Biosolids are emerging as a sustainable and cost-effective alternative to traditional fertilisers.
What are Biosolids?
- Biosolids are organic materials obtained from the wastewater treatment process.
- During treatment, solid waste is separated from liquids and further processed to create nutrient-rich semi-solid material.
- These biosolids contain essential nutrients like nitrogen, phosphorus, and potassium, making them highly beneficial for soil health and crop production.
- Examples: Milorganite, Loop, TAGRO, Dillo Dirt.
Benefits of Using Biosolids in Agriculture
- Reduces Dependence on Chemical Fertilisers: Biosolids help reduce the need for synthetic fertilisers, cutting costs for farmers.
- Improves Soil Fertility: They enhance soil quality by adding organic matter and essential nutrients.
- Supports Sustainable Farming: By promoting the reuse of waste, biosolids contribute to environment-friendly agricultural practices.
- Helps in Waste Management: Using biosolids prevents waste accumulation and supports the principles of a circular economy.
- Reduces Greenhouse Gas Emissions: By reducing groundwater extraction and fertiliser production, biosolids lower carbon dioxide emissions.
Biosolids vs. chemical Fertilisers: A comparative Analysis
| Feature |
Biosolids |
Chemical Fertilizers |
| Source |
Treated sewage sludge; organic matter from wastewater treatment. |
Synthetically produced inorganic compounds; derived from mineral sources. |
| Nutrient Content |
Contains a broad spectrum of nutrients, including nitrogen, phosphorus, potassium, and micronutrients; organic matter. |
Typically focuses on primary macronutrients (nitrogen, phosphorus, potassium) in concentrated, readily available forms. |
| Soil Impact |
Improves soil structure, water-holding capacity, and organic matter content; slow-release nutrients. |
Provides rapid nutrient availability; can lead to soil acidification and reduced organic matter with overuse. |
| Environmental Considerations |
Potential concerns regarding trace metals, pathogens, and pharmaceuticals; regulated application. |
Potential for nutrient runoff, water pollution, and disruption of soil microbial balance; requires careful application to minimize impact. |
| Nutrient Release |
slow release of nutrients |
Rapid release of nutrients. |
| Long term effect on soil. |
Increases organic matter, improving long term soil health. |
Can degrade the soil long term, with repeated use. |
| Use. |
Often used to improve soil structure, and return needed nutrients to depleted soils. |
Primarily used for providing high concentrations of readily available nutrients, to maximize crop yield. |
Biosolids Production and Usage in India
- India has about 1,024 Faecal Sludge Treatment Plants (FSTPs), generating 500 tonnes of biosolids daily.
- These biosolids, when treated properly, can be used to enrich soil, enhance crop productivity, and reduce pollution.
- Examples of Biosolids Use in India:
- Karunguzhi, Tamil Nadu: The local Faecal Sludge Treatment Plant (FSTP) processes biosolids and sell it to farmers
- Loni, Uttar Pradesh: Plans are in place to sell biosolids to farmers at ₹12 per kg.
- Odisha: Advanced co-composting and drying techniques are being used to manage biosolids effectively.
- Devanahalli, Karnataka: Biosolids from wastewater treatment plants are converted into compost which is used in agriculture as it is a low cost soil enhancer.
Difference between biosolids and sewage sludge
| Feature |
Sewage Sludge |
Biosolids |
| Definition |
The untreated or partially treated semi-solid byproduct of wastewater treatment. |
Sewage sludge that has been treated to meet specific regulatory standards for beneficial use. |
| Treatment Level |
Untreated or partially treated. |
Treated to reduce or eliminate pathogens and harmful substances. |
| Safety |
May contain high levels of pathogens and harmful substances. |
Significantly reduced levels of pathogens and harmful substances, making it safer for use. |
| Potential Use |
Generally considered waste; disposal is the primary concern. |
Used as fertilizer, soil amendment, or in land reclamation. |
| Regulation |
Subject to disposal regulations. |
Subject to strict regulations regarding treatment and application. |
| Overall. |
Untreated waste product. |
Treated and regulated product for beneficial reuse. |
Government Initiatives Supporting Biosolids Reuse
- Swachh Bharat Mission 2.0 & AMRUT 2.0: Focus on improving sanitation and waste management.
- Waste to Wealth Mission: Encourages converting waste into useful products like compost and biogas.
- National Mission for Clean Ganga: Aims to reduce pollution and promote biosolid reuse to clean the Ganga River.
Challenges in Using Biosolids
- Lack of Proper Regulations: India does not have specific national guidelines for biosolids use.
- Public Perception and Awareness: Many people are hesitant to use biosolids due to cultural beliefs.
- Quality Standards: Unlike other countries, India’s Fertiliser Control Order (FCO) does not specify quality norms for biosolids.
- Treatment and Infrastructure Issues: Many FSTPs lack advanced treatment facilities to ensure biosolids are safe for use.
The Way Forward
To effectively integrate biosolids into Indian agriculture, the following steps are essential:
- Establish Clear Regulations – Develop strict quality standards for biosolid use.
- Improve Treatment Facilities – Invest in better technologies to ensure biosolids are safe.
- Raise Public Awareness – Educate farmers about the benefits of biosolids.
- Promote Public-Private Partnerships – Encourage businesses to invest in biosolid processing and distribution.
International models for biosolid policies
- United States (USEPA Standards):
- The United States Environmental Protection Agency (USEPA) classifies biosolids into two categories:
- Class A: Treated to eliminate pathogens, safe for unrestricted use, including agriculture.
- Class B: Contains reduced pathogens but requires controlled application with site restrictions.
- These standards ensure biosolids are safe for use while protecting public health and the environment.
- Update Fertilizer Control Order (FCO):
- Include comprehensive quality checks for biosolids, especially focusing on:
- Heavy Metals: Establish limits to prevent soil contamination.
- Pathogen Control: Ensure safety for agricultural applications.
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11 Mar 2025
