Pramita Flashcards

Question

Modeling BOD as first order reaction

Answer 1

BOD=L(1-e^-kt) Where k20 is the value of k at 20 o C and is an empirical constant. theta= 1.135 T => is between 4 - 20 oC; theta= 1.056 T => is between 20 - 30 o C

Answer 2

a. Organic matter which can be biologically oxidized is called biologically active b. Organic matter which cannot be oxidized biologically is called biologically inactive.

Answer 3

oxygen required for the complete oxidation of both biodegradable and non-biodegradable matter. ● COD is a measure of the oxygen equivalent of the organic matter content of a sample that is susceptible to oxidation by a strong chemical oxidant.

Answer 4

milligrams per liter (mg/L), which indicates the mass of oxygen consumed per liter of solution.

Answer 5

● Bacteria ● Virus ● Parasites ● Algae

Answer 6

Encompasses not only the pollution of the water itself but also the impact on the entire aquatic ecosystem. This includes the water, the organisms living in it (fish, plants, microorganisms), and the surrounding environment. Water pollution primarily focuses on the quality of the water itself,

Answer 7

which occurs when the environment becomes enriched with nutrients, increasing the amount of plant and algae growth to estuaries and coastal waters.

Answer 8

Nutrients are chemical elements found in the food that plants and animals need to grow and survive. Although there are many kinds of nutrients, two of the most important and abundant are nitrogen and phosphorus.

Answer 9

● Fertilizer Runoff or Leaching : ● Algae Growth Due to Presence of Nutrients : ● Bacteria Use Oxygen to Break Down the Algae : ● Oxygen Depletion (Hypoxia) Due to Lack of Oxygen

Answer 10

Oligotrophic waters are nutrient-poor, with low concentrations of nitrogen and phosphorus. The water is usually clear with high oxygen levels, particularly in deeper layers. These ecosystems typically support a variety of fish species, TP: 5-10 µg/L TN: 250-600 µg/L

Answer 11

Examples: High-altitude mountain lakes and deep, clear lakes are often oligotrophic.

Answer 12

moderate levels of nutrients, leading to an intermediate level of biological productivity. Algal growth is more noticeable. Oxygen levels can begin to decrease, particularly during warm months or in deeper layers example Many natural lakes and reservoirs that receive moderate nutrient inputs from surrounding land use may be classified as moderately eutrophic. TP: 10-30 µg/L TN: 500-1100 µg/L

Answer 13

water is often green colour due to frequent algal blooms. Oxygen levels in deeper waters may become depleted (hypoxic), especially during periods of high algal activity and subsequent decay. This can lead to the death of fish and other aquatic organisms that depend on oxygen. example - receive high nutrient inputs from agricultural runoff, urban stormwater, or wastewater discharges are often eutrophic. TP: 30-100 µg/L TN: 1000-2000 µg/L

Answer 14

excessive algal blooms, often leading to severe ecological and water quality issues. turbid and can have a strong, unpleasant odor These conditions can result in fish kills, loss of biodiversity, and the proliferation of harmful algal blooms (HABs), which can produce toxins harmful to both aquatic life and humans. TP: >100 µg/L TN: >2000 µg/L

Answer 15

● The overgrowth of algae consumes oxygen and blocks sunlight from underwater plants. ● When the algae eventually dies, the oxygen in the water is consumed. The lack of oxygen makes it impossible for aquatic life to survive. ● The dead zone is in the United States – about 6,500 square miles – is in the Gulf of Mexico and occurs every summer as a result of nutrient pollution from the Mississippi River Basin. located in thelower part of the Black Sea, forms naturally. Oxygenated water is confined to the upper layer of the sea, where the Black Sea's waters interact with those of the Mediterranean Sea.

Answer 16

common term used for a harmful algal bloom This bloom, like many HABs, is caused by microscopic algae that produce toxins that kill fish and make shellfish dangerous to eat. The toxins may also make the surrounding air difficult to breathe. As the name suggests, the bloom of algae often turns the water red.

Answer 17

● At the surface, photosynthesis consumes CO2 , so CO2 levels remain relatively low. In addition, organisms that utilize carbonate in their shells are common near the surface, further reducing the amount of dissolved CO2 . ● In deeper water, CO2 concentration increases as respiration exceeds photosynthesis, and decomposition of organic matter adds additional CO2 to the water.

Answer 18

X-Axis (pH): The pH values ranging typically from around 2 to 12. Y-Axis (Concentration or Fraction): The relative concentration (or fraction) of each species. Curves: The curve for H₂CO₃ (carbonic acid) is dominant at lower pH values. The curve for HCO₃⁻ (bicarbonate) peaks at a mid-range pH (around 6-9). The curve for CO₃²⁻ (carbonate) becomes more significant at higher pH levels (above 10).

