Composting: Types, Process, Stages of Composting and Optimal Conditions for Composting

Dr. Manishika Jain- Join online Paper 1 intensive course. Includes tests and expected questions.


Biodegradation of organic wastes by aerobic process

Chemical Reaction Involved in the Process

Organic matter + O2 + aerobic bacteria CO2 + NH3 + H2O + Energy + other end products

Types of Composting

Passive Composting

  • It is a slow process
  • It takes around 6 months to degrade the waste

Active Composting

  • It is a fast process
  • Regular turning off and maintenance of 40 - 60 % moisture will fasten up the composting process

Composting Process

  • Collection, segregation and storage of solid waste: It is the initial stage where collection of waste takes place followed by segregation of materials such as glass, ferrous and non-ferrous metals etc.
  • Shredding and homogenization: Pre-processing of wastes is done to remove contaminants and poorly segregated wastes. It involves shredding and pulverization.

Stages of Composting

  • High rate composting stage: It is the first composting phase. It involves increase of temperature and a high rate of microbial activity.
  • Thermophilic or Stabilisation stage: Here, biodegradation takes place by thermophilic microorganisms. It is an exothermic process where temperature goes up to 70°C.
  • Maturation stage – Cooling and curing: It is marked by lower temperatures. During this phase, the microorganisms that were replaced by the thermophiles, regain in the pile and digest the coarser and more resistant organic particles.
  • Sieving and product grading: This final stage involves removal of un-composed materials and contaminants such as glass, plastics and metals and then size reduction and screening.

Optimal Conditions for Composting

Optimal Conditions for Composting

Technical Options for Solid and Liquid Waste Management in Rural Areas

  • Pile Method of composting
  • NADEP Method
  • Bangalore method
  • Indore method
  • Coimbatore Method
  • Vermicomposting
  • Thermophilic Composting
  • Biogas Technology

Multiple Choice Questions

1. Which among the following is a slow process?

  1. Passive composting
  2. Active composting
  3. Both of the above
  4. None of the above

Answer: a

2. Thermophilic microorganisms are formed at which phase of composting?

  1. High rate composting stage
  2. Thermophilic
  3. Stabilisation stage
  4. Both b and c

Answer: d

3. The optimal pH condition required for composting are

  1. 6.5 - 7
  2. 7 - 7.5
  3. 6.5 - 8
  4. 7 - 8

Answer: c

4. Which among the following is not a technical Options for Solid and Liquid Waste Management in Rural Areas

  1. Vermicomposting
  2. Thermophilic Composting
  3. Biogas Technology
  4. Incineration

Answer: d




#Types of composting

#Composting process

#Stages of composting

#Optimal conditions for composting

#Technical Options for Solid and Liquid Waste Management in Rural Areas

Developed by: