9: Water - the Ultimate Green Substance
- Page ID
- 285339
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\(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)“Although the wastewater from Mexico City that the farmers in Mexico’s Mezquital valley use for irrigating their crops is a foul concoction that sometimes causes boils and other ailments to those who contact it, the farmers that use it are concerned that a new drainage and treatment system may remove nutrients and enable recycle of water back to the city depriving them of the irrigation water upon which their livelihoods depend.
- 9.1: H₂O - Simple Formula, Remarkable Molecule
- This page highlights the critical importance of water in the hydrosphere for the environment and living organisms, discussing water pollution, treatment processes, prevention, and recycling. It outlines water's unique properties—such as high heat capacity and polarity—that stabilize temperatures and support life. The chapter also emphasizes water's role as a solvent and in nutrient transport, contributing to ecological balance.
- 9.2: Occurrence, Availability , and Utilization of Water on Earth
- This page discusses Earth's water, emphasizing that 97.6% is saltwater and only a tiny fraction is freshwater available in rivers. It highlights the importance of surface water, groundwater, and desalination, especially in arid areas. Water distribution is uneven, influencing drought-prone regions. The role of watersheds in water quality and management is significant. Human activities, such as dam construction, have altered rivers and ecosystems.
- 9.3: Water Chemistry
- This page discusses the unique chemical and biochemical properties of water, particularly in seasonal stratification, where a warm, oxygen-rich layer exists above a cold, anoxic layer. Photosynthesis influences organic matter and oxygen depletion, and microorganisms affect oxidation-reduction processes, impacting water quality.
- 9.4: Water Pollution
- This page discusses water pollution, detailing its impact on water quality, aquatic life, and oxygen levels. Key pollutants include sediments, sewage, nutrients causing eutrophication, heavy metals, industrial chemicals, pesticides, pharmaceuticals, and radionuclides. The interplay of these factors highlights the need for continuous research and management to safeguard water resources and ecosystems.
- 9.5: Greening of Water - Purification Before Use
- This page discusses the pollution of the San Marcos/Cazones River in Mexico, highlighting the effects of untreated sewage. It details essential water treatment processes for various uses, including aeration, sedimentation, filtration, hardness removal, and disinfection, with ozone being preferred for its effectiveness and safety.
- 9.6: Wastewater Treatment
- This page explains municipal wastewater treatment, focusing on its three main processes: primary (solid removal), secondary (biodegradable organic matter reduction using microorganisms), and tertiary (effluent refinement). It highlights the activated sludge process, where air keeps microbes suspended for biodegradation, and notes that sewage sludge is either recycled or anaerobically digested to generate methane for fuel.
- 9.7: Advanced Wastewater Treatment and Recycling
- This page discusses advanced water treatment techniques applied to secondary wastewater treatment to reduce excess BOD and algal nutrients, thereby alleviating environmental concerns. Despite some public resistance to treated sewage, it remains a viable source of water, especially compared to seawater. Key processes involved include filtration, reverse osmosis, and UV irradiation.
- 9.8: The Many Uses of Water
- This page discusses water's versatility and sustainability, highlighting its essential role in technologies such as steam generation and district heating. Water's properties as a solvent are valuable in industrial processes. Despite the environmental benefits of waterpower, challenges like river damming and clean water access persist. Innovative technologies are being developed to harness water's energy while preserving natural water flows.
- 9.9: Hot Water - Pressurized Subcritical Water
- This page discusses supercritical water, which, above 374.4 °C and high pressure, exhibits unique behaviors, particularly between 100 °C and 205 °C, where it mimics a methanol mixture. Its decreased dielectric constant enhances its solvent properties for organic materials, making it effective in extracting substances from biomass and contaminated sites.
- 9.10: Supercritical Water
- This page discusses supercritical water, which exists at temperatures over 374.4°C and pressures above 217.7 atm, losing distinct liquid properties. It serves as a versatile solvent for both organic and polar materials, with applications in chemical processes like organic synthesis and waste treatment. Its ability to dissolve gases, such as oxygen, improves its effectiveness as an oxidant for degrading organic wastes.
- Literature Cited
- This page lists two publications by Stanley E. Manahan: "Environmental Science and Technology: A Sustainable Approach to Green Science and Technology" (2006) and "Water Chemistry: Green Science and Technology of Nature’s Most Renewable Resource" (2010). Both emphasize sustainability in environmental practices and water chemistry, published by Taylor & Francis/CRC Press in Boca Raton, FL.
- Questions and Problems
- This page presents inquiry-based questions about environmental science and chemistry, focusing on topics like Hetch-Hetchy Valley restoration, Mulholland's history, acid-base behavior, fertilizer pollution, and water quality. It explores wastewater irrigation, water characteristics, and historical water power usage, aiming to enhance understanding of water's significance and the environmental consequences of human activities.
- Supplementary References
- This page lists reference books on water science, treatment, and ecology from various publishers, highlighting notable works on industrial water treatment, water chemistry, limnology, and freshwater ecology. It mentions various authors and includes titles relevant to environmental scientists and water management professionals, reflecting the significance of water as a natural resource.