Answer 19

As the pH drops (moving toward the acidic side), more carbon dioxide (CO₂) remains dissolved in water instead of being converted into other forms like bicarbonate (HCO₃⁻) or carbonate (CO₃²⁻). A decrease in pH leads to a reduction in carbonate ion (CO₃²⁻)This reduction in carbonate is particularly concerning for marine organisms, such as corals and shellfish, that rely on carbonate ions to build their calcium carbonate (CaCO₃) skeletons and shells. As pH decreases, the ocean's buffering capacity weakens. This means that further increases in atmospheric CO₂ will cause larger and faster changes in oceanic pCO₂ (partial pressure of CO₂), accelerating acidification.

Answer 20

increase by 30%

Answer 21

Waterborne Pathogens:E. coli and salmonella, which can cause severe diarrhea, vomiting, Long-Term:Contaminants conditions such as cancer, neurological disorders, reproductive issues, and developmental abnormalities. Impact On The Fishing Industry: Decreases in fish stocks Impact On Agricultural Industries contaminated water used for irrigation which can lead to reduced agricultural productivity and biomagnification Cost Of Water Treatment & Restoration Impact On Tourism & Recreational Activities:

Answer 22

see the plot

Answer 23

Benzene, Toluene and xylene

Answer 24

2⁄3 of CO, 1⁄2 of hydrocarbons and nitrous oxides

Answer 25

Petroleum refineries, paper mill, sugar mill, rubber manufacturing plants are responsible for 1⁄5 th of the air pollution

Answer 26

CPCB method: AQI range 0-500 transforms the weighted values of individual air pollution related parameters (eg: pollutant concentration) into a single number or a set of numbers.

Answer 27

Oil is a liquid fossil fuel that is formed from the remains of marine microorganisms deposited on the seafloor. ● After millions of years the deposits end up in rock and sediment where oil is trapped in small spaces. It can be extracted by large drilling platforms. Natural gas is a gaseous fossil fuel that is versatile, abundant and relatively clean compared to coal and oil. ● Natural gas is formed from the remains of marine microorganisms.

Answer 28

the Gulf War of 1991.

Answer 29

Natural gas has now overtaken coal in developed countries.

Answer 30

term "Peak Oil" refers to the point at which maximum production is reached. After the peak, oil production enters a permanent decline, and the availability of cheap and easily accessible oil starts to dwindle.

Answer 31

The Suess effect refers to the decrease in the ratio of carbon-14 to carbon-12 in the atmosphere due to the combustion of fossil fuels. Evidence for the anthropogenic nature of increasing CO2 during the past 200 years.

Answer 32

Over time, 14C, a radioactive isotope of carbon, decays to nitrogen-14 because of its half-life of about 5,730 years. Fossil fuels, therefore, contain almost no 14𝐶 as they are far older than the half-life of the isotope. When fossil fuels are burned, they release large amounts of 12C (and small amounts of 13C), but virtually no 14 C.

Answer 33

Most of the nuclear explosions and 14C production took place in the Northern Hemisphere.

Answer 34

The Haber-Bosch process, which converts hydrogen and nitrogen to ammonia.

Answer 35

using medium temperature (~500oC) very high pressure (~250 atmospheres) a catalyst (a porous iron catalyst, Fe3O4). ● Osmium is a much better catalyst for the reaction but is very expensive.

Answer 36

increased in food production by 7∼8 times since the beginning of the 20th century, during which the Earth’s population has increased by 4.2 times.

Answer 37

Agricultural industries are the major users of ammonia. Ammonia is a very valuable source of nitrogen that is essential for plant growth. Ammonia and urea are used as a source of protein in livestock feeds for ruminating animals such as cattle, sheep and goats. used as an anti-fungal agent on certain fruits and as preservative for the storage of high-moisture corn.

Answer 38

In addition to the fossil fuel energy used to drive the reaction, the Haber-Bosch process uses H2 sourced from steam methane reforming (CH4 + 2H2O →4H2 + CO2) or coal gasification(C + 2H2O →2H2 + CO2), thereby contributing enormously to anthropogenic CO2 emissions. ● It is estimated that 1.5% of all anthropogenic CO2 emissions (420 Mt year−1) are linked to the Haber-Bosch process

Answer 39

It represents the total amount of energy a star, such as the Sun, produces and radiates into space in the form of electromagnetic radiation.

Answer 40

It is defined as the amount of solar energy per unit area on a sphere centered at the Sun. Solar Constant (S): The solar constant represents the solar energy density at the mean distance of Earth from the Sun, approximately 1.5×10-11m.

Answer 41

Solar energy incident=(Solar constant)×(Shadow Area) Since the shadow area of Earth is a circle, the area can be expressed as: Shadow Area =𝜋𝑅𝐸^2

Answer 42

reflected/incoming sunlight

Answer 43

solar energy incident - reflected solar flux

Answer 44

Solar radiation+Infrared radiation from the atmosphere=Infrared radiation emitted by Earth’s surface