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UGC NET Environmental Science Unit-VII: Solid and Hazardous Waste Management Flashcards
51 question-and-answer cards covering Unit-VII: Solid and Hazardous Waste Management as it is examined in UGC NET Environmental Science. 24 of them are printed below, taken from across the deck — no signup, no paywall on the preview.
24 sample cards from the Unit-VII: Solid and Hazardous Waste Management deck
Sampled from the end of the deck, so these are different cards from the ones shown on the syllabus page.
What is materials recovery facility (MRF)?
A facility where commingled or source-separated recyclables are received, sorted, processed, and baled for sale to markets.
What mechanical processing techniques are used to recover materials from waste?
Size reduction (shredding/grinding), size separation (screening/trommels), density separation (air classification), magnetic separation (ferrous), and eddy-current separation (non-ferrous).
What is air classification in waste processing?
A density-based separation that uses an air stream to separate light (paper, plastic) from heavy (glass, metal) fractions of shredded waste.
How does magnetic separation work in waste recovery?
A magnetic field (e.g., overband or drum magnet) extracts ferrous metals from the mixed waste stream.
What is composting?
The aerobic, controlled biological decomposition of the organic fraction of solid waste by microorganisms into a stable, humus-like product (compost).
What are the optimum conditions (C/N, moisture, temperature, pH) for aerobic composting?
C/N ratio ~25–30:1, moisture 50–60%, thermophilic temperature 55–60°C, and pH ~6.5–8.0.
What is vermicomposting?
Composting using earthworms (e.g., Eisenia fetida) to break down organic waste into nutrient-rich worm castings (vermicompost), operating at mesophilic temperatures.
What is anaerobic digestion of organic waste?
Biological decomposition of organic matter by microbes in the absence of oxygen, producing biogas (CH4 + CO2) and a digestate, with energy recovery.
What is refuse-derived fuel (RDF)?
A fuel produced by shredding, drying, and processing the combustible (high-calorific) fraction of MSW into pellets or fluff for use in incinerators/boilers.
What is incineration of solid waste?
Controlled high-temperature (≈850–1000°C) combustion that reduces waste volume by 80–90% and mass by ~70%, with optional energy (waste-to-energy) recovery.
What is pyrolysis in waste processing?
Thermal decomposition of organic waste at 400–800°C in the absence of oxygen, yielding char (solid), pyrolytic oil (liquid), and syngas (gas).
How does gasification differ from incineration and pyrolysis?
Gasification is partial oxidation at high temperature in a limited (sub-stoichiometric) oxygen supply, producing combustible syngas — unlike full-oxygen incineration or oxygen-free pyrolysis.
What is a sanitary landfill?
An engineered method of disposing of solid waste on land by spreading in thin layers, compacting to the smallest practical volume, and covering with soil daily to minimize environmental impact.
What are the essential engineered components of a sanitary landfill?
A liner system (clay/geomembrane), leachate collection and treatment system, landfill gas collection system, daily/final cover, and groundwater monitoring wells.
What is leachate?
The contaminated liquid that percolates through the waste in a landfill, carrying dissolved and suspended pollutants, requiring collection and treatment to protect groundwater.
What is landfill gas and its main constituents?
Gas produced by anaerobic decomposition of waste, composed mainly of methane (~50–55%) and carbon dioxide (~45–50%), with trace gases; methane is recoverable as energy.
What are the phases of gas generation in a landfill?
Phase I aerobic; Phase II anaerobic acid (acidogenic); Phase III unsteady methanogenic; Phase IV steady methanogenic; Phase V maturation/stabilization.
What is a hazardous waste?
A waste that, due to its physical, chemical, or biological characteristics, poses a substantial present or potential threat to human health or the environment when improperly managed.
What are the four characteristic properties that classify a waste as hazardous?
Ignitability, corrosivity, reactivity, and toxicity (the ICRT characteristics).
What defines the 'corrosivity' characteristic of hazardous waste?
Aqueous wastes with pH ≤ 2 or ≥ 12.5, or those able to corrode steel at a specified rate — capable of damaging tissues and containers.
What is the TCLP test used for?
The Toxicity Characteristic Leaching Procedure simulates leaching in a landfill to determine whether a waste's leachate exceeds regulatory toxicity limits for specified contaminants.
What are the major treatment methods for hazardous waste?
Physical (sedimentation, filtration, adsorption), chemical (neutralization, oxidation/reduction, precipitation), biological (bioremediation), thermal (incineration), and stabilization/solidification before secure landfilling.
What is solidification/stabilization of hazardous waste?
Treatment that immobilizes contaminants by binding them in a solid matrix (e.g., cement, lime, fly ash) to reduce mobility, leachability, and toxicity before secure land disposal.
What is a secure landfill for hazardous waste?
A highly engineered disposal facility with double liners, leachate detection/collection, leak-detection layers, and continuous monitoring designed to isolate hazardous waste from the environment.
What this deck covers
The Unit-VII: Solid and Hazardous Waste Management deck follows the UGC NET Environmental Science Unit-VII: Solid and Hazardous Waste Management syllabus — 5 chapters and 7 topics — so questions land on material that is genuinely examinable rather than trivia around it. That works out to roughly 10.2 cards per chapter.
Answers are written to be recallable, not just readable — averaging about 157 characters, which is long enough to carry the reasoning and short enough to say out loud.
A deck like this earns its keep on the second and third pass. Read the syllabus first so you know the shape of the subject, then use the cards to find the specific facts that have not stuck.
Unit-VII: Solid and Hazardous Waste Management flashcards FAQ
How many Unit-VII: Solid and Hazardous Waste Management flashcards are in this UGC NET Environmental Science deck?
51 cards. This page previews 24 of them, sampled evenly across the deck so you can judge the difficulty before installing anything.
Are these UGC NET Environmental Science flashcards free?
Yes. The preview here is free to read with no signup, and the full 51-card deck is free inside the Examius app.
What do the Unit-VII: Solid and Hazardous Waste Management cards cover?
They follow the UGC NET Environmental Science Unit-VII: Solid and Hazardous Waste Management syllabus — 5 chapters and 7 topics — so the questions track what is actually examinable.
How should I use these flashcards?
Read the syllabus first so you know the shape of the subject, then drill the deck. Examius schedules each card with spaced repetition, so cards you keep missing come back sooner and ones you know drift further apart.