Looking at the options available to small towns and rural communities to manage their waste. Ways to make landfills last longer and support the local circular economy.
Managing 150 tonnes per day (TPD) of municipal solid waste (MSW) in a rural Indian town requires an integrated approach that combines various waste processing technologies. Below is an analysis of several suitable technologies, considering their impact on residual landfill tonnage, energy dynamics, emissions, land requirements, and costs.
1. Biogas (Anaerobic Digestion)
Process: Decomposition of organic waste by microorganisms in the absence of oxygen, producing biogas (methane and carbon dioxide) and digestate.
Residual to Landfill: Approximately 10% of input, primarily inert contaminants.
Energy: Produces biogas with a methane content of 50–80%, which can be used for electricity and heat generation.
Emissions: Low; controlled anaerobic conditions minimize greenhouse gas emissions.
Land Requirement: Moderate; requires space for digesters and biogas storage.
Capital Costs: Moderate to high; depends on plant size and technology.
Operating Costs: Moderate; involves maintenance of digesters and gas handling systems.
Additional Benefits: ✔️Produces liquid fertilizer as effluent. ✔️Solids from digester can be used for soil amendment or sent for composting or RDF production. ✔️Biogas can be used to generate electricity, brunt for heat or upgraded for Compressed Natural Gas used (at additional cost).
2. Composting
Process: Aerobic decomposition of organic waste into humus-like compost.
Residual to Landfill: Approximately 5–15% of input, mainly non-compostable materials.
Energy: No direct energy production; however, compost enhances soil fertility, potentially reducing the need for chemical fertilizers.
Emissions: Low; proper management minimizes methane emissions.
Land Requirement: High; requires significant area for windrows or composting piles.
Capital Costs: Low to moderate; depends on the scale and mechanization level.
Operating Costs: Low; primarily labor and equipment for turning compost.
Additional Benefits: ✔️Simple technology available for all to use. ✔️Can be accelerated with closed vessels at additional cost.
3. Pyrolysis
Process: Thermal decomposition of waste in the absence of oxygen, producing bio-oil, syngas, and char.
Residual to Landfill: Approximately 10–15% of input, mainly char and inert materials.
Energy: Produces syngas and bio-oil, which can be used for energy generation.
Emissions: Moderate; requires emission control systems to manage pollutants.
Land Requirement: Moderate; compact facilities but require space for feedstock storage.
Capital Costs: High; advanced technology with significant initial investment.
Operating Costs: Moderate to high; technical expertise required for operation.
Additional Benefits: ✔️locally produced technology can provide lower capital costs. ✔️ Can be linked to other processes. ✔️ Market Demand – Growing demand for bio oil and biochar.
4. Gasification
Process: Partial oxidation of waste at high temperatures to produce syngas.
Residual to Landfill: Approximately 5–10% of input, primarily ash.
Energy: Produces syngas usable for electricity or chemical production.
Emissions: Moderate; emission controls necessary to manage pollutants.
Land Requirement: Moderate; similar to pyrolysis.
Capital Costs: High; complex technology with substantial initial costs.
Operating Costs: Moderate to high; requires skilled operators.
Additional Benefits: ✔️Can be linked to the production of hydrogen and methanol. ✔️ Efficient Sorting can be used to keep moisture content in range.
5. Incineration
Process: Combustion of waste at high temperatures, reducing waste volume and generating heat.
Residual to Landfill: Approximately 20–25% of input, mainly ash.
Energy: Generates heat that can be converted to electricity; energy recovery efficiency varies.
Emissions: High; necessitates advanced flue gas treatment to control pollutants including dioxins.
Land Requirement: Low; compact facilities.
Capital Costs: High; significant investment in infrastructure and emission controls.
Operating Costs: High; ongoing costs for maintenance and emission management.
Additional Benefits: ✔️Robust. ✔️ Best suited to large volumes in urban areas of where there is no landfill nearby. ✔️ Easiest technology to finance.
6. Recycling
Process: Sorting and processing of recyclable materials (plastics, metals, paper) for reuse.
Residual to Landfill: Varies; depends on the efficiency of sorting and market demand for recyclables.
Energy: Indirect energy savings by reducing the need for virgin material production.
Emissions: Low; reduces overall environmental footprint by conserving resources.
Land Requirement: Moderate; facilities needed for sorting and processing.
Capital Costs: Moderate; depends on the scale and technology used.
Operating Costs: Moderate; influenced by labor and market dynamics for recyclables.
Additional Benefits: ✔️New Industries can collocate using energy and heat from related processes. ✔️ High social impact by employment.
7. Refuse-Derived Fuel (RDF) Production
Process: Shredding and dehydrating non-recyclable waste to produce fuel for industrial use.
Residual to Landfill: Approximately 20–30% of input, depending on preprocessing efficiency.
Energy: Produces fuel that can substitute conventional fossil fuels in industries.
Emissions: Depends on the combustion process in end-use facilities; requires emission controls.
Land Requirement: Moderate; space needed for processing and storage.
Capital Costs: Moderate; involves investment in processing equipment.
Operating Costs: Moderate; ongoing costs for operation
Additional Benefits: ✔️High Demand from Cement industry for good quality RDF. ✔️ Process can make use of materials mined from nearby landfills.
8. Black Soldier Fly (BSF) Larvae Processing for Food Waste Management
Process: Black Soldier Fly (BSF) larvae efficiently convert uncontaminated food waste into high-protein animal feed and organic fertilizer. The larvae consume the waste, reducing its volume while producing frass (larvae excrement), which can be used as a soil amendment.
