ICAR AICE-JRF/SRF Circular Economy & Bio-based Resources: practice questions

Question 1 · medium

'5R' lists in waste-management teaching differ between sources. Which pair of items is common to almost every version?

1. Refuse and rot (compost)
2. Reduce and reuse
3. Repurpose and recover
4. Rethink and repair

Question 2 · hard

When can direct energy recovery be preferable to a cascade of material uses for a biomass residue?

1. Never, because cascading is mandatory for all biomass under international law
2. Always, because energy uses sit at the top of the biomass value pyramid
3. Only when the residue is a technical nutrient such as a metal, glass or a mixed plastic consumer product
4. When collection and processing losses or transport make the cascade worse on life cycle grounds

Question 3 · easy

Who popularised the term 'industrial ecology' in a 1989 Scientific American article?

1. Boulding and Daly
2. Frosch and Gallopoulos
3. McDonough and Braungart
4. Meadows and Randers

Question 4 · medium

In a molasses-based distillery, what does zero liquid discharge (ZLD) mean?

1. Effluent is diluted with fresh water until it meets the discharge standard for rivers and streams
2. Effluent is stored in unlined lagoons on site until it evaporates naturally over time
3. Effluent is injected into deep wells so that none appears at the surface
4. No liquid effluent leaves the site; water is recovered and residues are dried or burned

Question 5 · easy

A farm's nitrogen inputs are 220 kg N/ha and outputs in products are 120 kg N/ha. What is its nitrogen use efficiency (NUE)?

1. 183.3 %
2. 54.5 %
3. 45.5 %
4. 83.3 %

Question 6 · easy

In a farm-gate nutrient balance, what is the 'surplus'?

1. Nutrient outputs minus nutrient inputs
2. Nutrient inputs minus nutrient outputs in products
3. Fertiliser bought minus fertiliser applied
4. Nutrients in manure minus nutrients in crops

Question 7 · medium

Which practice is the main circular alternative to open burning of rice straw in South Asia?

1. Burning straw at night to reduce visibility of the smoke from nearby cities
2. In-situ incorporation or collection of straw for energy, board, feed or mushrooms
3. Burning straw only after spraying it with urea to speed combustion
4. Leaving straw on the surface and flooding the field with saline water

Question 8 · medium

Black soldier fly larvae are reared on organic by-products. What most limits which substrates they can be fed?

1. Feed and food safety law, which restricts substrates such as catering waste and manure in many countries
2. The larvae can digest only pure sugar solutions and cannot use mixed organic matter
3. The larvae require living plants as substrate and cannot use any processed by-products
4. The larvae are classed as pests in all countries, so rearing them is illegal everywhere outside research laboratories

Question 9 · medium

Why should nitrogen use efficiency (NUE) be judged together with the nitrogen surplus and productivity?

1. A farm mining soil nitrogen shows a very high NUE that is not sustainable
2. NUE cannot be calculated without knowing the surplus first
3. NUE is always below 10 % on productive farms, so it says little about losses
4. NUE applies only to livestock farms and not to arable farms

Question 10 · medium

Why is a 'cascade factor' for biomass use difficult to compare between studies?

1. There is no standard definition, so each study must state how it was calculated
2. It can be calculated only for metals and not for any biomass material
3. It is a legal limit set by the EU and changes each year by a delegated regulation
4. It is measured in currency, so exchange rates distort comparisons