The sludge from Indian sewage treatment plants (STPs) is significant in treating polluted water from the Ganga River. A recent study highlights the potential of this sludge as a fertilizer and biofuel.
GS III: Environment and Ecology
Dimensions of the Article:
- What is Sludge?
- Main Findings from the study
- About Project Arth Ganga
- The National Mission for Clean Ganga is an initiative aimed at preventing pollution and rejuvenating the Ganga River.
- The initiative ‘Arth Ganga’ has been introduced as part of this mission to derive livelihood opportunities from the river rejuvenation program.
- The primary objective of this initiative is to monetize and reuse treated wastewater and sludge, which are byproducts of sewage treatment plants.
What is Sludge?
- Sludge is the thick residue generated during wastewater treatment.
- It is the semi-solid material left after separating and treating the liquid portion of the sewage.
- The composition of sludge varies depending on the source and treatment processes used.
- It can contain organic compounds, nutrients, microorganisms, as well as contaminants such as heavy metals, industrial pollutants, and pathogens.
Treatment and Classification:
- Treatment and processing of sludge can yield organic fertilizers, biogas, or construction materials.
- Contaminants in sludge require careful handling to avoid negative impacts on water bodies and agricultural land.
- The United States Environment Protection Agency classifies sludge as Class A or Class B based on their safety for disposal and use.
- Class A sludge is safe for open disposal and serves as organic fertilizer.
- Class B sludge can be used in restricted agricultural applications, with precautions to avoid exposure of edible parts of crops to sludge-mixed soil and to limit contact with animals and people.
Sludge Disposal in India:
- India does not have established standards for classifying sludge as Class A or B.
- Contractors under the Namami Ganga Mission are assigned land for sludge disposal.
- Inadequate treatment of sludge by these contractors leads to its release into rivers and local water sources during rainfall.
- Data on the chemical characteristics of sludge is essential to incentivize private players to treat and dispose of sludge properly.
Main Findings from the study:
- The majority of the analyzed dried sludge belongs to the class B category.
- Nitrogen and phosphorus levels in the sludge exceed India’s fertilizer standards, while potassium levels are lower than recommended.
- Total organic carbon content in the sludge is higher than recommended, but heavy metal contamination and pathogen levels surpass fertilizer standards.
- The calorific value of sludge ranges from 1,000-3,500 kcal/kg, which is lower than Indian coal.
Recommendations for Improving Sludge Quality:
- Storage of sludge for at least three months is suggested to kill pathogens.
- Blending sludge with cattle manure, husk, or local soil can help reduce heavy metal content.
- However, these measures would still classify the sludge as class B.
- Converting the sludge into class A would require more extensive treatment.
About Project Arth Ganga
- PM Modi first introduced the concept during the first National Ganga Council meeting in Kanpur in 2019, where he urged for a shift from Namami Gange, the Union Government’s flagship project to clean the Ganga, to the model of Arth Ganga.
- The latter focuses on the sustainable development of the Ganga and its surrounding areas, by focusing on economic activities related to the river.
- At its core, the Arth Ganga model seeks to use economics to bridge people with the river.
- The project has been assisted by the World Bank.
Features of the project:
Under Arth Ganga, the government is working on six verticals.
- Zero Budget Natural Farming, which involves chemical-free farming on 10 km on either side of the river, and the promotion of cow dung as fertiliser through the GOBARdhan scheme.
- The Monetization and Reuse of Sludge & Wastewater, which seeks to reuse treated water for irrigation, industries and revenue generation for Urban Local Bodies (ULBs).
- Arth Ganga will also involve Livelihood Generation Opportunities, by creating haats where people can sell local products, medicinal plants and ayurveda.
- To increase public participation by increasing synergies between the stakeholders involved with the river.
- The model also wants to promote the cultural heritage and tourism of Ganga and its surroundings, through boat tourism, adventure sports and by conducting yoga activities.
- The model seeks to promote institutional building by empowering local administration for improved water governance.
Significance of the project
- The project is a holistic viewpoint of the Ganga rejuvenation project which seeks to promote sustainable livelihood of the population in this area.
- Inland Waterways being the most important part of the Arth Ganga project, will create huge economic activities while focusing on inclusive and sustainable livelihood.
- Trade and market access benefits, local community economic growth, and passenger convenience all have a big impact.
- According to the World Bank, this project’s infrastructure-related operations will lead to the creation of 100–150 direct jobs per industry.
- The Arth Ganga project will also ensure large scale skills enhancement and public/private sector capability development.
- The ease of transportation and doing business will have a huge impact on the farmers especially horticulture farmers in the region.
-Source: The Hindu