It is fairly obvious that most urban centers are drowning in garbage and struggling to find ways to get over the solid waste disposal problem.
We can say that there are two specific types of challenges in the context of solid waste management:
- Managing/disposing specific types of waste, and
- Ever-increasing quantum of waste generated
The latter seems to be the main problem at first sight, but it might not be. Many cities worldwide are smoothing out the logistics of collection when it comes to the normal, easy-to-handle and harmless household waste – be it through recycling, or use to make compost or as a last resort, to generate energy (usually power). I am saying there is no problem here, just saying that there is definitely light at the end of the tunnel.
Managing and disposing of some select types of waste is more vexing. What types of waste are these?
These mainly include very thin film plastic waste, hazardous waste from industries, medical waste that could contain pathogens, and of course nuclear waste.
The last one (nuclear waste) is a specialised sector with the entire value chain for nuclear energy generation to waste disposal is tightly controlled. I will not hence discuss this here.
The other three tricky types of waste – thin film plastic waste, hazardous waste from industries and medical waste – are more prevalent and need to be dealt with directly by the municipality.
Recycling of very thin plastic film waste (either as pure plastic film or as a laminate with other material) is challenging mainly owing to its flimsy nature. In many municipalities, these actually go to the landfills – not a great solution, but that’s what you have. Some municipalities ensure that these plastics are incinerated (this process could actually generate power).
Assuming we have somehow taken care of the very thin plastic waste, we are left with hazardous solid industrial waste and medical waste.
The following two are the accepted methods of disposal for these types of waste:
- Storing in a secure landfill – Landfilling of hazardous solid waste is regulated more stringently than landfilling of municipal solid waste. Hazardous wastes must be deposited in so-called secure landfills, which provide at least a certain amount of separation between the bottom of the landfill and the underlying bedrock or groundwater table. It should also have two impermeable liners and leachate collection systems. All these are two to ensure that none of the hazardous components in the waste gets into the surrounding environment, especially water.
- Used in very temperature environments (cement kilns, high temp incineration units) for heat or power generation. Under ideal conditions, good combustion destroys most of the non-metallic, toxic organic compounds in hazardous waste and leaves ash residues which are easier to dispose than raw, untreated waste.
In some countries, the hazardous waste may make its way from the secure landfill to cement plants or other high temperature incineration facilities. In others, the hazardous waste is just let to stay in the secure landfills.