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In order to decrease the financial costs for delivering services such as the supply of green energy and for building the required services, source material from the mainstream society can be gathered (in addition to local available free materials as wood, adobe, ...). This can be done through the collection of the "waste" -or rather what which they consider waste-. This waste includes:
- recyclable plastics such as PE, PP, PVC, PS, SB; PSE, ABS PMMA, PTFE, PA, PC, PUR, EP, UP and PET. ISF has made 2 documents on how respectively discarded plastics and aluminum can be salvaged and reused in developing countries.
- ferrous waste materials (eg cans, ...)
- sewage sludge (for use as a fertiliser)
The waste materials can be gathered by waste pickers, or -if possible- with more sophisticated machines such as materials recovery facilities (MRFs),and solid waste processing facilities. The latter may allow better separation of the different metals, plastics, ... resulting in a higher -and more efficient- yield. Also, waste pickers -besides usually not being equipped to disassemble the materials- risk being exposed to various poisonings.
Sewage sludge is collected not by hand, but through a sludge processing plant that automatically heats the matter and conveys it into fertiliser pellets (hereby removing possible contamination by chemical detergents, ...) This approach allows to eliminate seawater pollution by conveying the water directly to the sea without treatment (a practice which is still common in developing countries, despite environmental regulation). Sludge plants are useful in areas that have already set-up a sewage-system, but not in areas without such a system, as composting toilets are more efficient and do not require sewage pipes (which break over time).
After collection, the obtained materials often need to be melted and recasted in forgeries[verification needed] and/or may require bending, cutting, folding, ... in a workshop.[verification needed] Plastics are a special case that are too melted in a workshop, using small, purpose-build hand-operated melting containers.[verification needed] Metalworking tools that can be used to cut, fold, ... the metal are the OpenLathe and Multimachine. Also, some CNC metalworking tools can be appropriate.
In some cases, generally for very small scale and one-off applications, melting and recasting is not required, as some parts can be simply cut and used as is in different devices. An example is the passive solar collector build from old refridgerator tubing.