The Donald Seaweed Project
An innovative project supported by the National Landcare Program
In August 2003 Phil Dyson (Phil Dyson & Associates P/L) approached the Business Development Officer for the Shire of Buloke with a proposal to conduct field trials for seaweed cultivation at Donald in the eastern Wimmera Region of Victoria. The proposal recognised opportunities to extract marine colloids for industrial applications from seaweed grown from the region's saline groundwater.
The Donald region was selected by Dyson because: (a) it suffered from extensive salinity issues that might be offset by alternative technologies and production systems, (b) the lower catchment was known to comprise an alluvial aquifer that afforded a large saline groundwater resource, and (c) the people of the Donald region were known to be progressive in exploring potential opportunities for alternative rural industries.
The project was enthusiastically adopted by the Donald and District Landcare Group (DDLG). Late in 2003 they applied for a federal funding grant to progress the field trials. In February 2004 it was announced they had been successful in obtaining an innovation grant from the National Landcare Program.
Funding from the NLP grant began to flow in March 2004, and since that time the Donald and District Landcare Group have worked very closely in a team environment to realise the project.
The team is extremely grateful for the opportunity afforded by the National Landcare Program Innovation Fund. The opportunity that this grant program affords rural regional Australia in developing new technologies and new industries is immeasurable.
Dryland salinity and saline groundwater discharge
Dryland salinity results from an increase in saline groundwater discharge following changes in the water balance brought about by the clearing of native vegetation and the development of European agriculture. After clearing more rainfall percolates to groundwater as less is used by vegetation. This causes aquifers to fill and ultimately discharge saline groundwater to the land surface.
In some small groundwater systems the problem can be tackled by adopting farming systems that use more water and allow less rainfall to drain to underlying groundwater. In most large groundwater systems, however, the time required to restore the water balance to the point where a salinity benefit will be realised is far too long, and other options need to be considered. This is certainly the case where important natural and man-made assets are endangered by discharge of saline groundwater from regional aquifers. In these systems a more realistic approach involves (a) adaptation to salinity through strategies that afford production from saline land and saline water resources, and (b) application of engineering approaches that afford the protection of high value assets through local water table management.
In some instances it is possible to couple adaptation and engineering strategies so that groundwater removed in protecting assets can be utilised as a resource in systems that support saline production. The options might include production of industrial or food grade salts, production of marine fish through saline aquaculture, and opportunities for production of salt tolerant plants supported by saline irrigation.
Growing seaweed in saline groundwater
A somewhat innovative option for saline production is being explored by a group of landholders at Donald in North Central Victoria. The group was successful in attracting a grant from the federal government and this has them working with Phil Dyson (Phil Dyson & Associates) and others in an effort to realise production of industrial seaweed from saline regional groundwater.
Link to Donald and District Landcare Group
Why grow seaweed?
Certain types of seaweed can be processed to produce marine colloids that have a very wide range of industrial applications. Seaweed gels are used, for example, to stabilise ice-cream and toothpaste and pet food. They are also widely used in the production of cosmetics and for certain inks required within the printing industry.
Why grow seaweed at Donald?
The Donald region of North Central Victoria experiences dryland salinity that is the result of saline groundwater discharge from two regional groundwater systems. Both systems comprise saline groundwater that ranges in concentration from about 20,000 to 30,000 uS/cm This is broadly equivalent to about 40 - 60 percent of the salinity of sea water. This groundwater is very similar in chemical composition to that of the ocean. This is not surprising since most of the salt has been introduced from the ocean via rainfall over millennia. Small quantities of salt introduced in ionic form in rainfall have been concentrated in soil and weathered rock during transpiration by native vegetation.
Groundwater in the Donald region is in most instances quite saline and very similar in chemical composition to seawater. These circumstances, together with long hours of sunshine over the summer months, present opportunities to trial the cultivation of seaweed for industrial purposes.
Strong community interest in supporting a somewhat innovative potential regional development opportunity is also a large factor underpinning the Donald research.
The plan
The Donald trials involve five distinct phases of activity:
Phase 1 - Review of hydrogeological data and drilling to location appropriate sources of groundwater of sufficient quality and quantity to support the cultivation of seaweed.
Exploratory drilling
on three farms located immediately
east of Lake Buloke commenced in early May 2004
Phase 2 - Establishment of production wells including pumping infrastructure to realise sufficient groundwater for cultivation of seaweed from small production basins
Phase 3 - Design and construction of small production basins (0.1 Ha) to develop and trial the production of seaweed.
Phase 4 - Development of operational systems/technology that allow appropriate/optimum water conditions for seaweed production to be sustained in the production basins
Phase 5 - Trial production of seaweed
Photos of the First Site
This salt pan occurs on Paul and Karen Sheridan's farm some four kilometres east of Lake Buloke. It is one of several salinas that occur as large elliptical areas encompassing some 10 to 20 hectares of extremely saline land. Prior to about 1917 the area was a freshwater wetland. Evidence of this can be seen from the remnant dead trees that are still present on the saline discharge zone. The site is now almost completely barren as almost all forms of vegetation have been destroyed by the influx of saline groundwater.
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Drilling Commences at Paul and Karen Sheridan's farm
Chemical composition of regional groundwater
Salinity is most commonly assessed by measuring the electrical conductance of the water and converting this result so that readings are considered at a standard temperature of 25 degrees Celsius. The salinity of groundwater from Paul and Karen Sheridan's bore, and from Peter and Robin Sheridan's bore, both gave readings of about 34,000 uS/cm (micro-siemens per centimetre). Since the electrical conductivity of ocean is normally around 50,000 uS/cm the groundwater salinity is about 70 percent of that of sea water.
