Innumerable technologies have surfaced in order to combat the solid waste menace. However, none of them seem to be working well as they do not incentivise enough nor motivate. The impacts of municipal solid waste on the environment as well as on human health are manifold.
Municipality landfills emit methane gas into the atmosphere. This poses a problem as this particular gas has 24 times the potential to trap heat in the atmosphere as compared to Co₂ (carbon dioxide), adding to already existing climate change. Toxic chemicals from the mixed waste seep into land and pollute the ground water which naturally poses potential risks to human health.
Usually in the solid waste management hierarchy, land filling is the least preferred method as compared to the 3 R (reduce, reuse and recycle) approaches. In India, the present scenario most often still opt for land filling.
Solid waste management policies in India are at par with global waste management policies but implementation here is not at the same scale. The only way to encourage the people working in MSW sites is to attach a more favourable monitory value to the other options. Making use of municipal waste to manufacture briquettes is the need of the hour. Briquettes are an inexpensive energy source which can be used in brick kilns (cooking) and in various industrial machinery (such as steam boilers). Briquettes although a slow evolving idea, is a real game changer since it comes with strong scientific backing and financial underpinning.
Composition of Municipal Solid Waste
There are other alternatives likes composting and anaerobic digestion ( to generate methane - biogas) from municipal solid waste but in accordance with decentralization aspects, briquette production wins the race. Briquettes can be manufactured and sold easily in small quantity which provides livelihood opportunities for those below the poverty line. Briquettes can be used for household water heating and cooking purposes.
Assume a family of 4 will heat 30 liters a day for bathing and washing (over 30 days).
(The Energy required to heat water from 20°C to 40°C (Normally used for bath) is 1.8 MJ.)
The energy value from all the fuel type is derived by using the formula
q =mass x specific heat x delta T = m x spc heat x ∂T (temperature)
The Cost of heating the water (30 liters) over a month using:
Electricity = Rs. 275
Fuel wood = Rs. 140
Briquette = Rs. 100
LPG = Rs. 600
Currently briquette manufacturing uses ground nut husk, coffee husk and other biomass as inputs. The market for this has evolved very systematically. In municipal solid waste, paper, plastic, organic waste (Need to be dried before process) which accounts for nearly 80% of the waste composition can be used for briquette manufacturing. Certain materials such as metals, stones and textile cannot. Taking the example of Bangalore, in a day, out of the 5000 tonnes of municipal solid waste nearly 2500 tonnes can be used to produce briquettes. Briquettes are priced at a wholesale rate of Rs. 5 per kilogram.
Bangalore’s solid waste as a whole can fetch up to nearly Rs 1 crore a day, if they are converted into briquettes. With the steep rise in price of fossil fuel, heat intensive industries which earlier used furnace oil have already begun switching to over to briquettes.
Potential industries (for briquette use).
- Gasifier System applications
- Refractory Industries
- Chemical Industries
- Vegetable Plants
- Leather Industries
- Milk Plant
- Rubber Industries
- Textile Units
- Dyeing Units
- Brick making units
- Ceramic Industries
- Solvent Extraction Plant
- Steam generation for various industrial applications
- Food Processing Industries
- Lamination Industries
- Any Industrial Thermal Applications
A briquetting machine which has the capacity of making 1 tonne per hour costs Rs. 20 lakhs
Points to remember about Briquettes:
- Briquettes are cheaper than COAL, OIL or LIGNITE
- Once used cannot be replaced.
- There is no sulfur in briquettes.
- Biomass briquettes have a higher practical thermal value and much lower ash content (2-10% as compared to 20-40 % in coal).
- There is no fly ash when burning briquettes.
- Briquettes have a consistent quality, have high burning efficiency and are ideally sized for complete combustion.
- Combustion is more uniform compared to coal and boiler response to changes in steam requirements is faster due to higher quantity of volatile matter in briquettes.
- Unlike coal, lignite or oil, briquettes are produced from renewable source of energy, biomass.
- Briquettes have high specific density (1200 kg/m3) compared to 60 to 180 kg/m3 of loose biomass.
- Loading/unloading and transportation costs are much less and storage requirement is drastically reduced.
- Briquettes are clean to handle and can be packed in bags for ease of handling and storage.
- Briquettes are usually produced near the consumption centers and supplies do not depend on erratic transport from long distances