WATER POLLUTION-UEN008

Page 1: Overview of Water Pollution

• Thapar Institute of Engineering & Technology

  • School of Energy & Environment (SEE)

  • Course: UEN008 - Energy and Environment

  • Topic: Water Pollution

Page 2: Water Cycle

• Continuation of coursework regarding the water cycle as it pertains to water pollution.

Page 3: Water Pollution

• Further detailing the issue of water pollution under the same course.

Page 4: Definition of Water Pollution

• Definition: Water pollution is the contamination of water bodies mainly due to human activities.

• Water Bodies Affected: Includes lakes, rivers, aquifers, and groundwater.

• Cause: Results from excess concentrations of contaminants introduced into the environment, leading to a loss of beneficial uses of water caused by changes in its composition due to human activity.

Page 5: Characteristics of Water Pollution

• Physical Characteristics:

  • Solids, temperature, color, odor, turbidity, oil and grease, conductivity.

• Chemical Characteristics:

  • Organics: Proteins, carbohydrates, lipids, surfactants, phenols, pesticides, etc.

  • Inorganics: pH, chlorides, alkalinity, nitrogen, phosphorus, and heavy metals.

  • Gases: Oxygen, hydrogen sulfide, methane.

• Biological Characteristics:

  • Pathogens, indicators, viruses, and invertebrates.

Page 6: Sources of Water Pollution

• Point Sources: Single, identifiable sources of pollution.

• Non-Point Sources: Diffuse source of pollution, such as:

  • General runoff of sediments.

  • Pesticide spraying.

  • Fertilizer runoff from farms.

Page 7: Point and Non-Point Sources

• Overview of the classification and differences between point and non-point sources of water pollution.

Page 8: Major Water Pollutants and Their Sources

• Identifying significant water pollutants and understanding their origin.

Page 9: Contaminants Affecting Water Bodies

• Key Contaminants:

  • Biodegradable organic matter.

  • Suspended, colloidal, and dissolved solids.

  • Nutrients, pathogens, soaps, detergents, pesticides.

  • Acidic, basic, and ionic species; as well as thermal and radioactive materials.

Page 10: Categories of Pollutants

• Fund Pollutants:

  • Those with some absorptive capacity in the environment.

  • Examples:

    • Degradable (organic residues) broken down by bacteria.

    • Thermal (heat injection) and Eutrophic (excess nutrients like nitrogen and phosphorus).

• Stock Pollutants:

  • Have little or no absorptive capacity. Ex: Heavy metals, synthetic chemicals.

Page 11: Nature and Characteristics of Wastewater

• Overview of wastewater characteristics.

Page 12: Dissolved Oxygen (DO)

• Importance: A critical measure of water quality.

• Key characteristics:

  • Oxygen solubility is inversely proportional to temperature; max DO at 16°C is 10 mg/L.

  • Obtained through diffusion from air, aeration, and photosynthesis.

  • Stress for aquatic life occurs below 5 mg/L.

Page 13: Dissolved Oxygen Levels

• Classification of water quality based on DO levels:

  • 8–9 mg/L: Good

  • 6.7–8 mg/L: Slightly polluted

  • 4.5–6.7 mg/L: Moderately polluted

  • 4–4.5 mg/L: Heavily polluted

  • Below 4 mg/L: Gravely polluted

Page 14: Physio-Chemical Characteristics of Water

• Aggregate organics including:

  • Total Organic Carbon (TOC)

  • Chemical Oxygen Demand (COD)

  • Biochemical Oxygen Demand (BOD)

• Chemical and physical constituents affecting water quality:

  • Organics, Inorganics, Gases.

Page 15: Total Oxygen Demand (ThOD)

• Total oxygen required to oxidize a known compound to CO2 and H2O.

• Illustrated by stoichiometric calculations with organic compounds.

Page 16: Chemical Oxygen Demand (COD)

• Measures the pollution potential of organic matter.

• Higher COD values than BOD, as it does not differentiate between degradable and non-degradable matter.

  • Measured using potassium dichromate.

Page 17: COD Measurement Procedure

• Procedure: Measured by the amount of potassium dichromate reduced during a controlled reaction.

• Formula used for COD calculation:

  • COD(mg/l as O2) based on volumes of FAS in blank and sample samples.

Page 18: Example Problem on COD

• Problem description involving estimation of COD in wastewater.

