Day-643 | Daily MCQs | UPSC Prelims | ENVIRONMENT

Answer. B
Explanation:
Root Zone Treatment Systems are planted filter-beds consisting of sand/gravel/soil. The system uses a natural way to effectively treat domestic & industrial effluents.
The term ‘Root Zone’ encompasses the life interactions of various species of bacteria, the roots of reed plants, soil, sun and water. They are also known as constructed wetlands or subsurface flow systems. In this system, these plants conduct oxygen through their stems into their root systems and create favourable conditions for the growth of bacteria. The wastewater flow through the root zone in a horizontal or vertical way where the organic pollutants are decomposed biochemically by the bacteria present in the rhizosphere of root plants.
The filter media are selected carefully to provide favourable conditions for both plants & bacterial growth and to avoid clogging.
Organic pollutants are removed drastically from wastewater and are reduced to their elemental forms.

Answer. B
Explanation: Coal gasification means the complete conversion of coal into gas using heterogeneous gas solid reactions. The main process is the reaction of the carbon of coal with steam, at pressures below 10 MPa and temperatures above 750°C, to form a “synthesis gas” containing mainly CO and H2 with smaller amounts of CO2 and CH4, depending on process conditions.
Coal gasification is considered a cleaner option as compared to burning of coal and has diversified use of coal in other forms of energy. It is a more efficient way to generate electricity compared to conventional coal-fired power plants. Coal gasification is said to have greater efficiency than conventional coal-burning because it can effectively use the gases twice: the coal gases are first cleansed of impurities and fired in a turbine to generate electricity. Then, the exhaust heat from the gas turbine can be captured and used to generate steam for a steam turbine-generator.
Statement 1 is correct: The combustible gases generated from coal gasification consist of hydrogen, carbon monoxide, carbon dioxide and methane. These are the constituents of the syngas produced through coal gasification.
Statement 2 is incorrect: Carbon monoxide can not be used in internal combustion engines but other combustible gases produced in the process of coal gasification, viz. CO2, CH4 and H2 can be used in internal combustion engines.
In internal combustion engines, hydrogen, methane and mixtures of hydrogen and methane offer a high potential to reduce emissions.
Statement 3 is correct: Syngas can be used to produce Gaseous Fuels such as Hydrogen, Substitute Natural Gas (SNG or Methane), Di-Methyl Ether (DME), Liquid Fuels such as Methanol, Ethanol, Synthetic diesel and Chemical and Petrochemicals like Methanol derivatives, Olefins, Propylene, Mono-Ethylene Glycol (MEG), nitrogenous fertilizers including Ammonia, DRI, Industrial Chemicals along with Power Generation.

Answer. C
Explanation: Options 1, 2 and 3 are correct.
Declaration – Focus/Motive – India is a part or not
Glasgow Leaders’ Declaration (UNFCCC COP26 in 2021) – Under the Glasgow Declaration, the signatory world leaders committed to work collectively to halt, and reverse, forest loss and land degradation by 2030 while delivering sustainable development and promoting an inclusive rural transformation. – No
Seoul Declaration (adopted at the XV World Forestry Congress in 2022) – Tripling investments for restoring degraded land by 2030 – No
New York Declaration (Spurred by the UN Secretary General’s Climate Summit in September 2014) – Halving the loss of natural forests by 2020 and striving to end it by 2030. – No
Beijing Declaration and Platform for Action (adopted by the UN at the 1995 IV World Conference on Women) – Principles governing gender equality Agenda for women empowerment – Yes

Answer. D
Explanation:
The Angel shark (Squatina Squatina) is a shark species inhabiting the shallow coastal waters of the Mediterranean Sea and Eastern Atlantic. It is a bottom-dwelling species and can often be seen resting on the sand or muddy sea floor during daylight hours.
Angel sharks have a distinct flattened body that resembles a guitar. They are opportunistic predators, feeding on a variety of prey, including bony fishes, crustaceans, and cephalopods.
Angel sharks have some other names – Monkfish, Angel Fish, Sand Devil, Fiddle Fish, and Sea Devil. They have flattened bodies and wingspan-like tails, making them look like rays – hence the name ‘angel.’ They are camouflaged to blend in with the ocean floor and ambush their prey from below. They display nocturnal behaviour.
They are listed as “Critically Endangered” by the International Union for Conservation of Nature (IUCN), with only a few hundred individuals remaining in the wild.
The 14th Conference of the Parties to the Convention on the Conservation of Migratory Species of Wild Animals (CMS COP14) on February 2024 adopted the Single Species Action Plan for conservation of the Hawksbill Turtle (Eretmochelys imbricata) in South-East Asia and the Western Pacific Ocean Region.

Answer. B
Explanation:
Statement 1 is correct: Perovskites are useful in the manufacturing of nanostructured solar cells. A perovskite solar cell is a type of solar cell, which includes a perovskite structured compound, most commonly a hybrid organic-inorganic lead or tin halide-based material, as the light-harvesting active layer.
● In material science, the word ‘perovskite’ refers to a certain crystal structure in which the atoms are arranged. It is in the form of ABX3. For example, Calcium titanium oxide, or CaTiO3 is a perovskite. Solar cells made with perovskite material are highly efficient at converting light into electricity. However, they are unstable and degenerate when exposed to light.
Statement 2 is incorrect: Lead (Pb) and other materials in PSCs are ecotoxic and biotoxic. Due to improper disposal of the decommissioned devices, serious heavy metal Pb and solid waste pollution incidents may occur.
Statement 3 is correct: Perovskite materials can be recycled.

● Perovskite materials are usually cheap to produce and relatively simple to manufacture.
● They possess intrinsic properties like broad absorption spectrum, fast charge separation, long transport distance of electrons and holes, long carrier separation lifetime, and more, that make them very promising materials for solid-state solar cells.
● In nature, perovskites are primarily found as oxides, with the majority being silicates (such as bridgmanite minerals), but they also exist as fluorides, chlorides, hydroxides, arsenides, and intermetallic compounds.