Sources and elimination
Sources of POPs
Since the first half of the last century, POPs have been intentionally developed and used in a wide range of products (e.g. pesticides, insecticides, dielectric and hydraulic fluids in industrial machinery, capacitors and transformers).
They are unintentionally generated in a wide range of processes involving combustion. The following industrial processes are amongst those believed to be likely sources:
Backtracking route - Source of concern:
- Food : Fertilizers, pesticides, packaging, and food additives
- Clothing: Synthetic fibers, dyestuffs, textile auxiliaries
- Health: Phannaceuticals, disinfectants
- Hygiene: Soaps, detergents, cosmetics, insecticides
- Shelter: Building and finishing materials
- Energy: Fuel, chemicals, water, recreation
Destroying/transforming stockpiles of POPs
POPs are very toxic chemicals that are harmful to living species. Therefore, POPs stockpiles must be destroyed in a manner which does not further degrade the environment by generating or releasing POPs. According to the Stockholm Convention, the disposal of POPs should be carried out in such a way that it is destroyed or irreversably transformed, so that it is no longer a POP. The Stockholm Convention is also calling for community participation in the process, care on safty of the community, full disclosure of information, monitoring, and release of data.
There are several methods that have been used for the destruction of POPs. Traditional methods use landfilling, ground storage, deepwell injection and combustion by open burning, incineration or in cement kilns or metal furnaces. However, there are serious limitations to normal incineration process. Mainly these are open systems, which have process upsets.The process also produce chemicals such as dioxins, PCBs and HCBs at significantly higher levels, which affect the health of workers and local populations. Generation of waste such as stack gases, scrubber water, quench water and solid wastes (bottom ash, fly ash, sledges etc.) are additional problems. Longterm implications include ongoing treatment and disposal of incinerator residues (ashes and sledge), and accumulation of persistent by-products in the environment. Studies have shown that cement kilns also have serious limitations. High level of dioxin, cement kiln dust and heavy metal releases are some of the major problems
Alternatives for incineration based technologies are commercially available. The potential benefits of non-incineration destruction technologies are that no dioxin and other POPs are generated. Furthermore, the process has control over all outputs or by-products for re-processing and offers a degradation-free environment.