We re-cycle very little of our waste products, so that we not only create an enormous disposal problem, but we waste energy which could be salvaged. We should aim to re-cycle at least 80% of our waste products.
All "grey" water should be re-used or treated locally. In urban areas, the run-off rainwater should be captured or passed into wetlands. Farming techniques should minimise evaporation and maximise the return of water to the subterranean acquifers. Sewage residues and other organic matter should be composted, and used as mulch to improve soil structure and to reduce evaporation, erosion and water run-off.
The methane gas which is produced during sewage treatment in domestic and agricultural plants should be used for heating or for power generation. This has been done for more than 45 years at the Bolivar Sewage Treatment Works in South Australia.
The increasing establishment of "wetlands" is of great benefit in the recycling of "grey" water, by removing heavy metals, such as mercury and cadmium.
Potable Water
Wherever possible, waste water should be converted into potable water by distillation or by reverse osmosis, before return to the drinking water supply. There is no reason to restrict the full use of recycled water, provided that it has been treated to eliminate harmful chemicals and bacterial agents.
Recycled water is already added to the drinking water supply in many countries. It is considerably less expensive than desalinated or distilled water.
The establishment of water distillation plants, using waste heat from power generation, makes a considerable reduction in the cost of potable water.
The salt which is produced by water desalination is a commercially valuable by-product. Note that the successful recovery of salt in the recently-commissioned West Australian installation avoids a potentially adverse effect upon the marine environment. Dry salt is a standard by-product of the Passarell Desalination Process.
Organic Waste
In many instances, the trash from field crops which are grown as part of the normal cycle of crop rotation, e.g. nitrogen-fixing legumes, is ploughed back to improve soil structure, to mulch the next crop and to reduce dependence upon artificial fertilisers.
Sugar cane waste (bagasse) may be use to manufacture low density wallboard, or added to compost. Recent technological developments have improved the conversion rate of fermentation. to produce bio-fuel from plant cellulose.
The solid wastes which are produced at sewage treatment plants should be added to household organic wastes, composted and used for soil improvement.
Scrap Metal
Recovered scrap metal may be used directly and profitably in the manufacture of new metal products.
Waste paper may be used in the manufacture of paper, packaging boards, and such products as egg crates and insulated wall boards. It may be included in compost, as a mulch.
Attractive and reusable, recyclable dishes and drinking vessels may be manufactured from papier mache, using recycled paper and a suitable plastic such as casein resin.
Scrap Tyres
A novel stand-alone processing plant is now available, which offers the profitable 100% recovery of high-quality raw materials from scrap rubber automotive tyres.
Lubricating & Cooking Oils
Spent lubricating and cooking oils should be recovered 100% and re-processed into bio-fuel.
Re-cycled plastics may be re-processed into a wide rnge of products, including building boards.
When combined with other materials, they could provide a ready supply of pack-flat kits for lightweight, thermally insulated accommodation, which could be economically deployed by airlift for disaster relief.