Turning trash into energy
Municipal solid waste (MSW) is a huge, renewable source that contains a high amount of energy. Waste to energy (WTE) is the efficient and viable solid waste management technique. Some kitchen waste, we can easily convert them into energy efficiently. Energy may be a form of compost fertilizer, liquid fertilizer, biogas, and electricity through various processes. Other imperishable, plastic trash can be converted into a usable form of energy including electricity, fuel, and heat. MSW management has been a severe issue in a country like Nepal where rapid and unmanaged urbanization is a considerable challenge.
As an example, Denmark incinerates the municipal waste generating 5 Percent of total electricity demand and 20 Percent of total district heating. Amager Bakke incinerator plant in Copenhagen is a most energy efficient plant with high environmental profile and low emission.
Singapore is another successful country in MSW management. Singapore recycles 60 Percent of total MSW and remaining waste generates electricity which is 3 Percent of total electricity demand.
Ethiopia is another country building astonishing Plant ever in Africa. Previously, Ethiopia has the massive waste problem and converting into WTE leader in Africa. This plant has a capacity of supplying 30 Percent of the total demand of Addis. Our neighbor, India generates 211MW of electricity from municipal waste.
Scenario of Nepal
We have inferior MSW management techniques. More than 80 Percent of the waste is landfilled, and waste is sweeping on the street some days. Landfill fires and open burning of trash are a constant problem in Nepal. Use of landfill as a primary waste disposal method is an unsustainable use of land and not suitable for environmental concerns. Generally, wastes that are not reusable or recyclable are dumped off in the landfill.
The total estimated waste generation is 2000 tones in which Kathmandu valley produces 500 tonnes of solid waste per day. In Metropolitans, the average amount of waste generated by each consumer is continually increasing. The waste only from Kathmandu valley can generate electricity up to 6 MW. Some private companies collected debris from some specified area of the valley is not sufficient to meet this immense challenge
Some Biogas Plants are already installed, and some are in process. The group of environmentalist proposes a WTE plant for poultry farms in Nepal. This plant seems viable and expanding throughout the country. Also, sugar mills are generating electricity by using waste heat and sell surplus electricity to the grid. The government took such initiative, private companies and environmental scientist was commendable but needs more to convert the ambition into a reality.
Viability and long-term impacts are the most pressing question in incineration. The emission from such plants include dioxins, heavy metals, and other toxic pollutants. Modern technology use pollution control innovations, which mainly reduces the emission of toxic pollutants. The WTE researchers are doing research in making a more refined plant. The primary motive of incineration is not producing electricity, and it is to manage nonrecyclable waste. Incineration is a fourfold win where land is limited, it saves space, generates electricity, prevents the formation of leachate, and reduces the release of methane into the atmosphere. In overall, incinerator plants are viable and suitable at commercial scale.
Another way of management of waste is to generate biogas from putrescible waste. Based on the latest research on WTE, this biogas system of a single unit can produce 2-3 hours of cooking gas from the only 2kg of kitchen waste which is very efficient. This biogas plant reduces the use of Liquefied Petroleum Gas (LPG) by 50-60 Percent. This alternative not only suits in an urban area but also in a rural area that largely depends on agriculture. This type of portable Home biogas plays the crucial role in managing garbage.
Organic Solid waste management can be done via aerobic composting. Worm composting may be another sustainable option. Worm compost is an amazing amendment for soil. There are several methods of converting waste to energy. We must choose the most viable, efficient and sustainable option.
What do we need?
We can’t say roughly that this model suits the scenario of Nepal. The percentage ratio of perishable and imperishable waste is different in different countries. It mainly depends on the lifestyle of people and level of awareness. The food residue waste in China is 55 Percent while food residue waste in the USA is only 15 Percent. So we have to think about our scenario first which model suits us instead of jump into vogue.
If we can’t maintain the basic standard of air pollution, incinerator plants may not be a good option. In China, the opposition of public to incineration project causes cancellation of projects. So we have to establish the more refined plant. We must be aware that the proposed incinerator plant should meet efficiency and climate goals.
The government should make a rule of packaging recyclable and compostable to some extent by classifying the product. This reduces the 10 percent of plastic trash in an environment if government go through such rule. Plastics dominate our packaging and essential for some packaging because it is moisture proof. The environmental goal could easily be achieved if all packaging were made of modified paper-based materials. The government should encourage the private sectors by making no tax strategy and subsidized policy for WTE companies.
More importantly, government efforts should require for the improvement of MSW management. The government should give attention to systematic waste collection method to achieve a goal. For the effective waste management, the government should spend sufficient budget. Thus, WTE helps to break the reliance on fossil fuels and country to address serious energy deficit as well as support on the national economy.
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