- Applications: Fuel cells, transportation, industrial processes
- Advantages: Zero emissions when used, high energy density, versatile
- Disadvantages: High production cost, storage challenges, infrastructure needs
- Hydrogen Economy: Potential for clean energy storage and transportation
Self-Study Component (SSC): Alternative Energy Sources
Energy from organic matter including wood, agricultural residues, and animal waste.
- Direct combustion for heat/electricity
- Biofuels like ethanol and biodiesel
- Biogas from anaerobic digestion
Heat energy from Earth's interior accessed through hot springs, geysers, and underground reservoirs.
- Electricity generation
- Direct heating applications
- Low emissions and reliable
Energy from ocean thermal gradients, waves, tides, and salinity differences.
- Tidal energy systems
- Wave energy converters
- Ocean thermal energy conversion (OTEC)
Devices that convert chemical energy directly to electrical energy through electrochemical reactions.
- Hydrogen fuel cells
- Proton exchange membrane (PEM) cells
- High efficiency, zero emissions
Micro and mini hydro systems that generate electricity from flowing water on a smaller scale.
- Capacity up to 10 MW
- Environmentally friendly
- Suitable for remote areas
Technologies that store energy for later use, complementing intermittent renewable sources.
- Battery systems (Li-ion, flow batteries)
- Pumped hydro storage
- Compressed air energy storage