From waste to electricity: A dream or yet another tale of squander?
While the project has potential, there are some environmental and financial concerns. Careful consideration is needed to make sure we have the capability to fully run the incineration mill
In 2023, the government initiated a project in Aminbazar, Dhaka, for the production of electricity from waste. In a sense, it is a viable project for solving Dhaka's waste problem. Considering the population density of Dhaka city, a lot of waste is generated in a small area.
Generally, incineration mills are quite useful for places where a lot of waste is generated as it can be a cost-effective solution. Otherwise, the delivery cost of transporting the waste elsewhere would be higher than the price of electricity. A significant portion of New York's waste management is done through incineration. Similarly, Singapore manages its waste through incineration.
While the project has potential there are some environmental and financial concerns. China Machinery Engineering Corporation (CMEC) is investing around $300 million to implement the project. However, some of the clauses in the contract are a cause for concern. Careful consideration is needed to make sure we have the capability to fulfil our requirements.
The incineration method is basically like a stove. Similar practices are still prevalent in our rural areas; we cook by burning wood or cow dung in the same way waste is burned in the incineration method. The heat generated by burning waste will evaporate water and the produced steam will drive a turbine to generate electricity.
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While it is a simple method, the problem lies in the type of waste we have. When we try to light a fire with wet wood on a stove, there is a lot of smoke. And the more smoke there is, the more heat it takes, which is why it takes longer than dry wood. Therefore, we have to first dry the firewood.
Generally, in countries where the income is higher, there is more plastic and paper waste. In the United States, 23% of their waste is paper, 15% is plastic, and about 30% is food waste.
The most heat is generated when plastic is burned. On the other hand, food waste contains 50-70% water. So, if food waste is burned, less heat is generated. According to research, if there is more food waste in the waste, then it will not generate much heat when burned.
Approximately 50-60% of Bangladesh's waste is food waste. Moreover, our rainy season lasts for about three months. During this time, there will be more water in the waste due to rain. So, it will reduce calorific value. To mitigate these potential issues, the size of the plant will have to be increased, which will play a role in increasing the initial investment.
Alternatively, a system for drying could be installed. The gas emitted from the plant is sometimes burned through the waste, which helps to dry a bit of the huge amount of waste. However, it is not believed that this will help in drying bigger amounts of waste.
The big question is how they plan to keep operations running during monsoon season. One limitation of the incineration plant is that if it is shut down once, a lot of energy is wasted to restart it. So, supplying the right amount of waste at the proper or consistent calorific value will be a challenge.
One major factor in generating electricity from waste is the air pollution control system. If this system is not adequate, the gases produced from here will create various respiratory diseases as air pollution will increase.
In the case of incineration, the air pollution control system is one of the major expenses. Developed countries often compel companies through their policies to bear this cost. There is a policy on the quantity and quality of gas you can emit. Without a similar policy, the emitted gas can become a threat to public health.
Next, let's talk about the future of the residue after incineration. Many things in our waste cannot be incinerated, for example, a lot of construction waste, solid waste from leather factories, metal products and glass.
In each type of waste, there are some elements that turn into ash after incineration. Generally, if there is any heavy metal present, it will remain in ash form. If this ash is not properly disposed of in a landfill through appropriate engineering, then it can create environmental and health problems.
These types of plants store the waste under the open sky. So, wherever the rainwater falls, the water that will drain the waste from there will be harmful to the environment. This is called leachate.
The plant has been planned to be installed on the bank of a river and mixing the leachate with the water of the river will pollute it. Again, it will be harmful to the biodiversity of the river. So, leachate management will also be a big factor in this project.
China Machinery Engineering Corporation (CMEC) is investing around $300 million to implement the project. The deal with the company requires 3,000 tonnes of rubbish daily from Dhaka. If the project fails to do so, they have to pay a fee of $3,000. If they do not meet the pre-established power output, they will also be fined the same amount.
Now the question arises about the condition of our waste quality. We still do not know whether they have included any clause regarding what type of waste they will accept. Will they take all types of waste? If they don't, then there is quite a hassle. In that case, separate disposal of waste will be required.
As a result, our supply costs will increase. The biggest cost of waste management is collection and supply. If the collection and delivery costs increase, we will not have any economic benefit, rather it will just be another burden.
Such a situation is not uncommon; China may have stipulated in the clause that they will accept "X" tons of dry waste or waste at a specific calorific value. Due to our lack of understanding of the calorific value of the waste, we may have signed this agreement.
In reality, when the project starts, it will be seen that we may not be able to provide enough waste, which could lead to fines, as has happened with our Quick Rental Power Plants.
I was inspired to pen this based on a statement by our honourable Mayor when he claimed that when this plant starts, we may need to bring waste from outside. If that is the case then the project will face complications both in financial and environmental terms.
Naimul Haque is a PhD student living in the United States.
Disclaimer: The views and opinions expressed in this article are those of the author and do not necessarily reflect the opinions and views of The Business Standard.
