Hydrochem Notes - Raw

What is the origin of water on Earth?

Water molecules were created during the formation of stars and brought to Earth by asteroids. Most of Earth's water is approximately 4.5 billion years old.

Why is water considered a limited resource?

Water is not renewable in the sense that it does not grow; it is a finite resource.

What happens to water's self-purifying ability?

Water is losing its self-purifying ability due to environmental changes.

What complicates the treatment of water from the Vltava River?

As water flows from the spring to Prague, it becomes contaminated by settlements, making purification increasingly complex.

What essential elements are removed during water purification?

Purification removes essential elements like calcium (Ca) and magnesium (Mg), which must be added back artificially.

What are the phases of water?

Solid, liquid, and gas.

What are the meteorological forms of water?

Precipitation, clouds/fog, and spindrift.

What types of water occurrence are there?

Groundwater, melt water, fresh water, sea water, etc.

What are some uses of water?

Tap, bottled, purified, potable, deionized, etc.

What are the features of water?

Soft (like rainwater), hard (like groundwater), heavy water, and tritiated water.

What is the significance of microorganisms in potable water?

Microorganisms should be dead in potable water, typically achieved through tap temperature, UV light, or chemicals like chlorine.

How does water hardness develop?

The longer water remains as groundwater, the more minerals it carries, increasing its hardness.

What is deionized water?

Deionized water is the clearest type of water, with ions removed, resulting in low or no conductivity.

What is the story behind bottled water?

Bottled water companies sell accessible water with a marketing story to convince consumers they will benefit from drinking it.

What type of bond is present in water molecules?

Water molecules have a polar covalent bond.

What is the significance of hydrogen bonds in water?

Hydrogen bonds between water molecules lead to anomalies like higher boiling points and changes in density when freezing.

Why does ice float on water?

Ice has a more organized structure than liquid water, creating more space for air particles, making it lighter.

What is lake stratification?

Lake stratification refers to the layering of water in lakes based on temperature and density differences.

What is the epilimnion in a lake?

The epilimnion is the upper layer of water that circulates due to wind and allows photosynthesis.

What is the metalimnion?

The metalimnion, or thermocline, is a stagnant layer with a dramatic temperature change that separates the epilimnion from the hypolimnion.

What occurs in the hypolimnion?

The hypolimnion is where respiration and decomposition occur.

What is positive stratification in lakes?

Positive stratification occurs in summer when the epilimnion is warmer and pushes down on the metalimnion.

What are amictic lakes?

Amictic lakes are perennially ice-covered and do not circulate.

What characterizes cold monomictic lakes?

Cold monomictic lakes never exceed 4°C and have one period of circulation at or below this temperature.

What is the circulation pattern of dimictic lakes?

Dimictic lakes circulate freely twice a year in spring and fall, with direct stratification in summer and inverse stratification in winter.

How do warm monomictic lakes behave?

Warm monomictic lakes circulate freely once a year in winter at or above 4°C and remain stably stratified for the rest of the year.

What are oligomictic lakes characterized by?

Oligomictic lakes are thermally stratified much of the year but cool sufficiently for rare circulation periods at irregular intervals; they are not ice-covered.

What defines polymictic lakes?

Polymictic lakes experience frequent or continuous periods of mixing per year and are not ice-covered.

How does climate change affect lake circulation?

Climate change leads to longer summers and shorter winters, resulting in less oxygen in warm water, which can harm biotic life and promote harmful algal blooms.

What is the impact of prolonged stratification in lakes due to climate change?

Prolonged stratification can drive toxic algal blooms, fish die-offs, and increased methane emissions, potentially lasting over a month longer under high emissions scenarios.

What happens to stratification periods in a warmer climate?

Stratification periods are expected to begin earlier and end later, accelerating lake deoxygenation and affecting nutrient mineralization and phosphorus release.

What is a halocline and chemocline?

A halocline or chemocline can lead to higher risks of anaerobic conditions in water, potentially creating environments with hydrogen sulfide.

What is the significance of water's high heat capacity?

Water's high heat capacity moderates climate by buffering temperature fluctuations and is a result of extensive hydrogen bonding.

What is the heat of vaporization of water?

Water has a high heat of vaporization of 40.65 kJ mol -1, due to hydrogen bonds requiring significant energy to break.

Why is water considered a universal solvent?

