Recycling

The term recycling commonly applies to recycling goods and consumer items. For the large scale recycling of water and air, see Water infrastructure and Life support articles.

Recycling is the third of the three R of waste reduction : Reduce, Reuse and Recycle.

A colony on Mars uses a number of materials to build everything they need for living. Mining or ISRU in the main way of adding materials to the settlement. Importation from Earth or other planets is another.

To reduce the need for production or importation of materials, Recycling can be used. Especially if the litter consists of only elements including just a few materials, and most easily if the pieces of litter are made from a single material. The concept requires special manufacturing that takes care to use pure single material if possible, or allows for easy disassembly.

Products made from single materials

Bottles from glass.
Boxes from plastics (e.g. polyethylene).
Cans from aluminum.
Insulating foam from melted and expanded regolith or plastics.

Products made from multiple materials

The following products need more than one material, but the materials can be separated easily for recycling. Alternatively, some may be re-used directly.

Electric cable from metal and plastics (e.g. polyethylene).
Insulating mat from mineral fiber and plastics casing (e.g. polyethylene).
Laminated safety glass.

Economics of Recycling

As the colony grows in size and population, the economics of the colony starts. The free market will determine whether it costs more to extract new material or recycle the existing materials in products. Recycling will be cheaper than mining in many cases. This is already obvious on Earth, where plastics, lead, aluminum and steel have higher and higher recycled content as the recycling systems develop.

List of recyclable materials

This list comprises recyclable materials, that are really needed by an autonomous colony.

Water - Water is typically recycled for most services using water treatment. Some water will be consumed for propellant production and for energy storage.
CO2 - For propellant production and plants. CO2 is one of the rare products than can return to the environment before re-use.
Concrete - for structures and infrastructures.
Steel - for digging machines, pipes, equipment, structures, buildings and infrastructure.
Plastics - for greenhouses, space suits.
Glass - for windows an recipients.
Silicon - for solar panels and microprocessors.
Metals: Aluminum, copper, chromium and Lithium.