LAISHA
Open Laisha

Central and State Pollution Control Board recruitment Circular Economy & Bio-based Resources: practice questions

Central and State Pollution Control Board recruitment (Scientist, Environmental Engineer, AEE) · India · Central Pollution Control Board and State Pollution Control Boards / state PSCs

Original practice questions written to the published syllabus · not past papers
10worked here, free
26written to this exam in this subject
8syllabus units

What this subject covers

Designing waste out of the system: circular-economy principles, the biological cycle, industrial symbiosis, material flow analysis and the bioeconomy. Composting, biogas and briquetting technology are in the Agricultural Engineering subjects bioenergy-systems and waste-management-environmental-engg; this subject covers the system design, metrics and policy.

In the exams: GATE ES Sections 5 and 7 (recycling, zero liquid discharge, waste hierarchy); ICAR AICE subject 71 Unit 5 (5R concepts); SEA (GBCI) core concepts

Where the 26 questions fall

How our questions for Central and State Pollution Control Board recruitment spread across the units of Circular Economy & Bio-based Resources. Difficulty: 7 easy, 17 medium, 2 hard.

Industrial ecology and industrial symbiosis7
Extended producer responsibility and eco-design7
Bio-based and biodegradable materials: claims and evidence6
Circularity indicators and policies2
Linear versus circular economy; the butterfly diagram1
Biological and technical cycles1
Material flow analysis and resource-efficiency metrics1
Circular agriculture: nutrient and carbon recycling1

10 practice questions, worked

Choose an answer, then open the working. Each explanation says why the right answer is right and why the others are not.

1 · Linear versus circular economy; the butterfly diagram · easy

What is the order of priority in the EU waste hierarchy, from most to least preferred?

  1. Recycling, prevention, energy recovery, preparing for reuse, disposal
  2. Prevention, recycling, preparing for reuse, disposal, energy recovery
  3. Preparing for reuse, prevention, recycling, disposal, other recovery
  4. Prevention, preparing for reuse, recycling, other recovery, disposal
Answer and working

D. Prevention, preparing for reuse, recycling, other recovery, disposal

Directive 2008/98/EC sets prevention, preparing for reuse, recycling, other recovery (including energy recovery) and disposal. The other orders misplace prevention, reuse or disposal.

Further reading: Directive 2008/98/EC (Waste Framework Directive)

2 · Biological and technical cycles · medium

A pesticide container stewardship scheme asks farmers to triple-rinse empty containers before return. Why?

  1. Rinsing converts the container into a biodegradable material that composts in the field within one season
  2. Rinsing increases the container's mass so that the producer meets a weight-based target
  3. Rinsing is needed only to remove the label so the container can be resold for food use
  4. Rinsing removes residues so containers can be handled and recycled as non-hazardous plastic
Answer and working

D. Rinsing removes residues so containers can be handled and recycled as non-hazardous plastic

Triple rinsing (with rinsate added to the spray tank) removes most residues, allowing collection and recycling into non-food products. It does not make plastic biodegradable, does not add mass, and recycled containers must not be used for food.

Further reading: Crop protection container stewardship guidance

3 · Industrial ecology and industrial symbiosis · easy

Which town is the classic example of industrial symbiosis, with a power station, refinery, plasterboard factory and pharmaceutical plant exchanging by-products?

  1. Rotterdam, Netherlands
  2. Gothenburg, Sweden
  3. Kalundborg, Denmark
  4. Hamburg, Germany
Answer and working

C. Kalundborg, Denmark

Kalundborg's symbiosis grew from bilateral exchanges from the 1970s: steam, heat, gypsum, fly ash, water and fermentation biomass. The other cities are major ports and industrial centres but not the textbook case.

Further reading: Chertow 2000

4 · Material flow analysis and resource-efficiency metrics · medium

A packaging stream has a 70 % collection rate, 85 % sorting yield and 90 % reprocessing yield. What is the effective recycling rate?

  1. 70.00 %
  2. 53.55 %
  3. 81.67 %
  4. 90.00 %
Answer and working

B. 53.55 %

Effective rate = 0.70 × 0.85 × 0.90 = 53.55 %. Quoting the collection rate (70 %) overstates recycling; averaging gives 81.67 %; 90 % is only the last step.

5 · Bio-based and biodegradable materials: claims and evidence · medium

Which polymer is largely fossil-based yet biodegradable?

  1. Bio-PE (bio-polyethylene)
  2. PET (polyethylene terephthalate)
  3. PVC (polyvinyl chloride)
  4. PBAT (polybutylene adipate terephthalate)
Answer and working

D. PBAT (polybutylene adipate terephthalate)

PBAT is made from petrochemical monomers but is biodegradable and often blended with PLA or starch. Bio-PE is bio-based but not biodegradable; PET and PVC are fossil-based and not biodegradable.