Water is a universal solvent because it can dissolve many substances, with hydrophilic substances mixing well and hydrophobic substances not mixing.

What is the solubility of mercury in water?

The solubility of mercury in water is 20-60 g/l, with an acceptable limit in drinking water being 1 g/l.

What factors influence solubility in water?

Solubility is influenced by water mineralization, temperature, and whether the reaction is endothermic or exothermic.

What is the effect of pouring acid into water?

Pouring acid into water is safe because water has a high heat capacity and can absorb heat, warming up slowly.

What is the compressibility of water?

Water has very low compressibility.

How is steam used in inventions?

Steam has high compressibility, allowing for inventions like the steam engine.

What is the relationship between water's salinity and freezing point?

Saltwater lowers the freezing point by about 2 °C and begins to freeze at −1.9 °C for normal salinity seawater.

What is the significance of water's miscibility?

Water is miscible with many liquids and forms a homogeneous liquid, being completely miscible with air.

What happens to the density of ice formed from saltwater?

Ice that forms from saltwater is essentially salt-free and has a density approximately equal to that of freshwater ice.

What is trophic mismatch in aquatic ecosystems?

Trophic mismatch occurs when phytoplankton grow sooner than the species that rely on them for food, disrupting the food chain.

What are the consequences of oxygen depletion in lakes?

Oxygen depletion can have fatal consequences for living organisms, as there is no thermal refuge due to low dissolved oxygen.

What is the impact of high wind speed and low air temperature on stratification?

High wind speed and low air temperature can lead to later stratification onset in lakes.

What are the forms of water?

Water has 19 forms: 16 crystalline and 3 amorphous.

What is the triple point of water?

The temperature and pressure at which solid, liquid, and gaseous water coexist in equilibrium, used to define the kelvin and indirectly the degree Celsius and Fahrenheit.

What is surface tension and how is it created?

Surface tension is the cohesive force created by water molecules at the surface forming stronger bonds, allowing some objects to float or walk on water.

What is the Mpemba Effect?

The phenomenon where hot water freezes faster than cold water under certain conditions.

What are the two protection levels for surface water?

Sensitive water bodies, which are sources of potable water or habitats for sensitive aquatic species, and normal water bodies.

What are some major global water problems?

Leeching and run-off from fertilizers (eutrophication), microplastics, and acidification.

What is the optimum temperature range for drinking water?

8-12°C, as colder water is harder to drink and can promote microorganism growth.

What does electrical conductivity indicate in water?

It indicates how well water can conduct electric current, reflecting the amount of dissolved ions in the water.

What is the significance of turbidity in water quality?

Turbidity measures suspended particles in water, which can affect light penetration and aquatic life.

What are the units used to measure turbidity?

NTU (Nephelometric Turbidity Units), FTU (Formazin Turbidity Units), or JTU (Jackson Turbidity Units), with NTU being the most common.

How does temperature affect electrical conductivity in water?

Changes in temperature can alter the conductivity of water, as warmer water typically has higher conductivity due to increased ion mobility.

What is the role of detergents in surface tension?

Detergents can reduce surface tension, impacting the behavior of water and its ability to support floating objects.

What is the significance of water's high compressibility?

High compressibility allows for inventions like the steam engine and affects how water behaves under pressure.

What are hydrophilic and hydrophobic substances?

Hydrophilic substances are attracted to water, while hydrophobic substances repel water; this distinction is crucial for biological processes.

What is the importance of lake circulation?

Lake circulation affects water temperature and density, which are vital for maintaining aquatic ecosystems and resources.

What is the Cobalt Platinum scale used for?

It is used to compare the color of water to determine if changes are due to natural or anthropogenic causes.

What is the euphotic layer in water?

The euphotic layer is the depth of water where enough sunlight penetrates for photosynthesis, typically measured by the Secchi disk.

What does a Secchi disk measure?

It measures water transparency by determining the depth at which the disk becomes invisible.

What are the sensory parameters of water quality?

Sensory parameters include temperature, taste, smell, color, and transparency, which can indicate pollution levels.

What can cause a rotten egg smell in water?

The presence of hydrogen sulfide (H2S) or certain species of cyanobacteria can cause a rotten egg smell.

What is the impact of electrical conductivity above 500 mS/m?

Aquatic life is negatively impacted as the water is considered very polluted at this conductivity level.

