Unit Processes of Water and Wastewater Treatment

Chapter 10 Water Softening

10.1 Hard Waters

10.2 Types of Hardness

10.3 Plant Types for Hardness Removal

10.4 The Equivalent CaCO3 Concentration

10.5 Softening of Calcium Hardness

10.6 Softening of Magnesium Hardness

10.7 Lime-Soda Process

10.7.1 Calculation of Stoichiometric Lime Required in the Lime-Soda Process

10.7.2 Key to Understanding Subscripts

10.7.3 Calculation of Stoichiometric Soda Ash Required

10.7.4 Calculation of Solids Produced

10.8 Order of Removal

10.9 Role of CO2 in Removal

10.10 Excess Lime Treatment and Optimum Operational pH

10.11 Summary of Chemical Requirements and Solids Produced

10.12 Sludge Volume Production

10.13 Chemical Species in the Treated Water

10.13.1 Limits of Technology

10.13.2 Concentration of Ca2+

10.13.3 Concentration of Mg2+

10.13.4 Concentration of HCO-

10.13.5 Concentration of CO^-

10.13.6 Concentration of Na+

10.14 Relationships of the Fractional Removals

10.15 Notes on Equivalent Masses

10.16 Typical Design Parameters and Criteria

10.17 Split Treatment

10.18 Use of Alkalinity in Water Softening Calculations Glossary

Chapter 11 Water Stabilization

11.1 Carbonate Equilibria

11.1.1 Ionic Strength

11.1.2 Equilibrium Constant as a Function of Temperature

11.1.3 AH298's for Pertinent Chemical Reactions of the Carbonate Equilibria

11.2 Criteria for Water Stability at Normal Conditions

11.2.1 Saturation pH and the Langelier Index

11.2.2 Determination of (Ca2+j

11.2.3 Total Alkalinity as Calcium Carbonate

11.2.4 Precipitation Potential

11.2.5 Determination of Percent Blocking Potential of Pipes

11.3 Recarbonation of Softened Water Glossary

Symbols Problems Bibliography

Chapter 12 Coagulation

12.1 Colloid Behavior

12.2 Zeta Potential

12.3 Colloid Destabilization

12.4 Coagulation Process

12.4.1 Coagulants for the Coagulation Process

12.4.2 Coagulant Aids

12.4.3 Rapid Mix for Complete Coagulation

12.4.4 The Jar Test

12.5 Chemical Reactions of Alum

12.5.1 Determination of the Optimum pH

12.6 Chemical Reactions of the Ferrous Ion 12.6.1 Determination of the Optimum pH

12.7 Chemical Reactions of the Ferric Ion 12.7.1 Determination of the Optimum pH

12.8 Jar Tests for Optimum pH Determination

12.9 Chemical Requirements

12.9.1 Chemical Requirements in Alum Coagulation Treatment

12.9.2 Key to Understanding Subscripts

12.9.3 Chemical Requirements in Ferrous Coagulation Treatment

12.9.4 Chemical Requirements in Ferric Coagulation Treatment

12.10 Chemical Requirements for pH Adjustments

12.11 Alkalinity and Acidity Expressed as CaCO3

12.12 Sludge Production Glossary

Symbols Problems Bibliography

Chapter 13 Removal of Iron and Manganese by Chemical Precipitation

13.1 Natural Occurrences of Iron and Manganese

13.2 Modes of Removal of Iron and Manganese

13.3 Chemical Reactions of the Ferrous and the Ferric Ions 13.3.1 Practical Optimum pH Range for the Removal of Ferrous and Ferric