Further reading: Bioplastics textbooks

6 · Bio-based and biodegradable materials: claims and evidence · medium

A café switches to PLA cups labelled 'compostable', but the city has no industrial composting and collects them with general waste for landfill. What is the most accurate assessment?

  1. The cups will compost in landfill within six months, as EN 13432 guarantees in any disposal setting worldwide
  2. The compostability claim brings no end-of-life benefit there, because the required composting is absent
  3. The cups will be recycled with PET bottles, because PLA and PET are the same polymer
  4. The cups remove all life cycle impacts, because bio-based materials are carbon neutral
Answer and working

B. The compostability claim brings no end-of-life benefit there, because the required composting is absent

PLA needs industrial composting temperatures; in landfill it degrades very slowly. EN 13432 conditions are those of controlled composting, PLA contaminates PET recycling, and bio-based materials still carry production impacts.

Further reading: EN 13432; ISO 14021

7 · Extended producer responsibility and eco-design · medium

In an EPR scheme, what are eco-modulated fees?

  1. Fees that rise each year with inflation regardless of the design of the product
  2. Fees paid by municipalities to producers for collecting their packaging
  3. Fees that are lower for easily recycled designs and higher for hard-to-recycle ones
  4. Fees charged only to importers, so that domestic producers pay nothing
Answer and working

C. Fees that are lower for easily recycled designs and higher for hard-to-recycle ones

Eco-modulation varies the producer's fee with environmental performance — recyclability, recycled content, absence of problem substances — to reward better design. The other options misdescribe who pays and why.

Further reading: OECD 2016

8 · Extended producer responsibility and eco-design · medium

A deposit-return scheme sells 80 million containers with a 0.10 deposit each; 72 million are returned. What are the return rate and the unredeemed deposits?

  1. 90 % and 7.2 million
  2. 72 % and 0.8 million
  3. 90 % and 0.8 million
  4. 10 % and 8.0 million
Answer and working

C. 90 % and 0.8 million

Return rate = 72/80 = 90 %; unredeemed = 8 million × 0.10 = 0.8 million currency units, which help fund the scheme. 7.2 million values the returned containers; 72 % reads the count as a percentage; 10 % is the non-return rate.

9 · Extended producer responsibility and eco-design · hard

Which is a recognised weakness of EPR schemes with weight-based targets?

  1. They make producers responsible for consumer behaviour, which is unconstitutional
  2. They reward heavy materials and tonnage rather than reuse or recycling quality
  3. They prevent municipalities from collecting any packaging waste at all
  4. They apply only to biodegradable materials and exclude conventional plastics
Answer and working

B. They reward heavy materials and tonnage rather than reuse or recycling quality

Weight targets can favour heavy formats and low-quality recycling; free-riders and certificate fraud are other weaknesses. Good schemes add eco-modulation, audit and quality metrics. The other options are not general features of EPR.

Further reading: OECD 2016

10 · Circularity indicators and policies · medium

Under India's Solid Waste Management Rules, which basic duty is placed on waste generators?

  1. Burning dry waste in the open to reduce the volume collected by municipalities
  2. Sending all mixed waste directly to landfill without any separation
  3. Paying producers to collect their packaging from each household
  4. Segregating waste at source into categories such as wet, dry and domestic hazardous
Answer and working

D. Segregating waste at source into categories such as wet, dry and domestic hazardous

The 2016 rules require generators to segregate waste at source (biodegradable, non-biodegradable and domestic hazardous) and hand it to authorised collectors; open burning is prohibited. Mixed landfilling and payments to producers are not the duty.

Further reading: Solid Waste Management Rules 2016 (India)

Ten here, 26 in the app. The Laisha app has every practice question we have written to Central and State Pollution Control Board recruitment in this subject, marked as you go, with timed papers, a jump-to-unanswered list and a certificate when you pass at 70 per cent.

Free for ten days, then one subscription of US$10 a month. We would rather say so here than have you find it later.

Practise the full set in Laisha →

Read the subject

Circular Economy & Bio-based ResourcesThe full study manual, free Central and State Pollution Control Board recruitmentFormat, sections and how it has changed

More Central and State Pollution Control Board recruitment practice

Environmental Monitoring & Instrumental AnalysisAir & Noise Pollution: Monitoring & Control

Circular Economy & Bio-based Resources for other exams

Sustainability Excellence Associate and Sustainability Excellence Professional · InternationalUGC NET · IndiaGATE · India

Ask Laisha about this

Opens Laisha's chat with your question ready to send. Sign in or start free.