UGC NTA NET/JRF Exam, Environmental Sciences, June-2020

Concentrations of gaseous pollutants is sometimes given in units of mass per volume. and at other times in ppb or ppm. ppb (v) is parts per billion by volume (i.e., volume of gaseous pollutant per 10⁹ volumes of ambient air). g/m² is micrograms of gaseous pollutant per cubic meter of ambient air.
The conversion assumes an ambient pressure of 1 atmosphere and a temperature of 25 degrees Celsius.
Hence 80 ppb = 80 × 1.88 = 150.4 µg/m³.

From equation,
Lp = 20 log10 p + 94 [dB(re 2.0 × 10-5 pa)]
Lp = 20 log10 (100) + 94 = 40 + 94 = 134.
[dB(re 2.0 × 10-5 pa)]

A-weighting is the most commonly used of a family of curves defined in the International standard IEC 61672:2003 and various national standards relating to the measurement of sound pressure level.

The curves were originally defined for use at different average sound levels, but A-weighting, though originally intended only for the measurement of low-level sounds (around 40 phon), is now commonly used for the measurement of environmental noise and industrial noise.From graph we see that, In the 'A' weighting network used in noise measurements, sounds of 1000 Hz frequencies would require the least correction

Frankia is a genus of nitrogen-fixing, bacteria that live in symbiosis with actinorhizal plants, similar to the Rhizobium bacteria found in the root nodules of legumes in the family Fabaceae.

Frankia also initiate the forming of root nodules. Most Frankia strains are specific to different plant species.

The bacteria are filamentous and convert atmospheric nitrogen into ammonia via the enzyme nitrogenase, a process known as nitrogen fixation.

Frankia can resist low concentration of heavy metals such as, Cu, Co, and Zn. Frankia may be an advantage for degraded soil. Frankia is a gram-positive Bacteria that is found on the roots of plants.

The fact that Frankia is grampositive means that the bacteria is made up of thick cell walls made out of protein called peptidologlycan. This helps with the resistance of the heavy metals that may be in the degraded soil.

The Basel Convention is an international treaty drafted in 1989 in response to public outcries against the indiscriminate dumping of hazardous waste.

The convention went into force in 1992. It intends to reduce the movement of hazardous waste between nations and to prevent the "trade" in waste that resulted in developed countries' dumping hazardous waste in developing countries.

Under the convention, the movement of hazardous waste can take place only with written notification by the exporting state to the importing state and the approval of the importing state.

Vermicomposting, the conversion of organic waste into vermicompost, is mediated by the combined action of earthworms and microorganisms.

Soil is not required in vermicomposting as the organic matter acts as both the substrate and food, and therefore only epigeic earthworms can be used in the process.

Several earthworm species have been evaluated for their potential use in vermicomposting, including Eisenia fetida (Savigny), Eisenia andrei (Bouché), Dendrobaena veneta (Rosa), Dendrobaena hortensis (Michaelsen) Eudrilus eugeniae (Kinberg), and Perionyx excavatus (Perrier).

The species most commonly used in vermicomposting and vermiculture facilities worldwide are Eisenia andrei and Eisenia fetida.

Pyrolysis processes can be categorized as slow pyrolysis or fast pyrolysis. Fast pyrolysis is currently the most widely used pyrolysis system. Slow pyrolysis takes several hours to complete and results in biochar as the main product.

On the other hand, fast pyrolysis yields 60% bio-oil and takes seconds for complete pyrolysis. In addition, it gives 20% biochar and 20% syngas.

Anaerobic digestion (AD) is a unique process where different microbial species decompose organic materials in the absence of oxygen.

Anaerobic digestion is widely used for treating various waste streams such as municipal sludge or animal waste. For treating microalgae using anaerobic digestion, the digesting materials can be either raw algal biomass or the residue after oil extracted from the biomass.

CH₄ and CO₂ are the dominant products of anaerobic digestion of municipal solid waste. Methane produced from anaerobic digestion can be used as a heat source or for electricity generation.

Ecological engineering may be based on one or more of the following four classes of ecotechnology:

1. Ecosystems are used to reduce or solve a pollution problem that otherwise would be (more) harmful to other ecosystems. A typical example is the use of wetlands for wastewater treatment.

2. Ecosystems arc imitated or copied to reduce or solve a pollution problem, leading to constructed ecosystems. Examples are fishponds and constructed wetlands for treating wastewater or diffuse pollution sources.

3. The recovery of ecosystems after significant disturbances. Examples are coal mine reclamation and restoration of lakes and rivers.

4. The use of ecosystems for the benefit of humanity without destroying the ecological balance (i.e., the utilization of ecosystems on an ecologically sound basis).

Typical examples are the use of integrated agriculture and development of organic agriculture; this type of ecotechnology finds wide application in the ecological management of renewable resources.

Ahead of proposed auction of mines, including those bearing iron ore and limestone, the government has made it clear that firms having valid environment clearances (EC) for their projects are not required to obtain fresh green nod at the time of renewal of the leases. The maximum period of validity of the EC being given for mining lease for 30 years.