Input Waste: 5 tonnes per day of uncontaminated food waste from the 150 TPD municipal solid waste(MSW) stream. Requires uncontaminated food scraps.
Expected Outcomes: Residual to Landfill: 5% (~0.25 TPD) primarily consisting of non-digestible contaminants.
Energy Output: No direct energy recovery, but significant protein production (~1 tonne of dried larvae per day). Minor Energy input.
Emissions: Net negative (-50 to -100 kg CO₂e per tonne of waste) due to carbon sequestration in insect biomass.
Land Requirement: Only 2 acres due to compact, modular rearing systems.
Economic Considerations:
Capital Cost: ~$3 million USD, including rearing facilities and automation.
Operating Cost: ~$1.5 million USD per year, mainly labor, feedstock processing, and harvesting costs.
Additional Benefits: ✔️Sustainable Alternative to Soy & Fishmeal – High-protein BSF larvae reduce pressure on marine and agricultural protein sources. ✔️ Efficient Waste Reduction –Can process large amounts of organic waste in a small footprint. ✔️ Market Demand – Growing use in poultry, aquaculture, and pet food industries.
The most important part of technology selection and pairing is the market for the offtake of primary products and by products. Multi-process installations will have a number of revenue streams. The price for energy, emissions reductions, re-dumping fees and other items will effect the choice. In a related article, we will go through these costs based on persons whom we profile.
References for the Article
1 Life Cycle and Energy Balance Composting Emissions and Carbon Sequestration https://pubs.acs.org/doi/10.1021/acs.est.0c00364 BIRI7
2 Black Soldier Fly Production https://www.researchgate.net/figure/Summary-on-the-chemical-composition-of-BSFL-fed-with-food-waste-NA-Not-available_tbl2_348627678 BIRI 7
3 Refuse Derived Fuel (RDF) Production and Market Viability https://www.renewableenergyworld.com/baseload/refuse-derived-fuel-potential-and-challenges/ BIRI7
4 Pyrolysis Process and Emissions Reduction https://www.ieabioenergy.com/blog/publications/new-publication-trends-and-drivers-in-alternative-thermal-conversion-of-waste/ BIRI 9
5 Waste Gasification and Energy Recovery https://www.ieabioenergy.com/wp-content/uploads/2022/03/Status-Report2021_final.pdf BIRI 9
6 Incineration and Greenhouse Gas https://www.ipcc.ch/site/assets/uploads/2018/02/ar4-wg3-chapter10-1.pdf BIRI 10
7 IPCC Waste Management and Emissions https://www.ipcc.ch/report/ar4/wg3/waste-management/ BIRI 10
Additional Resources
Biogas (Anaerobic Digestion):
- The "Global Methane Tracker 2022" by the International Energy Agency (IEA) can provide empirical data supporting the role of biogas in reducing methane emissions, thus confirming its environmental benefits and energy production capabilities.
[IEA. (2022). Global Methane Tracker 2022. https://www.iea.org/reports/global-methane-tracker-2022 BIRI 10]
Composting:
- The "How composting can reduce our impact on the planet" provides a good explainer for composting as a low-emissions technology of waste management practice.
[UNEP How composting can reduce our impact on the planet https://www.unep.org/news-and-stories/story/how-composting-can-reduce-our-impact-planet BIRI 10]
Pyrolysis:
- Research from the "International Energy Agency (IEA)Bioenergy" on pyrolysis can validate the process's efficiency in producing syngas and bio-oil, while also highlighting the necessity for emission control systems to manage by-product pollutants effectively.
[IEA Bioenergy https://www.ieabioenergy.com/blog/publications/biomass-pyrolysis/ BIRI 10]
Gasification:
- Ankur Scientific explains gasifiers and their emissions.
[Ankur Scientific. https://www.ankurscientific.com/technology.html BIRI 6]
Incineration:
- The "Stockholm Convention on Persistent Organic Pollutants (2001)" provides international guidelines on managing dioxins, which can substantiate the high level of emission controls necessary for incineration facilities.
[Stockholm Convention. (2001). Stockholm Convention on Persistent Organic Pollutants. http://www.pops.int/ BIRI 10]
Recycling:
- The "Basel Convention on the Control of Transboundary Movements of Hazardous Wastes and Their Disposal (1989)" can underscore the importance of safe and regulated recycling practices, reinforcing the low-emission benefits of recycling while ensuring proper handling of hazardous materials.
[Basel Convention. (1989). Basel Convention on the Control of Transboundary Movements of Hazardous Wastes and Their Disposal. http://www.basel.int/ BIRI 10]
Refuse-Derived Fuel (RDF) Production:
- The "IEA Bioenergy Task 36: Trends in the use of solid recovered fuels" provides a detailed analysis of solid recovered fuels of which RDF is one, backing up the claim of its utility as a substitute for conventional fossil fuels and demonstrating its market viability.
[IEA Bioenergy Task 36 https://www.ieabioenergy.com/wp-content/uploads/2020/05/Trends-in-use-of-solid-recovered-fuels-Main-Report-Task36.pdf BIRI 10]
Black Soldier Fly (BSF) Larvae Processing:
- Research from the "Food and Agriculture Organization of the United Nations (FAO)" on sustainable animal feed production can confirm the efficiency of BSF larvae in waste reduction and their value as an alternative protein source, supporting the premise of BSF processing as an innovative waste management solution.