13.4 Chemical Reactions of the Manganous Ion [Mn(II)]

13.4.1 Determination of the Optimum pH

13.4.2 Practical Optimum pH Range for the Removal of Manganese

13.5 Oxidation of Iron and Manganese to Reduce Precipitation pH

13.6 Unit Operations for Iron and Manganese Removal

13.6.1 High pH Range

13.6.2 Low pH Range

13.7 Chemical Requirements

13.7.1 Requirements in the Ferrous Reactions

13.7.2 Requirements in the Manganous Reactions

13.8 Alkalinity Expressed in OH- and Acidity Expressed in H+

13.9 Chemical Requirements for pH Adjustments

13.10 Sludge Production Glossary

Symbols Problems Bibliography

Chapter 14 Removal of Phosphorus by Chemical Precipitation

14.1 Natural Occurrence of Phosphorus

14.2 Modes of Phosphorus Removal

14.3 Chemical Reaction of the Phosphate Ion with Alum 14.3.1 Determination of the Optimum pH Range

14.4 Chemical Reaction of the Phosphate Ion with Lime 14.4.1 Determination of the Optimum pH

and the Optimum pH Range

14.5 Chemical Reaction of the Phosphate Ion with the Ferric Salts 14.5.1 Determination of the Optimum pH

and the Optimum pH Range

14.6 Comments on the Optimum pH Ranges

14.7 Effect of the Ksp's on the Precipitation of Phosphorus

14.8 Unit Operations for Phosphorus Removal

14.9 Chemical Requirements

14.10 Sludge Production Glossary

Symbols Problems Bibliography

Chapter 15 Removal of Nitrogen by Nitrification-Denitrification

15.1 Natural Occurrence of Nitrogen

15.2 To Remove or Not to Remove Nitrogen

15.3 Microbial Thermodynamics

15.3.1 Enthalpy and Entropy

15.3.2 Free Energy

15.4 Oxidation-Reduction Reactions of Nitrogen Foods 15.4.1 Criterion for Spontaneous Process

15.5 Modes of Nitrogen Removal

15.6 Chemical Reactions in Nitrogen Removal

15.6.1 Nitrification: Nitrosomonas Stage

15.6.2 Nitrification: Nitrobacter Stage

15.6.3 Overall Nitrification

15.6.4 Denitrification: Heterotrophic Side Reaction Stage

15.6.5 Denitrification: Normal Anoxic Stage

15.6.6 Denitrification: NO2-Reduction Side Reaction Stage

15.7 Total Effluent Nitrogen 15.7.1 Units of Cell Yields

15.8 Carbon Requirements for Denitrification

15.9 Alkalinity Production and Associated Carbon Requirement

15.10 Reaction Kinetics

15.10.1 Kinetics of Growth and Food Utilization

15.10.2 Material Balance around the Activated Sludge Process

15.10.3 Nitrification Kinetics

15.10.4 Denitrification Kinetics

15.10.5 Carbon Kinetics

15.10.6 Reactor Sizing

15.10.7 Determination of Kinetic Constants Glossary

Symbols Problems Bibliography

Chapter 16 Ion Exchange

16.1 Ion Exchange Reactions

16.2 Unit Operations of Ion Exchange

16.3 Sodium, Hydrogen Cycle, and Regeneration

16.4 Production of "Pure Water"

16.5 Active or Exchange Zone

16.6 Design of Ion Exchangers

16.6.1 Quantity of Exchange Materials

16.6.2 Quantity of Regenerant

16.6.3 Wastewater Production

16.7 Head Losses in Ion Exchangers Glossary

Symbols Problems Bibliography

Chapter 17 Disinfection

17.1 Methods of Disinfection and Disinfectant Agents Used

17.2 Factors Affecting Disinfection

17.2.1 Time of Contact and Intensity of Disinfectant

17.2.2 Age of the Microorganism

17.2.3 Nature of the Suspending Fluid

17.2.4 Effect of Temperature

17.3 Other Disinfection Formulas

17.4 Chlorine Disinfectants

17.4.1 Chlorine Chemistry

17.4.2 Design of Chlorination Unit Operations Facilities

17.5 Dechlorination

17.5.1 Chemical Reactions Using Sulfur Dechlorinating Agents

17.5.2 Chemical Reactions Using Activated Carbon

17.5.3 Effect of Dechlorinated Effluents on Dissolved Oxygen of Receiving Streams

17.5.4 Unit Operations in Dechlorination

17.6 Disinfection Using Ozone

17.6.1 Unit Operations in Ozonation

17.7 Disinfection Using Ultraviolet Light 17.7.1 Unit Operations in UV Disinfection

Glossary Symbols Problems Bibliography

Solar Panel Basics

Solar Panel Basics

Global warming is a huge problem which will significantly affect every country in the world. Many people all over the world are trying to do whatever they can to help combat the effects of global warming. One of the ways that people can fight global warming is to reduce their dependence on non-renewable energy sources like oil and petroleum based products.

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