In addition to measuring salinity by the electrical conductivity method concentration of total dissolved salts (TDS) in the groundwater was also measured. The TDS method involves taking 100 ml of groundwater and evaporating the water off to reveal the salt. This is then weighed and the concentration in milligrams per litre is computed. This figure is almost equal to parts per million. Results from Paul and Karen Sheridan's bore revealed a salinity of 26,000 mg/l. Again, since the ocean normally has a salinity of about 35,000 mg/l salinity the groundwater has a salinity that is about 70 percent of that of sea water.
Comparison of the chemical composition of Donald groundwater with sea water
In addition to the above analyses a comparison between the chemical composition of groundwater from the regional gravel aquifer at Donald and sea water has also been assembled. For the purposes of this comparison the chemistry of the ocean was sourced from Garrels & Christ (1965), and the chemistry of regional groundwater from Donald was sourced from Ryan (1993). A summary of the results indicating a very strong correlation between the major ion chemistry of groundwater and sea water is presented in graphical form. Comparison between Donald groundwater chemistry and sea water
References:
Garrels R. M., and Christ L. (1965) Solutions Minerals and Equilibria. Published by Freeman Cooper & Company
Ryan S (1993) The Relative Influence of Regional and Local Groundwater Processes on the Development of Secondary Salinity in Dryland Areas of Northern Victoria. MSc thesis Monash University
Landscape
Evolution and Groundwater Systems
in the Donald Region
The above
link is to a PowerPoint presentation prepared for
Landcare groups in the Donald Region.
The file is fairly large (about 35 megabytes), and is probably best
downloaded by right clicking and using the 'save target as'
option
Construction of Production Basins and evaporation basins
During the latter half of the 2004 production basins for the trials were constructed. Two basins were built at each of the two trial sites.
At the outset of the project the group had planned to dispose of saline groundwater realised from the production process to saline swamps in the immediate area of the trials. Small additions of saline groundwater added to these wastelands was seen to have an almost negligible impact on the environment compared with vast areas of land already degraded through saline groundwater discharge from the regional aquifer. The Environment Protection Authority (Victoria), however, specified that the project fully contain all saline groundwater in purpose built evaporation basins.
Permeability tests were completed in November 2004 to comply with EPA regulations. The results showed that the soils were well within the standards for basin construction and both production and evaporation basins were completed by mid December 2004.
The additional cost resulting from the need to construct evaporation basins exceeded $10,000. This presented a severe budget shortfall for the project, but thankfully additional financial support from the Commonwealth National Landcare Program allowed the group to overcome the setback.
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Construction of production and evaporations basins |
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Groundwater pumps installed
A good deal of research was completed during November and December of 2004 to ascertain the most suitable technology for pumping saline groundwater. A pumping test was completed for the high yielding bore on Peter Sheridan's property. Initially this involved lifting groundwater out of the bore through continuous injection of large volumes of compressed air. The test demonstrated that the bore was capable of producing in excess of one megalitre per day.
The 'air lift' test also indicated that groundwater could be extracted at relatively low cost by using centrifugal pump that would simply draw water from the upper part of the well. To assess this option a further pump test was completed. A standard 'fire fighting' pump was set up over the well and pumping occurred continuously over periods of five to six hours.
The test with the fire fighting pump indicated the well could indeed be fitted with a centrifugal pump. Hydraulic pressure from the aquifer prior to pumping brought groundwater within a metre of the land surface. After six hours of pumping at three litres per second the draw down of groundwater within the well was less than 2 metres.
In mid January 2005 the bore on Paul Sheridan's property was fitted with an electric submersible pump. Low permeability of the aquifer at this site resulted in a groundwater yield of about 1.5 litres per second. Continuous pumping over a 5 to 6 week period, however, demonstrated that this pumping could be sustained on a continuous basis and extraction was more than adequate for the trial of seaweed production.
During February-March 2005 power was connected to the site on Peter Sheridan's property and a centrifugal 'transfer' pump established over the well. The pump appears to be working well and whilst no formal measurements of extraction rates have yet been recorded it is clear that the volume being pumped exceeds 3 to 4 litres per second.
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Groundwater pumps installed |
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Seaweed trials commence
Seaweed trials commenced in the production basins in late December 2004. Prior to electricity arriving and pumps being installed groundwater was extracted by an air lift system, and through the deployment of a fire fighting pump.
Whilst much work still needs to be completed to ascertain optimum conditions for seaweed growth early trials in saline groundwater realised from the regional deep lead aquifer appear quite promising. Seaweed introduced to the production basins appears to survive and growth rates of up to 3 percent per day have been recorded thus far.
Early growth trials indicate there is substantial opportunity to optimise seaweed growth through the adoption of more advanced technologies that allow for greater control over the water chemistry and production regime. Some of these opportunities are currently being examined by the project team.
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Seaweed Production Trials Commence |
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Leaking basins and seepage losses
It seems that in all projects that seek to be innovative through the adoption of alternative technologies must face and overcome many different problems. This is certainly true of the inland seaweed business. It appears we were very ambitious and perhaps somewhat naive believing we could overcome every obstacle and realise trial production through a relatively small budget, within a relatively short period of twelve months.
We have succeeded in established the infrastructure needed for seaweed production but new challenges have appeared on the horizon. The immediate issue arises after filling the production basins with very saline groundwater. High salinity groundwater is suppressing dispersion in the clay that lines the basins and causing seepage losses. The loss of groundwater together with the fertiliser it contains is excessive and cannot be economically sustained. Accordingly, pumping of groundwater has ceased pending installation of plastic liners in the immediate future.
Contact Details
For more information on the Donald Seaweed project please contact Mr Leo Tellefson. Leo Chairs the Donald and District Landcare Group. You can reach him on e-mail leotellefson@bigpond.com or you can phone him on 0408 146 530.