Pipeline - July 2006
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In This Edition:
Water Costs and Recycling
- Swimming Pool Water Recycling
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What will Energy Cost in Future Decades? - Water
Recycling in Australia
Latest Edition Arrives!
It is some time since our previous newsletter, published in April. Of course,
the time of year imposes administrative and financial priorities which we all
experience.
Our office has been busy and the newsletter has slipped down the queue. Anyway,
we hope you will enjoy our latest offering.
Water Costs and Recycling
The future of our water supplies, drought and dire warnings of long-term water
restrictions and cost increase have been much in the news lately.
Various engineering publications have featured a range of schemes designed to
reduce water consumption of process plant and building services, and no doubt
this trend will result in efficiency gains over time. Both commercial and infrastructure
pressures will ensure this.
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Swimming Pool Water Recycling
Public swimming pools are significant consumers of water through evaporation
and the need to maintain public health standards by regular cleaning and backwashing
of filters. Significant volumes of ‘contaminated’ backwash water
are traditionally discharged to sewer or other drainage systems at each backwash
cycle. Water scarcity and increasing costs have already lead some municipal
authorities to announce closure of public facilities.
AEC happens to have been
designing modernization or upgrades to several large swimming centres during
the past year, and the question of backwash water recycling has naturally been
of interest. We decided to invest some time to investigate cost-effective options
and have come up with some promising results.
The first approach was possible use of backwash water for irrigation, since
most outdoor pools have large lawns and landscaping. After talks and enquiries
with several commercial turf suppliers and a horticultural expert, we found
we couldn’t recommend this approach to clients because the chemical content
of the backwash discharge would be detrimental if not fatal to the ‘growies’.
So what to do with the large quantities of expensive water?
Industry under commercial pressure is a wonderful thing! It seems that several
organisation have already responded with schemes to treat backwash water so
it can be put back in the pool. These are in various stages of development and
vary greatly in their potential for savings and success.
We have spent some time and effort looking at these schemes and at the moment
are discussing incorporating a system into the design for a client. Our studies
to date indicate:
- The design will not require "frontiers of science" technology.
- It will be relatively simple to install.
- Over a number of years it will save surprisingly large volumes of water when
applied to a centre with, say, an Olympic sized pool plus a wading pool.
- The cost is significant (around $50,000 for the above swimming centre) but at
present city water costs, payback should be achieved in between two and three
years. (Commercial suppliers of equipment are predicting better than this.)
- We assess a system life-cycle around 20 years.
This may not solve everyone’s water problems but it seems the application
of some simple engineering can once again benefit the community whilst actually
saving water and money.
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What will Energy Cost in Future Decades?
AEC recently had cause
to investigate the major factors currently impacting the prediction of long term
energy costs. Our discoveries may surprise you.
As their project presented several mechanical services options, our client requested
energy consumption and lifecycle cost analysis of each option. In the present
volatile world energy market, this proved an interesting exercise for our engineers.
The expected useful life of the subject options varied between 25 and 30 years
(common for building services systems). In this time, energy costs will be the
single most significant item in the life budget. As usual at present, the plant
will consume a combination of electricity and natural gas.
Our Energy Reserves
Australia has sufficient natural gas reserves for at east 30 years, and it’s
cheap to obtain and deliver. Our electricity is almost all generated by burning
coal, of which we also have an abundant cheaply accessible supply. Since neither
of these energy sources depends significantly on oil, with its vulnerability to
so much political and military manipulation, it may appear electricity and gas
should remain reliable and relatively cheap energy sources.
The Struggle for Control
Enquiries through contacts in Australia’s largest energy supplier reveal
a number of competing factors which may radically effect the cost and availability
of energy in Australia. In Canberra we have already seen the merger of our gas
and electricity retailers to create a virtual energy monopoly, and gas has largely
lost its economic advantage. Commercial and political pressures in the national
and international energy arenas are apparently on a much grander scale.
We are informed there has been long standing lobbying to tie the price of natural
gas to that of oil. Fortunately, our contacts in the industry do not believe this
scheme will succeed, but given the stakes in the current world struggle for control
of oil, it can’t be completely discounted.
The Environment
Burning an ever increasing amount of coal to generate electricity can’t
be sustained indefinitely. Fuel availability isn’t the problem, rather pollution,
acid rain and ‘greenhouse’ gasses. There are engineering solutions
to these but they would probably price coal out of the market. Natural gas powerstations,
whilst cleaner, do not solve a these issues.
The Nuclear Option
To the rescue of electricity apparently comes riding the new white knight of nuclear
energy, and it’s not nearly so dangerous as previously publicised. We’re
not currently debating this, but we are told that the recent nuclear lobby is
supported internationally and likely to succeed. Large capital investment is predicted.
Renewable Sources
You may notice the absence of ‘renewable’ energy sources in this equation.
They just don’t have capacity to significantly change the outcome. So what
is the outcome? With all these competing factors can we predict with any confidence
the cost of energy for the long term?
The Prediction
The ‘experts’ we’ve spoken to respond that discounting the possibility
of gas/oil price nexus, the average escalation rates over 25 to 30 years can be
taken as:
- Natural Gas 2% per annum
- Electricity 3% per annum
Not too bad if they are correct.
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Water Recycling in Australia
Australia is currently the second highest per capita user of domestic water in
the world. High rates of water consumption and diminishing supplies of useable
water, principally due to emerging climate change and population growth, are further
emphasised by extensive drought in recent years.
This presents a golden opportunity to lead the world in water conservation
and reuse.
Rainwater, stormwater, greywater and reclaimed water will all form part of a necessary
future direction for water supply in urban areas.
Compared with the traditional storage-based approach, water recycling is one of
the most effective ways of improving efficiencies in cities where water resources
are constrained. In the past, wastewater and stormwater were seen as nuisances
to be disposed of rather than resources to be captured and processed effectively
for reapplication.
The most common recycled water uses are non-potable (not for drinking) and include:
- Landscape irrigation of golf courses, parks, sportsfields;
- Industrial uses such as cooling, laundries, car washing facilities;
- Agricultural uses such as irrigation of produce, pastures for animal feed, and
nurseries;
- Emergency use in dust suppression and fire-fighting;
- Use in office buildings for toilet flushing;
- Aquaculture (the cultivation of aquatic organisms like fish); and
- Groundwater recharge.
Some of the benefits of water recycling which are becoming more widely recognised
include:
- Substitution of potable water for recycled water for non-potable applications
where water quality is less important.
- Improved water quality due to more comprehensive and rigorous monitoring systems,
or in contexts where recycled water has a better quality than existing raw supplies.
- Boosting reliability of current water supplies for drought periods.
- Meeting environmental requirements by improving wastewater treatment plants
and reducing the quantity of effluent discharged to coastal waters.
- Provision of new supplies for environmental enhancement and aquifer recharge.
- Displacement of reliance on potable water for primary production by irrigation
with recycled water.
- Recycled water can provide a supply of nutrients useful when irrigating crops.
The main barriers to reuse of water in Australia are issues of public confidence,
health, the environment, reliable treatment, storage, economics, and the lack
of knowledgeable awareness.
However, with a pressing need to implement sustainable projects that adequately
address our diminishing water supply, Australia could become a world leader in
water recycling. The expertise and technology are certainly available to us.
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