What is the cohesive nature of water molecules?

Water molecules are cohesive, meaning they tend to stick together, which contributes to surface tension and the spherical shape of water droplets.

What is Reduction Potential (redox potential)?

A measure of the tendency of a chemical species to acquire electrons and thereby be reduced.

What is the significance of Oxidation Reduction Potential (ORP) in aquatic environments?

It indicates the concentration of dissolved oxygen and the redox state of the water.

What ORP values indicate aerobic conditions?

Positive ORP values indicate aerobic (oxic) conditions with dissolved oxygen.

What ORP values indicate anaerobic conditions?

Negative ORP values indicate anaerobic conditions where methane and hydrogen sulfide are produced.

What is the pH range preferred by most aquatic organisms?

A pH range of 6-9 is preferred by most organisms.

What does a pH of 7 indicate?

A pH of 7 indicates a neutral solution.

What happens to pH levels in water bodies with cyanobacteria and algae during the day?

During the day, photosynthesis increases pH, making the water less acidic.

What are Total Dissolved Solids (TDS) and Total Suspended Solids (TSS)?

TDS are particles smaller than 2 micrometers, while TSS are larger than 2 micrometers.

How do suspended solids impact aquatic life?

They can obstruct gills, cover benthic life, and prevent photosynthesis.

What is the role of phosphorous in living organisms?

Phosphorous is essential for DNA, RNA, bones, teeth, and energy transfer (ADP).

What is the daily phosphorous requirement for humans?

Humans need approximately 0.75 grams of phosphorous per day.

What are common anthropogenic sources of phosphorous in water?

Inorganic sources include fertilizer application and sewage waste; organic sources include animal waste and decomposition.

What is a significant consequence of using artificial fertilizers?

PSDE - pollution, salination, desertification, and erosion

What is the difference between photic and aphotic layers in a lake?

Photic layers receive light and support photosynthesis, while aphotic layers do not receive light.

How can you differentiate between cyanobacteria and algae in water?

If water remains at the top layer after 20-30 minutes, it is cyanobacteria; if it spreads throughout, it is algae.

What is orthophosphate?

Orthophosphate is the form of phosphorous that can be readily used by organisms.

What is the phosphorous cycle missing compared to other biogeochemical cycles?

The phosphorous cycle lacks an atmospheric component.

What can cause a decrease in pH in aquatic environments?

Acidification, often caused by aluminum and other pollutants.

What is the impact of acid peat bogs on aquatic organisms?

They can create conditions favorable for specific organisms but may also lead to decreased pH.

How does the presence of phosphorous affect cyanobacteria and algae competition?

Cyanobacteria can obtain nitrogen from the air, allowing them to thrive even when nitrogen is limited, unlike algae.

What is a common smell associated with anaerobic conditions in water?

A 'rotten egg' smell, due to the production of hydrogen sulfide.

What is the impact of suspended solids on water temperature?

Suspended solids can absorb heat, affecting the water temperature.

What is the cyclical problem associated with artificial fertilizers?

The solution to problems caused by artificial fertilizers often involves applying more fertilizers, leading to further environmental degradation.

What are the four types of phosphorus (P) defined by environmental behavior or analytical methods?

Total P (TP), Soluble P (SP), Particulate P, and Bioavailable P.

What does Total P (TP) refer to in water samples?

All chemical forms of phosphorus present in a water sample.

What is Soluble P (SP)?

Dissolved phosphorus in water.

What constitutes Particulate P?

All material containing phosphorus, both inorganic and organic, that is captured on filters.

What is Bioavailable P and why is it important?

The portion of Total P available to algae as a nutrient; it includes all dissolved P and the part of particulate P that can be used by plants or microbes.

What environmental impact did mining on the Island of Nauru have?

All phosphorus from guano was mined, which took thousands of years to create, in just a few decades.

How does urban drainage affect pollution by phosphorus, as seen in the case study of Pribram?

The wastewater treatment plant increases water discharge and phosphorus levels in local water bodies, leading to environmental and economic consequences.

What are the potential consequences of increased phosphorus in water bodies for downstream communities?

Higher costs for water treatment, environmental degradation, and increased eutrophication affecting wildlife.

What is the definition of Population Equivalent in wastewater treatment?

The actual waste produced by a person, including not just excrement but also materials like garbage disposal.