Desert Oases
Aside from minimising greenhouse gas emissions, our main priority for the future must be to reduce the effects of drought upon Australia.
Wherever we generate electric power, we should use off-peak surplus generating capacity and the waste heat to produce potable water, so that we may establish a self-sufficient community in the area. Existing rural communities may be given new purpose, provided that buildings, recreational facilities, sanitation services, educational services, health services, employment, electric power and potable water are readily available. Where possible, we should aim to exploit our existing infrastructure, rather than to embark upon "greenfields" projects.
Each such community should be surrounded by suitable areas for horticulture, animal husbandry, acquaculture, agriculture and timber plantations. The oases should be linked to the existing metropolitan areas by efficient electric train services, for the movement of freight and people. However, community planning should avoid the need for excessive commuting. Broadband data access through the fibre optic network should be planned for each community. As our economy grows we should be able to produce a more relaxed, pleasant lifestyle, with better access locally to employment, leisure activities, health services, education and care for the ageing population.
(If considering the expansion of shipbuilding capacity in South Australia, then the existing industrial and civic facilities at Whyalla should be carefully evaluated before committing to further re-building at Port Adelaide.)
(In 2008, an ABC Landline programme highlighted local government initiatives to revitalise Port Broughton in South Australia. That community will almost certainly prosper, provided that sufficient water is made available to support a balance of primary and secondary industries.)
All wastes should be recycled locally. Surplus water should be stored in underground acquifers or in covered reservoirs. Organic wastes, such as plantation trash, treated sewage sludge and food wastes, should be composted and used as mulch to improve soil structure and to conserve water. The use of "grey" water should be maximised for the watering of trees and plants. Harmful chemicals should be removed from the formulation of detergents.
We should plan for the anticipated effects of global warming by identifying future crop systems which will be suitable for future climatic conditions, rather than for the current climate.
Smaller communities may process sewage for each household in individual septic tanks, disposing of the digested sewage by a common effluent drainage system, feeding a local sewage treatment works. Alternatively, waterless composting toilets are successfully used in many rural areas and offer a less expensive installation with no plumbing.
In either case, the digested sewage sludge may be collected at intervals and added to other wastes for composting. 'Grey' water from households and from rain water run-off may be piped to water treatment plants, to produce potable water or to provide water for irrigation.
If bores are not in use, so that contamination of ground water is not a problem, and if the soil structure is suitable, the liquid effluent from septic tanks may be disposed of in soakage drains, or used to irrigate garden trees and other non-food plants.
If there is any possibility of flooding in the area, sewerage systems should be elevated to avoid contamination of water supplies. Houses should be elevated on stilts, using the ground level for storage, vehicle parking, or utilities.
Where a sewage treatment or composting plant is established, the methane gas produced may be used for power generation, e.g. to drive pumps. Alternatively, if grid power is unavailable, then provide electric power by solar cells, solar-thermal installations, wind generation, diesel generators, hot rocks or thermo-nuclear power stations. Install solar photo-voltaic or solar thermal hot water systems on all buildings, to minimise power consumption.
Health Care
At least as a minimum standard for rural and isolated communities, "cottage hospital" facilities should be provided for normal nursing care, for such treatments as vaccination, post-operative care, physiotherapy, childbirth, dialysis, diet education, X-ray diagnosis, basic nurse training, etc. If possible, subject to a viable patient load, a local GP network should be available on a regular basis.
Other procedures may require the removal of clients to area health facilities, but this should be avoided if possible because of the resultant disturbance to the patient, and the difficulty in maintaining family social support.
Provided that an adequate rail network is constructed, the practicability of bringing major medical and dental care to remote areas through Hospital Trains should be considered.
Reverse Osmosis De-salination
To date, reverse osmosis plants have been most commonly used to desalinate seawater. brackish bore water or saline surface water. They require regular maintenance of the particulate filters and of the semi-permeable filters.
The first large Australian example is the RO system installed near Perth, which desalinates seawater. Electric power is provided by windmills. The stated output is 45 G litres per annum, which seems impressive until we read that this will provide only 17% of the domestic and industrial water requirements for Perth, and that a second similar plant will be ordered as soon as possible.
A similar plant was ordered in May 2008 and completed in 2013, to supplement Adelaide's potable water supply. It is understood that Brisbane will follow suit.
While this type of plant may be suitable for domestic or industrial water desalination, it is inevitably incapable of producing the very large capacity which would be required for wide-area farming, or for the replenishment of underground acquifers by pumped storage. In considering the desirable capacity of an agricultural desalination plant, try expressing the capacity in acre-feet per annum for a realistic estimate of requirement.
There has been concern over the discharge of the saline waste-water from Perth's RO plant, as this might adversely affect marine plants and animals. The salt will be removed from the waste-water by evaporation, and sold as a commercial by-product. Presumably the same technique will be adopted in Adelaide.
Distillation Desalination
If waste heat is available, e.g. from a fossil fuel or thermo-nuclear power station, then co-generation with a water distillation plant will result in a significant improvement in the thermodynamic efficiency of the joint installation, to as high as 90%. Distillation plants are readily scaled-up in size. They require less critical filters, and less maintenance than RO de-salination plants.
An example of this type of plant, using the Passarell process, is described at http://www.passarell-desalination-australia.com web site. It uses a patented Advanced Vapour Compression Distillation process, with energy recycling, and is claimed to have a capital cost and operating cost of less than 50% of that of an equivalent RO plant. Service life is in excess of 25 years. The ground area is much less. The brine output may be produced as solid salt, so that there is no environmental impact.