Page 19: COD Solution Example

• Calculated COD based on given data and formula:

  • Result: 12000 mg/L.

Page 20: Biochemical Oxygen Demand (BOD)

• Definition: Indicator of organic matter concentration in wastewater.

• Determined based on aerobic biological decomposition of organic waste.

• Known as BOD5, measures DO before and after 5 days incubation at 20°C.

Page 21: Factors Affecting BOD

• Not a specific pollutant measure but a gauge of oxygen needed by microorganisms.

• Influences include temperature, time, and light conditions.

Page 22: BOD Exponential Decay Curve

• Illustration of BOD decay over time.

Page 23: BOD Testing Procedure

• BOD determination using initial and final DO measurements, dilution factor applied.

Page 24: Dilution Factor Explained

• The dilution factor used in BOD calculations.

Page 25: BOD Calculation Method

• Formula to calculate BODt over time based on decay.

Page 26: BOD Numerical Problem

• Example problem involving calculations of BOD at different temperatures.

Page 27: Temperature Correction for BOD

• Discussion on correcting BOD values based on temperature variations.

Page 28: BOD and COD Relationship

• Relationship noted: COD > BOD, indicating biodegradable versus non-biodegradable particles present.

Page 29: Total Organic Carbon (TOC)

• Indicates pollution load through carbon content.

• Tested using TOC analyzers.

Page 30: Physical Parameters of Water

• Overview of solids in water including TSS, TDS, TVS, and their measurement methods.

Page 31: Further Physical Parameters

• Additional categories of suspended and dissolved solids.

Page 32: Turbidity Measurement

• Definition: Light transmission property of water.

• Measurement technique: Nephelometry; units are NTU.

Page 33: Additional Physical Parameters

• Colour: Measured by spectrophotometer in PCU.

• Temperature: Key in chemical reactions.

• Electrical Conductivity: Indicates water's capacity to conduct electricity related to TDS.

Page 34: Physico-Chemical Characteristics Summary

• Summary of chemical constituents affecting water quality including alkalinity, nitrogen, phosphorus, etc.

Page 35: Importance of Alkalinity and Nitrogen in Water

• Alkalinity from hydroxides, crucial for biological treatment.

• Nitrogen compounds measured include NH3, NO3, etc.

Page 36: Phosphorous and Metallic Constituents

• Importance of phosphorus as a nutrient and effects of metals like cadmium, mercury as priority pollutants.

Page 37: Wastewater Treatment Overview

• Stages of treatment:

  • Primary: Removes solids.

  • Secondary: Targets organics.

  • Tertiary: Nutrient removal.

Page 38: Unit Operations in Wastewater Treatment

• Overview of typical operations within a treatment plant.

Page 39: Primary and Secondary Treatment

• Focus on the suspended growth process in these treatments.

Page 40: Screening Process

• First operation in treatment focused on removing objects that may damage equipment.

• Types of screens included: coarse, medium, and fine.

Page 41: Primary Clarification/Sedimentation

• Process of gravity separation to remove suspended solids and organic material.

Page 42: Sludge Removal Techniques

• Use of scrapers in circular clarifiers.

Page 43: Biological Treatment Fundamentals

• Basics of enzymatic reactions involved in biological treatment.

• Environmental factors affecting microbial growth described.

Page 44: Activated Sludge Process (ASP)

• Description of ASP as an aerobic treatment method utilizing biomass to degrade organic matter.

Page 45: ASP Continued

• Further details on the functioning of activated sludge processes (ASPs).

Page 46: Trickling Filters

• Explanation of trickling filters as aerobic treatment systems for biodegrading organic matter.

Page 47: Trickling Filter Overview

• Summary and visual representation of the trickling filter process.

Page 48: Additional Trickling Filter Information

• Further information detailing the trickling filter treatment process.

Page 49: Anaerobic Fluidized Bed Process

• Combination of suspended and attached growth processes in a treatment method.

Page 50: Disinfection Process

• Describes the partial destruction of pathogens, key characteristics of ideal disinfectants.

Page 51: Disinfection Methods

• Overview of physical and chemical methods used for disinfection in water treatment.

Page 52: Mechanism of Disinfectant Action

• Describes how different disinfectants interact with pathogens and factors affecting their efficacy.

Page 53: Acknowledgement

• Closing slide thanking the audience.